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February 1

Project

Latest comment: 18 years ago15 comments12 people in discussion

For our project at Uni, we have been asked to pick an animal to make extinct and argue our case. It has to be a vertibrate and not man. I dont want to pick panda cos it is too obvious and it doesnt really do any harm, does it? It should be preferrably something that does harm to the environment or nature or something. I thought beaver or something. Do you agree? Any further suggestions and why?

Beavers have a huge impact on ecosystems, providing wetlands for many other species to use, so removing them would probably have many repercussions. From a purely pragmatic and uninformed point of view, I would argue for the extinction of a species that is critically endangered or extinct in the wild, as I would imagine this would have the lowest impact on the planet's eco-system as a whole. Flipping the assignment on its head, you could go the satirical route and argue for the extinction of a species that would cause as large of an impact/disaster as possible, in effect showing that everything plays their part. Atropos235 01:20, 1 February 2007 (UTC)Reply

The ranchers in the American West are after timber wolf (a.k.a. gray wolf) again; they want to see it extinct in their area again. American suburbians everywhere think the coyotes should all die.

Atlant 01:21, 1 February 2007 (UTC)Reply

Nah! I go for the Roadrunner!--Light current 01:33, 1 February 2007 (UTC)Reply

The safest thing to pick is a parasite. Not to sound utterly heartless, but humans are by far the most damaging parasite. But then, I like history and culture and being alive enough that I wouldn't want to wish the end of all humanity. This is a tough call for anyone to make. Think about the environmental impact removing a single animal would do. 67.174.211.89 06:00, 1 February 2007 (UTC)Reply

I'd pick an introduced species, like the cane toad, and argue that it's value in it's native ecosystem is trumped by it's impact on it's introduced ecosystem. --Cody.Pope 06:54, 1 February 2007 (UTC)Reply

What about the dreaded mosquito? | AndonicO ^{Talk · Sign Here} 11:39, 1 February 2007 (UTC)Reply

Unfortunately, our questioner is limited to vertebrates. Otherwise, the mosquito is the obvious choice.

Atlant 13:10, 1 February 2007 (UTC)Reply

You can really pick anything you want. It doesn't even matter. Species are rising, falling, gaining, being pushed back, bottlenecking, exploding, all the time everyday. It is simply the way of nature to kill off species. It may not be nice, but that's just how it is. That is normal, and it is change. It is absurd to try and do something with the intention of changing nothing, because the environment will change on its own, it doesn't matter what part of the environment changes it (may it be a particular species), because each species is part of nature. Since we are being so inherently anthropocentric, you can say humans have helped some species, and humans have destroyed some species, directly or indirectly. We can relate alien species invasion since it is the opposite of entirely removing a species. Both on the same continent and at the same time Bos taurus was being bred in vast quantities, while Bison bison was being hunted to near-extinction. Cattle are aliens too, and are among the most destructive friends we tend. The grazing and trampling of livestock threaten more than three and a half times as many native plant species globally as are threatened by nondomesticated aliens. Livestock threaten almost as many native animal species as alien predators do. Pueraria montana is an Asian plant despised in the southeastern states for aggressive growth. American gardeners of the late 1800s loved its fragrant blossoms, and in the 1920s it was promoted as Bos torus chow, and in the 30s widely planted by the Soil Conservation Service for erosion control. The Department of Agriculture declared it a weed in 1972. Similar in history, Taraxacum officinale, or "common dandelion" was introduced to North America from Eurasia for its medicinal and culinary properties. Even if you don't agree with me, you perhaps should mention it to bring something new to the table. [Mαc Δαvιs] X (How's my driving?) ❖ 12:24, 1 February 2007 (UTC)Reply

Vertebrate eh? I'd pick the Panda. Think about all the resources, time & money that have been squandered to protect or preserve a species that has become so specialized that even without our intervention, was likely to become extinct in the very near future. Are there even enough Panda's left to sustain a genetically diverse viable population? Now if those same resources had been applied to a species not quite so cute and cuddley perhaps the passenger pigeon, great auk, or any now extinct species you can name might still be with us. This then brings into question the entire reason why we choose to protect some species while ignoring others? If the Panda was an ugly mollusc that crawled up your leg and bit you on the ass, would we be so willing to protect it? Extinction is a natural process. It is not that extinction occurs that should concern us rather, the acclerated rate of extinction that we as a species seem to be responsible for. Canis sylvaticus

How about the Water moccasin or Copperhead snake?, or maybe the Rattlesnake? Your study could look at whether nonvenomous species could step up to replace their pest control benefits without harming humans. In other words, would we be overrun by rats and mice without the venomous snakes, or could the less harmful species take care of the pests. These species do harm humans and their pets and livestock, and the water moccasin and copperhead snakes make the enjoyment of the outdoors difficult in the southern US in the summer, as the rattlesnake does in the west. I acknowledge that many people love all animals, and that they are all pretty to look at, unless you have just stepped over a log and they have sunk their fangs into your leg. (edited to add: Here I refer to the snakes, not the animal lovers as biters). Keep the panda. They do not bite humans as often, and are not known to be venomous. Edison 16:38, 1 February 2007 (UTC)Reply

Human deaths from venomous snake bites in the USA (those species in particular are US snakes, yes?) are so uncommon today as to be statistically negligible. You get far more deaths from dog bites per year, more deaths related to riding the bus. --140.247.248.95 17:33, 1 February 2007 (UTC)Reply

Country people in the southern U.S. avoid wooded or grassy areas, or creekbanks in the southern US in weather above freezing because of the presence of copperheads. They are numerous and aggressive, and like to live near human habitation, and move into outbuildings or onto farm equipment. I have had several close calls. Besides deaths, they cause painful injuries with lengthy recuperation. No one claimed that poisonous snakes are leading cause of deaths, and more people obviously ride buses that step on copperheads. Dogs are domesticated pets and offer the benefit of companionship or guarding as a tradeoff for the chances of biting soemone. Copperheads make poor pets, but if it were known that they lived in a building, people would, I guess, pretty much stay out. Edison 21:43, 1 February 2007 (UTC)Reply

I'm just pointing out that you'd have to indicate that the number of lives you'd be saving would be in the dozens, whereas the likely ecological damage would be quite high. In terms of cost/benefit the panda is an easy one in comparison to the venomous snakes of the US, which cost very little (in terms of human costs and resources) to live with. The panda's non-venomous quality does not really give it an edge over the snakes in a strictly utilitarian model. --24.147.86.187 00:22, 2 February 2007 (UTC)Reply

I'm sure if you made your presentation on a list of animals you initially thought you might like to make extinct, then talked about what made you reconsider, and concluded the whole exericse to be abhorrent, you would not receive an autofail. That's what I'd do. Vranak

---

I would pick the goat or the Norway Rat. Goats devastate ecosystems, and rats have a huge impact on humans. The one you pick will depend on your perspective. -Arch dude 02:39, 2 February 2007 (UTC)Reply

If you want to be a smartass you could go for the Madagascar Pochard. The rationale being that everyone thought it was extinct 15 years ago anyway, and the world kept turning. Then a few of them were spotted last year. However, they are clearly critically endangered and - one could argue - removing the few remaining would have a negligible environmental impact. The opposing argument is that the Madagascar flora and fauna is rich in genetic diversity. Rockpocket 06:21, 2 February 2007 (UTC)Reply

Excellent idea! Frilled shark, Megamouth, coelacanth, and Lazarus taxon. [Mαc Δαvιs] X (How's my driving?) ❖ 18:03, 2 February 2007 (UTC)Reply

And the Tazmanian wolf

purifying water and sourdough

Latest comment: 18 years ago2 comments2 people in discussion

I have recently heard that the brewing industry use to use sourdough (from bread) to purify water. I wondered if there was anyone who could validate this. Also, how does it work? Thanks Valerie

Sourdough bread is bread that is leavened with sourdough starter, a symbiotic colony of yeast and bacteria (lactobacilli). The closest to "purifing" water might be the microorganisms living in the starter form somewhat hostile conditions to "squeeze out" other potential micro-invaders.That process is fairly slow and complex compared to filtering water through activated charcoal or distillation, and you'd end up with a bunch of floury water. I'm not a big beer aficionado, but using some sourdough starter in a ferment might impart some of the same acidic, complex flavors you can get in sourdough bread. Atropos235 02:44, 1 February 2007 (UTC)Reply

Is it at all possible that this is a garbled version of the idea that alcoholic drinks were once drunk in great quantity because they were less likely to poison you than the water? That was mostly (if not entirely) due to the boiling involved in the production of alcoholic drinks. Skittle 15:36, 1 February 2007 (UTC)Reply

Petroleum Oil

Latest comment: 18 years ago9 comments9 people in discussion

I am doing a science fair project for my 8th grade class. My question that i want to ask you is this: What is oil's real purpose in the Earth? Does is it act like some sort of insultaor or anything else? I mean, everthing on this Earth is here for a purpose. I am stuck and do not know what to do. I found one website that asked the same question to but did not have any information that I needed. Template:Please Help Me 4.129.87.148 00:57, 1 February 2007 (UTC)Reply

Oil wasn't intentionally placed into the Earth for any sort of reason, but it is just the result of dead biomatter being compressed and heated under millions of years of sediment. Man's persistant exploration of the world lead to the discovery of petroleum and its seemingly millions of uses over the ages, from lighting up ancient homes to sending people to the moon. It can easily seem like everything in the world has a purpose because we are the ultimate tool-users and we can find a purpose for just about anything. Atropos235 01:36, 1 February 2007 (UTC)Reply

For all we can tell, purpose is not inherently present on anything. There's no purpose for the existence and presence of oil, or even life, on Earth. It exists because that's how chemistry and physics work. Things also tend to naturally find their most stable state throughout time, so the feeling of deliberation and purpose arises naturally everywhere, since everything ends up fitting together so well. That being said, oil has no purpose, we just happen to find it very, very useful for many different things. — Kieff | Talk 01:44, 1 February 2007 (UTC)Reply

The scientific way to phrase it is that purpose is not scientifically testable in experiment and therefore not relevant in a scientific sense. However, to absolutely claim there is no purpose is making a leap that science cannot explain so claiming there is no purpose or deliberation goes beyond the scientific method. --OpusPenguin 03:17, 1 February 2007 (UTC)Reply

I personally believe "everything having a purpose" to be rubbish. As Richard Dawkins said, "We see the world through purpose-colored spectacles," because our nature is to see objects of having potential uses to us, we assume if we can't use it, it has a use to some other organism. [Mαc Δαvιs] X (How's my driving?) ❖ 12:17, 1 February 2007 (UTC)Reply

See Teleology for a discussion of the old notion that someone (God?) placed everything herre for a purpose. This view might say that if I am hiking and have to make a pitstop in the woods, that my excrement is there for the purpose of nourishing a bush which will grow into a tree and provide shelter for some future weary travellor. A less teleological and more naturalistic view might be that "excrement happens." Edison 16:44, 1 February 2007 (UTC)Reply

If you were to put any purpose to oil, surely it would be to warm up the Earth, not that there's anything wrong with that. Vranak

You are in 8th grade. Teleology is usually considered to be way too heavy for your age: Plato thought that one should not be concerned with Philosophy until age 40. Science fair: you are probably in time trouble: you don't need generalities, you need an answer, NOW. Here is what we are trying to tell you in simple terms:

• forget "purpose." That is way too complicated. It is philosophy, not science.
• Try to rephrase your hypothesis into something more scientific and less philosophical.

If you can reply with your current hypothesis, We can probably critique it for you and suggest a better hypothesis. I just got home from judging a high-school Science Fair, so I am sympathetic. -Arch dude 02:33, 2 February 2007 (UTC)Reply

What did Plato know? Him and his ilk never understood inertia nor evolution nor planetary harmonics. Nonetheless, the above statements correctly emphasize that purpose is not testable and has no place in science. We can study much about petroleum - how it forms, what it is made of, what we can make out of it... but none of this implies a purpose. However, I think the original question was asking whether there petroleum performs a geological function - such as "insulating. "Petroleum reserves do not really insulate very much; but they contain lots of dissolved gases (notably, helium, sometimes hydrogen, and very often methane or other natural gas.They also serve as boundaries between rock layers (though this is probably an effect due to their formation). Nimur 08:05, 2 February 2007 (UTC)Reply

Since no one actually gave the simple answer to your questions, I will: The purpose of the oil is for people to burn it for fuel. Do you think it needs some other reason to be there? Ariel. 13:11, 4 February 2007 (UTC)Reply

Database for lab experiments

Latest comment: 18 years ago8 comments6 people in discussion

Hello, I am currently working on my PhD in the biopharmaceutical field. I am doing a number of lab experiments and I am looking for a way to store information about the experiments and the outcomes in a database.

Typical data about an experiment would be: Title, notes, Dates (when run, when analysed), material used, method used (i.e. word files), raw data (i.e. sampling points), secondary data (i.e. halflifes), graphs.

I have attempted to come up with an MSAccess solution, it works more or less but it has its bugs and entering data can be somewhat time consuming.

I was wondering if anyone knows a flexible tool to handle this kind of task. (I think there should be, since the core of what I need it to do is probably needed by uncountable other people working in similar areas. I haven't really found anything practical so far though).

Thanks, Lukas 04:32, 1 February 2007 (UTC)Reply

Honestly, I'd use a spreadsheet if you don't have any prior experience with RDBMSes. Spreadsheet software is very flexible and useful for sufficiently small amounts of data. Most of the data I need to process goes directly from my notebooks into a spreadsheet program. -- mattb @ 2007-02-01T05:50Z

I don't think you could include all of the data he wants in just that. However it sounds to me like it is a flat database anyway, so you don't necessarily need it to be relational. Have you tried something like FileMaker Pro? It is like MS Access but much simpler on the whole. It doesn't let you do as complicated or customized things with the data but it doesn't sound like you are using Access to its full capabilities anyway. Access is probably the most "flexible" thing you are going to find, but being able to use that capability well requires a lot of time and experience with it. If you wanted to post the nature of the bugs to the computing desk, I am betting we can iron out some of them (I say this as someone who has wrestled with Access for eight years or so at this point). --24.147.86.187 12:49, 1 February 2007 (UTC)Reply

Well, he didn't specify how much data he is working with...If we're talking single data sets with a million rows, then a spreadsheet will be insufficient. A few thousand rows is reasonable, though. -- mattb @ 2007-02-01T15:08Z

I'm not talking about total records. Look at the types of data he describes -- Word files, lengthy descriptions, etc. It is not easy to do that in a spreadsheet program, at least not any I have seen. The lines get very long and hard to read, use, and edit. --140.247.248.95 17:27, 1 February 2007 (UTC)Reply

Need to share the data among workers ? Why not try a hosted DB solution like www.teamdesk.net at 7 $ / month / user. I found it easy to customize. Pcarbonn 16:03, 1 February 2007 (UTC)Reply

Be very careful when using spreadsheets to store experiment results. See for instance The December 1 DWIM effect (reported on RISKS Digest 24.19; some comments on 24.20 and 24.21). Some other spreadsheet horror stories can be found at the European Spreadsheet Risks Interest Group site. --cesarb 18:57, 1 February 2007 (UTC)Reply

Thanks for the replies so far. Especially thanks for the warning on excel, I've encountered some bugs in it myself before. Excel/spreadsheed is not a viable option for me. The reason to use the database is, as correctly pointed out, not that I have thousands of records, but that I have descriptive text data, files, etc. I do not need to share the data (and I don't see that happening within this project). I want to be able to easily enter data into a form and retrieve data matching certain characteristics (this is what I have attempted in my test database (msaccess2002). One thing it should take over is the task to think of where I should save which files and make it easy for me to find them again. I'm still looking for a product or an msaccess template which is designed for this or a similar purpose (there are should be tons of other people out there with similar requirements as me....). Lukas 01:47, 2 February 2007 (UTC)Reply

Having a look at the teamdesk thing, too. Thanks Lukas 01:51, 2 February 2007 (UTC)Reply

Many computer science types make a hefty profit handling other people's databases, because to even this day it gets messy and application-specific. Though numerous utilities exist (MySQL, MS Access, etc) which supposedly make managing data "simple(r)", I don't know of any that make the solution "user-friendly" to an inexperienced operator. It may be worth paying a fee to an outside service provider, or hire an undergraduate CS intern, if you are unable to develop a complete solution on your own. Nimur 08:11, 2 February 2007 (UTC)Reply

Squid Brains and CNS?

Latest comment: 18 years ago7 comments6 people in discussion

Hello all!

I was talking to a friend recently who said that he couldn't understand how it worked, not being scientifically oriented, but that while in Japan he had been told that the liquid he was eating was squid brain, and that it was a liquid. This puzzled us both, as I, too, have not studied marine biology in great depth. Any idea if a) the brain really is liquid, and b) if so, how does the nervous system of a squid work? I know they are invertebrates, but that's about it. The Squid article doesn't seem to reap much information. 67.174.211.89 05:57, 1 February 2007 (UTC)Reply

And hello to you too. Your brain is about 60% water, and can be liquified in a blender and is considered a gastronomic delicacy on R'tyrovkv in the Betegeuse system (lucky for us they are so far away). The unique thing about squid neurons from a neurophysiologist's point of view is that the individual axons are unusually large and were heavily used in the 1960s-80s to study depolarization and potential propagation. They work basically the same way your neurons work. alteripse 10:45, 1 February 2007 (UTC)Reply

Some more info is at Squid giant axon. --David Iberri (talk) 18:04, 1 February 2007 (UTC)Reply

On the brain into a liquid tangent, ancient Egyptians removed the brains in their mummification process by sticking a flexible tube up their nose and jiggling it several times to turn it into a mush, which was easily extracted from the cadaver from the nostril. bibliomaniac15 01:45, 2 February 2007 (UTC)Reply

The brains of squids, like all other invertebrates, lack a myelin sheath. Not sure if this would affect the taste or texture of the brain from a culinary perspective however. Mikmd 17:55, 5 February 2007 (UTC)Reply

After reading the myelin article, and the references, it seems that squids may have some form of myelin after all. However, it seems to have evolved independently from vertebrate myelin. Mikmd 18:05, 5 February 2007 (UTC)Reply

I'd never heard of a "squid brain paste" food here in Japan so I looked it up, and the only thing I can find close is shiokara. It IS a liquid of sorts, but as far as I know there is no variety that is purely made of squid brains (though the brains are most certainly included with the rest of the pureed, fermented squid).  freshofftheufoΓΛĿЌ  05:18, 2 February 2007 (UTC)Reply

Top 10 Engineering Projects With The Most Human Fatalities?

Latest comment: 18 years ago7 comments7 people in discussion

Hello wikipedians,

My brother in law and I were discussing the top 10 human engineering projects with the most fatalities. So far we have come up with the Death Railway (116,000 deaths of workers) and the Panama_Canal (27,500 deaths of workers).

What other engineering projects would be in the top 10?

Incomplete or unfinished projects are fine.

We are more interested in projects that have fairly specific numbers. For example, we know that lots of people died making the pyramids of Egypt but for obvious reasons we will never really know even approximate figures.

Thanks in advance, Kategorian 11:21, 1 February 2007 (UTC)Reply

Interesting question. I suppose one would have to look at the oldest major engineering works, such as dams and canals. Searching Wikipedia for "workers died" suggests that 120,000 people died during construction of the Suez Canal, and 80,000 during the building of "the British railtrack" in Egypt.--Shantavira 11:55, 1 February 2007 (UTC)Reply

Chinese urban myth claims that thousands upon thousands of people died while building the Great Wall. There are songs and stories that claim human meat and bone was used for the mortar. However, those horror stories have very little evidence to back them up. --Kainaw ^(talk) 12:52, 1 February 2007 (UTC)Reply

You might also look into massive modern works produced in socialist countries in the 1940s and 1950s. I don't know whether many workers died in the construction of the dam on the Dnieper river, for example, or Magnetogorsk, but I would be surprised if they were bloodless, having been constructed with Gulag labor. --24.147.86.187 12:59, 1 February 2007 (UTC)Reply

The Trans-Siberian railroad has to be a candidate. Clarityfiend 15:56, 1 February 2007 (UTC)Reply

The production of military goods for the German army in WW2 should count as an engineering project, and very many imprisoned workers died in it, including death camp inmates and persons from occupied countries. China's Great Leap Forward was an engineering program to make China into a leading industrial country. It took a great many lives: villagers were told to make steel in little backyard furnaces by burning their doors and furniture and all trees as fuel, and all they managed was to convert their plows and pots into lumps of molten iron. The harvests were neglected, and in a pretense that agricultural yields had increased, the actual small harvests wer seized for export. The death toll is stated in the article as 14 to 43 million excess deaths. Edison 17:12, 1 February 2007 (UTC)Reply

Among single construction projects in modern times, the White Sea-Baltic Canal has to rank pretty high.--Rallette 17:55, 1 February 2007 (UTC)Reply

Cigarette lighters

Latest comment: 18 years ago3 comments3 people in discussion

why cigarrette lighter cant be lit by smouldering cigarette? —The preceding unsigned comment was added by 221.134.57.69 (talk • contribs). (Arun singh Bagh)

Basicalliy it seems that smouldering cigarrete is not hot enought to rase the gas temp above the critical temerature. See flash point for some info on this.--Light current 16:44, 1 February 2007 (UTC)Reply

There was an episode of MythBusters where they featured a popular Hollywood myth, that dropping a lit (smoldering) cigarette into a pool of gasoline could ignite it. They were never able to make it happen, but deemed it plausible because the temperature of the cigarette was hotter than the flash point of gas so it "could" happen. I've also heard of anecdotes of people putting out cigarettes in jet fuel (similar to kerosene or diesel). Atropos235 18:25, 1 February 2007 (UTC)Reply

Yep - the lighter hydrocarbons are always easier to light - lighter gas is propane or butane, the flash point increases with molecular mass. And yes kerosene and diesel are difficult to light, especially diesel - you ever need a wick or otherwise it helps if you heat it in a frying pan first until it starts smoldering - then it lights easily..

Plus a straight cigarette contains significant amounts of nitrate to get sudden flashes of high temperature as the tobacco impregnated with the nitrate burns - these are like little sparks and help ignite things. A 'roll your own' cigarette doesn't have this nitrate and burns much colder and is less likely to ignite a lighter flame - in general they don't..87.102.77.95 19:30, 1 February 2007 (UTC)Reply

Sodium vapour lamps

Latest comment: 18 years ago7 comments5 people in discussion

why sodium vapour lamps are used for street lights? —The preceding unsigned comment was added by 221.134.57.69 (talk • contribs). (Arun singh Bagh)

The most amount of light for the least amount of electricity. See Sodium vapor lamp.

Atlant 16:14, 1 February 2007 (UTC)Reply

High efficacy?--Light current 16:37, 1 February 2007 (UTC)Reply

From a desire to make everything look yellowish with monochromatic 590 nm illumination, to make the skies over cities look orange, or to save electricity. Edison 17:15, 1 February 2007 (UTC)Reply

its gotta be efficacy. If someone invented a higher efficacy green light, our night skies would turn green.--Light current 18:33, 1 February 2007 (UTC)Reply

One consideration is that low-pressure sodium-vapor lamps are good for astronomers, because their light pollution can easily be filtered out (that's because they're so nearly monochromatic; you just have to block that one single line). In my opinion they're also less ugly than high-pressure sodium-vapor lamps (those are the pink ones). --Trovatore 18:37, 1 February 2007 (UTC)Reply

It's what we already have, and would cost too much to replace all of them:)Hidden secret 7 19:40, 1 February 2007 (UTC)Reply

 

Xenon arc lamp

New lamps can vary greatly. I've seen several recently which look to be high-intensity fluorescent lights (sort of like the Compact_fluorescent_light_bulb soft-glow lightbulbs. And of course xenon arc lamps are used, especially on high traffic highways.

Sorry, no. A variation on xenon arc lamps may be in your car's headlamps, but they're not used for overhead lighting on highways (because sodium vapo[u]r lighting is so much more efficacious).

Atlant 14:10, 2 February 2007 (UTC)Reply

Chlorophyll efficiency

Latest comment: 18 years ago3 comments3 people in discussion

Is there some reason why the green part of the visible spectrum is not absorbed by chlorophyll and associated pigments? Why is chlorophyll able to absorb only red and blue light? Would a more efficient system absorb all visible light? — Preceding unsigned comment added by 220.236.73.126 (talk • contribs)

I'm not sure, but at a guess I would say that plants just doesn't need to. They get sufficient energy from the wavelengths that they do absorb. Also, if plants were absorbing all wavelengths in the visible spectrum, they would probably overheat. (And who wants a world full of black plants anyway?) BenC7 07:14, 2 February 2007 (UTC)Reply

I think the best way to explain this is that "nature" didn't just engineer the optimum system. It evolved this way, probably based on prior chemical reactions. I'm not entirely sure how the chemical reaction operates, but it very likely cannot use any arbitrary energy, requiring specific frequencies to serve as activation energy for chemical changes. Nimur 08:22, 2 February 2007 (UTC)Reply

• Chlorophyll is green. The reason we can observe that is because it doesn't get absorbed. If it did, it wouldn't be green anymore. - Mgm|^(talk) 11:09, 2 February 2007 (UTC)Reply

Don't some plants already have black leaves

Body Changes

Latest comment: 18 years ago13 comments8 people in discussion

I am not sure how to phrase this correctly nor have the proper terminology, but my question is:Is it possible that your genetic makeup can change throughout your life. When I was a child, I remember having very straight hair and I longed for curly hair. However, in my early 20's, my hair became very thick and curly. Now, I am in my mid 30's and my hair changing it's structure again. It is becoming straighter. Any ideas?

It is not possible for your genetic makeup to change (aside from random DNA mutation that would likely only result in damaged or cancerous individual cell populations). There are many reasons why your hair might be changing structure, including age, changes in diet, or moving to a different climate. It's not at the DNA level. -- Scientizzle 16:28, 1 February 2007 (UTC)Reply

This is probably common knowledge to anyone who has taken high school biology, but I couldn't locate anything in our article on DNA that says as much. Vranak

It is hard to believe that the dramatic changes of my hair structure was from what I ate or where I lived.Please understand that I had pin straight hair (similar to Asian hair) when I was 8 but by the time I was 21, it was very thick and curly...

Though I've never heard of what you describe specifically, hair does respond in a variety of way to the levels of certain hormones that increase during puberty/maturation and fall off during middle age.See Hair#Growth.Dragons flight 17:46, 1 February 2007 (UTC)Reply

It isn't just puberty, my hair has been getting darker from light blond to a very dark brown at least since I was born:)Hidden secret 7 19:44, 1 February 2007 (UTC)Reply

It's very common for light hair to get darker through childhood - lots of kids are born with blond hair but don't keep it - blond kids are usually born with very white hair. I don't know if this means you will go platinum in later years or not. It's common in the animal world for juveniles to have a different colouration to adults.87.102.77.95 19:56, 1 February 2007 (UTC)Reply

As for your hair changing from curly to straight again - don't know.87.102.77.95 19:58, 1 February 2007 (UTC)Reply

I always thought it was strange that my hair behaved this way.Someone mentioned that our skin(?) completely changes every 7 years and maybe so with hair texture.Maybe I am not human!

I don't think I am either:)Hidden secret 7 20:50, 1 February 2007 (UTC)Reply

There is one important exception to the rule that your DNA doesn't change during life, which applies to cells of the immune system, i.e. B lymphocytes and T lymphocytes. During maturation, the DNA coding for these cells' receptors is rearranged, see VDJ recombination. The changed DNA is inherited by daughter cells. The rearrangement occurs in a random fashion, and because various fragments are involved, each of which comes in a large number of variants, combinatorics ensures that the number of different receptors is formidable. In addition, there are enzymes that insert non-coded nucleotides at the points where the DNA is spliced. The potential number of antigen receptors is enormous. Lymphocytes which encounter antigens that happen to match their receptors, are selected in a Darwinian manner. This is the basis of immunization - somatic DNA recombination is the reason why we are able to make antibodies against such an enormous number of pathogens. The fact that the receptors aren't "hard-coded" makes this a very flexible system, which can adapt to new threats. To my knowledge, it is the only known example of somatic DNA recombination in vertebrates. --NorwegianBlue ^talk 20:56, 1 February 2007 (UTC)Reply

Only known example, except of course somatic mutations that lead to cancer. --NorwegianBlue ^talk 21:03, 1 February 2007 (UTC)Reply

In your comment NorwegianBlue,"The rearrangement occurs in a random fashion, and because various fragments are involved, each of which comes in a large number of variants, combinatorics assures that the number of combinations is formidable", are you saying as our DNA changes during maturation for immunizations against pathogens, this possibly can affect hair texture, iris color, etc?I also know of an African-American person who also experienced the same issue as well...

No. This process only applies to the genes coding for the T cell receptor and the B cell receptor (immunoglobulin), and "maturation" refers to the maturation of the individual cell. --NorwegianBlue ^talk 21:03, 1 February 2007 (UTC)Reply

Think of your hair changes similar to how your body changes when you go through puberty. When you hit puberty, you grow facial hair, get bigger & stronger & grow an adam's apple etc. This is not your DNA changing, but instead hormones & internal changes stirred by chemicals. Your body can change drastically without warning. Keep in mind however, that indeed DNA can affect whether we do have curly or straight hair, but changing between the two isn't unheard of either. Many children may have curly or straight hair in childhood & then have the opposite later in life. When babies are born, they may have a different eye colour to later on in life & so on & so on. Your DNA does not change unless you're one of the X men. Hope this explains it easily... Spawn Man 21:45, 1 February 2007 (UTC)Reply

And if you're interested in whats going on on the molecular, level, you might want to read the article regulation of gene expression. --NorwegianBlue ^talk 08:45, 2 February 2007 (UTC)Reply

I also experience this. When I was little, I had curly, thick blonde hair. Later my hair became really straight and black, and now my hair is this dark brown, but it's really curly and somewhat thick. All this happened in 16 years of my existence. I have a question, if it's not possible for your genes to change, where does evolution happen? Surely your genes have to change. ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 13:30, 5 February 2007 (UTC)Reply

There are in fact mutations and genetic recombinations, and even DNA repair, but there are no deliberate, routine, permanent changes to DNA made by any organism. (The result would be very hard to do safely, after all.) Evolution is a result of the accumulated random changes to DNA inherited by offspring. See, however, the current field of genetics research dealing with promoters and company, which do not modify DNA but have much the same effect by dynamically affecting how it is used. --Tardis 19:15, 5 February 2007 (UTC)Reply

If you tied a rope around the moon and let the other end hang down onto the surface of the earth...

Latest comment: 18 years ago6 comments6 people in discussion

1)When the moon moved, would the rope drag across the surface of the earth, and if so how fast? 2)And if not, would it go out into space and trail behind the moon or what would it do? The gravity field of the earth and the moon are significantly less than the amount of empty space in between the earth and the moon. 3)If the answer to the first question is no, could you hold onto the rope as it pulled you up into the sky? 4)How much weight would it take to keep the rope vertical to the earth? 5)Would that amount of weight cause the moon to stop moving and come crashing down onto the earth?

This will be a big help for one of the questions on my thirty-problem physics project, thanks! Xhin 16:47, 1 February 2007 (UTC)Reply

(numbered the questions to make responses easier). During a single night, the earth's rotation makes the moon appear to move across the sky. Per Moon the Moon makes one complete orbit about the Earth every 27.3 days. The nearest point to the moon on the earth's surface makes a revolution every day, with adjustment for the moons 27.3 day cycle. What does that suggest about the rope staying at one point? Per Earth the planet's mean circumference is 40,041.47 km, and its sidereal rotation period is 0.997 258 d (23.934 h). Earth's rotation velocity at the equator is 465.11 m/s or 1040 miles per hour, which has to be adjusted plus or minus for the moon's travel around the earth.The question implies that the rope starts on the earth's surface. The statement "The gravity field of the earth and the moon are significantly less than the amount of empty space in between the earth and the moon." makes a meaningless comparison between gravity and space. How can gravity be less THAN space. Did the question originally say IN space? I suggest the hypothetical rope would have to be extremely strong and perhaps fireproof. I suggest that no amount of weight could keep it absolutely vertical to the earth, but the deflection from passage through the atmosphere would be a difficult calculation depending on air resistance, which would depend on the diameter and surface of the rope, and more complex because it would change with altitude. Edison 17:31, 1 February 2007 (UTC)Reply

The question would be interesting if rephrased for a sitution where both bodies are tidally locked with respect to each other (eg. Pluto and Charon). What stresses would be suffered by a space elevator linking these two bodies? Carcharoth 18:01, 1 February 2007 (UTC)Reply

You should note the difference between the apogee and perigee of the moon's orbit.—eric 18:12, 1 February 2007 (UTC)Reply

Well I've come up with a simple answer to your question. All the roads in New Zealand, lined back to back, would make it 3 quarters of the way to the moon. Now all you have to do is measure all the roads in New Zealand & then do the math. ;) Spawn Man 21:49, 1 February 2007 (UTC). P.S. The rope might catch on a rock & send the moon crashing down in the Atlantic, so be sure you use duel fibre twine... ;)Reply

To question 1, I think yes. The rope would be close to vertical most of the way, but once it hits the Earth's atmosphere, the atmospheric drag will push it forward (since the Earth rotates faster than the moon orbits), so it will be slanted at an angle near the surface of the Earth. To question 4 (if I understand what you mean), that is impossible, because the atmospheric drag pushes the rope forwards, and if were vertical, there would be no force to oppose it going the other way. --Spoon! 23:55, 1 February 2007 (UTC)Reply

Why Don't They Send Hubble's Twin in Orbit?

Latest comment: 18 years ago10 comments10 people in discussion

When they constructed the Hubble telescope two decades ago, all key components were manufactured in pairs (in case one breaks down, the redundant component is available right away). Now that the one currently in operation is approaching its end of life--and that another shuttle repair mission will cost a fortune--why don't they just put all the spare parts together and launch the thing up there? The twin may not be the latest technology, but it sure could be a cheaper way to get a new telescope in orbit, serving science for the next two decades.--JLdesAlpins 17:23, 1 February 2007 (UTC)Reply

Is there evidence they made a second mirror? At the time of its making, there was an article about how expensive it was, and that it was the best mirror ever built. Later it turned out they had totally botched the fabrication and testing and the thing had to have corrective lenses added. Have some of the spares been used on the repair missions? An unanswered question is how similar the general optics of spy satellites are to those of Hubble. They are supposed to have amazing resolution, but would lack some of the aiming ability and some of the special astronomical optics. Edison 17:38, 1 February 2007 (UTC)Reply

One of the largest differences between an earth-observing satellite and the Hubble is the amount of light collection area and maybe to a lesser extent the ability to keep attitude very precisely.Images like the Hubble Deep Field require an extremely long exposure time, even with the Hubble's large mirror.Images like [1] also show what vistas large amounts of light gathering area can give you.Like spy satellites, you or I can easily see things on Earth because they're illuminated so well, could never see anything like that with our pair of 1x 1-cm refractors. Atropos235 18:03, 1 February 2007 (UTC)Reply

See Hubble Space Telescope#Optical Telescope Assembly (OTA) for information about the second mirror. --cesarb 18:30, 1 February 2007 (UTC)Reply

Hubble was designed to be orbited in the carbo bay of the space shuttle.Given that you'd have to launch a shuttle either way, it is unlikely that there would be much cost savings.Dragons flight 17:42, 1 February 2007 (UTC)Reply

Lets not forget the cost to acctually form the second hubble. putting the spare parts together will still require extreamly skilled scientest to put it together and many months to do it right Maverick423 17:51, 1 February 2007 (UTC)Reply

And lets not forget, the spare parts were there in case something goes wrong, so imagine something went wrong while assembling the spare parts, they'd have no redundancy.Vespine 21:32, 1 February 2007 (UTC)Reply

Hubble's "dubble"? Clarityfiend 01:20, 2 February 2007 (UTC)Reply

OK, suppose that everything on Hubble was duplicated - Hubble has been serviced a couple of times since launch - might some of those duplicate "spares" have been used up in servicing it? Richard B 01:31, 2 February 2007 (UTC)Reply

I think it's probably an engineering exaggeration to say "everything" was doubled; furthermore, the likelihood that all parts are carefully cataloged, stored in one warehouse, with blueprints and assembly instructions is virtually zero.Significant engineering effort would be needed; and even the original engineers probably don't even remember all of the design properties.It is probably easier and cheaper to start from scratch.After all, the most expensive part of spaceflight systems is very rarely the actual components costs. Nimur 08:29, 2 February 2007 (UTC)Reply

Narcotics

Latest comment: 18 years ago6 comments4 people in discussion

Is there any type of narcotic drugs that include iodine atoms in the molecule? TERdON 18:07, 1 February 2007 (UTC)Reply

The simple answer is yes - but they are not common. Iodine (and also other halogens chlorine, bromine and fluorine) is sometimes incorporated into the basic drug structure - one of the main reasons this is done is that the resultant compound is easier to absorb through the gut walls as it is more 'fatty'.

(also Iodinated and brominated 'ecstacy' derivatives are found often enough to be called common, I'm not sure that amphetamines are classed as narcotics though.)

I don't have enough knowledge to say if there are any drugs of this type in common use.87.102.77.95 19:23, 1 February 2007 (UTC)Reply

In Sweden, no doubt amphetamine is illegal, I suppose the same holds true of its derivates. Thanks for the answer! :) TERdON 20:18, 1 February 2007 (UTC)Reply

I don't think amphetamine is a narcotic (narcotics are derivatives of opium), but perhaps you meant psychoactive drug? − Twas Now ( talk • contribs • e-mail ) 22:13, 1 February 2007 (UTC)Reply

I didn't mean they were narcotics by the scientific definition, but by the Swedish legal definition, which includes all kinds of addictive drugs that aren't, technically, narcotics. TERdON 22:18, 1 February 2007 (UTC)Reply

Yes, "crack," but it's not in the narcotic.Instead it's part of the precursors, see Iodine in Methamphetamine production.As part of the "war on drugs," some states in the USA require that iodine suppliers record and retain customer information on anyone buying iodine. --Wjbeaty 20:42, 1 February 2007 (UTC)Reply

Source

Latest comment: 18 years ago8 comments7 people in discussion

Is their there enough kinetic energy in a human body to move an object?— Preceding unsigned comment added by 71.201.233.107 (talk • contribs)

People move things every day - I'm not sure what else you could be asking? please explain..87.102.77.95 19:15, 1 February 2007 (UTC)Reply

Do you know what kinetic energy is?It's the energy of a mass in motion.One way to tell that an object in motion has kinetic energy is to watch what happens when the object hits another object: in a collision, one moving object can impart kinetic energy to the collided-with object, causing the collided-with object to move as well.Does this answer your question? --Steve Summit (talk) 19:19, 1 February 2007 (UTC)Reply

are you trying to talk about telekinetic energy? which is more of a phycic power then anything. Maverick423 21:09, 1 February 2007 (UTC)Reply

See Psychokinesis. I would have to answer "No, there is not enough psychokinetic/telekinetic energy in a human body to move anything." But I have an open mind and would be ready to be proven wrong. There are many ways to fake it or to think it is observed in poorly controlled experiments. Edison 21:30, 1 February 2007 (UTC)Reply

There's often just enough to move money from a believer's wallet/purse to the claimant's. Spooky! Clarityfiend 21:53, 1 February 2007 (UTC)Reply

It might just be that things that can be moved like this are too small to see:)Hidden secret 7 20:47, 3 February 2007 (UTC)Reply

To move an object with the kinetic energy of a human, you would need to have the human collide with the object.Imagine body-slamming a box.Then, your kinetic energy would (partially) transfer and the box would jolt forward.Perhaps you mean potential energy which may be stored in the muscles in chemical form (adenosine triphosphate)?This can be converted into kinetic energy, (probably also generating thermal energy and other forms...) allowing the muscle to move an object. Nimur 08:32, 2 February 2007 (UTC)Reply

Hah.I'm now having hilarious visions of ragdoll-physics style "human collisions" to test the inelasticity of collisions.Efficient transfer of kinetic energy from the human to the object is almost as much fun as inefficient transfer. Nimur 08:34, 2 February 2007 (UTC)Reply

High density polyethylene

Latest comment: 18 years ago3 comments3 people in discussion

Hello, does anyone know of a supplier for blocks of high density polyethylene.I'm looking for a small cube of the stuff that I can mill down a little bit.

Try McMaster-Carr. anonymous6494 20:55, 1 February 2007 (UTC)Reply

Isnt polyethylene always the same density? --Light current 01:36, 2 February 2007 (UTC)Reply

No. See HDPE vs LDPE. DMacks 02:46, 2 February 2007 (UTC)Reply

Water on Mars

Latest comment: 18 years ago1 comment1 person in discussion

is there really water in Mars?–––Thanks

There is no doubt about the presence of water on Mars. A more intriguing question is whether or not there is liquid water on Mars, and recent evidence has been pointing towards a positive answer. — Kieff | Talk 00:29, 2 February 2007 (UTC)Reply

Lava and Magma

Latest comment: 18 years ago12 comments8 people in discussion

Which is thinner, magma or lava?

same stuff I thought!--Light current 01:32, 2 February 2007 (UTC)Reply

Well according to Chloe Talbot from The Simpsons, magma is the word for lava when it's underground. Which would mean that lava would be more viscous, but magma would be denser. Anchoress 01:42, 2 February 2007 (UTC)Reply

No no Yes. Lava is magma when its under ground.When its erupted its lava. Pumice--Light current 02:28, 2 February 2007 (UTC)Reply

That's what Anchoress said. =) Chickenflicker---♣ 04:33, 2 February 2007 (UTC)Reply

Quire rite sorry. It was the Simpsons who put me off.8-)--Light current 11:45, 2 February 2007 (UTC)Reply

If it had to be one or the other, it would be lava; but not by much, I would imagine. As the molten rock comes closer to the surface it experiences less pressure and presumably expands, making it less dense or "thinner". I'm not sure, however, the degree to which it would expand, or if that would be significant to appropriately label it "thinner". BenC7 07:22, 2 February 2007 (UTC)Reply

If lava can be approximated as an uncompressable fluid, the pressure change would have little effect on the density.One thing that does significantly affect density is silica content.Hawaiian volcano lava is quite different from, say, Mount Saint Helens (which has more silica, is more dense, and thus exploded violently!)Hawaiian lava flows gracefully with much less exploding. Nimur 08:37, 2 February 2007 (UTC)Reply

(comment) doesn't the explosiveness of magma relate to the amount of dissolved gas in it (eg water) - that is released when the pressure vessel that is the inner volcano is opened..(or does silica rich magma have greater ability to hold gases???)87.102.4.6 11:55, 2 February 2007 (UTC)Reply

I too would expect lava to be thinner thicker (less more viscous) than magma since it is cooler. I don't know how pressure affects viscosity. Reading both articles it explains that the viscosity depends on the composition - so there may not be a definative answer.87.102.4.6 10:33, 2 February 2007 (UTC)Reply

Both lava and magma is made of all types of substances, and are all different temperatures. [Mαc Δαvιs] X (How's my driving?) ❖ 18:09, 2 February 2007 (UTC)Reply

I would have expected lava to be more viscous as it is cooler, since this would mean less kinetic energy for each molecule, and therefore less energy to move them apart:)Hidden secret 7 20:50, 3 February 2007 (UTC)Reply

Unlike gases, there is no "ideal law" for fluids, let alone an accurate one. Non-ideal effects will dominate what factors determine density. Nimur 01:08, 4 February 2007 (UTC)Reply

February 2

Appendectomy and oxygen

Latest comment: 18 years ago5 comments3 people in discussion

Is it normal for a person who has undergone an appendectomy (burst appendix) to be on post operative oxygen?--Light current 01:31, 2 February 2007 (UTC)Reply

THis would be for a person abot 70 years old.--Light current 11:46, 2 February 2007 (UTC)Reply

I was about 5 when it happened, but I remember them putting tubes down my nose, so I wouldn't think it'd be somewhat normal. It is a potentially fatal thing. --Wirbelwindヴィルヴェルヴィント (talk) 03:59, 2 February 2007 (UTC)Reply

For any procedure involving general anesthesia, and intubation, one can expect to wake up with an oxygen mask on, especially at an advanced age. High oxygen will help a patient overcome the trauma of the surgery, and more important it will help that patient clear infections from the perforation and the surgical insult. ^tucker/_rekcut 12:11, 2 February 2007 (UTC)Reply

Ah thank you. Just the ans I wanted!--Light current 12:12, 2 February 2007 (UTC)Reply

Best position to land

Latest comment: 18 years ago4 comments3 people in discussion

When falling from high up (for example, a fifth storey), what would be the safest position to land when hitting solid ground? --Codell ^{[ Talk]} 02:39, 2 February 2007 (UTC)Reply

[2] [3] -- Consumed Crustacean (talk) 02:43, 2 February 2007 (UTC)Reply

Dunno if it was ever proven, but I'd always heard if you can somehow pull off a rolling landing, you could possibly survive (height depending of course). Cyraan 02:51, 2 February 2007 (UTC)Reply

Thank you, Consumed Crustacean. This answers my question.--Codell ^{[ Talk]} 03:47, 2 February 2007 (UTC)Reply

as far above the ground as possible

How to draw: trans-3,5-dibromocyclodecyne?

Latest comment: 18 years ago6 comments4 people in discussion

This is the only problem I can't do for my alkyne nomenclature homework. I submitted the structure, but the program keeps telling me to show the trans configuration of the Br Atoms.But I'm pretty sure I put the Br atoms where they're supposed to be.I'm also sure that I have the cyclodecyne structure right, so it must be something else I'm missing.I tried all combinations of where the Br are located respective of one another.Because it's trans, I'm guessing that one of the Br atom is inside the ring, and the other on the outside.I tried that, but it wasn't correct.Any ideas?Thanks in advance 128.163.214.199 03:06, 2 February 2007 (UTC)Reply

By saying "inside" and "outside", you're thinking about the ring and everything attached to it as being flat. Ain't so...visit your textbook chapter about alkanes or orbital hybridisation to see why things attached to the ring are often described as "above" and/or "below" the plane of the ring, never inside/outside the ring. DMacks 03:14, 2 February 2007 (UTC)Reply

from trans "A similar phenomenon is seen in cyclic compounds (in which the atoms form a closed ring), where substituents can be on the same "face" of the ring (cis) or opposite faces (trans.)" - so agree with above - it's above or below the plane of the ring.87.102.4.6 11:06, 2 February 2007 (UTC)Reply

Geometric isomerism has more details, and a diagram for the cycohexane case.87.102.4.6 11:07, 2 February 2007 (UTC)Reply

3,5-dibromocyclodecyne is chiral at both the 3 and 5 positions, usually a trans structure refers to atoms on opposite sides of a thing (atom, double bond) - it sounds like you need to know the most stable conformation of the molecule and put the bromines on opposite sides. In actuality the name you've got doesn't seem to be a useful description of the molecule - I'd expect something like R,R 3,5-dibromocyclodecyne, R,S 3,5-dibromocyclodecyne, S,R 3,5-dibromocyclodecyne, S,S 3,5-dibromocyclodecyne.87.102.4.6 10:31, 2 February 2007 (UTC)Reply

Thanks a lot, everyone. I misinterpreted the diagram in the book; somehow I didn't look at the type of bond (up/down). Now I understand the concept better.128.163.224.201 18:08, 3 February 2007 (UTC)Reply

Time for Escape!!!

Latest comment: 18 years ago7 comments5 people in discussion

How long would it take to accelerate human passengers in a craft to about eight miles per second, and lets say they are traveling at a constant 3g?67.127.96.131 03:39, 2 February 2007 (UTC)Reply

Sorry, but we don't answer homework questions! But to help you out: have a look at the acceleration article, you'll notice the following equation:

${\displaystyle \mathbf {\bar {a}} ={\mathbf {v} -\mathbf {u} \over t}}$ 

Using that, you can find the time required. All the best. - Akamad 03:48, 2 February 2007 (UTC)Reply

Oh man thank you someone finally gives me an equation and thank you but this is not homework I am just very curious about these things.67.127.96.131 05:19, 2 February 2007 (UTC)Reply

Yes, I am similarly curious about how long it will take a train leaving Philadelphia traveling at 180 km/h to reach a train that has left New Jersey traveling at 200 km/h. But of course, not for my homework! − Twas Now ( talk • contribs • e-mail ) 06:50, 2 February 2007 (UTC)Reply

Several of the times when I've tried it, Amtrak or New Jersey Transit has had equipment failures. Where does that go in the equation?

Atlant 14:04, 2 February 2007 (UTC)Reply

We surely don't want to confuse the questioner, but this equation might be helpful as well.

${\displaystyle x(t)=x_{0}+vt+1/2at^{2}}$ 

${\displaystyle v(t)=v_{0}+at=dx(t)/dt}$ 

Nimur 08:42, 2 February 2007 (UTC)Reply

Awesome eqautions but once again it's not homework and believe it or not I haven't ever had a physics class. Someone just please tell me how to plug in the numbers.

What you want to do is solve the equation (the equation I gave you, the first equation that Nimur gave is for finding displacement, and the second equation is the same as the one I wrote down) for t (the time variable). Here is a link on how to solve equations if you need help: http://www.sosmath.com/algebra/solve/solve0/solve0.html. You already know the final velocity (8 miles/second) and the acceleration (3g). From your question, you can assume the initial velocity to be zero. So all the variables are known. But make sure all your units are the same (for example, you'll have to change the 3g to miles/second/second, have a look at this article: Earth's gravity for what the "g" means. Hope that helps. - Akamad 11:17, 3 February 2007 (UTC)Reply

Okay, I'll assume good faith and give the answer. The simplest form of the relevant equation is just v = at: speed (assuming you start from 0) is acceleration times time. So t = v/a: time is speed divided by acceleration. g is 9.8 m/s², so the acceleration 3g is 29.4 m/s². 8 miles is 12,875 meters, so 8 mi/s = 12875 m/s. So the answer is 12875/29.4 = 438 s (see, dividing the units of m/s² by m/s gives seconds) or 7.3 minutes. I've rounded the numbers along the way since I assume the 8 mi/s was not intended to be an exact number. --Anonymous, February 3, 2007, 22:02 (UTC).

Okay thank you because I did attempt to do the eqaution given to me by Akamad and I ended up with 8.76 hours! The reason why I asked this I wanted to know if the speed could be acheived without killing the passengers. Now the next problem to face is making it through the atmosphere without burning up or the craft loosing velocity. Anyways everyone thank you again.

Note that real-life space launches achieve orbital velocity of about 5 miles/second without killing the passengers. Achieving 1.6 times the speed could be done by accelerating 1.6 times as long. (In practice the acceleration is not constant, so it's a bit more complicated than that, but that'll do for a rough idea.) --Anon, Feb. 4, 05:05 (UTC).

Light

Latest comment: 18 years ago9 comments7 people in discussion

Greetings,

I have done small studies an have a theory. Light has mass and weight. It must, because a black hole pulls in light. I don't understand the technical jargon. Please let me know if it has mass. (In layman's terms)

Fare thee Well, AlexanderTG 05:58, 2 February 2007 (UTC)Reply

What is your theory? This sounds like the wave–particle duality of light. − Twas Now ( talk • contribs • e-mail ) 06:52, 2 February 2007 (UTC)Reply

General Relativity is exactly the technical jargon which explains how gravity can "pull" something (like light), even if it has no mass.Some people try to explain this by saying that the gravity bends space and time.It is very well established that light has no mass, and many experiments and equations exist to back this up. Nimur 08:44, 2 February 2007 (UTC)Reply

You might also consider General Relativity at the Simplified Wikipedia if you are having difficulty with technical jargon. Nimur 08:46, 2 February 2007 (UTC)Reply

Also, what do you mean by mass? Mass in general relativity is very complicated and may not be well defined at all. --Spoon! 09:25, 2 February 2007 (UTC)Reply

Short answer - light is made up of photons; photons do not have rest mass, but they do have relativistic mass, because they have momentum. This article answers the question "If light has no mass how can it be deflected by the gravity of a star?". Gandalf61 14:12, 2 February 2007 (UTC)Reply

They say gravity bends space, but the experiment they do to show this where the balls roll toward each other only works because of the earths gravity below it:( Is this because they can't find any real way to show what is happening, and are hoping we don't notice, or am I missing something important here:(Hidden secret 7 20:54, 3 February 2007 (UTC)Reply

You didn't miss anything - the bending thing is bogus. The reason light is attracted to black holes is that is has mass, just like any other particle. True it doesn't have rest mass, but that doesn't make the mass any less real. There is no need to invent bending of space or anything like that. Ariel. 13:19, 4 February 2007 (UTC)Reply

Ariel's comments are a simplification which may adversely affect the original questioner's understanding. It is not correct to say that light has mass in the conventional sense. As noted above, in certain treatments of relativity, the semantics of "mass" can be redefined, but this is playing games with human language and word choice. The "bending thing" is another way to work out the equations. After all, science is just a model of our universe, not a perfect description. Nimur 03:33, 8 February 2007 (UTC)Reply

donut constellation

Latest comment: 18 years ago1 comment1 person in discussion

There seem to be models for ethernet structures described as a donut constellation. The descriptions of the structure are too technical for me to understand. I have heard the term donut constellation used to described the way energy revolves in some physical structures as well. The philosphers Deleuze and Guattari describe social maps and organizations that evolve rhizomatically along a number of axi and levels. As a result many creative and visual thinkers use this structure as an exploratory model. I think the donut constellation whereby energy is constantly revolving on a number of planes around a vacant middle maybe used to as an alternative model for describing the way chunks of the creative thought process evolves. I would like to read more about this type of structure. I think there is a more accurate word, that those versed in physics would use to describe it.

The word is torus, the surface is represented by a quartic equation in three dimensional space. As for a doughnut shaped ethernet this would be a ring shaped data bus with various data items branching off it.87.102.4.6 10:24, 2 February 2007 (UTC)Reply

Antagonism vs Inhibition | Enzymes & Neurotransmiters

Latest comment: 18 years ago14 comments7 people in discussion

• On the other hand, compounds that inhibit reuptake but also inhibit release of dopamine, such as Wellbutrin and vanoxerine, have mild stimulant effects and little abuse potential, and can be used to treat stimulant addiction. ^{[citation needed]}

• Zyprexa's antipsychotic activity is mediated primarily by antagonism at dopamine receptors.

Scientifically speaking, is there any differece between Antagonism and Inhibition? Please provide references to back up your answer.

I would appreciate the answers provided. Thnx. --Parker007 12:37, 28 January 2007 (UTC)Reply

I'd suggest that the usage choice is a language one, (I can't call a difference between the two). Medical dictionary (is this a good source?) has the two lumped together for the same definition see http://www.wrongdiagnosis.com/medical/inhibitor_antagonist.htm

The real difference is actually in other usage - an antagonist 'works against' eg pairs of muscles that pull on either side of the bone, an inhibitor prevents the action itself. I'm not sure that in biochemical usage the distinction is made (of perhaps even known).

Also http://www.thefreedictionary.com/antagonist defines antagonism in a biochemical sense as "Biochemistry A chemical substance that interferes with the physiological action of another, especially by combining with and blocking its nerve receptor" eg as an inhibitor.

So in biochemistry they seem to have the same meaning - though if more becomes known about the mode of action of a given substance perhaps in the future a distinction will be made.

Comment on proper usage...

For instance a compound that causes dopamine uptake is antagonistic to a compound that causes dopamine release - but does not inhibit.

Whereas a compound that binds to a site causing dopamine release (not activating it) can be called an dopamine release inhibitor. (But may also be decribed as antagonistic to a compound causing dopamine release by the nature of it's inhibitory action). Hope that helps.87.102.33.144 13:04, 28 January 2007 (UTC)Reply

Actually, antagonism and inhibition are two distinct concepts in most biomedical contexts. Antagonism usually refers to interference with the action of a substance, or sometimes to the production of an effect that opposes that of another substance. An example of a steroid antagonist is spironolactone, which reduces mineralocorticoid effects and androgen effects. Inhibition usually refers to interference with production of a substance. An example of an inhibitor of steroid production is metopirone. alteripse 17:22, 28 January 2007 (UTC)Reply

I see that competitive anatagonist, noncompetitive antagonist & uncompetitive antagonist need articles...I'll have to work on that.

For maybe a litle semantic clarity of the difference between antagonism and inhibition...Inhibition is the prevention of some event and antagonism is one biochemical pathway through which one might cause inhibition. Enzymes or biological receptors, for example, can be inhibited by several means (phosphorylation state, missing co-factors, pH, etc.), including antagonism. An antagonist may inhibit by one of several methods (see below), but chiefly it interrupts the the otherwise natural activity of the enzyme/receptor in the local state. Types of enzyme inhibition | Competitive inhibition | Uncompetitive inhibition | Non-competitive inhibition | Suicide inhibition | Mixed inhibition | -- Scientizzle 00:22, 30 January 2007 (UTC)Reply

I am inclined to agree with User:Alteripse & User:Scientizzle, otherwise I wouldn't have asked the question, because I already read the dictionary before asking the question. --Parker007 05:52, 2 February 2007 (UTC)Reply

Wow, so biochemists can just make up new definitions of words can they! If 'you' used the words in correct context of their english meaning maybe you wouldn't have this problem???87.102.4.6 10:38, 2 February 2007 (UTC)Reply

I'd just like to point out that we do have articles on Receptor antagonist and agonist, as well as the featured atricle Enzyme inhibitor, which also was linked to above. It might be better to expand on those, and add some redirects, rather than create new articles. --NorwegianBlue ^talk 09:24, 2 February 2007 (UTC)Reply

Yeah...I know. I was considering how best to go about either combining receptor dynamics into the enzyme inhibition articles or making new, separate articles. Receptors and enzymes are very unrelated in terms of activity, and are separate targets for drug interactions (through which most antagonism occurs), but the molecular methods and pharmacological models of inhibition are largely similar...I'll figure it out... -- Scientizzle 16:14, 2 February 2007 (UTC)Reply

How do enzymes have anything to do with neurotransmitters? --Parker007 09:41, 2 February 2007 (UTC)Reply

Enzymes are to substrates as receptors (eg, neurotransmitter receptors) are to ligands (eg, neurotransmitters). --David Iberri (talk) 01:19, 3 February 2007 (UTC)Reply

That makes no sense; So what does enzymes do to neurotransmitters? --Parker007 00:10, 4 February 2007 (UTC)Reply

What David Iberri is trying to say is that the interaction between enzyme-substrate is analagous to receptor-ligand. The kinetics are often very similar. -- Scientizzle 07:31, 4 February 2007 (UTC)Reply

In english? :) --Parker007 06:11, 9 February 2007 (UTC)Reply

An enzyme binding to its target substrate exhibits very similar kinetics as a receptor binding a signaling molecule. The final action is different (enzymes will alter the substrate in some way, a receptor will activate a distal signaling pathway, without altering the signaling molecule), but the modeling is similar. Is that any better? -- Scientizzle 16:02, 9 February 2007 (UTC)Reply

Bending of light.

Latest comment: 18 years ago7 comments6 people in discussion

Why does a light ray bend when there is mass in vicinity of it's line of journey? Considerable bending has been observed when the amount of mass is large.Does bending occur even when amount of mass is small?Is there any relation between gravity and electromagnetism?Well, something fishy is going on.I think unification of gravity and electromagnetism is not far.(Ecclesiasticalparanoid) —The preceding unsigned comment was added by 210.212.215.141 (talk) 10:13, 2 February 2007 (UTC).Reply

• Light is an odd thing. It can behave both like a wave and like particles. Since particles have mass, they are affected by the gravitational pull of a mass in its vicinity. Light probably bends too when the mass is small, the effect is just smaller. 'Small' is a relative term in that case. Usually we're talking planet-sized masses in discussions like this. - Mgm|^(talk) 10:59, 2 February 2007 (UTC)Reply

At the moment there is no known way to unify gravity and electromagnetism into one force though it is presumably the goal of a Theory Of Everything. Many people have sought such a connection, including Albert Einstein (see Unified field theory), and failed. Whether it is far away or not probably depends on whether you think they are going the right direction with string theory or not. --24.147.86.187 13:33, 2 February 2007 (UTC)Reply

Unless I'm mistaken, classical electromagnetism and modern gravitational theory (general relativity) have already been shown to be consistant.My answer to your last question contained a link to Kaluza-Klein theory, which shows that Maxwell's equations (the basis of classical electromagnetics) can be derived from principles in general relativity.In other words, KK theory more or less united modern gravitation theory and classical electromagnetics back in the 1920s.

Also note that it isn't just light that exhibits wave-particle duality, but all matter at sufficient scales.However, pertaining to the question you originally posed, I'm not sure if it's totally appropriate to embark on a discussion of quantum mechanical effects (which is where you would consider wave-particle duality).In general, QM and GR haven't been reconciled, so I don't know if it's appropriate to talk about wave-particle duality in the same breath as gravitational (spacetime) effects on light.Look at Maxwell's equations in curved spacetime and General relativity.Perhaps a physicist can fill in some of the gaps I've omitted in my explanation...I'm definitely not a GR person, and I can only do fairly basic QM.

P.S. - The photon is massless (at rest). -- mattb @ 2007-02-02T13:42Z

I believe the current understanding is that the light really doesn't bend. It travels straight in spacetime and it is spacetime itself that is distorted by the presence of the mass. The analogy usually used for us non-physicists is to imagine spacetime as a rubber sheet and the massive objects as heavy objects pressing down into that rubber sheet. The depressions thereby formed are analagous to the bends in spacetime.

Atlant 14:07, 2 February 2007 (UTC)Reply

Light also distorts space-time depending only on it's frequency. The fundamental understanding of Einstein's theories is that Energy and Mass are equivalent. --Tbeatty 07:09, 3 February 2007 (UTC)Reply

If i remember correctly Lightning consist of Plasma, which is a super hot gas; gas has mass. in anyway if your talking about lightning i can see why it would bend, however if you were talking about regular light, light accelrates Ions or electrons or something (someone here should know) in anyways these ions or electrons also have a mass (although its not much its still there) that would explain how a high gravity mass can alter light in such ways. Maverick423 15:07, 2 February 2007 (UTC)Reply

Nobody said anything about lightning as far as I can tell.Please don't take this the wrong way, but given your second sentence I would suggest reading some of the linked articles.The article on light itself provides a pretty good overview. -- mattb @ 2007-02-02T15:13Z

Meh sorry and thanks for the corrections its been a while since i read or studied about light so i can get my info confused at time =( Maverick423 15:32, 2 February 2007 (UTC)Reply

No need to apologize.I'm by no means an expert on modern physics, and I've probably said some things that aren't totally accurate.Just take a moment sometime to read that article on light. -- mattb @ 2007-02-02T15:40Z

Statistics/Normal Distribution

Latest comment: 18 years ago1 comment1 person in discussion

(repost of a question previously posted on another reference desk and previously moved to the math desk. Te Q and A have been moved there as well. Please do not doublepost.)Edison 16:17, 2 February 2007 (UTC)Reply

Another poision question

Latest comment: 18 years ago5 comments3 people in discussion

Hi there again its me! im sure you know me from my old question from radiation =P anyways here i go again. my curiosity has gotten Intrested in the cyinade (think thats how its spelled). Cyinade Poisioning yes it says its fast and kills rapidly, but exactly how does it do it? What does a person feel (yes i am intrested in stuff like this as you can see) when they get cyinade poison? does the skin melt does the person feel immense pain or is it just a drink and fall dead with no feelings of the poison coursing through your body?? what about the range of cyinade? how far can it reach if a cup of it was spilled on the floor and how fast does it evaproate? there are lots of questions about this i want awnsered but well i dont know if people sugar coat it when they talk about it or what but please guys DONT sugar coat it i am intrested in the raw effects of it. thanks Maverick423 15:24, 2 February 2007 (UTC)Reply

Ok try not to get carried away - the skin does not melt.

Cyanide poisons (in one way I know of) by complexing to metal ions such as the iron in haemoglobin - (it may be poisonous in other ways) - this is similar to carbon monoxide poisoning - effectively you aspyhyxiate due to lack off oxygen.

The 'cyanide capsule' is often sodium cyanide solution.

Hydrogen cyanide is a gas and also poisonous.

In the case of swallowing cyanide choking and spluttering occurs - followed by loss of conciousness - the death. There is not much pain - but the choking and spluttering is unpleasant but not that bad.. People poisoned by cyanide can be saved - the longer they are out the less chance they have of surviving.

Sodium cyanide and potassium cyanide are solids - as solutions they may produce a small amount of hydrogen cyanide - adding an acid to a cyanide salt will produce the hydrogen cyanide gas - this is capable of spreading - I don't know how fast though.

Interestingly hydrogen cyanide will burn.

The cynanide links above all give more info on mode of action and lethal doses etc. Suggest you read them..87.102.4.6 15:49, 2 February 2007 (UTC)Reply

Alright great info man thanks much! so then what they say about cyanide being a quick and painless death is a lie? i kinda figured there was something about that line. well anymore information is greatly appreciated as for me i got some stuff to look at thanks again! Maverick423 15:57, 2 February 2007 (UTC)Reply

I'm afraid much of the above is incorrect. Cyanide does not act on hemoglobin, but on cytochrome oxidase, as a metabolic poison. Cytochrome oxidase is an important electron carrier in the electron transport chain. It is a necessary component of mitochondrial respiration, and without it the mitochondria are not able to induce a proton gradient for their ATPase. Cyanide binds to cytochrome oxidase and renders it useless. Also, death from cyanide poisoning would probably not be very painful; first, it only takes about a minute to become unconscious with a reasonable dose, and second, reduced ATP would not be likely to initiate nociception in the appropriate nerves until long after a victim was unconscious (if at all). Usually the "choking and spluttering" described above does not happen while the patient is conscious. A time course might look like this: cyanide is introduced to bloodstream, cyanide enters central nervous system and renders the (high ATP consuming) neurons unable to function, unconsciousness occurs, cyanide in heart renders Ca++ uptake/sarcomere resetting impossible via reduced ATP, cardiac arrest occurs, rest of cells in body die either from cyanide exposure/ATP paucity or anoxia resultant from cardiac arrest. ^tucker/_rekcut 22:52, 2 February 2007 (UTC)Reply

thanks much for the corrections and thanks much IP dude for telling me about the corrections on my talk page =). I will ask another question about the information on the bottom in a bit because by this time many people dont read this far up. Maverick423 22:44, 5 February 2007 (UTC)Reply

body temperature

Latest comment: 18 years ago6 comments6 people in discussion

How do you raise your body temperature? —The preceding unsigned comment was added by Andiman56 (talk • contribs) 15:26, 2 February 2007 (UTC).Reply

Ahh good one well there are many ways to do this. one such way is exercising. the other is involenttary shivering in the cold. Maverick423 15:33, 2 February 2007 (UTC)Reply

Give it better fuel. Vranak

Put more layers of clothing on. Eating spicy food feels like it does too, but I don't know if it does. A hot drink and hot food. Lower your exposed surface area by huddling as tightly as you can. Skittle 17:25, 2 February 2007 (UTC)Reply

Spicy foods actually help lower body temperature. Thats one of the reasons why they are consumed in warmer climates. --Russoc4 04:18, 3 February 2007 (UTC)Reply

Indeed. You eat spicy foods, which causes you to sweat, which leads to puuuuuuure coolness! − Twas Now ( talk • contribs • e-mail ) 09:00, 3 February 2007 (UTC)Reply

Increase the speed of your metabolism, so you produce heat faster from your food:)Hidden secret 7 20:56, 3 February 2007 (UTC)Reply

Feeling Gassy

Latest comment: 18 years ago2 comments2 people in discussion

Are there foods that I can eat during the day (at work) that causes the LEAST gas?I seems that no matter what I eat, I end up feeling uncomforatable all day or until I relieve myself...

As you know, we can't give medical advice. But I think it's safe to mention that any carbonated beverages (such as soda) will free their carbon dioxide gas inside of you and it's got to go somewhere.

Atlant 16:19, 2 February 2007 (UTC)Reply

This shouldn't be a request for medical advise.If you would like for me to rephrase it, what type of foods would cause the least amount of gas produced in the stomach for humans?I am assuming that vegatables like broccoli is one of the culprits, but what other types of foods?

Peppermint tea can help settle the gastrointestinal system.Vranak

Flatulence#Causes may be of some help -- WikiCheng | Talk 10:56, 3 February 2007 (UTC)Reply

I heard ginger is good for seyyling the gutts

Muscle Cramps

Latest comment: 18 years ago1 comment1 person in discussion

I infrequently get cramps in various muscles.Most often in my calves.However, I have found that I can make myself get these cramps very easily by holding my calves or bicepts in a flexed position.My question is what do these cramps do to the muscles in which they occur?Is it like lifting weights at all, or is it somehow detrimental?Thank You. —The preceding unsigned comment was added by 66.99.100.66 (talk • contribs).

How does your leg feel afterwards – better or worse? Vranak

I don't have an answer to your question, but FYI a common cause of calf spasms is calcium deficiency. Anchoress 17:16, 2 February 2007 (UTC)Reply

CD28 gif 3d rotating structure

Latest comment: 18 years ago1 comment1 person in discussion

I really enjoyed the rotating 3d image of CD28 on your CD28 page.My question is simply that I would like to know if I could use your .gif format software (code) to portray the 3d structure of another protein molecule for which I have the .pdb file (3d coordinates)on my website?Can you please help me with how to do this if it is indeed legal?Thanks again for another terrific Wikipedia page, as always!

Don Kaiser <Rm email to reduce spam>

• If you click on the image, you will find yourself on a page that indicates who created it...ask him how he did it. I've used the free Jmol program to make 3D molecular models from PDB files. I think it can export animated gif images, but not sure. DMacks 20:48, 2 February 2007 (UTC)Reply

Plantiferitus

Latest comment: 18 years ago2 comments2 people in discussion

Plantiferitus... what is this word? It is a very painful foot condition and I can't remember it. [Mαc Δαvιs] X (How's my driving?) ❖ 18:18, 2 February 2007 (UTC)Reply

Have you tried at "foot.com" http://www.foot.com/info/info_cond.html Plantar fasciitis. ?83.100.183.48 18:30, 2 February 2007 (UTC)Reply

abnormal oozing of blood from skin,teeth etc

Latest comment: 18 years ago3 comments3 people in discussion

recently came accross a person suffering from peculiar problem of loosing blood from skin,has already supplemented 3 bottles of blood in last 2 year.Seems condition is detoriaoting day by day.Blood report are about to come in few days.Pls advice. —The preceding unsigned comment was added by 59.93.247.53 (talk • contribs).

Have them see a doctor. Considering that a blood report is being performed, it seems this if being taken care of. We can not provide medical advice. -- Consumed Crustacean (talk) 18:55, 2 February 2007 (UTC)Reply

Think this person your talking about might have Hemophilia. im not sure but u might wanna check it out and compare. Maverick423 20:30, 2 February 2007 (UTC)Reply

Are you the patient, a friend of the patient, the nurse, or what? Your IP suggests Australia. Don't they have an established health system there which could diagnose and treat the problem? Edison 03:40, 3 February 2007 (UTC)Reply

hovercrafts

Latest comment: 18 years ago11 comments4 people in discussion

Is it possible that in the next 20-30 years, we would have hovercrafts as a normal mode of transportation replacing automobiles?

I think it's unlikely since hovercrafts expend (quite a lot of) energy just to keep themselves of the ground - so I'd suggest that they are intrinsically less efficient. Plus they are not as easy to steer as cars especially in a high wind - they definately wouldn't be good on motorways - unless they had big bumpers like dodgems. Given that it seems important to increase fuel efficiency I think the answer is definately most unlikely.83.100.183.48 20:18, 2 February 2007 (UTC)Reply

i dont know about hover cars however i do know that this car has been in prototype testing for quite some time and is already being considered for mass production soon! check out the Moller Skycar Maverick423 20:36, 2 February 2007 (UTC)Reply

That's what they told us 10 years ago about that Skycar... Face it, it's not going to happen. — Kieff | Talk 21:42, 2 February 2007 (UTC)Reply

Aw kieff come on its possable sooner now then later. after all they are getting the permission from that agency that says its ok to fly them. since the car is also in production and has actually flown, the chances of it comming out soon is great. Moller said his car was going to come out by 2008 and then mass produced by 2012. people have already bought the car itself and are going to recive it soon. also in Iran they are also making a flying car that is going to be used in rescue and police related instances. http://www.cnn.com/2007/TECH/01/31/israel.flying.car.ap/index.html http://www.moller.com/purc.htm

Maverick423 21:55, 2 February 2007 (UTC)Reply

Flying cars - are you mad - I can just imagine coming home oneday and finding one sticking out of my roof.. Hopefully never83.100.183.48 22:14, 2 February 2007 (UTC)Reply

dont ya worry the flying car has full safety features including backup engines, full car parchute, GPS locater, Automatic GPS Driver. simply enter the place you want to go and sit back and read a book the car will do the rest itself! Read Mollers Website to find out more on the car itself. Crashes will be reduced massively! Maverick423 22:50, 2 February 2007 (UTC)Reply

The thing has barely hovered so far, and this project has been going on as far as I can remember. I can't see something like that becoming mainstream and affordable in the near future. — Kieff | Talk 01:34, 3 February 2007 (UTC)Reply

Ah but the smaller version of the car has already flown across the country in previous test. its smaller (1 passenger) and ligheter and has more power (10 Engines 5 main 5 back up) instead of the 8 (4 main 4 back up). it goes faster and uses less fule since it is lighter. i think the problem with the 4 passenger one is that it only has 8 engines and uses more fule its less how can i say it? well i guess cost effectiveness is less for that one. think the smaller version has already been proven to go 64 miles per gallon then the bigger version (which only hovers) at 20 miles per gallon. tell ya what ill get back to you with this one i just need to make sure k. Maverick423 20:05, 3 February 2007 (UTC)Reply

ahh sorry here it is it appears that the smaller version has this http://www.moller.com/m150.htm ( i took out the list that i placed cause it was bigger then i thought so i just linked it for ya ((should of done that to begin with))) well those are the specifications on that 1 passenger one so the engines are acctually 2X2 enginesMaverick423 20:22, 3 February 2007 (UTC)Reply

I really don't expect a project like this will ever get off the ground:@Hidden secret 7 21:00, 3 February 2007 (UTC)Reply

Acctually from what i heard the plane and the car were both being considered for use in public travel. the only problem was that planes were more expensive to buy then cars used more fule and needed a flat surface to take off. that is what made the car as the primary mode of transportaion. if these issues were assest from the begining we would be saying traveling on the ground is impossable or primitive. Maverick423 15:26, 5 February 2007 (UTC)Reply

Do Snails Have Eyelids?

Latest comment: 18 years ago1 comment1 person in discussion

I was wondering if snails have eyelids.

Thanks!

It seems not - but the eyes are on muscular stalks and can be retracted - in fact snails don't have very good eyes apparently - relying more on touch and taste - the entire body is a bit like one big tongue.

See this website http://www.applesnail.net/content/anatomy/senses.php for more info on one type of snails eyes - a bit of the way down there's an diagram/image showing just how bad their eyesight is - it's probably not worth them having eyelids anyway.83.100.183.48 20:38, 2 February 2007 (UTC)Reply

Deep Fat Frying

Latest comment: 18 years ago4 comments3 people in discussion

Does deep fat frying potato chips (including the skins) reduce the nutritional value? I don't care about the fat that's added (I only eat them on occasion) but rather the nutrients that may be leached out or otherwise rendered useless. --Seans Potato Business 20:45, 2 February 2007 (UTC)Reply

Some vitamins, Vitamin C for example (and including other water-soluble vitamins if I'm not mistaken), are sensitive to high cooking temperatures. Although this section seems to contradict what I said (but note the fact tag), so maybe my belief is in error. Anchoress 21:09, 2 February 2007 (UTC)Reply

Flash frying (don't know if we have an article) preserves many sensitive compounds due to the short time the stuff in the the pan - plus I don't think water solubilty has a lot to do with it - that would be boiling - it's all a matter of degree - it's usually air (oxygen) that degrades vit C - so a minute at 200C probably won't make much difference - though obviously prolonger frying will degrade all the nutrients.83.100.183.48 21:23, 2 February 2007 (UTC)Reply

As a rule I'd say no - with modern preparation methods the degredation is very small - the time on the shelves way have a bigger role - though if the food package is airtight/block out light this shouldn't be a problem either - In general the nutritional value is increased by frying - by virtue of the increase in calorific value due to the fat; this doesn't apply if you are supposed to be on a diet obviously..83.100.183.48 21:27, 2 February 2007 (UTC)Reply

Need help at Big Bang

Latest comment: 18 years ago9 comments2 people in discussion

There are some edits there today that I don't agree. Can we have some physicists over at Big Bang? Thanks. Xiner (talk, email) 20:52, 2 February 2007 (UTC)Reply

Christ - good luck - as the big bang is speculative (or not if you're a big bang scientist) - this entire topic is open to original research and speculation. For instance this difference http://en.wikipedia.org/w/index.php?title=Big_Bang&diff=105174931&oldid=105171230 replaces expands on something that is already purely speculative - what is one to do?83.100.183.48 21:02, 2 February 2007 (UTC)Reply

However if the edits get too much for you, you can always fall back on our good old friend ^{[citation needed]} - use {{fact}} - I'd suggest removing debateable parts to the talk page - stating your reasons for the removal and suggesting that adequate citations are provided before it's readdition.83.100.183.48 21:06, 2 February 2007 (UTC)Reply

Plus there are so many variants on this theory in terms of explanation and outcome that you've got a real minefield..83.100.183.48 21:10, 2 February 2007 (UTC)Reply

Could you say which edits were problematic?83.100.183.48 21:10, 2 February 2007 (UTC)Reply

Actually, the one you pointed out is the one I'm having most trouble living with. I don't mind speculations, but this guy is putting things down as fact, with no way to check its veracity. He's editing a lot of articles too. Xiner (talk, email) 21:20, 2 February 2007 (UTC)Reply

I'd suggest the method of removing and asking for citations - that's the way here I've learnt - even if the guy's right... Mention that the information must be verifyable - see Wikipedia:Verifiability "The threshold for inclusion in Wikipedia is verifiability, not truth" that's official policy.

It looks like they are adding fairly respectable explanations-I wouldn't expect it to be difficult to find citations for them - but I doubt that those explanations are the only subsets of the theories out there..I'm sure there are many other ones - The article might need a rewrite to cover the various possibilities and explanations thereof - with a non-contentious introduction.

I'd say the second paragraph about the 'origin from nothing' either has or should have it's own article - the info is relevant - but I'm not sure how much in the context of the article being called 'big bang' - it would be worth pointing out that the two theories are consistent in this respect - but I don't think in the main body of the article - maybe in a 'comparison with other cosmological theories' section. If the two were inconsistent that would be worth noting too.83.100.183.48 21:48, 2 February 2007 (UTC)Reply

I see. I'll see what I can do. Thanks a lot for the advice. Xiner (talk, email) 22:04, 2 February 2007 (UTC)Reply

By the way I do it like this (on the talk page):

..Removal of .... ..

I removed this text "the x is y because of z" because I'm unsure/think it's wrong/think it's exaggerated/think it's in the wrong place...

Could somebody please provide a reference for this infomation before re-adding it.

or

This is not relevant to the section it's in and should be in a new/existing section - I will/could you create such a section..

or

Shouldn't this be in a separate article - named '....' -

I wouldn't recommend just removing stuff without pasting it to the talk page - that can be annoying/seem aggressive.. (unless of course it is obviously vandalism - not the case here).

If you copy debated stuff to the talk page then they can discuss it there or they haven't got a leg to stand on - separates the reasonable from the unreasonable people. Also (from experience) if someone makes grammatical changes - don't revert - make little edits (taking into account their addition) until the article is satisfactory to all of you - that works too (though it can be very time consuming) -

I don't envy you...probably one of the worst articles to have on your watchlist, jesus, and george bush being slightly worse.83.100.183.48 22:10, 2 February 2007 (UTC)Reply

Stick bomb.

Latest comment: 18 years ago5 comments5 people in discussion

I was reading the article stick bomb and a quick google search on it didn't really tell on how to construct one. Is there a website that shows how, that perhaps I missed? --Proficient 21:34, 2 February 2007 (UTC)Reply

I agree that there should be the basic popsicle stick bomb I made as a kid. Somebody will have to whip up the 3D software and make a model! (Perhaps me, one day). --Zeizmic 22:10, 2 February 2007 (UTC)Reply

Is that article a copy-vio, or is it just really weirdly written? I can't see any of it on Google, but Google isn't the world. I've never heard of stick bombs before, so I can't really do more than remove references to an 'Author'. Anyone here able to improve it? Skittle 22:43, 2 February 2007 (UTC)Reply

Me neither, and I'm guessing that's not their running name then. The current article is an obvious self-promotion by that Tim guy, so if you guys think this stuff is notable enough for an article, rename, rewrite and get us some sources. — Kieff | Talk 01:30, 3 February 2007 (UTC)Reply

This video has instructions for the type I used to make as a kid: http://www.youtube.com/watch?v=KyzsDmkYnJY 75.138.84.159 00:58, 3 February 2007 (UTC)Reply

Point drag coefficient

Latest comment: 18 years ago2 comments2 people in discussion

Does anyone know the definition of the point drag coefficient? What I know is as follows...

${\displaystyle C_{D}=\int _{-\infty }^{+\infty }{{C_{D}}'\,d({\frac {z}{c}})}}$ 

where ${\displaystyle C_{D}}$  is the drag coefficient of the aerofoil, and c is the chord length. ${\displaystyle {C_{D}}'}$  is apparently the point drag coefficient. Can anyone tell me the definition of ${\displaystyle {C_{D}}'}$ ? I have the ${\displaystyle {C_{p}}}$  distribution over the aerofoil, which I presume is needed. Thanks! Readro 22:56, 2 February 2007 (UTC)Reply

The point drag coefficient ${\displaystyle {C_{D}}'}$  (or section drag ${\displaystyle C_{d}}$ , as I learned it) is the coefficient of drag for a 2-D cross section, with chord length replacing wetted area to nondimensionalize the drag per section span. It seems what you have is the definition, that is if you split the wing into infinitely small cross sections, each cross section will have a section drag coefficient. Integrating all of these over the wing span gives the total drag coefficient ${\displaystyle C_{D}}$ . anonymous6494 00:30, 3 February 2007 (UTC)Reply

February 3

Abs and Resting Time

Latest comment: 18 years ago4 comments4 people in discussion

How often can you work out your abs without them needing rest? I've heard that you can work out the abs nearly every day, whereas the other muscles need rest. Why the difference? Also, how much resting time is needed for abs? PitchBlack 03:45, 3 February 2007 (UTC)Reply

Do sit ups until it hurts? --Russoc4 04:17, 3 February 2007 (UTC)Reply

I didn't find any real sources, but google results did say to treat your abs like any other muscle and excercize them about 3 times a week. On a related note, 6 Week Abs has 7 myths about abs. I'm curious now too, because when I used to work out (yea, yea, I got lazy), I could lift barely more than I weigh with my upper body, but I can use ab machines at max weight and not have them hurt afterwards while my arms did. --Wirbelwindヴィルヴェルヴィント (talk) 06:19, 3 February 2007 (UTC)Reply

I have never had sore abs when I would exercise them 5-6 times a week, whereas my arms and legs needed a day to rest afterwards. − Twas Now ( talk • contribs • e-mail ) 23:50, 3 February 2007 (UTC)Reply

A plant that is also a pathogen

Latest comment: 18 years ago4 comments3 people in discussion

I recently added to the article protothecosis that Prototheca was the only known pathogen that is also a plant. I got this from the Journal of Clinical Microbiology. Is it true, or am I forgetting some other plant that causes an infectious disease? --Joelmills 04:19, 3 February 2007 (UTC)Reply

Wow, that's pretty cool. [Mαc Δαvιs] X (How's my driving?) ❖ 05:26, 3 February 2007 (UTC)Reply

Hello Joelmills, this is very nice, but when you're not sure, why not asking before updating ? Now it's only because fungus are not sorted along with plants that your first case [meaning of prototheca] is an 'only plant' candidate. -- DLL ^{.. T} 10:57, 3 February 2007 (UTC)Reply

I was sure when I added it, having the reference to back me up and a precursory google search not showing any contradiction. But then I thought that it was a pretty big claim to make, so I better ask here, where I know that there are a lot of knowledgable people. Protothecosis hasn't attracted many edits in the months it's been in existence, so I figured a few hours of waiting to doublecheck something was OK. --Joelmills 19:37, 3 February 2007 (UTC)Reply

Wireless control

Latest comment: 18 years ago1 comment1 person in discussion

HI friends,I have undertaken a project "Multi-axis wireless control for Robots".In it's details,all I have to do is to control the robot using my transmitter pad.I have planed to use 5 to 6 keypads to control different axis.Then at the receiving end,using some RF module,the data is decoded and it will be used to control the relay using a microcontroller and ULN driver.Which will then be interfaced to PLC for robotic arm movement....For this entry level,I have stuck somewhere in choosing the exact means of communication.At first someone stated to go for IR,later someone suggested RF and now few others state to pick bluetooth for industrial standard...Now I have decided to ask to you guys in this forum so that I can get a good solution for this..For IR based TX and RX,I have seen many circuits practically used,but I still can't get one for multiple device control...For Rf based TX and RX,I tried MAXIM-1472(TX) and 1473(RX)...All pin connections and other spec seems pretty nice but I'm not able to get any practical circuits for it's contruction.I also tried Cypress wireless solution.But the practical construction seems almost impossible...Should I have to only buy modules?.Isn't there any other solution?..Guys can anyone get me some more detailed view in designing using such SOCs please?..I don't know what type of data format that should be used for this chip.No proper details in Maxim Website...I tried...Please someone help me out...And about bluetooth project,I have simply no idea...I thank you all in advance for you consideration..Looking up for the suggestions........ —The preceding unsigned comment was added by 59.96.23.95 (talk • contribs).

I'm slightly confused about what you're asking. When you mean practical circuit, you mean you can't do it because the traces of the MAX1472 and 1473 are too small, or you don't have a schematic? IIRC, one of those is TSSOP and have a pin clearance of like 0.2 mm or something tiny. There are adaptors available for them, I believe, which cost around $10 a piece. But even then, they're surface mount. I'm not sure what your level is, etc, so it's hard to tell if I can even provide you an answer when you ask for a more detailed view in designing. The datasheet usually has that kind of info, and the 1472/1473 uses SPI I believe. If the problem is that you're making prototypes, you should look for DIP packages for chips to construct them easily. Somehow, I doubt I helped any, so do tell if anything applies, and if not, what info you need (design software, RF packages, comparison of RF / Bluetooth / IR, etc). --Wirbelwindヴィルヴェルヴィント (talk) 08:54, 3 February 2007 (UTC)Reply

How does window gel work?

Latest comment: 18 years ago1 comment1 person in discussion

My kids have window gel toy stickers (hearts, snow flakes, and so on) that stick to non-porous surfaces like windows, mirrors, and metal. They don't stick to fingers. From my research all I've been able to determine is that window gel toys are primarily manufactured in China and South America, mostly Brazil.

What is window gel made of? How is it made? How does it work? Does it leave a film behind? —The preceding unsigned comment was added by Dstinchf (talk • contribs).

They appear to be static cling vinyl. See also Colorforms. --Wirbelwindヴィルヴェルヴィント (talk) 17:50, 3 February 2007 (UTC)Reply

Unknown Bird

Latest comment: 18 years ago2 comments2 people in discussion

Found browsing flickr : "IF anyone know the bird's name please write clicking the comments link. " http://www.flickr.com/photos/subirbose/167852801/. Seems the guy's photos are from the Himalaya and surroundings. Thanks for your help and more : which method do you use and recommand to find the name of a [living creature] from its photo or sketch ? -- DLL ^{.. T} 10:50, 3 February 2007 (UTC)Reply

To find a species, you want to use an Identification key. There are plenty around; you'd need to find one for the class Aves (birds) to find the identity of this bird. Laïka 13:18, 3 February 2007 (UTC)Reply

Skin aging

Latest comment: 18 years ago1 comment1 person in discussion

I was trying to find some information on the process of the aging of the skin, and I guess both physical aging in general and the (human) skin are not as well covered, unfortunately, as some other biology-related topics on WP. I am particularly interested in how the dermis ages vs. the epidermis - it is my intuitive understanding that while the epidermis' aging concerns wrinkles and other skin imperfections more, it is the dermis' aging that is responsible for the sagging of the skin and the fact that our cheeks and neck don't look south youthful anymore :(

I was inspired to research Wiki for that by reading about this company's product: [4]. Even if their product actually works, it is my understanding that it affects epidermis only (even if it's "all five layers of the skin" as the company claims, I understand it is epidermis), so the product wouldn't prevent the skin from sagging anyway. OTOH, Wikipedia says stretch marks form in the dermis, and the company advertises using a "testimonial" from a customer saying her stretch marks have "faded" after using the product.

OK, what I would like to learn is how the skin actually ages and how, theoretically and practically, it can be prevented/alleviated, and what is the state of research into it - not to mention it would be nice to be able to find out the same about other tissues... I guess it is not a "question" one could answer overnight at the reference desk, I am rather counting on drawing the attention of editors who are into biology/medicine to that topic. It wouldn't hurt, though, if somebody could provide a quickie lowdown on the topic here :D

Thanks a lot to any merciful soul who would take interest in that request. PrinceGloria 11:17, 3 February 2007 (UTC)Reply

Energy saving Light bulbs?

Latest comment: 18 years ago2 comments2 people in discussion

I'd like to know just how much energy it takes to make an energy saving light bulb compared to the older glass filament type. It is widley known that the energy saving kind will use less energy to generate light of a similar intensity as a filament type and will last around ten times longer. But what about the enery of production? Hesaurus 12:37, 3 February 2007 (UTC)Reply

See Talk:Compact fluorescent lamp#Energy used to manufacture CFLs Rmhermen 01:38, 4 February 2007 (UTC)Reply

Genetic Variation in and between Populations

Latest comment: 18 years ago7 comments4 people in discussion

I have heard many times, normally when discussing race and whether it exists, sentences like (and this is a real example from the reference desk) "there is more genetic variation among Africans than there is between Europeans and Africans". What does this mean? That a randomly selected African will have more in common with a randomly selected European than another African? Because that sounds hard to believe. Or that the standard deviation in the African population is larger than the differences between an average European and African? 85.1.5.207 13:37, 3 February 2007 (UTC)Reply

It means that there is more genetic variation within an African population than within a European population, measured by things like the number of minor varieties of genes (called polymorphisms). The most economical explanation is that several African "peoples" (i.e., populations, like Bantu, Khoisan, etc) partly separated from each other far longer ago than did the various European "peoples" (like Nordic, Mediterranean, Basque, etc). It does not mean that a random African is likely to share more gene polymorphisms with a random European than with another African. alteripse 14:22, 3 February 2007 (UTC)Reply

Thanks, although the statement made seems to suggest that there is more variation within Africans, than between Africans and Europeans. Are people who make this statement misunderstanding the claim, or is this a different claim? It is normally made in the context of proving how similar humans are, so we shouldn't be racist. Maybe it should be that we shouldn't lump all blacks together as one, which we don't do to white Europeans.85.1.5.207 14:45, 3 February 2007 (UTC)Reply

Which "statement made"? A number of research studies have shown more genetic variation among the large population of people whose ancestors lived in Africa a couple of centuries ago than among those whose ancestors lived in Europe a couple of centuries ago. I do not know how to say it any more plainly. This statement itself is neither racist nor anti-racist. All of us recognize gradations of physical difference more easily among those who are most similar to the people among whom we grew up. This is the origin of the "all ___ look alike to me" kind of statement-- it reflects a nugget of truth about human perceptions and recognitions of other people, but it is an entirely relative fact, as the same assertion can be made by a member of the "other" population. Or should I have simply stopped at the first sentence? alteripse 23:34, 3 February 2007 (UTC)Reply

It means that two randomly selected Africans have less in common with each other than the average African has with the average European. − Twas Now ( talk • contribs • e-mail ) 23:43, 3 February 2007 (UTC)Reply

The above statement is true, however: there is more genetic variation among Africans than among any other group (Asians, Native Americans, Europeans, Australian Aborigines). This is, in very simle terms, because they have been there the longest. − Twas Now ( talk • contribs • e-mail ) 23:45, 3 February 2007 (UTC)Reply

Thanks to both of you. Alterprise, the statement I was referring to was the quote in my original post, but thanks for your info. The stuff I mentioned on racism was simply to try and clarify the difference between your explanantion and how I interpreted the original quote. Obviously facts cannot be racist or not, they are simply facts. Also thanks Twas Now for your answer, that would have been my guess but the statement seemed open to interpretation. (Same user - different IP!)137.138.46.155 08:05, 5 February 2007 (UTC)Reply

Sex in evolution

Latest comment: 18 years ago4 comments4 people in discussion

How can evolution explain how species evolved sexes? The primitive life forms didn't have sexes, so when did it all start? Did it have to evolve in one generation of a species? Or what? My biology teacher said that no-one really has an answer for this. Also, if natural selection or whatever found it necessary for two sexes to exist, will we be able to evolve a third or fourth sex? Please take this seriously, I'm not trying to attack evolution or anything, I'm just really interested in this. ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 14:33, 3 February 2007 (UTC)Reply

Well, no one has a definite answer to this, though there is a lot of speculation going back even before Darwin's work. You might check out our article on evolution of sex for quite a lot of discussion of it. Once you've evolved sexual reproduction of this sort, the specialization of the different sexes to different functions, appearances, etc. is, I think, a comparatively easy thing to understand. --24.147.86.187 14:45, 3 February 2007 (UTC)Reply

Sex#Animal species shows that there are several animals with more than two sexes. − Twas Now ( talk • contribs • e-mail ) 23:41, 3 February 2007 (UTC)Reply

Yeast is a "primitive life form," and it has a sexual form of reproduction, too. In fact, bacterial conjugation is kind of like sex. -- Scientizzle 01:26, 4 February 2007 (UTC)Reply

Land fill solution or not...?

Latest comment: 18 years ago4 comments2 people in discussion

After watching the movie Soylent green and reading the article on Digestion I was wondering if it would be possible (and practical) to process solid waste both mechanically and chemically in a similar fashion as digestion or using the steps in Quantitative analysis or Qualitative analysis to produce a resource for useful byproducts such as plastics or for other purposes such as eliminations of Toxins or Pathogens? 71.100.10.48 15:23, 3 February 2007 (UTC)Reply

Yes, indeed - I assume you mean household waste..

There are methods similar to digestion for treating household waste, see Waste_management#Waste_management_techniques subsection Composting and anaerobic digestion, also for sorting the waste see subsection Mechanical biological treatment - just as food is broken down in the gut by enzymes (an sometimes bacteria) - in the treatment of biodegestible household waste bacteria and enzymes break down some waste producing 'soup' that may be suitable for fertilizer, and possibly gas (methane). Any organic matter might be suitable for this - includes waste food obviously, but also wood, paper, some plastics, non synthetic clothes - it all depends on how good the bacteria are..

As for a similar process to the steps in Quantitative analysis or Qualitative analysis - I assume you mean as in chemical analysis, and again the answer is a resounding yes.

See subsection Pyrolysis & gasification in Waste_management#Waste_management_techniques - in this case waste is heated to a very high temp (eg much greater than 200 degrees C - maybe much greater than 1000C depending on method), but air (oxygen) is excluded so it doesn't burn - this causes all organic matter including synthetic plastics to break down (see also cracking (chemistry)) - the process typically yields a great mixture of products - that can be separated by distillation. It's comparable to the process where chemicals used to be obtained by heating coal (eg Karrick process or similar).

We have excellent articles on this see pyrolisis and gasification - both are great routes to synthetic 'diesel' and other petroleum replacement products - it's a form of recylcing of organic matter.87.102.9.55 16:20, 3 February 2007 (UTC)Reply

If you want to read more I can suggest

Gasification#Gasification_process_examples and all the article pyrolysis - similar to chemical analytic methods.

For methods similar to digestion see Anaerobic digestion

If you look at the page on waste_management you may find other useful links.87.102.9.55 16:26, 3 February 2007 (UTC)Reply

As for getting rid of toxins and pathogens - there is some infomation in the articles - the answer seems to be yes in some cases - specifically biological toxins.87.102.9.55 16:31, 3 February 2007 (UTC)Reply

This is not a joke and is not me trying to be sarcastic

Latest comment: 18 years ago9 comments7 people in discussion

This is not a joke so please answer seriously. Is it possible to kill someone by throwing (using their arms) an almond or a soybean at high enough velocity or by hitting a vulnerable part of the head. If you have heard any anecdotes of this please respond. Thanks. Again, this is not a joke, as ridiculous as it may sound. 63.135.8.94 15:42, 3 February 2007 (UTC)Reply

No. A human arm can't give those objects enough kinetic energy to do any lethal damage on their own. But, I guess the person could choke and die of asphyxiation if it happened to go down their throats... — Kieff | Talk 15:46, 3 February 2007 (UTC)Reply

Even if the KE of the almond cannot exceed whatever amount of joules, is it not entirely impossible that it may hit a certain area of the head, such as a vein or artery or a nerve and cause death or serious injury? Thanks again for your previous reply63.135.8.94 15:54, 3 February 2007 (UTC)Reply

Sure it is possible, but then any small, light object could also be considered lethal in these conditions. — Kieff | Talk 16:15, 3 February 2007 (UTC)Reply

Even with the assistance of a sling or slingshot, you need a projectile of at least 50 grammes to do any damage - many times heavier than an almond or soybean. The part of the body most vulnerable to injury by a small hand-thrown projectile is probably the eye. But I really don't see how it could be lethal (apart from the choking danger that Kieff mentioned). Gandalf61 16:29, 3 February 2007 (UTC)Reply

There are no parts of the head and neck that vulnerable to a small hand-thrown projectile in a healthy person If you want to make the person unusual, or if you want to add some more conditions, you can concoct all kinds of semi-plausible scenarios. The person has heart disease, gets angry, and dies of a heart attack. The person is standing on the edge of a crowded train platform as the train is approaching, and the thrown object startles him and causes him to fall in front of the train. The person is so depressed that this one additional unexpected expression of contempt and anger from a previous friend causes him to decide life is too painful. And so forth... alteripse 16:35, 3 February 2007 (UTC)Reply

It would be very, very difficult to kill (or even injure) someone with an almond or soybean. (Apart from Alteripse's "cooked" solutions, that is.) Theoretically, you can give even a lightweight projectile a lethal amount of momentum by shooting it fast enough. In practice, however, there are two crippling difficulties: (1) neither an almond nor a soybean is particularly aerodynamic -- they'd lose velocity rapidly between your gun and the target; and (2) neither an almond nor a soybean is particularly rigid, so it would be nearly impossible to accelerate them up to the stupefyingly high necessary velocity without disintegrating them. —Steve Summit (talk) 18:35, 3 February 2007 (UTC)Reply

If you think we don't take silly things seriously, check out Wikipedia:Reference desk/Archives/Science/2007 January 26 & 27#My other planet is made of meat. In high school, a guy I knew had a pencil thrown at him that lodged into his temple, and just stuck there. He was OK, and I think he didn't even notice until someone pointed it out. − Twas Now ( talk • contribs • e-mail ) 23:39, 3 February 2007 (UTC)Reply

I saw someone's eyeglasses broken by a thrown pingpong ball. An almond should have an easier time breaking the glass lens, and the broken glass could penetrate the eyeball leading to lethal infections. (Sure it's funny, until someone looses an eye) Edison 00:02, 4 February 2007 (UTC)Reply

Total Cholesteral Reduction

Latest comment: 18 years ago3 comments3 people in discussion

I am a 61 year old male. My TC was measured twice at a six month interval. It was 234 each time. The doctor reccommended exercise and diet to reduce the TC. I've engaged in 20 minutes per day of aerobic exercize and reduced my intake of cholesterol to less than 100 mg/day. I've also increased my intake of soluable fiber to more than 4 gm/day. I've followed a diet aimed at weight reduction and have lost 14 lbs in the last 33 days putting me at 192 lbs. What level of reduction in TC can I reasonably expect to achieve following this regimen? From a minimum to maximum?Brucearugg 17:56, 3 February 2007 (UTC)Reply

Because your cholesterol levels are going to be based on the interplay of a number of factors – environmental ones related to the changes you've made in your behaviour as well as luck-of-the-draw genetics – and because you've made so many (healthy!) changes to your lifestyle, any answer we give you here would be no better than a wild guess.

Moreover, total blood cholesterol is only one indicator of health. More important are the levels (absolute and relative) of HDL (so-called "good cholesterol") versus LDL ("bad cholesterol").

In any case, you're best off just asking your doctor or cardiologist what changes or benefits are likely to accrue from the specific changes you've made to your own, unique lifestyle. TenOfAllTrades(talk) 18:22, 3 February 2007 (UTC)Reply

I don't know the answer to your question, but let me just say: kudos on the positive changes you've made! Keep with it! —Steve Summit (talk) 18:29, 3 February 2007 (UTC)Reply

Do rats have spleens?

Latest comment: 18 years ago7 comments6 people in discussion

?

Don't you ? We're all mammals, ain't us ? -- DLL ^{.. T} 18:52, 3 February 2007 (UTC)Reply

I read that rats don't have bladders, so there might be other differences too. --84.69.30.24 19:26, 3 February 2007 (UTC)Reply

Rats have bladders. Chickenflicker---♣ 19:28, 3 February 2007 (UTC)Reply

There's a diagram and a discussion of rat dissection here: [5]. Rats do indeed have bladders, as well: [6]. TenOfAllTrades(talk) 19:31, 3 February 2007 (UTC)Reply

Sorry. I've clearly been misinformed. It was an article in the newspaper about ratcatching where it was stated by a ratcatching expert that rats do not have bladders and hence constantly dribble piss behind them wherever they go to mark a trail for other rats to follow. --84.69.30.24 19:36, 3 February 2007 (UTC)Reply

Rats don't have gallbladders. Maybe that is the source of confusion. --Joelmills 19:39, 3 February 2007 (UTC)Reply

....and ratcatchers have a wicked sense of humour. (At least, they're usually portrayed that way.)--Shantavira 09:12, 4 February 2007 (UTC)Reply

Question about pets and domestication

Latest comment: 18 years ago2 comments2 people in discussion

What's the difference between a tame pet and a domesticated pet? This comes up a lot on the birdkeeper forums and people actually have big arguments about it. Why would a cat be considered a 'domestic' pet while a cockatoo (for example) would be referred to by avian science people as a 'tame' pet? Is a budgie 'tame' or 'domesticated'? --84.69.30.24 19:25, 3 February 2007 (UTC)Reply

If you take a look at the article on domestication, it says that budgies are considered domesticated. "These species or varieties are bred and raised under human control for many generations and are substantially altered as a group in appearance or behaviour." As for cockatoos, the same article would probably put them in the category of "raised commercially" or "semidomesticated" rather than fully domesticated. Chickenflicker---♣ 19:47, 3 February 2007 (UTC)Reply

How should you heat up an embryo?

Latest comment: 18 years ago3 comments3 people in discussion

I have a curiosity about how can embryos be defrosted from the fridge prior to being implanted to avoid that the water present expands thus damaging it. Can you heat it rapidly without burning the specimen?20:09, 3 February 2007 (UTC)

I'd just let it warm up slowly, or in luke warm water - I think your question/my question should be "how can an embryo be frozen without causing frost damage from the ice crystals that will inevitably form" - the same goes for sperm.213.249.232.136 20:12, 3 February 2007 (UTC)Reply

Our article on cryopreservation gives a good overview of the challenges associated with freezing (and thawing) viable tissue and cells. Cryoprotectants are chemicals which are added to cells at the time they are frozen; these chemicals typically discourage the formation of ice crystals which would otherwise puncture and kill cells.

Thawing most frozen tissue or cells is actually a very straightforward process. There are two key goals in thawing. First, one wants to warm the tissue fairly rapidly through the temperature range where ice crystals are most likely to form; this runs from roughly -50°C to -15°C, give or take. Second, you want to wash off or dilute out the cryoprotectant. (Prolonged exposure to cryoprotectants will kill a warm cell.)

Accomplishing these goals is generally straightforward. Frozen specimens are normally in glass or plastic tubes or vials. They can be warmed rapidly by immersion in a body-temperature (37°C) water bath; this thawed solution can then be diluted to reduce the concentration of cryoprotected to below toxic levels. For thawing small volumes, rapid warming and dilution can be accomplished by directly adding warm liquid to the frozen-solid sample. TenOfAllTrades(talk) 21:27, 3 February 2007 (UTC)Reply

DMSO is commonly used for cryopreservation of cell lines...but I'm not sure if it's used for embryos... -- Scientizzle 07:28, 4 February 2007 (UTC)Reply

Scarlet Fever

Latest comment: 18 years ago1 comment1 person in discussion

I am doing a report in science on an infectious diseases caused by bacteria. I picked scarlet fever. Please tell me all that you can!!!!!!!!!22:44, 3 February 2007 (UTC)

Have a look at scarlet fever and Streptococcus pyogenes, the latter being the species of bacteria that causes the disease. --David Iberri (talk) 22:46, 3 February 2007 (UTC)Reply

Is FM radio lossless? If not, what bitrate is it at?

Latest comment: 18 years ago5 comments4 people in discussion

Hello, my question is concerning the audio quality of FM radio. Does the transmission of the sound through the air bring the quality down? Do radio stations load up lossy files on their playlists, like 128 kb/s mp3 files? Basically, what bitrate would be comparable to the quality of FM radio on the receiving end/through my stereo? Thanks! NIRVANA2764 23:11, 3 February 2007 (UTC)Reply

Its complicated to say, as it will depend upon the audio codec imployed, in the UK DAB broadcasts at 160 kb/s IIRC, via a form of MP2 encoding, with the speech only networks at a lower 128 kb/s and Radio 3 (classical music) at 192 kb/s. It is suggested that 192 kpbs is needed to give high quality audio broadcasts.

For more info checkout the Digital Audio Broadcasting page, more specificaly this section.

There are other issues of course - often audio will sound different between a CD, radio and television broadcast, and if you are used to a particular version of a song then even though the other is at a higher rate of transmission it may still sound worse! --Neo 23:31, 3 February 2007 (UTC)Reply

Er... Traditional FM radio uses a purely analog modulation method (ignoring some of the sub band extensions). You can't talk about it in terms of "bit rate" (as you could with digital modulation schemes like PSK and OFDM). Your usage of "lossless" seems to be in the sense of digital audio compression methods, which is simply irrelevant here. The article on frequency modulation proper provides some insights on maximum bandwidth, drift, SNR, etc. -- mattb @ 2007-02-04T03:30Z

FM Radio has a Signal to Noise ratio and is not digital. 1 bit corresponds to roughly 6 db (6 db is double signal level, 1 bit in base 2 is double). Original CD quality is 16 bits which corresponds to about 96db of S/N. Bit rate corresponds to the frequency range. IIRC, CD's are about 24KHz of range which for Nyquist is 48 KHz. So a CD plays 16 bits at 48 KHz => 768 kb/s. You can trade frequency or S/N to reduce this number and compression does it smarter than just the baseline cut.

FM as implemented has a frequency range to 15 kHz (30 KHz Nyquist) and I believe the noise floor give about 60dB of dynamic range (~10 bits). Note that this is best case in FM and in practice is worse than this. That's 30*10 or 300 Kbps for Nyquist sampling to Digitally recreate the best possible fidelity of FM analog. --Tbeatty 07:02, 4 February 2007 (UTC)Reply

A fair point - but FM is analogue - therefor the resolution (eg CD resolution is 16bit) could be considered infinite..(not quite true)

Resolution, whether it's digital or analog, is expressed as signal-to-noise ratio. Quantization error (the error between "infinite" analog and discrete digital) can be expressed as noise. In fact, moving the quantization error out of the baseband frequency is how 1-bit, oversampling works. It is entirely accurate to compare digital resolutions with S/N and analog with S/N. There is no additional resolution because of the continuous nature of the analog signal. That portion of continuity that distinguishes iteself from the digital portion is unrealizable signal that is lost in the noise. Analog FM is not infinite resolution because there is a finite noise floor that limits it. Currently that noise floor is 60 dB and that is an equivalent noise floor to 10 bits. You have to think in the frequency ___domain (for both anaolog and digital) to understand the mathematics that proves this. Fourier Transforms and the Discrete Fourier Transform/Fast Fourier Transform is the mathematics required for the analogue and digital respectively. --Tbeatty 19:22, 4 February 2007 (UTC)Reply

FM quality depends critically on reception conditions as it is an analogue signal - in general a good signal strength of FM radio would produce audio quality comparable to analogue records or cd's - but not quite as good - better than cassette tape though.

The weaker the signal the poorer the sound so yes - transmission affects quality.

I'd guess that FM radio stations don't usually transmit MP3 files - most likely they use CD's or another digital source such as DAT. However audio level compression is common on FM - resulting in a percieved loss of quality.

I wondered if you were thinking about DAB - digital radio - apparently a FM gives a comparable quality of sound as 192kbit/s digital radio as a best case - in reality it's probably a lot less.87.102.7.169 10:23, 4 February 2007 (UTC)Reply

Cold fusion? real?

Latest comment: 18 years ago8 comments6 people in discussion

How come wikipedia's article on Cold Fusion is written from the POV that Cold Fusion is real? Isn't it odd for an article to be writtin from such an obscure perspective?--71.249.19.4 23:43, 3 February 2007 (UTC)Reply

Could you quote an example of this alleged bias? I looked it over just now and it seems fine, but of course I could have missed something. Anyway, the reference desk is not for questions about Wikipedia. Next time bring it up on the talk page. —Keenan Pepper 00:39, 4 February 2007 (UTC)Reply

Actually, the Reference Desk can be for questions about Wikipedia. One of the Reference Desk's primary purposes is to help the project, and one way it does this is by assisting editors in their research. (There's a fine example just below.) —Steve Summit (talk) 01:05, 4 February 2007 (UTC)Reply

IMO, it does seem to be a bit biased towards cold fusion, but nothing blatant enough for a non-expert to object to. It would take someone really knowledgeable in the field to do that. Clarityfiend 03:16, 4 February 2007 (UTC)Reply

The original cold fusion claims reportedly lacked the emission of neutrons sufficient for the energy claimed. As I recall, the energy production was chalked up to normal electrochemical processes and inadequate process control. Reading this article, I get more of an impression of there being fusion than the earlier analyses implied. I believe there have ben recent reputable claims of cold fusion, but in processes which could never be energy sources, but still useful as neutron sources. Any nuclear engineers out there? Edison 05:14, 4 February 2007 (UTC)Reply

I too agree that there is no noticable bias - to a non expert - and in terms of the info. in the article. It is possible that information/papers against cold fusion occuring are underepresented and evidence for is over represented... But in terms of the writing style I can see no bias.

87.102.35.119 12:57, 4 February 2007 (UTC)Reply

The perceived "bias" may be that the article does not come out and say "Cold fusion is wrong! R O N G wrong! Fleischmann and Pons were charlatans and frauds! It was all a hoax!" But of course, that would be just as badly POV, in the other direction. —Steve Summit (talk) 13:40, 4 February 2007 (UTC)Reply

Now, now. Cool down; don't go nuclear on us. Clarityfiend 17:19, 4 February 2007 (UTC)Reply

February 4

Water as a yellow solid?

Latest comment: 18 years ago6 comments6 people in discussion

I left the lid on a pot of boiling water and came back thirty or so minutes later. Aside from my being an idiot, here's what I found: the lid had a thin layer of yellow power over in, and little balls of yellow powdery substance had formed in the pot. There was an intense smell, and the pot was hot enough to vaporize the hot water I poured on it on contact. Should I contact poison control? Is the pot safe to use again? And most importantly, what the heck just happened? --162.83.149.125 18:46, 4 February 2007 (UTC)Reply

What's the material the pot is made of, and what do you usually use the pot for? — Kieff | Talk 20:29, 4 February 2007 (UTC)Reply

It sounds like sulfur, but sulfur isn't water soluble. On the other hand, if it's water from the tap, there maybe lots of sulfur within the water (because it comes from the ground). Boiling water is one of extracting elements and compound within it.

I would call poison control, just to be on the safe side.--Honeymane_{Heghlu meH QaQ jajvam} 20:40, 4 February 2007 (UTC)Reply

Same here call poison control to check it out If it is toxic and was tap water then you need to bring it to the attention to the city you live in . but before you do that check your pipes (if you are using metal pipes then its probably rust) Maverick423 23:26, 4 February 2007 (UTC)Reply

You didn't happen to take a picture of the pot and these yellow balls, did you? —Steve Summit (talk) 23:41, 4 February 2007 (UTC)Reply

It sounds like gunge to me (it don't think the wikipedia article does the word justice) - it could be vaporised organic matter from the bottom of the sauce pan that condensed on the lid. The yellow stuff is not water! GB 23:57, 4 February 2007 (UTC)Reply

Dopamine reuptake inhibitor| Antidepressants | NEED REFERENCES

Latest comment: 18 years ago12 comments3 people in discussion

Q1. I am looking for references to back up this paragraph:

In general, the abuse potential of DAR inhibitors depends on how they affect the pattern of dopamine release and reuptake. Compounds that inhibit reuptake and also induce release of dopamine, such as methamphetamine or phenmetrazine, or compounds that inhibit reuptake but have no effect on release, such as cocaine or methylphenidate, tend to be addictive drugs with potential for abuse in humans. ^{[citation needed]} On the other hand, compounds that inhibit reuptake but also inhibit release of dopamine, such as Wellbutrin and vanoxerine, have mild stimulant effects and little abuse potential, and can be used to treat stimulant addiction. ^{[citation needed]}

I would appreciate the references provided. Thank you. --Parker007 07:10, 29 January 2007 (UTC)Reply

http://www.drugabuse.gov/NIDA_Notes/NNVol12N3/Compounds.html mentions the addictive properties, in relation to preventative treatments; http://www.medscape.com/viewarticle/418525 mentions addiction's reuptake patterns in general, and then in relation to methadone and some othe B-drug that I forgot the name of. All provided by this Goog search. V-Man737 07:10, 30 January 2007 (UTC)Reply

Please explain how the above references are actually related to: "On the other hand, compounds that inhibit reuptake but also inhibit release of dopamine, such as bupropion have mild stimulant effects and little abuse potential." I would much appreciate a reply. Thanks. --Parker007 07:30, 30 January 2007 (UTC)Reply

Oh - now I see the first article doesn't mention Bupropion specifically... hrmph. Perhaps the sentence in the article should be changed to match the source, rather than whoring up a source to fit an exact claim? I'm sorry for the scanty help, it's past my bedtime... V-Man737 07:44, 30 January 2007 (UTC)Reply

• On the other hand, compounds that inhibit reuptake but also inhibit release of dopamine, such as Wellbutrin and vanoxerine, have mild stimulant effects and little abuse potential, and can be used to treat stimulant addiction. ^{[citation needed]}
• I believe the above statement, I just want a reference. Please? --Parker007 00:05, 4 February 2007 (UTC)Reply

Please say which part of the statement you want a reference for.87.102.7.169 10:57, 4 February 2007 (UTC)Reply

Its "but also inhibit release of dopamine" --Parker007 02:05, 5 February 2007 (UTC)Reply

Searching for 'zyban' another name for bupropion - gives many references saying that it can be used to treat nicotine addition.

Searching for 'vanoxerine addiction' turns up numerous references saying that it may be useful for cocaine addiction eg http://dmd.aspetjournals.org/cgi/content/full/29/9/1216 (note this says it is a dopamine reuptake inhibitor..I haven't done a full search for the best example.

Is this what you wanted references for or did you want a reference that says specifically that they inhibit dopamine release? If so see below.87.102.7.169 10:47, 4 February 2007 (UTC)Reply

((Also the statement 'have little abuse potential' could be construed as weasel words when the articles on Bupropion clearly state that they have been abused by some patients.. Why not just re-write to match the facts.))87.102.7.169 11:10, 4 February 2007 (UTC)Reply

From what I can find it seems that Vanoxerine inhibits other drug induced dopamine release - eg it inhibits the action of dopamine release by another drug - so that's subtly different. here http://www.mdma.net/dopamine/vanoxerine.html a 60% reduction in the dopamine release under the conditions described if I've read correctly.

Here's a reference that states that bupropion decreases spontaneous dopamine release http://www.cocaine.org/dopamine/efflux.html 87.102.7.169 11:22, 4 February 2007 (UTC)Reply

Thank you very much friend; (I am looking for reference that states Wellbutrin/bupropion inihibits the release of dopamine; as there is already a reference in the article bupropion regarding it inhibits reuptake of dopamine.) from the last reference I got this:

“

Release of dopamine via the human transporter by Eshleman AJ, Henningsen RA, Neve KA, Janowsky A., Research Service, Veterans Affairs Medical Center, Portland, Oregon. Mol Pharmacol 1994 Feb;45(2):312-68 ABSTRACT A human dopamine transporter cDNA was cloned and transfected into COS-7 cells, a cell line that lacks vesicular storage and release mechanisms. Cells expressing the dopamine transporter acquired the capacity to take up and release dopamine via the transporter. Ionic conditions that stimulate inside-out transport in vivo, such as depolarizing concentrations of K+ or low concentrations of extracellular Na+, were found to stimulate Ca(2+)-independent release of [3H]dopamine from transfected COS-7 cells. Dopamine re-uptake inhibitors had one of three effects on transporter-mediated efflux. Some drugs, in addition to inhibiting re-uptake, inhibited spontaneous release of dopamine. Drugs in this class included mazindol, GBR-12935, bupropion, nomifensine, and benztropine. All of the drugs with the potential for abuse by humans either enhanced release (methamphetamine, amphetamine, and ethanol) or had no effect on release (phencyclidine, cocaine, and WIN 35,428). The ability to define classes of uptake blockers based on their effects on human transporter-mediated dopamine efflux may lead to the identification of structural features of the transporter that differentiate abused from nonabused drugs.

”

--Parker007 02:16, 5 February 2007 (UTC)Reply

Wikipedia:Reliable_sources --Parker007 11:58, 5 February 2007 (UTC)Reply

On the subject of cockatoos...

Latest comment: 18 years ago3 comments3 people in discussion

I've never owned a cockatoo myself but having spoken to cockatoo owners in real life and online, I have been told that peculiarly amongst pet birds, tame cockatoos (particularly Umbrella Cockatoos and Moluccan Cockatoos) actively enjoy being picked up and cuddled and will continuously pester their owners to be held like babies (screeching and screeching until they get their own way - and they can be *loud*). Now, as someone with experience keeping parrots, I know that the birds generally *hate* being picked up, especially if their wings are restrained. Anyone know what the deal is with cockatoos? More than one owner has reported to me that these birds behave like this 'out of the box', with little in the way of training required, like it comes completely naturally to them to enjoy being held by a potential predator. I find it a bit odd. --Kurt Shaped Box 00:24, 4 February 2007 (UTC)Reply

Not a cockatoo, but our sun conure loves being cuddled, climbing inside clothing, and the like.

Atlant 13:39, 4 February 2007 (UTC)Reply

I can't answer the "why", but my sister Suzy had a cockatoo (looked exactly like our picture), and I can confirm all of the above. Coral would spend as much time on my sister's shoulder as possible, even in the shower, lifting first one wing and then the other as my sister turned so that the bird could wash under both. Coral was also deeply sexist, vastly preferring the company of women, and hissing whenever I or Suzy's husband or any other man got near.

The arrival of first Suzy's husband, then their dog, then their first child -- all put deeper and deeper strains on Coral's emotions. It got so bad that on the day when I was at their house babysitting the first child while Suzy was at the hospital delivering her second, Coral walked into the room and started nuzzling up against my leg; that's how desperate the bird was for affection in what she seemed to see as her abandonment by Suzy. Eventually she had to give Coral away, to a bird farm where Coral found another cockatoo to fall in love with instead of a human, and was much happier after that.

I'll have to ask Suzy if she can give any insight into why cockatoos are like this. —Steve Summit (talk) 14:33, 4 February 2007 (UTC)Reply

Speed of Light

Latest comment: 18 years ago3 comments3 people in discussion

What is the speed of light, and how can we tell? It goes too fast to just use a speed gun on. 71.219.43.14 01:32, 4 February 2007 (UTC)Reply

THe speed of light is approximately 300 000 km/s or 186 000 miles/s. Have a look at the speed of light article for more information. The article also gives a description of how these numbers were reached. The method used is to reflect a beam of light off an object and time how long it takes. This site also gives a quick explanation. - Akamad 01:44, 4 February 2007 (UTC)Reply

The speed of light is different in different media. What is often colloquially referred to as "the speed of light" is actually the speed of light in a perfect vacuum. -- mattb @ 2007-02-04T03:21Z

Quite right, but the speed of light in air is practically the same. It's slower than speed of light in vacuum by only about 100 km/s or 60 miles/s, wihch is less than the roundoff error in the approximate numbers quoted above.

Not incidentally that a "speed gun", mentioned by the original poster, is a device that's only possible because we know what the speed of light is. (Well, it uses radio waves, but the speed is the same.) --Anonymous, February 4, 05:02 (UTC).

And that brings up another way to measure speed. Permittivity can be measured from capacitance and the relationship to the speed of light is known, therefore, two paths (one free space, the other through a dielectric) could be set up and the difference in arrival times measured. This will reduce measurement error as it is common to both measurements. Just a guess. --Tbeatty 08:30, 4 February 2007 (UTC)Reply

The sun

Latest comment: 18 years ago2 comments2 people in discussion

How old is the sun? Nucleocosmochronology has a different answer than sun. Also how does Nucleocosmochronology tell the age? The article is vague. 71.219.43.14 02:01, 4 February 2007 (UTC)Reply

Huh? Both articles say the Sun is 4.57 billion years old, give or take. Clarityfiend 05:13, 4 February 2007 (UTC)Reply

Phylogenetic tree

Latest comment: 18 years ago4 comments4 people in discussion

Hi! Would anyone know where i could find a phylogenetic tree of life, containing all groups, made in a nice and clear way, and up-to-date? It's to print and use as a poster. It can be in a book, article, website,... The best would be if it could have little drawings for species examples, derived characteristics, and maybe other features like that. Thanks!! —The preceding unsigned comment was added by 84.55.198.228 (talk) 02:39, 4 February 2007 (UTC).Reply

Try the tree of life project. --JWSchmidt 23:31, 4 February 2007 (UTC)Reply

Look at Phylogenetic_tree, but the images here are more useful as a page in a book rather than having the amount of detail presented on a poster. GB 23:50, 4 February 2007 (UTC)Reply

Given issues with copyright from other sources it might be a good idea to construct your own..87.102.8.103 12:40, 5 February 2007 (UTC)Reply

Methadone and Anestesia?

Latest comment: 18 years ago2 comments2 people in discussion

Is it safe to be a methadone patient (receiving methadone on a daily basis) and undergo surgery with a general anesthesia such as Propofol? I'm not asking for any kind of advice, diagnosis, nor would I have surgery while being on any kind of drug without first discussing it with my Doctor. I just would like to know if there are any problems or interactions with general anesthesia that is most commonly used and methadone. I'm sure there are tons of medications used, but there must be one that is commonly used such as Halothane or Propofol. Thanks

Sniggity 05:54, 4 February 2007 (UTC)Reply

I think you are asking a question that could pretty much only be answered by a qualified anesthetist, I don't know if there are any that read this board. I'm sure methadone patients have undergone surgery but as to how safe or which anesthetic is used, I have no idea. Vespine 10:58, 4 February 2007 (UTC)Reply

Fin Dimensions

Latest comment: 18 years ago3 comments3 people in discussion

Greetings... For a rated average power of 3 KW and frequency range of DC to 3.0 GHZ, what fin dimensions would I require in my heat sink??? As the coolant I would use Silicone oil, capacity of 1 Gallon Load resistor would be of 10-12 inches and Diameter would be 12-15 mm. All this is for building a RF Load as a part of engineering curriculum. —The preceding unsigned comment was added by 203.187.198.42 (talk) 06:45, 4 February 2007 (UTC).Reply

Sounds like homework. But for starters, don't you need to know the temperature requirement of the load resistor or temp limit of the oil or other components? --Tbeatty 07:08, 4 February 2007 (UTC)Reply

We absolutely need to know the max allowable temperature of the oil and the resistor, and also the ambient temperature (how hot of a room will it be in) and whether there is air circulating or not. Also, do you want it to be able to run continuously, 24/7, or will it have , say, a 50 % duty cycle, or be rated for 10 minutes of operation. As a refinement, will it be in the sun or in the shade, and if in the sun, what color will it be. As a thought experiment, I compare it to a distribution transformer with say a 4% loss at full load. Your 3 KW heat dissipation would then require about the same radiator as a 60 kilowatt transformer, which is HUGE compared to a 1 gallon paint can. Another comparison: [7] says an electric range burner uses about 800 watts, fso your device would need enough radiationg surface to siddissipate the heat of almost 4 range burners. 3000 amps is 12.5 amps at 240 volts, so you have a very large amount of heat to dissipate. I would go with a cooling fan. Your device wilkl heat up like two 4 slice toasters per the site listed. To avoid overheating you will need a large area of copper or aluminum fins connected to the can in such a way heat is efficiently transferred (soldered? Or tight fit with the special grease they use on top of PC chips to connet them to the heatsink.? (Someone who took a course in thermal engineering, should the radiator fins be painted black? And there will still be a tendency for the oil to overheat and expand, if you only have convection inside the can, so the top of the resistor might get excessively hot. Could you install a thermometer or thermocouple or an oil temp thermometer? Edison 23:23, 4 February 2007 (UTC)Reply

Firstly, I must apologize. I will operating at 600 Watts average and not 3KW which I errenously mentioned. Secondly, Thanks for responding. The max. allowable temp. of the oil is 250 degree Celsius and the resistor of about 200 degree celsius. NO, it wouldn't run 24/7 and ambient temp. would be 30-40 degrees depending on the climate.

Names for bioluminescence in the ocean

Latest comment: 18 years ago2 comments2 people in discussion

Are there any common (non scientific) names for bioluminescence in the ocean? (Note that Milky Sea is thought to be caused by bacteria, not by bioluminescencing plankton.) Thanks for your help. S.dedalus 06:47, 4 February 2007 (UTC)Reply

There is in Norwegian, Danish, German, and possibly also Turkish. My Norwegian-to-English dictionary has no entry for the word. Google translate translates Meeresleuchten (German) to "Sea lights", but that is simply a literal translation, I have no idea whether it's actually used. According to the German wikipedia, these "sea lights" play a key role in this children's novel, so if anyone's got a copy, they might check how it has been translated. --NorwegianBlue ^talk 15:42, 4 February 2007 (UTC)Reply

Wormholes in 3d space

Latest comment: 18 years ago3 comments3 people in discussion

Wormholes are commonly represented in images explaining them as 2d holes or tunnels, however, because space is 3d, and not 2d, I am having difficulty visualizing. How are things like wormholes represented in 3d, rather then the 2d represention. (like the warping of space time due to a massive object like the sun is shown as a ball on a plane).--Honeymane_{Heghlu meH QaQ jajvam} 08:15, 4 February 2007 (UTC)Reply

Notice how it takes 3-D to "visualize" the bending of 2-D space. So it will take at least 4-D to visualize the bending of 3-D space. Can you visualize in 4-D? --Spoon! 10:45, 4 February 2007 (UTC)Reply

We see in 4D all the time (no pun intended), its just 3D in relation to time (relative movement)...

The reason that it is difficult to visualise could be that a worm hole is impossible in 'conventional' 3D euclidean space - (I'd imagine that you visualise things in 3D euclidean space - I do anyway). I could say it's difficult to imagine because they don't exist...87.102.35.119 13:18, 4 February 2007 (UTC)Reply

developement of SPRING stl?

Latest comment: 18 years ago2 comments2 people in discussion

<email removed> —The preceding unsigned comment was added by 12.72.54.244 (talk) 12:52, 4 February 2007 (UTC).Reply

Please try to write a coherent question.. Did you mean 'can I have more info on the development of spring steel? (if so you may wish to look at the crucible steel and puddling process Please clarify?87.102.35.119 12:59, 4 February 2007 (UTC)Reply

ARUUN SINGH

Latest comment: 18 years ago3 comments3 people in discussion

what are the benefits of swallowing human semen? —The preceding unsigned comment was added by 221.134.58.58 (talk) 14:16, 4 February 2007 (UTC).Reply

The Master has already addressed one aspect of this question; see here. —Steve Summit (talk) 14:50, 4 February 2007 (UTC)Reply

Less messy than any other method of oral evacuation? Rockpocket 07:48, 5 February 2007 (UTC)Reply

And of course the possibility of gratitude if the donor is of the mind that any other method is some kind of insult.

Bird identification and image request

Latest comment: 18 years ago5 comments4 people in discussion

 

Hi, does anyone recognize this bird? Could a better image that's more suitable for printing be made? (It wouldn't have to be the same species, but I wonder if finding a bird with all the features would be easy.) Thank you. :) --Kjoonlee 14:57, 4 February 2007 (UTC)Reply

Is it the dreaded caption bird, who skewers would-be predators with sharp words, like a verbal porcupine? Clarityfiend 19:07, 4 February 2007 (UTC)Reply

I too would like to point out it's the green diagram bird (birdus diagrammaticus) - seriously it looks a lot like a finch, or tit - a passerine. I doubt it would be difficult to find and alternative - as long as the species has wing bars your in luck.87.102.8.103 11:17, 5 February 2007 (UTC)Reply

Yes, it's almost certainly a composite made up for the purpose of labelling. See insect for a really weird composite insect!--Shantavira 19:43, 4 February 2007 (UTC)Reply

Heh. :) The original uploader has responded to my inquiry.

Hi, this image was meant to describe the most important characteristics to the anatomy of a common (passerine) bird, and not to represent an actual species. However, this fantasy bird was loosely based on the anatomy of the chaffinch (although the colors do not match). I do not have a higher resolution version of this image, nor do I have an unlabeled version. Sorry. :-(

So I guess that's enough info to get someone to come up with a better image.. :) --Kjoonlee 15:06, 5 February 2007 (UTC)Reply

history of nitroglycerine as a medicine for heart pain

Latest comment: 18 years ago7 comments6 people in discussion

Hello- I am writing a historical novel set in the 1880's. One of my characters has heart pain (angina), and takes nitroglycerine for it. Is this appropriate for the times? I know that it had been discovered, and was being used as an explosive, but when did it start being used as a medicine? Thank you for your help.

Sincerely,  Irene Wolf 16:50, 4 February 2007 (UTC)Reply

I am not sure myself, but I think the article, Glyceryl trinitrate (pharmacology) may have what you are looking for. - Dozenist talk 16:55, 4 February 2007 (UTC)Reply

William Osler mentions it in his 1892 Principles and Practice of Medicine as an alternative treatment to amyl nitrite, which either he preferred or was the standard treatment of the time. The wording might be interpreted that nitroglycerin was relatively new and not universally considered standard. alteripse 17:11, 4 February 2007 (UTC)Reply

You're in luck. According to [8], it was first used for angina in 1879. Clarityfiend 17:56, 4 February 2007 (UTC)Reply

Off on a slight tangent but the topic reminded me of this Darwin Award story... --Kurt Shaped Box 18:58, 4 February 2007 (UTC)Reply

That raises another question. Who thought this up? Let's treat heart pains with...a dangerous explosive. An ancestor of Dr. Kevorkian? Monty Python? Clarityfiend 20:12, 4 February 2007 (UTC)Reply

A short history of nitroglycerine and nitric oxide in pharmacology and physiology. --JWSchmidt 23:17, 4 February 2007 (UTC)Reply

Dioxygen leak?

Latest comment: 18 years ago5 comments5 people in discussion

Is it true that a major dioxygen leak could have drastic effects on local plant and animal life? Is it true that leaks of this type have occured all over the country leaving very high dioxygen levels in the atmosphere? Isn't this hazardous?

See dioxygen. See also dihydrogen monoxide. TenOfAllTrades(talk) 19:59, 4 February 2007 (UTC)Reply

It's definitely a fire hazard. And I've heard that everyone who breathes it, expires. Clarityfiend 20:13, 4 February 2007 (UTC)Reply

Dioxygen is a good oxidizer, and therefore can be very dangerous in the presence of a fuel and ignition source. -- mattb @ 2007-02-04T20:35Z

But it is nothing compared to dioxin which comes from PCB. Edison 23:01, 4 February 2007 (UTC)Reply

Well that's true, even literally! No one lives forever!

Funnily enough, our atmosphere is 20% dioxygen! —LestatdeLioncourt 14:46, 5 February 2007 (UTC)Reply

mmmm mmm smell that beautiful dioxygen! i dont know man but for some reason i think you need to double check your sources lol you might find the extra info useful that is if you havent done so already. Maverick423 16:02, 5 February 2007 (UTC)Reply

Dioxygen is just oxygen —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

No, dioxygen is O₂. There is a difference between a molecule and an element, even if we are being silly and pedantic about it. -- mattb @ 2007-02-06T06:39Z

Free radical bromination of ethane

Latest comment: 18 years ago1 comment1 person in discussion

I already looked at the articles related to this subject, (free radical halogenation, and ethane) but I'm not sure I understand the initiation, propagation, and termination mechanisms behind it. Is there a visual examination for the free radical bromination of ethane that anyone knows of?

free radical halogenation has the answers - could you be more specific as to what you don't understand/want explaining.

Also I don't understand what you mean by 'visual examination' - do you mean a page with images to explain the process, or a way visually of telling if the process is occuring or something else?87.102.8.103 11:21, 5 February 2007 (UTC)Reply

Can't afford the real thing, so I make doo with sham poo

Latest comment: 18 years ago4 comments3 people in discussion

When my shampoo runs low, I leave the bottle turned over, so the last dregs accumulate at the cap. But I've noticed that it seems to eat the plastic in the cap (the color runs into the shampoo). What causes it? Is this harmful? Clarityfiend 20:20, 4 February 2007 (UTC)Reply

Wow, what are you putting in your shampoo?! [Mαc Δαvιs] X (How's my driving?) ❖ 14:30, 5 February 2007 (UTC)Reply

i think your using bleach as shampoo... nah just kidding its that thing that helps clean your hair thats causing that. its not harmful (unless swallowed ((or left on your hair for a long time))). Maverick423 16:04, 5 February 2007 (UTC)Reply

Lots of the chemicals in shampoo disolve other chemicals, so it could be one of these causing this:(

Some of these chamicals also disolve the proteins that hair is made from, so it probably isn't a good idea to wash with it at all:(

It's a nationally-marketed brand, not some weird generic glop. Oh well, I suppose the company may be saving money by using a cheaper, less durable plastic for the top. Clarityfiend 22:03, 5 February 2007 (UTC)Reply

jaw injury

Latest comment: 18 years ago6 comments6 people in discussion

What is the likelihood that a serious injury to the upper jaw, would subsequently cause a person to be reported as a chronic drunk? Consider the effect upon motility of the tongue, and the distinct possibility of affecting the inner structures involving balance. — Preceding unsigned comment added by 71.104.2.173 (talk • contribs) 20:50, 4 February 2007 (UTC)Reply

What is the likelihood? ?? Is that a serious question? What kind of answer do you want? The likely hood is unlikely? or, maybe a one in ten? Or do you want to discuss the various conditions? If it is dark and the observer is himself drunk then the likelihood is higher then if the subject is in an operating theatre being examined by physicians. Serious injury seems to imply some sort of pain and breakage if not bleeding, those are going to be hard to mistake for drunkenness. I work with a guy who has sclerosis and he was refused entry into a bar once because the bouncer thought he was drunk, no kidding.. So I guess it's not impossible. Vespine 21:30, 4 February 2007 (UTC)Reply

Given that someone with a recent serious jaw injury would be either - bleeding or screaming in pain - I'd say it's unlikely. They'd probably also be pointing to their jaw as well and be saying something like 'I've got a serious jaw injury - please help me..' - whereas a chronic drunk would stink of beer, smell of urine and probably be singing 'auld lang syne'...87.102.8.103 11:25, 5 February 2007 (UTC)Reply

It is phrased like a homework question. I feel sorry for the student-- if actually provided as cited, it is a question so poorly phrased that we are all guessing at the real intended question. My guess is that the teacher is asking, "An injury to what part of the vocal apparatus would produce speech that would sound like drunken slurring to most people." The answer is a stroke or an injury to the brain would be the best mimic, because most of us can readily tell the difference between defects of central speech processing and defects of articulation. If the answer is to be restricted to the area of the upper jaw, it would be an injury to efferent motor nerves controlling tongue, mouth and palate. Good luck to the student. alteripse 14:14, 5 February 2007 (UTC)Reply

Damage to the inner ear, which is very possible in an upper jaw punch, could cause damage to the semicircular canals, which measure the orientation of the head. Damage to the canals causes loss of balance and difficulty walking, just like alcohol. Laïka 21:25, 5 February 2007 (UTC)Reply

Well I suppose whatever had injured the upper jaw might also have caused other problems, like concussion. People with head injuries can be mistaken for being drunk, as occasionally happens in police stations and hospitals on Friday nights in town centres... Skittle 23:17, 5 February 2007 (UTC)Reply

Fermi Problems

Latest comment: 18 years ago8 comments5 people in discussion

When I get fermi problems, do I have to use my "own basic knowledge and experience" or am I allowed to look stuff up? I don't know how much cheese France consumes every year/day/month! How do I guess that? --JDitto 23:18, 4 February 2007 (UTC)Reply

One of the purposes of a Fermi problem is to get an idea of scale and the approximate magnitude of the answer, it is not intended to be that accurate. I don't know how many people live in France off-hand, but I might guess 20 million based on size relative to some US states and given Europe has a higher population density. The average person eats maybe a half-pound of cheese a week. 20 million people * 0.5 pounds cheese week/person = 10 million pounds per week, or roughly 1 million pounds a day, which is undoubtedly totally wrong, but I have some confidence that it isn't under 100 thousand per day, or over 10 million. On actually looking at the France article, my estimate is off by three times, but the magnitude of my estimate didn't change significantly. Atropos235 03:02, 5 February 2007 (UTC)Reply

Have you read our article on Fermi problems? As that article explains, you typically work with just a bunch of guesses. Certainly you can't look up the final answer -- if you could, it wouldn't be a Fermi problem -- and for the intermediate numbers leading up to the answer, most are either educated guesses, or "basic knowledge and experience". (In the "number of piano tuners in Chicago" example in the Fermi problem article, the only quantity you could easily look up is the number of people in Chicago; all the rest of the numbers are pulled out of the air.) The point of the exercise is usually to come up with a quick estimate, without doing any research, and perhaps at the same time to discover which potential avenues of research might be used to obtain a more accurate (non-guessed) answer later. —Steve Summit (talk) 02:50, 5 February 2007 (UTC)Reply

[P.S. It occurs to me in light of recent debate that the Fermi problem approach -- pulling a bunch of numbers out of the air, and combining them with some basic knowledge and educated guesses -- is precisely what Wikipedia's verifiability policy suggests we shouldn't be doing in answering questions on the Reference Desk... :-)]

I just need to know what I'm allowed to look up. I know I'm not allowed to look up the answers, so I want to stay away from reading the article itself right now. Thank you so far, though.--JDitto 05:37, 5 February 2007 (UTC)Reply

Wait -- you're not allowed to read the articles on cheese or France, or you're not allowed to read the article on Fermi problem??

I'd say the short answer is, no: for a proper Fermi solution you shouldn't look anything up. Background knowledge, armchair speculation, and erudite pontification only. —Steve Summit (talk) 12:37, 5 February 2007 (UTC)Reply

Fermi problems are problems where you are not able to calculate the answer, given the proper information. You are allowed to look up whatever you want, but at the end you will have to estimate a plausible answer anyway. Mr.K. (talk) 18:26, 5 February 2007 (UTC)Reply

I would say that a fermi problem should only include information known to you or easy to find and integral to the problem. so for the france one it seems fine to look up the pop of france. its a matter of effort and time not deliberate limitation of knowledge. Beckboyanch 02:44, 7 February 2007 (UTC)Reply

Okay, this is what I got for the "France eating the Moon", looking up as many non-internet sources as possible:

• Earth's Mass: 5.9 X 10²⁴ kg
• Children's Astronomy Book: Earth is 50X bigger than the Moon.
• Therefore: (5.9 X 10²⁴) / 50 = 1.18 X 10²³ kg

• MAYO Food Guide Pyramid says that 2-3 servings of milk group everyday.
• Each serving = 1 1/2 oz. of natural cheese
• 1 oz = 28.35 g
• Therefore: 2.5 X 28.35 = 70.875 g cheese eaten by a person per day, .0070875 kg

• France's population found in Encarta Encyclopedia: 58,609,285
• That's approximately 59 X 10⁶ people

• So the rate of consumption is: 59 X 10⁶ people X .0070875 kg = 418 163 kg consumed per day.

• In the arithmetic series equation, I'd have to solve for n.
• ${\displaystyle a_{n}=a_{1}+(n-1)d}$  would become ${\displaystyle n=(an-a1)/d+1}$ .
• Then it would be ${\displaystyle n=(1.18X10^{23}kg-418163)/418163+1}$ 
• So it would take France 2.82 X 10¹⁷ days to eat the moon.

What do you think?--JDitto 07:04, 6 February 2007 (UTC)Reply

Planet Rotations

Latest comment: 18 years ago4 comments4 people in discussion

Why do all of the planets (and many other stellar objects) have somewhat parallel orbits around the sun? Why aren't there things orbiting the sun that are more perpendicular to the orbit of the planets? Imaninjapirate^{talk to me} 00:55, 5 February 2007 (UTC)Reply

The prevailing theory (Planet#Formation) has the planets forming from a nebula condensing into a thin disk rotating around the proto Sun. There are things orbiting outside this narrow plane, but they're just not big things. Clarityfiend 01:06, 5 February 2007 (UTC)Reply

When matter starts to gather up, it tends to flatten in the shape of a disc, what we call protoplanetary disc (see article for a good explanation of why this happens.) This is how solar systems form. Most of the big objects in our solar systems were formed this way, that's why they all tend to have roughly the same orbital plane and move at the same direction. Smaller objects, however, are easily disturbed and have less-stable, irregular orbits. That's why smaller moons and asteroids have highly inclined orbits and all that. — Kieff | Talk 01:19, 5 February 2007 (UTC)Reply

The flattening of a nebula into a protoplanetary disc is simply a case of the conservation of angular momentum. It is exactly the same reason why an ice skater spins faster when they pull their arms in closer to themselves. Carcharoth 02:01, 5 February 2007 (UTC)Reply

Correlation of events...?

Latest comment: 18 years ago2 comments2 people in discussion

Where can I find the correlation between eating a big meal followed by a heart attack? 71.100.10.48 02:41, 5 February 2007 (UTC)Reply

This study found that:

Of the 158 patients who reported eating an unusually heavy meal during the 26 hours before their attack, 25 of them had the meal in the two hours right before the attack. Only 6 patients had their big meal in the corresponding two-hour period the previous day. By comparing the two time-slots-24 hours apart-the study controlled for the possibility that time of day, and not the meal itself, was the trigger. The remaining patients in the group of 158 had their heavy meal at various other times in the 26 hours before the heart attack, but no other time-slot emerged as significant.

Rockpocket 07:41, 5 February 2007 (UTC)Reply

Unknown disease

Latest comment: 18 years ago2 comments2 people in discussion

Anyone know of a disease nicknamed drop(s)? --The Dark Side 02:52, 5 February 2007 (UTC)Reply

Dropsy? —Steve Summit (talk) 02:55, 5 February 2007 (UTC)Reply

Reversed West and East on the Moon?

Latest comment: 18 years ago12 comments8 people in discussion

Hi - I read somewhere years ago that West and East are reversed on the Earth's Moon as a result of astronomers projecting our own West and East onto it - but now I can't find references to that idea anywhere - am I looking in the wrong places, or am I totally mistaken?

Thanks Adambrowne666 03:16, 5 February 2007 (UTC)Reply

Having a look at these two images: Western Hemisphere and Moon surface. It seems like they are not reversed. - Akamad 05:20, 5 February 2007 (UTC)Reply

That's what I keep finding too - I've got such a strong impression of this notion, but can't find evidence of it - I wonder if it has always been the way it is now - is it possible early astronomers mapped it that way, and it has been switched since? Adambrowne666 10:49, 5 February 2007 (UTC)Reply

It's an intersting point you make - it depends on how you define east and west - for instance does the sun always rise in the east? Is east defined by the rotation of the body? The earth and moon are separate bodies so it's difficult to say what is east on the moon??87.102.8.103 11:29, 5 February 2007 (UTC)Reply

It is either based on the rotation of the body, or the Earth as a reference. [Mαc Δαvιs] X (How's my driving?) ❖ 14:31, 5 February 2007 (UTC)Reply

It might have something to do with the fact that astronomical telescopes invert the image. Since reverting the image will degrade it, astronomers have gotten used the inverted images, to the point that even their drawings are inverted. This would mean that "west" is on the right. Perhaps this is what the questioner has in mind. (But before you take this to the bank, this is remembered from when I was an astronomy buff, about 35 years ago. Maybe 'scopes have changed in the meantime). Bunthorne 06:40, 6 February 2007 (UTC)Reply

Why would reverting the image degrade it? Surely a digitally stored image could be spatially inverted in a lossless fashion. I suppose you couldn't do it with an analogue form like a photograph, as you'd have to produce a new photograph from it, which would be a copy of a copy. Maelin (Talk | Contribs) 04:09, 7 February 2007 (UTC)Reply

Sorry, I wasn't clear. While astronomers no longer look through modern scopes (they use CCDs instead), historically (before cameras) they would look through the eyepiece directly at the image. The only way to save the image to paper was to draw it, and they drew it as they saw it. Due to the optics of the scope, the image would appear upside-down. To have it appear right-side up would require extra lenses (or an erecting prism), thus degrading the image. So for many years, it was the convention that drawings, prints, etc. would be printed upside-down, just as it would appear in the telescope.Bunthorne 07:12, 9 February 2007 (UTC)Reply

Well, rather than inverting the image, though that's a clever thought, Bunthorne, I always assumed it was because if the astronomer is facing North as he/she looks up at the moon, then West is to the left, East is to the right, and perhaps for ease of reference, he/she then maps the West to the left side of the Moon, East to the right - so that when you're standingg on the Moon itself, you get a reversed East and West ... does that make sense? Adambrowne666 21:36, 7 February 2007 (UTC)Reply

Yes I get that.. Though I've haven't yet found an example of a moon chart being labelled "east/west" - maybe astronomers have understood this two and avioded using east and west because of the potential for confusion? What they do use to describe degrees around the moon I have no idea - and the article moon doesn't seem to have the answer.83.100.250.165 21:41, 7 February 2007 (UTC)Reply

If you look at this image {Image:Moon map grid showing artificial objects on moon.PNG] and compare it with the list here List of artificial objects on the Moon you'll see that west on the moon is relative to the moon - not earth - so west goes right.. not left like on our earth maps...83.100.250.165 21:48, 7 February 2007 (UTC) Wrong way round - I'm asking at Wikipedia:Reference_desk/Science#moon eastReply

See Selenographic coordinates. --Heron 21:35, 9 February 2007 (UTC)Reply

only eating vitamins

Latest comment: 18 years ago3 comments3 people in discussion

What would happen if I stop eating conventional food and only eat vitamins? Would I die? What if I also eat sugar? Thank you. Renaud Miclette Lamarche

From nutrition: "There are six main classes of nutrients that the body needs: carbohydrates, proteins, fats, vitamins, minerals, and water. It is important to consume these six nutrients on a daily basis to build and maintain healthy bodily function." If you take vitamins, that'd cover vitamins.

And from Sugar#Health_concerns, "The panel [at WHO] stated that the total of free sugars (all monosaccharides and disaccharides added to foods by manufacturers, cooks or consumers, plus sugars naturally present in honey, syrups and fruit juices) should not account for more than 10% of the energy-intake of a healthy diet, while carbohydrates in total should represent between 55% and 75% of the energy-intake."

So the short answer is, no. --Wirbelwindヴィルヴェルヴィント (talk) 04:02, 5 February 2007 (UTC)Reply

YOu need some dietary fiber too. --Shantavira 08:15, 5 February 2007 (UTC)Reply

Vitamins are part of the group called micronutrients (along with minerals), which are needed in doses of milligrams or micrograms. Vitamins are needed for the body to be able to do properly some of its functions. Macronutrients, that is lipids, carbohydrates and proteins are the bulk of our needs (doses in the order of magnitude of grams), and they provide energy. If you only ate vitamins you would be lacking almost all the daily energy intake and would become weaker and weaker in a very short time span (maybe less than 3 weeks) and with die of hunger. --Taraborn 10:10, 5 February 2007 (UTC)Reply

You don't actually need polysaccharides, fat or protein for energy, but proteins are useful for other things instead

mitosis and meiosis

Latest comment: 18 years ago1 comment1 person in discussion

do you have any draws of meiosis and mitosis?

Meiosis and Mitosis? Splintercellguy 03:43, 5 February 2007 (UTC)Reply

Gummy Bear Rocket

Latest comment: 18 years ago11 comments6 people in discussion

I’m having a contest with my buddies to see who can make a device that can fling/shoot/launch a gummy bear the farthest, anything goes. I seem to remember a demonstration that rocketed a bear after it (the bear) was heated. Ring any bells? Thanks --Willworkforicecream 04:55, 5 February 2007 (UTC)Reply

You might want to see our article on Sabots. With such a device (and perhaps a railgun), I'd imagine you could impart nearly unlimited velocity to your Gummy (former) bear.

Atlant 12:48, 5 February 2007 (UTC)Reply

I would think that in order to have a contest, the bear would have to be a projectile in its natural state, and impact with full gumminess. Otherwise, you could just pour a melted gummy into a hollow-nose bullet, and fire away! --Zeizmic 13:12, 5 February 2007 (UTC)Reply

If anything really goes, how about sending the gummy bear by air mail to someone living on the other side of the earth? It will have flown most of the way. Or figure out some other way to get the gummy bear on an airplane.

To beat even that, you'll need a friend who works at NASA and owes you a big favor. Unfortunately, you missed your best chance by just over a year. —Ilmari Karonen (talk) 13:09, 5 February 2007 (UTC)Reply

Today they told me that "anything goes" means anything mechanical goes, so chemical, magnetic, etc. isn't allowed any more. Wusses, they were just scared of my coilgun idea. --Willworkforicecream 19:06, 5 February 2007 (UTC)Reply

You could build your own scale model of an aeroplane, and stick it to that

Well, if you aren't allowed any chemical or magnetic you can't use anything with an engine, I'm thinking: "What did people use to fling things far before engines and explosives and stuff?". I'd be investigating trebuchet and catapault. Vespine 21:50, 5 February 2007 (UTC)Reply

You could try a stomp rocket or a water rocket. Theresa Knott | Taste the Korn 21:57, 5 February 2007 (UTC)Reply

Hmm a red link! See here Theresa Knott | Taste the Korn 21:59, 5 February 2007 (UTC)Reply

And I've turned it blue. If anyone wants to help edit our brand new stomp rocket article please feel free. Theresa Knott | Taste the Korn 22:33, 5 February 2007 (UTC)Reply

Thanks for the ideas. I think that I'll go with a trebuchet because they're awesome. I'll blow everyone out of the water by putting the bear inside of a bouncy ball that will bounce and roll to gain extra distance. --Willworkforicecream 18:51, 6 February 2007 (UTC)Reply

That might be an excellent idea, if the terrain downrange is such that the ball will bounce nicely on it. If the terrain was, say, loose sand, I'd suggest a (mostly) solid iron/steel ball instead: maximizing the density of the projectile minimizes the effects of atmospheric drag. In any case, you may want to experiment with balls of various sizes and materials. Denser is still better, but elasticity will count a lot too if you go for the bounce. The optimal size of the ball (for a given material) will depend on how powerful your launcher is: too big and the initial velocity will be low, too small and you'll lose speed to drag; a back-of-the-envelope calculation of the optimal mass would be a nice physics exercise, but in practice an empirical approach will probably work just as well if not better. I'd expect a fairly large superball might do well, if you can get the gummy bear inside it without ruining its bounce. —Ilmari Karonen (talk) 20:13, 6 February 2007 (UTC)Reply

a weed pest called Wolsia or Wollsia

Latest comment: 18 years ago4 comments3 people in discussion

This pest is growing in our dam and we cannot find a way to get rid of it - the plant has been identified by the Department of Natural resourses Queensland but they have no knowledge of how to kill it Gwen Kelly

I can't find any info on those two names, I don't think you have spelt it right. If you can't find the correct name, would you be able to upload a photo here? Thanks. --liquidGhoul 12:46, 5 February 2007 (UTC)Reply

woollsia in Ericaceae  ?87.102.8.103 18:02, 5 February 2007 (UTC)Reply

Most pest plants aren't easy to kill - that's why they become pests - you need to find out how it can regenerate - for instance some plants can survive fire / chopping down - because they have a rhizome - the plant regenerates from the rhizome - is this is the case one way to proceed is to keep chopping it down - eventually the store of energy in the rhizome will be used up and the plant die.

You could try using a strong weedkiller - killing everything - don't forget to salt the ground as well.

An alternative is to add an even more invasive species that out grows it.

Or if you are lucky a pest that kills the plant can be found.

It's difficult to beat nature though.87.102.8.103 18:15, 5 February 2007 (UTC)Reply

You're evil. – b_jonas 20:45, 6 February 2007 (UTC)Reply

Han and Hong classification of inverted nipples

Latest comment: 18 years ago1 comment1 person in discussion

This classification is used by plastic surgeons to classify the three main types of inverted nipples. The Han and Hong classification is often cited in journals. I would like to know when this classification first came into effect, the first time it was published and where and also who owns the copyright to this classification. Thank you. Dharani.

Look at the last journal article in which you saw it cited-- it likely contains the reference that answers your question. alteripse 14:05, 5 February 2007 (UTC)Reply

Hyperbolic cooling

Latest comment: 18 years ago2 comments2 people in discussion

Do the huge "hyperbolic cooling towers" seen in power stations actually utilize a section from the perfect shape of hyperboloid? If so, how close to the shape is it? And how does this system improve water cooling efficency?Wbchilds 10:15, 5 February 2007 (UTC)Reply

I can't answer your first two questions. But the reason for the shape is one of structural integrity see Cooling_towers#Cooling_Towers_of_Nuclear_Reactors The shape is chosen for it's stabilty not to improve cooling efficiency. (Not sure if that was your question)87.102.8.103 11:36, 5 February 2007 (UTC)Reply

Projectile Motion

Latest comment: 18 years ago2 comments2 people in discussion

I'm currently doing a prac write up for year 12 Physics. At the moment I've hit some what of a road block. I'll try to describe the problem. A projectile is fired from a table (same height as the table) at a 45° angle, the projectile lands on the ground 2.54m away. The table is 0.75m high. The speed of the projectile is unknown, the time of flight is unknown. Is it possible to work out how far away from the origin the projectile is when it comes in line with the table. Heres a diagram I drew in MS Paint to help illustrate the problem:

 

The green question marks indicate the value I would like to know. Oh yeah, I almost forgot, Ignore air resistance.

P.S. If anyone works this out could they please tell me how because I would also like to do this with my measurements of other angles/distances.

P.P.S. This isn't really counted as "answering my homework" because we aren't required to put this info in our prac report, I simply want to enhance it.

Yes you can. First, if you were given the initial velocity, angle (which is known), and the time after firing, can you calculate where (x,y position) the projectile is? If so, you have a known (x,y) position of the projectile at some point (the position where it hits the floor, relative the the firing position). From that you should be able to solve for the initial velocity and time after firing (2 equations with 2 unknowns). With the initial velocity and angle, you should easily be able to solve your problem. --Spoon! 12:09, 5 February 2007 (UTC)Reply

(edit conflict) Well, ignoring air resistance, the trajectory is a parabola, which, in general, is described by the function ${\displaystyle y(x)=ax^{2}+bx+c}$ , with the first derivative ${\displaystyle y'(x)=2ax+b}$ . Setting the origin to the starting point on the table, we have ${\displaystyle c=0}$ , and the starting angle tells us that ${\displaystyle y'(0)=b=1}$ . The remaining condition is that ${\displaystyle y(2.54)=a(2.54)^{2}+2.54=-0.75}$ , which can be rearranged to give ${\displaystyle a=-(0.75+2.54)/(2.54)^{2}=-0.51}$  (approximately). Solving for ${\displaystyle y(x)=-0.51x^{2}+1x=0}$  the usual way, we get ${\displaystyle x=1/0.51=1.96}$  (again approximately). Depending on how pedantic your teacher is about significant figures, you may need to round that up to ${\displaystyle 2.0}$  meters (since the table height was technically given only to two significant digits), though in practice I'd consider the three-digit figure a more useful answer. Ps. If you do use these answers in your report, remember to be nice and credit the reference desk. —Ilmari Karonen (talk) 12:36, 5 February 2007 (UTC)Reply

science in transportation

Latest comment: 18 years ago2 comments2 people in discussion

information of what science contribute in transportation. — Preceding unsigned comment added by 210.186.3.142 (talk • contribs) 14:37, 5 February 2007 (UTC)Reply

I guess you mean "information from which sciences contributes to transportation (technology)." - if so the answer includes engineering primarily, computer science in modern computer controlled systems, mathematics - various models not related to engineering eg queueing theory, chemical engineering and metallurgy contribute to materials used in construction of transportaton devices, social sciences may also help in the design of public transportation systems, geography and geology relate to the way the transport network is built, meteorology is important easpecially in sea and air travel, in fact most of the common practical sciences contribute in some way.87.102.8.103 15:29, 5 February 2007 (UTC)Reply

To measure distances on earth

Latest comment: 18 years ago2 comments2 people in discussion

I woud like to know how i can measure shortest way from a place to an other, for exsamble from boston to london.Any solution for this.

hp

If you know the latitude and longitude of the two places, and you assume the earth is spherical it's quite simple.

First calculate the angle between the two places, using the latitude and longitude (relative to the centre of the earth. If you don't know how to do this please ask about it.

Then multiply the angle(in degrees) by 2πR/360 - ie Anglex2πR/360 this is the length of an arc(geometry) which subtends an angle of A - that is the distance 'as the crow flys' - R is the radius of the earth.

If you want the absolutely shortest distance from A to B (ie though the earth's crust in a straight line the distance is 2Rsin(πA/360) 87.102.8.103 16:30, 5 February 2007 (UTC)Reply

See the articles Great circle and Great-circle distance. The second article describes a method which uses a sphere to approximate the shape of the earth, and the article claims a maximum error of about 0.5%. The problem of finding a geodesic on an oblate spheroid is much more complex and cannot by solved analytically.

For calculating the shortest distance between two points along a straight line running beneath the surface, convert the latitude and longitude of the two points to earth centered, earth fixed coordinates:[9].—eric 16:59, 5 February 2007 (UTC)Reply

isn't the cross section of the earth elliptical, meaning the difference from the equator streight up is proportional to the distance from a line between the poles outward

Is denatured alcohol 100% volatile as a solvent?

Latest comment: 18 years ago1 comment1 person in discussion

If I were to extract some essential oils from lavendar using denatured alcohol, would it completely evaporate (like acetone or high grade ethanol)?

typically no. If it's surgical spirit no - it leaves an oil behind. If it's purple 'meths' no it leaves a purple residue.

You should be able to get denatured alcohol that does not leave a residue (I assume to avoid having to pay tax) if you seek it out specifically - that could be ethanol with only methanol in. Find a supplier (chemical or similar - and tell them what you want)

Alternatively you could distil some other denatured alcohol to get a residue free liquid (obviously this is a potential hazard and may even require a license to do..) and the distillate may carry over some impurities.

Or it's possible to use alternatives such as propanol.87.102.8.103 17:22, 5 February 2007 (UTC)Reply

Pissing too often

Latest comment: 18 years ago1 comment1 person in discussion

i recently switched from sitting down when i piss to standing up. all of a sudden, it seems like i need to take a leak too often. could it be because sitting down empties my bladder better or is this a sign i could have a serious male medical condition.. i dono prostate colorectal something like that? do i need to see the doctor? i dono why im asking all these questions.. shouldn't i just switch back to sitting and see if the problems stops?

There are lots of different causes of needing to piss more often - including mild infections, over injestion of diuretics (eg coffee), psychological reasons and more serious problems and diseases. As I/We can't see you and check your general health or ask about what other factors may be an issue it's really impossible to give you an good answer.

If it's a problem eg you can control your bladder (wet yourself), or are pissing many times more often than you should you should see a doctor - definately.

However if the difference in the amount of pissing you are doing is trivial - Could it be because it's easier to piss standing up that's why you go more often?

I'd recommend you go and see a doctor - and ask them about it. They usually give you a look over anyway so you should get some feedback on your general health as well as getting an answer to this problem.87.102.8.103 19:44, 5 February 2007 (UTC)Reply

Hmm Could be diabetes. Go to see a doctor soon! —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

Dog breeds -- Help!

Latest comment: 18 years ago6 comments5 people in discussion

Why are chihuahua, poodle, pit bull, labrador retriever, and alaskan husky considered different breeds of the same species, while lions, mountain lions, tigers, jaguars and leopards considered diffirent species of cat? they seem equally unsimilar to me. our Species article says something about a species being a group of animal that can succesfully reproduce and produce fertile offspring. is it even possible for chihuahua and the large domestic dogs reproduce togeher!? if so, is that what makes them one species? and thers so many species of jackal, coyote, and wolf. why arent they lumped together? they cant interbreed?

members of a specis also have to have physiological, morphological, biochemical and behavioral similarities, but this is mostly just for taxonomy which hardly anyone uses now

This discussion cover some aspects of dog breeding. However, the major difference is that the dogs you list are domesticated, while the felines are not. And thus the generation time since the last common ancestor of the dogs is much, much shorter than the last common ancestor of the cats. The cats have become speciated, the dogs have not. Rockpocket 20:00, 5 February 2007 (UTC)Reply

All breeds of dogs -- even a chihuahua and a great dane -- can reproduce and create fertile "hybrids". The fertility of the feline species in question is a bit more complicated, however. Also note that, for example while a coyote and a wolf can interbreed, their offspring tend to be less fit than a pure-bred and often die in the wild, whereas an interbred dog has about equal survival-ship (i.e. fitness) as a pure-bred. Check out speciation and hybridization. --Cody.Pope 07:50, 6 February 2007 (UTC)Reply

Do you have data for the assertion "an interbred dog has about equal survival-ship (i.e. fitness) as a pure-bred"? The common held belief is that a mongrel has a greater fitness than a pure-bred, due to a reduction in inbreeding depression. While I'm sure that isn't the case all the time, I would propose that on average, first generation outbreds would be fitter than first generation inbreds, due to a reduction in homozygosity. Rockpocket 07:45, 7 February 2007 (UTC)Reply

On that note, have a chihuahua and a great dane ever mated and produced offspring? I'd imagine the mother would have to be a great dane, as great dane puppies would probably be too big for a mother chihuahua... but then how would a male chihuahua... erm... "reach" the female great dane? And what would the offspring look like? --Candy-Panda 09:27, 6 February 2007 (UTC)Reply

I don't know if they have done it, but usually when breeders try to mate two creatures of very different sizes, they use artificial insemination. Certainly, new cat and dog breeds are sometimes started by crossing existing breeds. Skittle 00:41, 7 February 2007 (UTC)Reply

While I don't personally know of any actual examples of a chihuahua × great dane, if asked to bet I'd put my money on it having happened several times quite naturally. Where there's a will there's a way, after all, and dogs in heat certainly have the will. For what it's worth, I did once meet a dog that was reportedly the offspring of a (male) papillon and a (female) siberian husky. He seemed like a quite normal medium-sized dog, with somewhat fluffy fur, a distinctive bark and a strong temperament, but nothing that would've really struck me as particularly out of the ordinary. —Ilmari Karonen (talk) 14:46, 9 February 2007 (UTC)Reply

Using digital sound recorder as decibel noise meter?

Latest comment: 18 years ago3 comments3 people in discussion

I've just bough a digital sound recorder - a Tevion Digital Voice Recorder ET-880 to be exact. It can communicate with a computer via USB. It can record in "ACPCN", "ACTPC", and possibly "WMA" sound formats. I'm wondering if I could use it as a decibel noise meter by measuring the average sound intensity when the recorded file is transferred to the computer? — Preceding unsigned comment added by 62.253.44.193 (talk • contribs) 22:16, 5 February 2007 (UTC)Reply

(This answer is aimed at digital audio recorders in general, not this specific one which I only find very little information about.) I don't see how you could end up translating this into db. For one thing, whatever mic is built into the recorder is going to have certain compression characteristics. Also, the level of the sound in your digital recording is going to depend on where your level was set when you recorded, assuming the recorder lets you do this. Long story short- I think in order to measure sound pressure levels, you need a device specifically intended for this. Friday (talk) 22:34, 5 February 2007 (UTC)Reply

You you do, do you? And what do you knoew about anything/ —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

All the same I have known professional noise pollution specialists use a calibrated mic (don't know how calibrated, don't know brand) and a high quality portable recorder (Nagra back in the analog recording days) to record ambient sound on site before a plant is built, then run it through an analyzer back at the lab to determine the dB of noise pre- and post- plant operation. If they had just stared at a meter dial and written down the dB of ambient noise before the plant was built, they could have waited until a truck went by. If someone doubts the high pre-plant noise level, they can haul out the tape and show that it was the pig farm, birds, or bullfrogs. In general mics do not compress sound in the usual sense, but they have a certain gain, like -50dB and a certain frequency curve and directionality which has to be taken into account. The trick would be having a calibrated mic with a calibrated preamp, so that a certain sound pressure level produced a certain level n the recording, then to filter the sound per the applicable Weighting filter to get dbA, for instance. See Weighting filter and decibel for more info and more links. If the desire were to use the system for litigation or environmental health legal applications, an ad-hoc system would be subject to criticism, but if it were to satisfy curiosity, you might be able to conjure up a system. Edison 00:47, 6 February 2007 (UTC)Reply

Quality of radio reception dependent on where I stand

Latest comment: 18 years ago3 comments3 people in discussion

When I have the radio on in my room, sometimes the reception is good when I stand in a certain spot (even in a certain position) and turns crappy as soon as I move from there. How does this happen and is there a (easy) way to improve the reception? Thanks Lukas 22:32, 5 February 2007 (UTC)Reply

Yeah dont stand where the sound is crappy —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

I think that the reason you see the effect is generally capacitance between you and the antenna. To improve reception, either stand where reception is good the whole time, or try moving the antenna higher up. anonymous6494 23:33, 5 February 2007 (UTC)Reply

(Edit conflict) At about 3 metres, the wavelengths of broadcast FM signals are roughly the same size as you, so you can interact pretty strongly with those FM waves, diverting them around you or reflecting them. This can produce constructive or destructive interference at your radio's antenna. You may be able to reduce some of this by changing the position of the antenna (remembering that many table radios use their power cord as their antenna). In particular, if the antenna is oriented vertically (as you usually are when walking around), try orienting it horizontally.

Atlant 23:39, 5 February 2007 (UTC)Reply

weather

Latest comment: 18 years ago2 comments2 people in discussion

What type of weather does low air pressure usually indicate?24.34.194.200 22:47, 5 February 2007 (UTC)Reply

Stormy weather —The preceding unsigned comment was added by 88.109.41.162 (talk • contribs).

See also Cyclone. – b_jonas 20:33, 6 February 2007 (UTC)Reply

more for the poison question above

Latest comment: 18 years ago3 comments2 people in discussion

ok guys first i wanna say thanks so much for helping me understand the effects of the poisons and everything. its really grea and secondly i wanna say thanks for not sugar coating the effects!! now ok here we go as for cyinade posion. if you were to keep the heart beating and the lungs working (via CPR or another method) would it be possable to survive a normal Leathal dose of cyinade once it goes through the body (since it does so at a fast rate) ?? or will the cell damage the cyinade causes be too great to survive?? thanks again Maverick423 22:55, 5 February 2007 (UTC)Reply

You asked a similar question recently, and the first reply had a few errors in it, I would encourage you to scroll up and see the corrections if you haven't already done so.

So as stated above, ATP is the fuel with which the cell carries out many functions. Cyanide causes death by disabling ATP synthesis, and cells and by extension the entire human organism dies as a result. ATP acts on the enzyme cytochrome C oxidase by binding to it and preventing it from performing its normal duties. Cyanide also denatures the cytochrome, preventing further use. There are drugs which help avoid interaction between the cyanide and enzyme, but you are asking whether someone could be kept alive through CPR until the cyanide has the chance to exit the cells. The answer is, unfortunately, no. Cytochrome c oxidase takes four electrons (originally from NADH produced in the TCA) and adds them to molecular oxygen, creating (with dissolved protons, or hydrogen ions) water. This powers the Cytochrome c oxidase to push four hydrogen ions into a space in which they can power the transmembrane protein that creates ATP from ADP. The entire purpose of oxygen, despite the fact that it propagates toxic molecules and is itself reactive to vital cellular structures, is to accept these electrons from cytochrome c, as mediated by the oxidase. Oxygen, that vital substance, is just an electron sink. Without cytochrome c oxidase, oxygen is useless to the human body. Since CPR is little more than an artificial method to keep the body perfused with oxygenated blood, you can see why even perfect oxygenation of cells during cyanide poisoning is useless. Also note that, since the cyanide destroys the enzyme discussed, the body would have to make new cytochrome to replace it, which requires ATP, which is not available. All medicine can do in the case of cyanide poison is prevent it from interacting with cytochrome in the first place (and other important molecules) by introducing an agent which the cyanide prefers to bind with. See methemoglobin. ^tucker/_rekcut 02:12, 6 February 2007 (UTC)Reply

Thanks much tuckerekcut you have been very helpful in my quest for intellect. Maverick423 14:20, 6 February 2007 (UTC)Reply

dental hygienist/therapist

Latest comment: 18 years ago2 comments2 people in discussion

Hi, I am applying for a job as a dental nurse in Scotland, hoping to progress to a hygienist/therapist. What kind of uniform would I be wearing typically, and would I use a stethoscope etc in the latter jobs?

Yours, Alan

Hello Alan. Having been to a few dentists in Scotland, my personal experience is that the nurses and hygienists tend to wear tunics like this chap. I have never seen a stethoscope being used in a dental office. Rockpocket 01:05, 6 February 2007 (UTC)Reply

....Nor by a hygienist or therapist, though there are many different kinds of therapist, and some might have a use for a stethoscope. Stethoscope will explain what it's for.--Shantavira 08:40, 6 February 2007 (UTC)Reply

February 5

The 'pill' equals weight gain?

Latest comment: 18 years ago4 comments2 people in discussion

A couple of days ago I was reading the local newpaper's science page. One of the columns was a Q&A about science topics. The question was wether or not the 'Pill' really caused weight gain (or how). The answer was that, while older types of the pill did cause weight gain, newer ones had a different balance of hormones that did not cause much weight gain. The Doctor went on to say that the reason so much weight gain was from a natural increase of weight around the typically time the pill started to be used (IE 16 years or such)

Is this true? --Honeymane_{Heghlu meH QaQ jajvam} 00:16, 6 February 2007 (UTC)Reply

The authors of an academic study into that very question (Gallo M. F., Lopez L. M., Grimes D. A., Schulz K. F. & Helmerhorst F. M. Cochrane Database Systematic Rev., doi: 10.1002/14651858.CD003987.pub2. (2006)) conclude that:

'cause and effect' is merely anecdotal, and that patterns of weight gain among new pill users are no different to those seen in the population at large. The most logical explanation is that all of us, men and women, gain weight with age. The average American, for example, gains about one pound (0.45 kilograms) every year, but most people seek out something to blame for this other than their personal behaviour. [10]

Rockpocket 01:22, 6 February 2007 (UTC)Reply

Should the article be changed to reflect this?--Honeymane_{Heghlu meH QaQ jajvam} 23:10, 6 February 2007 (UTC)Reply

Why not be bold? Rockpocket 07:35, 7 February 2007 (UTC)Reply

air in potato chip bags

Latest comment: 18 years ago8 comments3 people in discussion

why is there so much air in potato chip bags? Is anything else a factor for their freshness?

It's in part to discourage breakage. Anchoress 00:46, 6 February 2007 (UTC)Reply

Air would actually make the chips spoil faster because of the oxygen; I believe nitrogen gas is used instead of air. (Potato chip makers in Korea state that they use nitrogen.) --Kjoonlee 00:55, 6 February 2007 (UTC)Reply

Was that a response to my comment? Because my point was that when the bag is inflated (with whatever gas) to maximum size the chips are less likely to break due to compression or impact during the journey from manufacture to sale. Anchoress 17:54, 6 February 2007 (UTC)Reply

I'm sorry, I meant my reply to point out that the original question had a weak point. I agree wholeheartedly with your comments. :) --Kjoonlee 18:36, 6 February 2007 (UTC)Reply

I always thought air in the bag was just to make it look more full then it is so that the person buying it wont feel as bad when they pay $3 for 10 ounces of chips. Maverick423 14:37, 6 February 2007 (UTC)Reply

Except it isn't air, as mentioned above; Korean manufacturers state it very clearly: "Filled with nitrogen to protect contents." --Kjoonlee 15:09, 6 February 2007 (UTC)Reply

Ooh, the potato chip article confirms the use of nitrogen. Isn't Wikipedia wonderful? :) --Kjoonlee 15:15, 6 February 2007 (UTC)Reply

Yes very intresting info well i guess you learn something new everyday =) Maverick423 16:30, 6 February 2007 (UTC)Reply

Point to point Rocket travel: How is it possible to get from any point on Earth to another in just 45 minutes?

Latest comment: 18 years ago3 comments3 people in discussion

Hello Volunteers:

I've tried to research Point to point Rocket travel: How is it possible to get from any point on Earth to another in just 45 minutes? All I'm able to locate is information about rocket/space travel and how point-to-point rocket travel can be done in 45 minutes etc...but I haven't been able to locate any info on how it works...why does it take only 45 minutes... ?

thanks in advance for all the answers

Shaum76 01:09, 6 February 2007 (UTC)Reply

An object in a low Earth orbit (LEO) takes about 90 minutes to complete one full orbit of the Earth. Now, think of a point-to-point rocket journey as a rocket in a slightly flattened (elliptical) orbit that intersects the surface of the earth at your departure point and at your destination. Neglecting the (relatively short) periods of acceleration at takeoff and landing, the furthest point on Earth from you will be no more than half the circumference of the Earth away (half an orbit): 45 minutes.

It is in principle possible to get from point to point even faster, but only at ruinous cost of fuel. A faster trip would essentially require you to burn fuel the whole way, instead of coasting for most of the trip. TenOfAllTrades(talk) 02:03, 6 February 2007 (UTC)Reply

You can do better than 45 minutes (actually about 42) using a Gravity train. Bunthorne 06:56, 6 February 2007 (UTC)Reply

Light: Vector or Scalar?

Latest comment: 18 years ago5 comments5 people in discussion

Me and a few of my friends at school have been debating whether or not light is a vector or scalar quantity. Is it the SPEED of light, or is it the VELOCITY of light? What is the convention used and how does light actually travel, and what are the reasons for this?67.70.30.223 02:01, 6 February 2007 (UTC)Adam ReidReply

Light is neither; its speed is a scalar and its velocity is a vector. Scalars and vectors are not mutually exclusive. I don't understand what you mean by how light actually travels. Clarityfiend 02:49, 6 February 2007 (UTC)Reply

Light is vector. It has energy and a direction. Interactions with other particles with vector properties preserves the vector/vector rules, not vector/scalar rules. Light has momentum which is the inherent vector quantity. Tbeatty 03:22, 6 February 2007 (UTC)Reply

I don't think you can classify light as vector just because it has energy and momentum. For example, you can not say that a moving car is a vector. Scalars and Vectors are physical quantities and not objects. But as Clarityfiend mentioned, if you say velocity of light, then you need to mention the direction too, because velocity is a vector. You can say 'the speed of light is so and so' but if you say 'the velocity of light', then you should specify 'in the eastern direction' or something like that. -- WikiCheng | Talk 13:15, 6 February 2007 (UTC)Reply

If you're thinking of light as an object, the above answers are correct: its speed is a scalar, but it's velocity is a vector. To muddy the waters, and not at all because I think this is what you were debating about, in electrodynamics, light is described by the electromagnetic four-potential; in quantum electrodynamics (the quantum-mechanical version), individual photons are little localized packets of this field. From this perspective, light is a vector after all, and photons are one example of a vector boson. (Any particle with spin of 1 unit, like the photon, is a vector; those with a spin of 0 units would be scalars.) -- SCZenz 13:38, 6 February 2007 (UTC)Reply

Too much tea?

Latest comment: 18 years ago6 comments5 people in discussion

I drink a lot of tea - at least 3 and sometimes up to 6 or 7 cups a day of green tea, white tea and regular black tea. I drink soy milk with black tea but I don't use sugar. I also consume other antioxidant-rich things like red wine and cranberry juice on occasion. Are there any possible negative side effects of so much tea consumption? --Grace 02:39, 6 February 2007 (UTC)Reply

Yes you can have too much caffein and get the jitters or insomnia. Also your teeth may be discoloured by too much tea. Is soy milk with black tea called white tea though? GB 05:52, 6 February 2007 (UTC)Reply

By the way, you know consuming too much antioxidants can be unhealthy, mostly happens with vegetarians though, but you seem like you get a lot. [Mαc Δαvιs] X (How's my driving?) ❖ 07:06, 6 February 2007 (UTC)Reply

Overconsumption of too much of one particular antioxidant chemical has been linked to health problems, but tea contains so many I don't think it's something to be worried about. (I don't think anyone has ever been diagnosed with antioxidant overconsumption from food, vegetarian or not). There are many folks who drink many cups of antioxidant-rich green tea a day with only positive effects that we know of. Also, white tea is a different variety of tea, similar to green tea. Frankg 15:28, 6 February 2007 (UTC)Reply

You might be interested in this article: Heart study pours cold water on adding milk to tea. Anchoress 15:33, 6 February 2007 (UTC)Reply

Thanks for your answers everyone...Mac Davis, what's wrong with consuming too much (too many?) antioxidants? In the article it mentions that they may prevent your body from using other important nutrients, would taking vitamins offset this? --Grace 23:49, 7 February 2007 (UTC)Reply

Dirty Glass Recycling

Latest comment: 18 years ago5 comments5 people in discussion

Some people put dirty jars in glass recycling bins. Are these jars just fed into a the glass melting machine all dirty or what? What about the label? What about the glue residue that attaches the label to the glass? --Seans Potato Business 04:28, 6 February 2007 (UTC)Reply

When I talked to the local recyclers about this they said there was no need to wash out leftovers or remove labels. The glass material is sorted out and the company washes it anyway, and then melts it down. However they don't want light globes, window glass, pyrex or any other weird kinds of glass that muck up the mix. You may wish to wash out the remains to cut down on odor as it decomposes though. The same story applied to metal cans for recycling. GB 05:50, 6 February 2007 (UTC)Reply

I'd agree with GB. Glass melts at such a high temperature that most things would just burn off. Any other oddities left behind (metals etc.) could just be separated out by density. --Cody.Pope 07:36, 6 February 2007 (UTC)Reply

Yes and no. Plenty of organic stuff, I'm sure, burns off without a trace. But glass is a pretty weird substance, and even when molten it's still very, very viscous. Lots of metals and minerals can remain intermixed with it and do not by any means separate out by density. Trace amounts of various metals and minerals are routinely added to glass to give it desired colors or other properties. But those elements, if present in waste glass, can't be used to make a new batch of glass if those elements aren't desired in the new batch. That's why window glass is not welcome in the recycled glass stream. Also, I learned during a visit to a glass recycling plant that even one green bottle mixed in with several thousand clear ones can ruin a batch of clear glass. —Steve Summit (talk) 13:10, 6 February 2007 (UTC)Reply

[Footnote: I said that "even when molten glass is still still very, very viscous". Let's not hear anything about the urban legend of its alleged viscosity at room temperature, 'kay? —s]

A lot of recycled materials are not sold as "virgin" versions of the same substance, such as paper. Old milk cartons go to make park benches, not new milk cartons. I wonder if old recycled glass likewise gets downgraded to brown or green glass or non-seethrough glass products. It would seem silly to try to have perfect clear windoe or bottle gmass when one speck of adulterant would tint it. The glass gets smashed to bit, then a furnace burns away bits of paper or glue or spaghetti sauce, then I expect some of the other undesired substances float to the top as scum or slag and get skimmed off. I have always been doubtful of the need to run empty jam jars through the dishwasher or to scrub them in the sink, due to the water and fuel energy wasted. Edison 18:26, 6 February 2007 (UTC)Reply

Trees

Latest comment: 18 years ago1 comment1 person in discussion

what is Adenanthera pavonina,L.?

It's red sandalwood, here's a page I found via google: http://www.tropilab.com/adenan-pav.html. By the way, in future, it's probably a lot quicker for you to search on google, or some other search engine for that matter. All the best. - Akamad 05:04, 6 February 2007 (UTC)Reply

Torpedo away

Latest comment: 18 years ago5 comments4 people in discussion

According to U-Boat#World War II, a magnetic torpedo worked by exploding underneath a ship, creating an air bubble that displaced the water supporting the weight of the ship; the unsupported hull then buckled. Is this true? Clarityfiend 04:39, 6 February 2007 (UTC)Reply

It does not sound like a true statement, as an exploding torpedo would increase the pressure, lifting the ship. The gas bubble should be able to support the ship due to its high pressure. Much of the damage would be due to the blast shock wave. GB 05:45, 6 February 2007 (UTC)Reply

My mistake. The article mentioned the air bubble, but the rest was my hallucination. Clarityfiend 06:42, 6 February 2007 (UTC)Reply

Actually I've heard the exact same thing - twice - from ex-naval people - though not torpedos - more mines - the mine explodes - releasing a lot of gas - the gas expands becuase it is under pressure - creating a huge gas bubble under the target - and because gas doesn't have the buoyancy of water the ship sinks - that's the theory - just because I heard it from a good source doesn't mean it has to be true.87.102.37.127 06:55, 6 February 2007 (UTC)Reply

It's not accurate. Refrence [11] for a complete description. Hipocrite - «Talk» 14:33, 6 February 2007 (UTC)Reply

Effect of radiation/nuclear bomb on U.S. currency tests

Latest comment: 18 years ago6 comments5 people in discussion

I heard from a reliable source that the U.S. had conducted tests concerning the effects of radiation/a nuclear bomb on United States currency. However after doing a little reaserch I was unable to find any information on any test or tests pertaining to this subject. If anyone knew any information concerning this (i.e. date, place, test name, results, ect.) please enlighten me.

Mattheyborne 04:53, 6 February 2007 (UTC)MattReply

If the currency (notes or coin) was near enough to the bomb, it would be destroyed (vaporised)--DarkFuture 06:19, 6 February 2007 (UTC)Reply

Despite what Mattheyborne says: I have heard about different types of Nuclear Weapon which are designed to produce a huge amount of fallout without much actual explosive yeild. for example to kill the inhabitants of a city without actually causing much damage to infrastructure. the information about this type of bomb can be found here. Not sure if this helps, but i hope so. Ben

You're talking about a neutron bomb, although why the government would be overly concerned about the survivability of currency in the event of a nuclear war is beyond me. You'd think it would have more immediate worries. Clarityfiend 17:21, 6 February 2007 (UTC)Reply

Governments generally assumed that nuclear warfare would not in fact end the world or their governments, but that it would be seriously disrupting. This is the "thinking the unthinkable" that think tanks did best at, realizing that there would in fact be survivors in almost any conceivable nuclear war and that one shouldn't simply close one's ears to the possibility because it was horrific. On the other hand, Lynn Eden at Stanford has recently published a book (Whole World On Fire) which in my mind conclusively demonstrates that the think tank theorists did not adequately take into account the fire effects of bomb shots, concentrating instead only on blast, heat, and radioactive effects, and in that sense probably severely underestimated the effects of nuclear weapons on inhabited areas. --140.247.250.21 17:38, 6 February 2007 (UTC)Reply

They definitely tested the results of atomic blasts against a Mosler bank vault during their civil defense-related testing at Nevada Test Site in 1957 (it is still there). These tests were done in the context of houses and facilities not at the epicenter of the blast, but some distance away. The assumption was that the world would in fact not end in such a salvo (and in the 1950s there were not enough warheads to really be "world-ending" in the possession of the USSR) and that things like material property would still be quite important. This was two decades before the so-called "neutron bomb" was developed. --140.247.250.21 17:35, 6 February 2007 (UTC)Reply

perhaps the original poster means the economy as opposed to the actual money, i could see governments taking lots of interest in disaster secanios and what would happen to prices etc --137.205.79.218 09:08, 8 February 2007 (UTC)Reply

Job requirements: Spectroscopy and chromatography

Latest comment: 18 years ago3 comments2 people in discussion

I have an interview for a co-op job that asks for knowledge of ultraviolet-visible spectroscopy and infrared spectroscopy, as well as gas chromatography. Now, I have experience with spectrophotometry and spectroscopy, but not specifically UV/VIS nor IR. Also, I have done paper chromatography, but not gas chromatography. This one seems more complicated .

My opinion is: spectroscopy is spectroscopy is spectroscopy. Am I being cocky, or are UV and UV-VIS quite different from regular (emission / absorption) spectroscopy?

Also, gas chromatography seems much more complicated than paper chromatography. Are these techniques that I can quickly learn, considering my previous experience? − Twas Now ( talk • contribs • e-mail ) 06:53, 6 February 2007 (UTC)Reply

uv spectroscopy is a type of electronic emission/absorbsion spectroscopy.

Gas chromatography (see http://www.gchelp.tk/ from that page for help) is more complicated than paper chromatography.

My guess is that they would like people who have experience operating uv spectra machines and gas chromatograph machines.

If you've used any spectroscopy machine (eg IR spec) before then using a iv or uv/vis machine should be simple for you to grasp - there's not a big difference in the way they are set up.

Gas chromatography is more complex - there's an oven, temperature control, it all depends on how much you are expected to do - just running a spectra would be simpler than setting up the machine, which in turn is simpler than knwoing how to set up a machine for a given sample. I'd expect at least some training - but anyone with experience would probably get first choice..

Recommend you read the two links above for GC and good luck. That's the best I can offer.87.102.37.127 07:02, 6 February 2007 (UTC)Reply

Thank you, that external link is great! If anyone else has some other comments, they would be appreciated. − Twas Now ( talk • contribs • e-mail ) 08:11, 6 February 2007 (UTC)Reply

Sodium laurel sulphate and sodium laureth sulphate.

Latest comment: 18 years ago4 comments3 people in discussion

I was just wondering... what are sodium laurel sulphate and sodium laureth sulphate and what do they do? Either one of those chemicals seems to be one of the first ingredients listed on all my shampoo bottles. --Candy-Panda 09:37, 6 February 2007 (UTC)Reply

Both are detergentia or tensides or simply spoken soap. --Stone 10:43, 6 February 2007 (UTC) Sodium laureth sulfate might help.--Stone 10:45, 6 February 2007 (UTC)Reply

Also Sodium dodecyl sulfate is sodium lauryl sulphate - they are quite similar - but not the same. Note detergent is a better term than soap - soap is typically Sodium tallowate or very similar - as found in a bar of soap. Sodium laur-- sulphates are more likely to be found in a liquid detergent such as Fairy Liquid.87.102.13.26 14:06, 6 February 2007 (UTC)Reply

They're the primary cleaning agents in shampoo.87.102.13.26 14:06, 6 February 2007 (UTC)Reply

1,3 butadiene

Latest comment: 18 years ago1 comment1 person in discussion

Do you have any information about a plant in India and Poland manufacturing butadiene from ethanol by two step process?

JACS paper 1949 might be an old process?--Stone 11:59, 6 February 2007 (UTC)Reply

Ethanol to actaldehyde to crotonaldehyde to butadiene with Ta₂O₅ at 350°C. The paper was first hit in google scolar with butadiene from ethanol

Heart deposits

Latest comment: 18 years ago2 comments2 people in discussion

Suppose you had HDL deposits in your heart, and you were to have a totally fat free diet, would they then melt away??

Fat is synthesized in our body! HDL free or better cholesterol free would also not benefit, because it is a key component of cellmembranes.--Stone 13:06, 6 February 2007 (UTC)Reply

High density lipoprotein (HDL) is the so-called "good cholesterol". A totally fat-free diet would be quite unhealthy, as fats are required! For example, they help in hormone production and the digestion of vitamins A, D, E, and K. Check out the article on essential fatty acids. − Twas Now ( talk • contribs • e-mail ) 14:04, 6 February 2007 (UTC)Reply

Acidity level of free fatty acids from waste cooking oil

Latest comment: 18 years ago2 comments2 people in discussion

Greetings,

How to check the acidic and content level of free fatty acids from waste cooking oil WITHOUT going thru lab tests..?As in..Can we use cetain chemical or device which we can test on our own...?

A flask some phenolphthalein, pipet, sodium hydroxide solution of a known concentration, and you can start your job. Titration os simple!

I would have liked to have said that but oil doesn't mix with water - making the titration most difficult.87.102.13.26 15:42, 6 February 2007 (UTC)Reply

Mixtures of alcohols help!--Stone 17:52, 6 February 2007 (UTC)Reply

Wellbrutrin

Latest comment: 18 years ago7 comments4 people in discussion

I read that Wellbrutrin increases sexual urges in women. How does this happen?

It could suppress inhibitions. Corvus cornix 16:52, 6 February 2007 (UTC)Reply

I think I would have to disagree. I believe that something chemically is happening...

for info on stuff like this check here http://people.howstuffworks.com/valentines-day.htm

and for more percise info on it check here http://health.howstuffworks.com/aphrodisiac.htm

Maverick423 17:41, 6 February 2007 (UTC)Reply

Does anyone know what takes place chemically?

Speculations on what takes place chemically are located on the http://health.howstuffworks.com/aphrodisiac.htm article. however i dont think anyone knows forsure what happens with aphrodisiacs because there are alot of factors to consider.Maverick423 18:27, 6 February 2007 (UTC)Reply

The thing is is that this is a anti-depressant, as in the description under Bupropion in Wikipedia: "Patients who complain of sexual dysfunction as a result of their SSRI have sometimes been prescribed small doses of bupropion, amphetamine or methylphenidate to correct it.[5]" Does anyone know how chemically this is affecting the human body?

A 2006 article (doi:10.1093/annonc/mdl304) notes "The mechanism by which bupropion has prosexual effects is unknown." DMacks 19:54, 6 February 2007 (UTC)Reply

Does anyone else find this question a bit creepy? − Twas Now ( talk • contribs • e-mail ) 07:06, 7 February 2007 (UTC)Reply

This is for Twas Now, I am the female who typed this question, is currently taking Wellbutrin and experienced the side effect mentioned in the question. There is absolutely no reason for you to underestimate my intention to gain more knowledge. I find you creepy for thinking so! In the future, I suggest that you do NOT answer anybody else's questions because no one appreciates your stupid comments!

Yes, I bet you are female. How did I underestimate your intention to gain more knowledge? Through the process of questionizationing? Oh I love verbal superfluousness.

Check out our article on bupropion (a.k.a. Wellbutrin) and please remember to sign your questions with the ~~~~ tag. − Twas Now ( talk • contribs • e-mail ) 10:13, 8 February 2007 (UTC)Reply

Twas Now (or never), you must be a womanizer or maybe you hate your mother but, again, I asked that you NOT contribute to this question. If you have any reading comprehension skills, you will see that I had already reviewed the article on bupropion in Wikipedia and, had you read such article, you will see that it doesn't, like you, answer my question. I also will like to know where I could submit a complaint on this forum.

I didn't know that was your comment, since you forgot to add four ~'s to sign your name (~~~~). Anyway, have a look at Wikipedia's suggested dispute resolution procedure. − Twas Now ( talk • contribs • e-mail ) 14:27, 8 February 2007 (UTC)Reply

How to make?

Latest comment: 18 years ago12 comments6 people in discussion

Asked this question on the nitrocellulose page however seeing as how people dont really respond to them on there im asking it here .

how do you make gun cotton or where can i get flash paper and is it possable to make flash paper??

buy it from magic or theatrical effects suppliers. Try searching on "flash paper" +cotton +cord --Wjbeaty 02:13, 8 February 2007 (UTC)Reply

the reason for this is for a film me and some friends want to make however we cant find flash paper (not even in magicians stores)

Also how does one go around making that Fireball from flash paper? you know the one that looks like its a supernatural power comming from the persons hand? in anyways thanks in advance !!! One more thing whats the safest distance to be at when making a fireball from your hand? (in the term of the other "object") Maverick423 17:33, 6 February 2007 (UTC)Reply

My heart bleeds for you! When I was a kid, I read books on how to make home-made explosives, rocket fuel, etc. I ordered flash paper through the mail, and I made my own guncotton. In this day and time, I wouldn't touch your request with a ten foot patch cord... :) --Zeizmic 17:55, 6 February 2007 (UTC)Reply

The synthesis is easy, but dangerous. The ingrediants are hard to get and even harder to dispose. And if you really search for it you will find a good synthesis description from a person which is careless and stupid enough to distribute it over the net.--Stone 18:03, 6 February 2007 (UTC)Reply

• crys on Zeizmic's sholder" WHY!!!!! man dude your lucky! i remember just once seeing flash paper in a magic shop but the store closed down. So with what you state i take it that the substance is now illegal right? Darn! but still i just wanted to know how to make it so ican show the real deal on that short video we are ganna make instead of adobeing it :( so i take it there is no or little chance that i will find this info anywhere eh? and i suppose u cant just buy the ingredients (as it was stated is hard to get) and just mix them up (as far as i know mixing chemicals without knowing the true danger is a death warrnt in itself) in a bucket or something Maverick423 18:13, 6 February 2007 (UTC)Reply

Yep, if you read nitrocellulose (redirect from gun cotton) you'll find it explains in some detail how to make it.. including "...very careful preparation of the cotton: unless it was very well cleaned and dried, it was liable to explode spontaneously.." - so maybe it's for the best the ingrediants are hard to get hold of (hopefully).87.102.13.26 18:25, 6 February 2007 (UTC)Reply

so its an extreamly unstable compound then... i take it you will need face masks and some sort of protection as a precaution from a accidental explosion then. hmmm but cotton is acctually used? thats intresting. Maverick423 18:32, 6 February 2007 (UTC)Reply

Explosion is not the problem during production, but a boiling burning nitic acid if the reaction gets a little bit hasty.--Stone 18:34, 6 February 2007 (UTC)Reply

The pure compound is quite stable on it's own (in the absence of sparks etc) - but impurities can make the gun cotton unstable. (I think)87.102.13.26 18:44, 6 February 2007 (UTC)Reply

Why are they so distrusting of young folks in the making of explosive and incendiary materials? Oh yeah, now I remember my experiences. The book says make a gram of something and note that it explodes with a pop. I thought that an ounce would be more fun, and it went off with a boom and I was lucky not to lose an eye or fingers. A friend burned down his grandmothers porch (wise enough to take his experiment outside). Fifty or 100 years ago was the golden age of chemistry sets, when the home experimenter could buy literally and reagent. Now kids are taught to be afraid of chemistry and science, except for maybe somesolution changing color. Edison 18:39, 6 February 2007 (UTC)Reply

20 years ago I bought a winchester of 98% sulphuric and over a litre of ~70% nitric from a 'pharmacist' - don't think I could do that now.87.102.13.26 18:44, 6 February 2007 (UTC)Reply

ehhg tell me bout it i bought a chemistry set with NaCl as the main compound it was very very "cool" at that time now im angered that everyone that was around 20 40 years before i was born had so much more stuff to play with in their chemistry set. and edison is right! in schools they always say (becareful around the lab if you get any liquid on you tell us so we can wash it off even if its just water) i mean comeon thats enough to cause a kid to crap his pants if he gets anything on him. 20 years have gone by for me and the only chemical reactions i have seen is a barbque pit lighting up, fireworks, and water evaporaiting. (of course i seen a bit more but u get my point) Maverick423 18:50, 6 February 2007 (UTC)Reply

There are online stores that sell flash paper -- mostly magic shops and theatrical suppliers. One is at http://www.theatrefx.com/moreinfo_fp01_flash_paper.html -- this is NOT a recommendation, just a site I found by Googling "flash paper." For anyone bemoaning the lack of fun explosive chemistry sets for kids, there's an interesting article from Wired at http://www.wired.com/wired/archive/14.06/chemistry.html.

God and science

Latest comment: 18 years ago17 comments11 people in discussion

Has science disproved God? Darkhorse06 18:00, 6 February 2007 (UTC)Reply

Science can only disproof things which are bound to the laws of physic!--Stone 18:03, 6 February 2007 (UTC)Reply

you know i always wondered that however i remember one thing

science still hasnt proven or showed how ,that pleage that moses used to kill all the first borns, occored or anything to explain the weird reactions that the pleage had on only targeting the first born and passing over the ones that had blood on the doors. (even though im a man of science seeing things that cant be explained makes me just wonder) Maverick423 18:22, 6 February 2007 (UTC)Reply

Plagues of Egypt#Historicity incidentally. Also, your last sentence suggests you witnessed the plagues yourself. How old are you? Skittle 19:55, 6 February 2007 (UTC)Reply

The existence of an omnipotent deity is (arguably) not within the realm of scientific discovery. Also, from at least some point of view, science cannot "prove" anything to an ultimate degree of certainty. It can only make predictions based upon past observations. These predictions become the laws and theories of science that we use. Theories in themselves can easily be disproved; in principle it takes only one repeatable experiment that disagrees with the theory. We sometimes call theories "laws" when they have been proven time and time again. Science could only "disprove" God if the existence of God made certain assertions or predictions that experiment and observation disagrees with. Whether that is the case depends largely on exactly what a person thinks a belief in God entails.

Can science disprove that some intelligence caused everything to be? Not really. Taking big bang theory as an example, we cannot answer what there was "before" the big bang, because, in the paraphrased words of Hawking, "that's like asking what is north of the north pole". Science is generally limited to what we can observe and measure somehow. If we cannot observe a god and quantify it, there's very little science can do to prove or disprove its existence. The very basic question is really a philosophical one, so you'll see lots of opinions. Now, as to individual claims that come along with many peoples' ideas of God and creation, those may be answered on a case-by-case basis. -- mattb @ 2007-02-06T19:47Z

ah sorry about that i didnt intend to make it come out that way. i ment that seeing as how science hasnt figured out what caused it; that gives me doubts about science being correct on evolution and stuff like that. thanks for the link i will start reading it right now. Maverick423 20:23, 6 February 2007 (UTC)Reply

Evolution is a pretty sound theory that is observable on the small scale. The concepts of mutation, variation, natural selection and adaptation can all be observed in a reproducable laboratory environment. People who claim that evolution is mere postulation are usually under one or more misconceptions. Perhaps it's abiogenesis that you doubt? -- mattb @ 2007-02-06T20:36Z

P.S. - If you want to get into the philosophy aspect of this question, Existence of God does a nice job in covering the high points. -- mattb @ 2007-02-06T20:20Z

Science is not complete and doesn't have all the answers at this time (or even ever for some things), which can be a very unsettling idea. It doesn't mean that what it has figured out is not well established. And you also seem unsettled by a distinction between how vs what. People long knew that things fell when dropped even without knowing what was going on. Even long before anyone had a clue how gravity actually "works", we had the law of gravitational attraction. DMacks 20:41, 6 February 2007 (UTC)Reply

Yes i admit im caught inbetween both these issues. the fact that both of them seem real at times is just confusing. god does this and that one person caught in the middle of it is spared while everyone around him dies. science cant explain what happened. yet... it has rumors of what might of happened but they cant confirm it. a higher being? God? or just a series of events that led to the persons survival while everyone else died. like i said its not a very good position to be in when your stuck in the middle. Maverick423 20:59, 6 February 2007 (UTC)Reply

Yes, the point about completeness is worth remembering. The best scientific theories stand only because nothing has yet proven them to be incorrect. Some of today's theories may be a footnote in tomorrow's science history books. A fun example is that of quantum mechanics (QM) and general relativity (GR), the two principle modern theories of "almost everything". The former describes three of the four fundamental interactions observed in nature (electromagnetism, strong and weak nuclear forces) while the former describes the fourth (gravitation). Both theories are widely accepted and are backed by plenty of experimental evidence. The theories also contradict one another; they cannot both be correct and we're not yet sure how to reconcile them (or whether they really can be reconciled).

I think QM in particular presents a more interesting case. Even if you know everything QM can tell you about a system (let's call it a "wavefunction"), you cannot predict with certainty what the result of a given measurement on that system will be, only probability. This presents an enormous philosophical debate: is quantum mechanics incomplete, and there is some other unknown factor outside QM that determines the characteristics of a system (the so-called realist view) or is there something fundamental about the act of measurement that causes a system to suddenly have a measurable parameter? Some of the greatest human minds have grappled with this and been unable to agree upon an answer yet. Science is constantly evolving and along with it our understanding of the universe; it's hard to say whether everything can be explained with science (another philosophical debate).

Anyway, I wouldn't feel too bad about being a little bewildered by all this. Nobody even remotely can provide all the answers (save for, perhaps, an omnipotent creature, if you believe in such a thing). Perhaps you'll find some solace in The Answer to Life, the Universe, and Everything. -- mattb @ 2007-02-06T21:02Z

Heh thanks much you been quite the help mattb. Maverick423 21:17, 6 February 2007 (UTC)Reply

I suggest reading God, the Failed Hypothesis: How Science Shows That God Does Not Exist for a talk about controlled experiments in search of God. [Mac Davis] 72.188.92.255 21:34, 6 February 2007 (UTC)Reply

It really depends on what you mean, if you mean. God does not 'exist' if you think of the bible or other such documents as theories, then yes, god is disproved, because a theory must be falsified (have proof). While personally I don't believe in a divine being(s), You really should do your own reading. Religion, god, etc, are all taken in faith, and thus, it's something personal, and something you much answer for yourself; does god exist?--Honeymane_{Heghlu meH QaQ jajvam} 23:18, 6 February 2007 (UTC)Reply

Mattb was right in saying that science, or at least empirical science, only works through present and observable events. While it's true that you can't absolutely prove the 10 plagues in Egypt because they're not repeatable events, evolution too falls upon the same rut. You cannot do evolution in a lab, (Although I have heard of scientists have claimed to do this by creating amino acids, which are not life, but merely the building blocks of life.) Evolution also has a lot of history that lacks evidence (ever heard of missing links?), putting both viewpoints in a state of controversy. This is because you can never prove through [empirical] science whether if God existed or not, or if evolution is fact or not because history is not repeatable through experiments (although you can reconstruct a past). Does that answer your question?

So what, does that mean we can rely on nothing now? Is everything just theory, and no one can ever be sure? Well, if that was true, then we can never prove anything in court, because all events took place in the past. But in a court they have what's called proof beyond a reasonable doubt (or if you want to do some further reading, read prima facie), which tells that while there is not enough evidence to absolutely prove something, it is enough to hold up in a court of law. However, there are a lot of arguments for both sides.

Those who support evolution quote of differentiation within species through allopatric speciation; those who support creationism (God created the world) ask why punctuated equilibrium relies on evidence of 'no change in species' to support that 'species do change'. Those who support God's existence quote first hand accounts of answers to prayer; those who reject this belief ask why can't people believe that was merely a 'freak accident'. Basically, both sides say that they're right. Yet what it really boils down to is not "which argument is right", but "which argument is more logical". Therefore, the court of law illustration is probably not the best one for this case, but a better one may be is two kids arguing about their past. So the answer is no, science cannot disprove God.

I hope I have answered your question thoroughly enough. For anyone who wants to know, I believe that God's existence is more logical. However, I have tried to provide sufficient evidence for both arguments, but if you do find any flaws to my answer, tell me, I'm not perfect. (As entertaining is the thought of having God answer questions on the Reference Desk, Bible text indicates Jesus wants you to receive Him personally [12]. :) ) I hope this helps, Darkhorse.--JDitto (talk to me!) 03:36, 7 February 2007 (UTC)Reply

Not meaning any disrespect, but your post indicates that you yourself are under several common misconceptions about what evolution is and what it asserts. Evolution and abiogenesis are different concepts, as I indicated earlier. It's untrue that evolution cannot be observed; it has been observed on many scales, from viruses to fruit flies. Further, you seem to be treading the line of misunderstanding what "theory" means in the scientific sense.

Please don't take this as an attack, I mean no ill will whatsoever. It's just that it really helps to be as informed as possible when discussing this subject. -- mattb @ 2007-02-07T05:24Z

It is rather natural for people to latch onto the idea that we can use reason and logic to decide what is true. Through millions of years of biological evolution, our brains have been crafted to do a good job of making such decisions about questions like: "Who has more bananas, Og or Urk?" Philosophers such as Wittgenstein have made the point that we easily get ourselves in trouble by using our intuitions, logic and reason to deal with abstract ideas that exist beyond the reach of objectively verifiable data. Proof is just an argument that other people accept. Carl Sagan suggested that we should all practice skepticism and apply this rule of thumb: "Extraordinary claims require extraordinary evidence." --JWSchmidt 05:18, 7 February 2007 (UTC)Reply

Here's another philisophy: we can always use reason and logic to decide "truth". The question of God however, falls outside of truth. truth has rules. Omnipotence has no rules and is therefore not subject to truth. The existence of God is a claim of Faith, not a claim of Truth. --Tbeatty 05:26, 7 February 2007 (UTC)Reply

To be valid, scientific theories have to be testable. The test may not be possible technologically, but it must be conceivable and not contradict the theory it is trying to prove. For example, the Theory of Relativity postulated certain relationships velocity, mass, time, energy and the speed of light. Actual measurements were then compared to the theory, which corroborated it. It is not "proved" but the lack of disprrof as well as it's ability to predict future events makes it science. In this context, the existence of an omnipotent being is non-testable because the outcome will be whatever the omnipotent being chooses (the beauty of being omnipotent). This simply moves the "question of God" out from being a question of Science to a question of Faith. They are complementary questions, not competing ones. --Tbeatty 05:26, 7 February 2007 (UTC)Reply

My own personal observation about evolution is that it is currently mostly an observable. Certainly there are genetic inheritance theories which have both testable, predictive value. But a lot of evolution is simply an obervable of current events. Much like the knowledge that an apple will fall from a tree and it occured long before Newton had his theory. Evolution has almost no predicitve value. Natural Selection is an obervable, not a theory. Sceintifically, we have no idea why certain species were "selected." We simply rationalize what is here vs. what is not but we can't predict what a future adaptation will be. What will the next predator on the Serengeti look like? What will the prey look like? We use the observables of extinct species and non-extinct species to try to identify what the distinction was, but we really have no way to predict what future species will out compete its neighbors. We only look in hindsight. If Hyenas live while Lions die we will look at distincitons and make broad claims. If lions live and hyenas die, we will rationalize their survivor traits. But we currently can't predict what Natural Selection means and what survivor traits are, only that some survive and some don't. We make up the rhyme and reason to fit the facts. --Tbeatty 05:26, 7 February 2007 (UTC)Reply

Nicely put. -- mattb @ 2007-02-07T05:45Z

Richard Dawkins' God Delusion has a chapter on why God is improbable (i.e. highly unlikely) and points out the fallacy in assuming that because two things cannot be proved 100% they must be treated equally. For example, noone can prove that fairies aren't pushing things down to cause gravity, but it's very unlikely, if it had been written down in a book nearly 2000 years ago people probably would believe it though! When it comes to something like the biblical plagues mentioned above. The statements made show the problems in disproving God. The Bible can make a statement about what God or Jesus did which is scientifically impossible. A sceptic might say science has proved this is impossible and therefore disproved God as described in the bible. A believer might say science can't explain this, therefore science is wrong (taking the truth of the bible as given). So how is it possible to prove or disprove God in these circumstances? But to me the likelihood of some supernatural being creating things seems much more unlikely than any scientific explanantion, when most of the evidence for God seems to be an old book, tradition and the fact that science isn't 100% perfect.137.138.46.155 08:17, 7 February 2007 (UTC)Reply

^^^ This made me remember about a old show i saw once. in it they brought up a question that stated something like this " was it god that created man or man that created god?" it does make me wonder like IP dude stated above all the proof of god is an old book. man could of created god to belive in something that something else something greater is out there. they might of used this as a way to explain how they came to be and now that science has found the truth they refuse to belive it because man is stubborn. BUT like i stated before i still have doubts about it but well we can only move forward and see what comes out of it Maverick423 14:34, 7 February 2007 (UTC)Reply

A lot of people seem to be ignoring the fact that the Judeo-Christian view of God isn't the only one. -- mattb @ 2007-02-07T17:31Z

Pet rats and Guinea pigs

Latest comment: 18 years ago1 comment1 person in discussion

What are the chief behavioral differences between pet rats and guinea pigs? --Andreas Rejbrand 21:22, 6 February 2007 (UTC)Reply

Search engine syntax

Latest comment: 18 years ago9 comments4 people in discussion

If I want to look for Martin Luther rather than Martin Luther King, what should I do? Let's say I want to list all ML-only, MLK-only and ML+MLK web pages, how do I do it? I just want to know it this is possible. This question is not specific to any search engine or database service (e.g., Internet and other proprietary databases). -- Toytoy 21:23, 6 February 2007 (UTC)Reply

"-King" without the quotes should be what you're looking for. Most search engines will exclude results containing a word with a minus in front of it. Additionally, putting a plus sign in front of a word will force results to contain it. You can also force the exact phrase to be searched for by putting it in quotes, as in "Martin Luther", but that may still pull up results about Martin Luther King if king has not been explicitly excluded. Cyraan 22:04, 6 February 2007 (UTC)Reply

-King or more specifically -"King Jr." will typically exclude all references to the man who "had a dream". The easiest way to look only for King is to search for, in quotes, "Martin Luther King". This will require "King" to be next to Martin Luther as a complete phrase. To get both, just search for "Martin Luther", but be aware that different search engines will optimize this differently (Google will return primarily hits about Martin Luther, not MLK, because of the way it indexes terms). --24.147.86.187 23:51, 6 February 2007 (UTC)Reply

It is possible to retrive "Martin Luther"-only entries: "martin luther" AND NOT "martin luther king".

-king, so search for Martin Luther -King, and in the unlikely event you get results for people names Martin, and people named Luther, use "Martin Luther" -king. On almost all search engines, putting a minus in front of a word will force it to exclude results that contain that word. Cyraan 05:00, 7 February 2007 (UTC)Reply

How do I retrive "Martin Luther King"-only entries? "martin luther king" BUT NOT "martin luther" will return nothing! I mean only "King" can go after "Martin Luther". -- Toytoy 04:52, 7 February 2007 (UTC)Reply

Put it in quotes, Martin Luther King will search for all of the words, no matter their placement on the page or order, putting it in quotes like this: "Martin Luther King" forces it to search for only that phrase, and only in that word order. Cyraan 05:00, 7 February 2007 (UTC)Reply

No "Martin Luther King" would retrieve entries with both "Martin Luther King" AND "Martin Luther". Example: "In 2000 B.C., Martin Luther King drove a second-hand Toyota to Nepal to visit Martin Luther." -- Toytoy 05:04, 7 February 2007 (UTC)Reply

Hmm, what search engine are you using? "Martin Luther King" on google doesn't turn up any results on Martin Luther for at least the first 5 pages (as far as I looked). On any engine I've used, using quotes forces only results that match the quoted phrase exactly to show up, if it doesnt have "Martin Luther King" in exactly that order, and containing every word, its not shown. "Martin Luther" might pull up both because both would match the quoted criteria, but thats where -king would come in. Cyraan 05:05, 7 February 2007 (UTC)Reply

I think the question is about pages that have both the strings "Martin Luther King" and "Martin Luther <X>" where <X> is anything other than "King". I think the answer is "you can't exclude these" (when looking for "Martin Luther King") and you probably don't want to, either. Searching for "Martin Luther King" will find pages that have this exact string on them, as well as pages that have this string AND other occurrences of "Martin Luther not King" and "Martin not Luther King" and "not Martin Luther King" and "not Martin Luther King", but all of them will have at least one occurrence of "Martin Luther King". -- Rick Block (talk) 05:37, 7 February 2007 (UTC)Reply

physics books

Latest comment: 18 years ago2 comments2 people in discussion

What is the best physics books escpecially in quantum physics for engineering ascpects?84.36.150.67 22:57, 6 February 2007 (UTC)mostafa elashramReply

Best is certainly a superlative. What criteria would you have us consider? If you're interested in QM (I'm assuming you don't yet have a solid grounding in the theory), a good introductory book is "Introduction to Quantum Mechanics" by David Griffiths. -- mattb @ 2007-02-07T03:11Z

P.S. - What field of engineering are we talking about? I'm a semiconductor person on the engineering side, but I can't think of too many other non-physicists outside the realm of semiconductors that would need to use QM regularly... Nuclear engineering, perhaps? -- mattb @ 2007-02-07T03:18Z

Material Sceintists working on solids (i.e. superconductors, carbon tubes, some polymers) use QM quite regularly. Optical engineers and people working on lasers use QM quite regularly. --Tbeatty 06:29, 8 February 2007 (UTC)Reply

Optical engineers might as well be physicists... -- mattb @ 2007-02-08T17:19Z

Rockoon

Latest comment: 18 years ago2 comments2 people in discussion

How powerful would a Rockoon have to be to reach the ISS? Lets say it was launched from 50Km and it was using todays technologies.67.126.140.7 00:08, 7 February 2007 (UTC)Reply

What do you mean "how powerful?" How much payload do you want it to carry to the ISS? Or do you just want to know the required delta-v? --Robert Merkel 07:41, 7 February 2007 (UTC)Reply

Saying I want to carry 12 tons of material to the ISS is the energy required the delta-v?

lightning

Latest comment: 18 years ago1 comment1 person in discussion

Where does lightning come frome? Aidan Age 9

I suggest reading our article on Lightning. Splintercellguy 00:51, 7 February 2007 (UTC)Reply

In a nutshell, lightning is the result of an electric charge buildup in the clouds. When charges are separated (the Earth itself has a charge), there is an electric field between those charged bodies. Once the electric field reaches a certain critical strength, the medium that separates the charged bodies (mostly air) breaks down (ionizes), creating a conductive path on which the charge may flow. This ionization and subsequent rapid current flow is what you see as lightning. -- mattb @ 2007-02-07T03:09Z

Reaction to rice...?

Latest comment: 18 years ago4 comments4 people in discussion

I have this strange reaction to rice: Whenever I cook a bowl of rice and add a can of vegetables or tuna or especially when I eat the cooked rice by itself it gets stuck in my Esophagus or if it makes it down gives me violent and quick sucession hiccups. What is going on? 71.100.10.48 01:53, 7 February 2007 (UTC)Reply

It would be helpful if you could elborate a bit more. Food getting tempoerarily stuck in the esophagus on its way down is a very common occurance (eating too fast, or trying to swallon too big lumps of food). If you've accidentally got sticky rice instead of normal rice, then i wouldn't be surprised at all. Hiccups is also a very common occurance, and generally do occur in quick sucession. Eating too fast also commonly gives people hiccups. I can't really see anything particularly strange in what you have described. --`/aksha 05:36, 7 February 2007 (UTC)Reply

• It could also be the result of something psychological. Do you like rice? If you don't, your dislike of the stuff is probably part of the reason why you're reacting this way. - Mgm|^(talk) 11:24, 7 February 2007 (UTC)Reply

I guess at a sticky rice theory - When I've boiled rice I often 'fry' (it's more like just heating through) in a big pan with a small amount of butter or oil - this really helps separate the grains - you could try that - and see if it still sticks. Hiccups often means you are eating too fast or swallowing too big mouthfuls - I get them all the time.83.100.251.239 12:26, 7 February 2007 (UTC)Reply

Car B has 5 times the mass of car A...

Latest comment: 18 years ago3 comments3 people in discussion

Car B has 5 times the mass of car A and car B has kinetic energy 25 times the kinetic energy of car A. What is the ratio:(speed of car B)/(speed of car A) 02:09, 7 February 2007 (UTC)

I do not think they answer test or homework questions on this board. 71.100.10.48 02:20, 7 February 2007 (UTC)Reply

Kinetic energy is calculated using E=1/2 mv^2m, which is 0.5 multiplied by the mass, multiplied by the square of the velocity. Try to work it out from there. --Bowlhover 03:12, 7 February 2007 (UTC)Reply

A prettier version: ${\displaystyle E={\begin{matrix}{\frac {1}{2}}\end{matrix}}mv^{2}}$  --antilived^{T | C | G} 11:06, 7 February 2007 (UTC)Reply

why is there no native human population in Antarctica?

Latest comment: 18 years ago7 comments5 people in discussion

Is it because it is simply too cold or infertile for human life, or is it because there were simply no humans there when continental drift occurred? The Mad Echidna 02:50, 7 February 2007 (UTC)Reply

Well a) continental drift is still occurring; but b) the answer is (your) a. Humans had not yet evolved by the time Antarctica was split off. Anchoress 02:58, 7 February 2007 (UTC)Reply

Also, since Antarctica is such a harsh environment, with little flora and fauna, even if there had been humans on it when it separated from the other continents, there is a good chance they would have died out as it drifted further south towards its current ___location, and its climate and ecosystem became progressively more inhospitable. Maelin (Talk | Contribs) 03:52, 7 February 2007 (UTC)Reply

Your guess is as good as any. The reality is that if there were people in antarctica and the question was "How did people evolve in Antarctica?" there would be just as valid scientific answers as the variables and permutations on life are nearly infinite. --Tbeatty 05:53, 7 February 2007 (UTC)Reply

Antarctica broke apart from South America about 23 mya. Modern humans only evolved around 100,000 years ago, and the split between what would eventually lead to humans and chimpanzees occurred 6 mya. In fact, according to Dawkins' The Ancestor's Tale it was only 25 mya that humans, chimps, gorillas, orang utans, gibbons, and Old World monkeys all shared a common ancestor! − Twas Now ( talk • contribs • e-mail ) 06:57, 7 February 2007 (UTC)Reply

Hawaii is newer than Antarctica and has people. They came by boat. I believe the latest genome studies show a "necking" in species which corresponds to a near die out (i.e. a very concentrated population) in the recent past. I don't think the species has been around long enough to support a theory that continents broke off and isolated people (but this is just a guess). I think it's more likely that constant growth away from the center created trait reinforcements. But rarely was isolation a barrier to establishing human cultures. Plenty of islands and continents are inhabited by migration either over land or by boat. --Tbeatty 06:23, 8 February 2007 (UTC)Reply

You are right, Hawaii was only colonized about 1,500 years ago—something I always find remarkable! However, I made the implicit assumption that, though it has been possible to sail to Antarctica for probably thousands of years, it is highly improbable that, since the evolution of modern humans, one would sail to Antarctica and decide to stay there, along with a group large enough to perpetuate the intrepid colony until modern times. It was improbable that Pacific islanders would sail to Hawaii, but once this event did happen, there was incentive to stay since the Hawaiian islands can support diverse macroscopic wildlife (both plants and animals), as opposed to lichen, rotifers, and penguins. − Twas Now ( talk • contribs • e-mail ) 10:25, 8 February 2007 (UTC)Reply

These are the same reasons why noone should have been living on australia until recently, but they were

electromagnetic pump

What equations govern the force exerted by a magnetohydrodynamic (electromagnetic) pump on the fluid running through it?

The Lorentz force is a good starter. ${\displaystyle {\vec {F}}=q({\vec {v}}\times {\vec {B}})}$ . -- mattb @ 2007-02-07T05:14Z

Basis for claims about the economic cost of poor eyesight (among other things).

Latest comment: 18 years ago3 comments3 people in discussion

I heard once on the radio that poor eyesight costs the Australian economy something like $1 bn. a year, or something like that (it may have been in the 100s of millions instead). How do people work out the economic costs of things like that? The Mad Echidna 07:24, 7 February 2007 (UTC)Reply

They buy glasses, and a new industry is born! Are you referring to the cost of eye care or the cost of incidents directly caused by less than optimal visual acuity? --66.195.232.121 15:14, 8 February 2007 (UTC)Reply

Yes, this refers to the economic costs of having poor eyesight. Economists are very talented guessers, who know how to use simple mathematics in order to substantiate their assumptions. − Twas Now ( talk • contribs • e-mail ) 15:21, 8 February 2007 (UTC)Reply

Just pulled out my bird's tail feathers by mistake

Latest comment: 18 years ago12 comments6 people in discussion

I was just trying to catch my budgie to give him his eye drops when I accidentally pulled out most of his tail feathers. He doesn't like being picked up and he flutters/runs all around his cage to get away from my hand. He's very quick. I thought I had him but he managed to slip through my fingers as my grip closed on him, so I only had him by the back end. He pulled away before I could reposition my hand, leaving me holding his long tail feathers.

The tips of the feathers have blood on them and he squeaked in pain when they came out but he's not bleeding from his body. He's just sat there looking unhappy now, giving me evil looks, shaking his backside and preening a lot.

Will his tail grow back eventually? --84.64.216.148 08:47, 7 February 2007 (UTC)Reply

According to the article on feathers, "a bird's feathers are replaced periodically during its life through molting, new feathers are formed through the same follicle from which the old ones were fledged." Do you know the state of the follicle? − Twas Now ( talk • contribs • e-mail ) 09:29, 7 February 2007 (UTC)Reply

No, sorry. I don't want to pick him up again and stress him out today. I wouldn't even know what I was looking for if I did anyway. :( --84.64.216.148 10:46, 7 February 2007 (UTC)Reply

If there was no substantial bleeding, he should be okay. Birds molt at least once a year and new feathers ought to turn up at that time. I actually wonder about the feathers pulling out; it sounds like it happened relatively easily. Maybe it's already molting time where you are?

There's a slight risk that your budgie will become habituated to not having those feathers,and may pick them out when they start to grow again, but I think this is a low risk for tail feathers. On the other hand, I could introduce you to one Sun conure who has become very habituated to having a naked chest :-(.

Atlant 13:20, 7 February 2007 (UTC)Reply

What do birds actually need tail feathers for, they don't seem to have any use, so don't worry about them:]Hidden secret 7 19:36, 7 February 2007 (UTC)Reply

Haha, what? How about for steering themselves, and keeping themselves upright in flight? Please don't buy birds, Hidden secret. − Twas Now ( talk • contribs • e-mail ) 20:09, 7 February 2007 (UTC)Reply

Yeah, the OPs budgie will steer like a brick until the new feathers grow in (which I'm pretty sure they will - I've accidentally broken/pulled the odd feather from my birds over the years when trying to catch them). Just be careful that he doesn't bang himself on something when he's flying until he figures out how to compensate. --Kurt Shaped Box 22:31, 7 February 2007 (UTC)Reply

A bird's tail feathers perform the same purpose as the spoilers, air brakes, elevator, and rudder of an airplane. --Carnildo 22:34, 7 February 2007 (UTC)Reply

So, why is it that different species of bird have different sizes and shapes of tail plumage? Compare a budgie's long, flared tail to the short fan-shaped tail of a gull for instance. --Kurt Shaped Box 22:46, 7 February 2007 (UTC)Reply

A budgie-style long tail would be a real pain-in-the-ass when the gull is sitting on the water.

Atlant 01:15, 8 February 2007 (UTC)Reply

Due to my favourite kind of selection pressure, sexual selection! Peacocks and birds of paradise have beautiful plumage because of selection by females. − Twas Now ( talk • contribs • e-mail ) 10:33, 8 February 2007 (UTC)Reply

Which brings us back to another question of mine - how the hell *do* gulls pair up in the first place, when they seem to live in a state of constant war with every other gull and living thing in the immediate vicinity? The only time gulls seem to interact with other gulls is to fight or chase them away. I've never noticed anything that I could even remotely comprehend as 'courtship behaviour' (unless courtship in gulls involves the cock and hen fighting each other) in these critters. I suddenly start noticing pairs of gulls stood quite close together - and not fighting each other. Then they make a nest and presumably have sex. --Kurt Shaped Box 12:09, 8 February 2007 (UTC)Reply

Meatomy

Latest comment: 18 years ago2 comments2 people in discussion

How do you define the medical term, meatomy?

• Try reading this site. Basically it involves a scalpel and a penis. - Mgm|^(talk) 11:21, 7 February 2007 (UTC)Reply

(Site doesn't seem to work? I'm not sure if I should be pleased about that!)83.100.251.239 14:06, 7 February 2007 (UTC)Reply

See Meatotomy. I could be more used to it, but the pictures are ok. 07:06, 8 February 2007 (UTC)

x-rays

Latest comment: 18 years ago1 comment1 person in discussion

i want information of x-rays

• Try reading our article on x-rays. - Mgm|^(talk) 11:18, 7 February 2007 (UTC)Reply

green electricity

Latest comment: 18 years ago7 comments6 people in discussion

What is the need for using green electricity in place of hydroelectricity? How is it useful? - Manavsi 11:54, 7 February 2007 (UTC)Reply

Well, there isn't enought hydroelectricity in many regions / countries. Also hydroelectricity isn't *that* green in certain areas - it is suggested that if you are flooding large areas of forest without having cleared away the vegetation then the anaerobic breakdown of it will cause enough methane to be released to offset CO2 savings from the dam for a couple of decades. --Neo 12:54, 7 February 2007 (UTC)Reply

I'd suggest that the total CO₂ available in say 10 square kilometres (is that reasonable for a resovoir) is piddling compared to the savings from the hydroelectric generation..Or look at it this way - if you burnt all the stuff in the flooded area to make electricity - how long would that last at the same level of production of power - it's nothing like decades.83.100.251.239 13:11, 7 February 2007 (UTC) Sorry - ignore me I was in unreasonably grumpy mood.!83.100.251.239 14:05, 7 February 2007 (UTC)Reply

It doesn't strike me as unreasonably grumpy! The reservoirs in question as well were (I'm recalling more of the article) those in places like the rainforests (so lots of plant matter) and in areas which only feature relatively shallow grades (so a large area of lands flooded). Plus its not CO2, but the global warming effect of the methane released which is at issue - hydropower is pretty much inevitably preferable in terms of CO2. --Neo 14:56, 7 February 2007 (UTC)Reply

Creating dams is not "green". They flood large areas, which further reduce habitat for flora/fauna of that region. It is like building a giant city all at once. Limnodynastes depressus was lost to science for 30 years (thought extinct), because its only known habitat was flooded by a dam. It has since been found elsewhere, but there is very little knowledge of it because nobody knew where it was for a long time. Also, the fact that it could have been completely wiped out because of a single dam doesn't justify it for me. I'm not totally against them, but there needs to be a lot of environmental considerations to take place before it happens. The Australian Greens movement of the present began with the opposition to an hydroelectric dam. --liquidGhoul 14:50, 7 February 2007 (UTC)Reply

It does not necessarily equal burning the submerged trees all at once. An article in a recent Popular Mechanics or Popular Science or some such told of billions of dollars worth of mature timber submerged but still harvestable after many years under water. The waterlogged and barkless timber can be sawn off at the base after a flotation bag is attached, by a robot submersible with a long chain saw. It is collected by a barge and taken to a sawmill. It goes from being a hazard to navigation when the water level is low, to being a resource, with a special "green" tag added to the final product when the lumber or furniture is sold at retail, so it can be sold at a premium. Edison 21:38, 7 February 2007 (UTC)Reply

Ah the cynic in me gets to come out. It's a truism that all substantial sources of energy in an industrialized country are, by definition, not "green." Therefore, Hydroelectric energy was green until it was built. Wind farms were green until they were builty. Nuclear was green until they were built, etc. --Tbeatty 06:07, 8 February 2007 (UTC)Reply

More possible chess moves than particles in the universe

Latest comment: 18 years ago10 comments5 people in discussion

I've heard it said that there are possible moves in a game of Chess than there are particles in the universe. Has anyone else heard this and does anyone know if it is true; it sounds absolutely ridiculous to me but I have no proof.--Ukdan999 12:20, 7 February 2007 (UTC)Reply

From Chess#Mathematics_and_computers: "..the number of legal positions in chess is estimated to be between 10^43 and 10^50, with a game-tree complexity of approximately 10^123.."

So thats half the question answered. The number of possible moves will be much greater than 10^43.83.100.251.239 12:40, 7 February 2007 (UTC)Reply

But surely there are way more particles in the universe. If there are around a 200-400 billion stars in our galaxy and around 100 billion galaxies in the universe, that's many trillions of stars, each with possible planets orbitting them. So how many particles in a typical star. And that's not even counting all of the asteroids and other bits and bobs floating through space. --Ukdan999 12:50, 7 February 2007 (UTC)Reply

I don't know but I'll ask - then the answer will come..

OK assuming most of the mass of the solar system is the sun, and most galaxyies are similar and have suns like are own that gives.. mass of sun = ~2x10³⁰kg x ~300x10⁹ (suns in galaxy) x ~100x10⁹ galaxyies per universe = ~60,000x10⁴⁸ = ~6x10⁵² kg of matter in the universe... Assuming most of that is hydrogen atoms that gives ~6x10⁵⁵ moles of hydrogen = ~6x10⁵⁵ x ~6x10²³ (atoms per mole) = 36x10⁷⁸ atoms... So thats still less than the number of chess games that can be played - but more than the number of positions..83.100.251.239 13:05, 7 February 2007 (UTC)Reply

Now given that for each position in a game of chess there is a maximum of ~150 moves (usually less) the total number of possible moves can be estimated by

moves per position x number of positions

which equals 10⁵⁰ x 150 = 1.5x10⁵²

That's many times less than the number of atoms, in fact 36x10⁷⁸ atoms/1.5x10⁵²positions = 2.7x10²⁷ times less.

ie there are around 2,700,000,000,000,000,000,000,000,000 times more atoms in the universe than there are moves in a chess game (very rough estimate)

You were right.83.100.250.165 14:36, 7 February 2007 (UTC)Reply

According to the article on atoms, there are approximately ~10⁸⁰ in the universe. Please remember to do some research before asking questions. − Twas Now ( talk • contribs • e-mail ) 20:14, 7 February 2007 (UTC)Reply

It's a fair point you make - but sometimes info is difficult to find - I would have never thought of looking in 'atom' for that - though I did look in 'universe' obviously..83.100.250.165 20:18, 7 February 2007 (UTC)Reply

Keep in mind that, when such estimates use the term "universe", they're generally talking about the observable universe; that is, that part of the universe that's close enough to have been influenced by the same event in the past. There may well be infinitely many particles in the whole universe. --Trovatore 20:17, 7 February 2007 (UTC)Reply

I don't believe that current scientific theories support that as a possibility, but I could be wrong, and for that matter the theories could also be wrong.

Anyway, I'd just like to point out that the original question referred to the number of possible moves in a game of chess. This is not a gigantic number. For example, a white rook could start on any of 64 squares and move from each one to any of 14 other squares, where either it won't capture or it will capture one of 5 possible black men, and there are also 2 ways to castle. That's 64x14x6 + 2 = 5,378 possible white rook moves -- actually less because there are some squares where there couldn't be a black pawn to be captured. You could increase the count if you say that rook from a1 to d1 giving check is a different move than rook from a1 to d1, or if you distinguish which rook (according to its original starting point) is moving, or which black pawn is captured, that sort of thing. The total number of possible moves in chess, depending on your definitions, might be something like 100,000 or 1,000,000 or maybe even 10,000,000... but it isn't going to be something gigantic.

The way the gigantic numbers arise is by considering the total number of positions, or even more, the total number of different possible games. Note that these are the numbers quoted above.

--Anonymous, February 8, 2007, 01:18 (UTC).

"Current scientific theories" do indeed support the possibility of an infinite (and infinitely massive) universe. There's a discussion in the observable universe article; also, you can look in Wikipedia talk:WikiProject Physics (or maybe its archives); I raised the question there some time ago. Search for "inflaton". --Trovatore 01:20, 8 February 2007 (UTC)Reply

Thanks for all the responses! So, to summarise, there are NOT more possible moves in a game of chess than there are particles in the universe. However, there ARE more possible games of chess than particles in the universe. This seems a lot more realistic to me than the original statement. Thanks again. --Ukdan999 01:31, 8 February 2007 (UTC)Reply

No. of particles in the universe

Latest comment: 18 years ago3 comments2 people in discussion

See Wikipedia:Reference_desk/Science#More possible chess moves than particles in the universe Could someone who knows please give us the (estimate of) the total number of particles in the universe. Thank you.83.100.251.239 12:56, 7 February 2007 (UTC)Reply

Google says somewhere between 10⁷² to 10⁸⁷. -- mattb @ 2007-02-07T13:19Z

Thanks83.100.251.239 14:02, 7 February 2007 (UTC)Reply

Observable universe#Matter content give a lower-limit estimate of 10⁸⁰ atoms in the universe. DMacks 14:54, 7 February 2007 (UTC)Reply

Searching for machine meant for washing biodiesel

Where to find or any relevant website to search for high tech machine for washing biodiesel...?

dynamometers

How long do typical racing car engines run over a race weekend? How many horse power does a typical F1 engine produce during pre-race testing? How many horse power does a typical saloon racing car produce during pre-race testing?

some questions about trees

Latest comment: 18 years ago5 comments3 people in discussion

A few years ago I decided to grow some trees from seeds, a horsechesnut and some oaks. Both of these are supposed to be deciduous, and since it is winter, none of them should have leaves on. But they do. So I have a few questions about leaves:

1 My horsechesnut tree started growing new leaves at the begining of january. Is there any reason why it would do this? 2 And will it have any effect on the health of the tree? 3 Some of the leaves on this tree haven't opened yet, is it normal for some leaf buds to open weeks after the others? 4 My oak trees have had the same leaves on them since they first grew, shouldn't they fall off every year? 5 These leaves are also sharp around the edges, like holly leaves. Is this normal for this sort of tree?

Seriously, what is going on with my trees?

Hidden secret 7 15:42, 7 February 2007 (UTC)Reply

Hello, is anyone there:? Can't anyone help me with this:(HS7 17:44, 8 February 2007 (UTC)Reply

How's the weather out there? − Twas Now ( talk • contribs • e-mail ) 17:48, 8 February 2007 (UTC)Reply

It's snowing a bit:)HS7

Maybe you have live oaks. − Twas Now ( talk • contribs • e-mail ) 18:37, 8 February 2007 (UTC)Reply

1.Could it be that you have had warm winters; not cold enough to cause the leaves to drop off -

2.This can be a problem in some plants as a sudden frost in Feb can kill the leaves harming the plant..

3. Leaf buds not opening - are the trees in pots or in the ground - if they were grown initially in pots and are still in them they might have reach the capacity of the pot - preventing any further leaf developement (root growth not sufficient)

5. Sharp - with points? The oak 'seed' is an acorn right? Just checking. Oak leaves are 'lobed' in my experience - though checking the article oak reveals that some species can have pointed leaves - see Oak#Classification - can you clarify - sorry I can't be much help.87.102.37.185 18:44, 8 February 2007 (UTC)Reply

We do usually have mild winters, which could have something to do with it:) I don't know exactly what type of oak they are, unfortunately:( And the leaves had already fallen off the horsechesnut, and more grew this year:) But I expect you are right about them being an unusual specis of oak:)HS7

Why do we have faces?

Latest comment: 18 years ago6 comments5 people in discussion

As silly as the headline seems, it is my question.

Most larger lifeforms on Earth have readily identifiable faces. Infants can differentiate between the face ends of animals. It's relatively easy to identify the 'face' of a fly, a spider, a bear, a pig, a flounder, a whale, etc.

How is it that life on Earth evolved with the vast majority of the critter having similar facial structures? Why don't some beasts have their mouths in their abdomens, near the stomach? Or their eyes in the palm of their hands, to raise them higher to see farther? Or their noses in their feet to facilitate tracking?

Why are most animals arranged in the two eyes, nose, mouth conformation?75.74.243.218 16:45, 7 February 2007 (UTC)Reply

Without giving an answer why not take a look at Symmetry (biology)#Bilateral_symmetry for a few reasons, and don't forget that not all animals have bilateral symmetry.

Note that the ability to move (with some speed - not crawling like starfish) demands a streamlined - eg linear shape (fish for example) - by extension to this putting the mouth and eyes at the front makes it more likely to catch food.. So that would be a reason to have mouth and eyes and other sensory organs - at the top/front.

Note that very slow animals often don't have bilateral symetry and often have the mouth in the middle - hope that helps.83.100.250.165 17:04, 7 February 2007 (UTC)Reply

A notable exception to your example is squid and their relatives - there's a lot of squid.. they also seem to match your description of "..mouths in their abdomens, near the stomach? Or their eyes in the palm of their hands.." to a certain extent..83.100.250.165 17:40, 7 February 2007 (UTC)Reply

Consider that the mouth is involved in lots more than just "getting food in, headed towards stomach". See also cephalization. DMacks 17:08, 7 February 2007 (UTC)Reply

It would seem useful to be able to see and smell what you are about to eat. A second eye adds a wider field of vision, Stereopsis when the two eyes face front as in humans and other Predators, and a spare when one gets injured.Edison 21:31, 7 February 2007 (UTC)Reply

There is good developmental and anatomic reasons for why the eyes, nose, ears and mouth (for tasting) are in close proximity to the brain. And there is good reasons for why the brain is found at the end of the spinal cord. Its also a good evolutionary strategy to have your sense organs facing the direction your move. Add all these together and you get the basic body plan - including the recognisible face - that is found almost ubiquitously in the chordates (at least, in Craniata) and in many invertebrates too. While its most likely that the facial arrangement is homologous (i.e our last common ancestor has a face like structure), its possible that a similar structure evolved multiple times. When a strategy works, nature tends to favour it (see convergent evolution). Rockpocket 23:35, 7 February 2007 (UTC)Reply

Space

Latest comment: 18 years ago9 comments5 people in discussion

I've moved this question from Wikipedia:Reference_desk/miscellaneous so that you are more likely to get a good response...83.100.250.165 17:10, 7 February 2007 (UTC)Reply

If a seed is germinated on earth, the roots go down while the leaves reach upward toward the sun, I assume this has something to do with gravity, thus allowing the roots to know where down is. So, in space, if one were to germinate a seed, a)would it germinate b)would it do so in an effective manner.

And as a second question. Menstration cyles in women are, or so i am told, coincide with the moon, (much like ocena tides) hence every 28 days. How would this be affected in a) zero gravity b)when out of the pull of the moon and c) if one were on another planet which had serveral moons or (b) no moons.

Thanks guys Mr Anonymous 81.144.161.223 16:08, 7 February 2007 (UTC)Reply

I doubt it has so much to do with gravity as with the roots seeking soil nutrients and the leaves seeking sunlight. So I imagine that they would do fine in space, see hydroponics? Just a brief mention there. -- Justanother 16:18, 7 February 2007 (UTC)Reply

Question 1. You should look at Root#Root_growth " At germination, roots grow downward due to gravitropism, the growth mechanism of plants that also causes the shoot to grow upward" - so lack of gravity will be an issue... I can't say more..83.100.250.165 17:43, 7 February 2007 (UTC)Reply

Excellent point. Here and here are some links. The first is a proposed experiment and the second an actual, if casual, experiment. In the casual experiment the plants did not grow because capillary action appeared to be stronger than the reach for light. A substrate might be designed that could negate that effect. --Justanother 18:02, 7 February 2007 (UTC)Reply

From a NASA chat session[13]

[ Yuli_Berkovich - 216 - 18:00:47 ]

RE: [ Does gravity affect your plant growth significantly?

Of course, gravity affect all plants significantly. Fortunately we can replace influence of gravity on root and stem orientation by means of another environmental stimulus: light distribution for stems and water distribution for roots.

--Justanother 18:09, 7 February 2007 (UTC)Reply

Regarding the second question, see Menstrual cycle#Etymology_and_the_lunar_month and Menstrual cycle#Menstrual_cycles_in_other_mammals, and be careful to avoid presuming that correlation means causation. DMacks 18:24, 7 February 2007 (UTC)Reply

Related to this, what experiments have been done to test the growth of plants in space? A greenhouse would have abundant sunlight, would help in some small way to convert carbon dioxide back to oxygen, and could furnish tasty sprouts and greens. It would be useful on a Mars mission and probably essential (with artificial light) on interstellar mission, manned stations away from Earth or Space colonization. Biosphere 2 has experimented with this in an Earth-born environment. What experiments have been done on seed germination and hydroponic gardening, in all of the history of the space program? Edison 21:20, 7 February 2007 (UTC)Reply

Well Googling on Yuli Berkovich I came up with this and this. Yuli seems to be "Da Man". --Justanother 22:14, 7 February 2007 (UTC)Reply

I greatly appreciate your help, and the answer the first part of my question, was very interesting, and thanks goes out to all responsible. However, to come back to the second part of my question. I have read the article on Menstrual cycle#Etymology_and_the_lunar_month How ever if one looks at the cite, I do not belive this to be conclusive as A) it was done by men. and B) they class their book with the paranormal!?!? There is nothing abnormal about menstration. : ^ As cited by Adams, Cecil, "What's the link between the moon and menstruation?" (accessed 6 June 2006): Abell, George O.; Barry Singer (1983). Science and the Paranormal: Probing the Existence of the Supernatural.

So concerning interplanetary colonization and space expolration in general, could any one help further with the above question? Thanks guys, and Ladies.

What is it that causes different meat to taste a different way?

Latest comment: 18 years ago3 comments3 people in discussion

Hi all, I am wondering why different meat that's unspiced still tastes a different way, ie beef and chicken, pork and fish. I understand that they are in different Classes biologically, but what is it specifically that alters their taste, in scientific terms? Do different proteins taste differently or what? Much help appreciated ! Xhin 18:42, 7 February 2007 (UTC)Reply

I'm not really qualified to give a full answer but this : http://www.madsci.org/posts/archives/Mar2003/1048043552.Gb.r.html may help..

It seems then that the maillard reaction is responsible for causing the formation of certain flavoursome compounds in cooked meat. I'm sure that's not the only factor.83.100.250.165 19:38, 7 February 2007 (UTC)Reply

Umami might be part of the answer. --JWSchmidt 01:48, 8 February 2007 (UTC)Reply

Alps and Mountains

Latest comment: 18 years ago3 comments3 people in discussion

What is the difference between alps and mountains? In Europe there are both alps and mountain ranges; why the dirrence?

The Alps are a specific mountain range:) But alpine areas are places with mountain like climates and vegetation, usually on mountains:)Hidden secret 7 19:33, 7 February 2007 (UTC)Reply

"Alp" does mean "any high, especially snow-capped, mountian" OED, but it is mostly used as such only in poetic or jocular contexts these days. The etymology is "said by Servius to be of Celtic origin, and variously explained as meaning ‘high’ (cf. Gaelic alp a high mountain, Irish ailp) and ‘white’ (cf. L. albus).]" OED. --Shantavira 08:40, 8 February 2007 (UTC)Reply

The description of a mountain range as 'alps' is quite common eg 'altai alps' 'himalayan alps' - I imagine it is necessary for the mountain to have snow on top to truly fit the description..87.102.2.204 10:06, 8 February 2007 (UTC)Reply

Changing Iris Color

Latest comment: 18 years ago3 comments3 people in discussion

What are some of the reasons that an iris will change color? Are their any possible ways to change it, say from dark brown to light brown?

Whilst you wait for a proper answer I can suggest that you look at Iris (anatomy)#Color, and maybe Eye color - it seems that melanin (as found in hair) is responsible for all the brown colour in eyes - and that it's levels can increase with age.. Also disease may cause an iris colour change..83.100.250.165 20:42, 7 February 2007 (UTC)Reply

Someone (probably a sceptic) has removed my answer:( But I searched on the internet and apparently medical treatment with iodine can also affect iris colour:)Hidden secret 7 20:48, 7 February 2007 (UTC)Reply

Something that should not have been removed is that you can get contact lenses with different colors.

Some treatments for glaucoma, such as prostaglandin analogs, are known to change eye colour in maybe 10% of patients. Its thought that prostaglandin acts on eye colour by mimicing a natural hormone that mediates melanin production. People have reported that when they are ill or under stress that their eye color becomes darker or lighter. A modified version of the pigmentary hormones are also produced during stress (and when you stress fish and frogs, they change colour for this very reason, see chromatophore). Rockpocket 23:13, 7 February 2007 (UTC)Reply

Just as an aside, I had a friend, Jaffa, whos eye colour would change with his moods, i cant now remember the corrolation but it was for example Brown when happy, green when sad, blue when arroused ect.

Are you sure it wasn't green for worried, black for angry, pink for embarrased...

As I said I dont remember the Emotional colour correlation.

Spinal cord syndrome by french doctor?

Latest comment: 18 years ago2 comments2 people in discussion

I am looking for a french doctor that had a syndrome named after him. The main symptoms were when you bend your head down you get numbing and pain radiating down your arms and legs. I am unsure how to spell his name and need the correct spelling and are also looking for specifics on this syndrome.

Probably not "Maladie de Charcot, after the French doctor Jean-Martin Charcot" ??83.100.250.165 20:21, 7 February 2007 (UTC)Reply

I suspect we're talking about L’Hermitte’s sign, named after Jacques Jean Lhermitte (or Jacques Jean L'Hermite) - Nunh-huh 03:47, 8 February 2007 (UTC)Reply

Lewis dot structure for XO32- (X = F,Cl,Br,I)

Latest comment: 18 years ago5 comments2 people in discussion

For the hypothetical compound XO32-, what would the most reasonable lewis structure be? I can think of two possibilities:

1) Two X-O single bonds, one X=O double bond. The singly bonded oxygens carry a negative charge, and the halogen carries a lone pair and an unpaired electron and is uncharged.

2) Two X=O double bonds, one X-O single bond. The singly bonded oxygen carries an unpaired electron and is neutral, the halogen carries three double bonds and a charge of -2.

Option two requires 16 valence electrons on the halogen and is unreasonable for fluorine. It does place the charge on the most electronegative atom for Cl,Br,I.

I ask this because I have been asked to draw the molecular shape of this compound. Am I correct in thinking both options give T-shaped geometry (making the point moot)? Thanks for comments 132.194.13.115 20:49, 7 February 2007 (UTC)Reply

OK before I start you wrote XO32 - did you mean XO₃ or X₂O₃ ???83.100.250.165 20:58, 7 February 2007 (UTC)Reply

Right did you mean XO₃^2-..83.100.250.165 21:02, 7 February 2007 (UTC)Reply

If so the theoretical ion is a radical anion, see radical (chemistry) - in terms of a lewis structure it has an unpaired electron - there are an odd number of electrons.

I get

Three X-O single bonds, each O is singly charged, the X is positively charged and carrys an unpaired electron - it has also expanded it's octet to 9 electrons.. (supposedly impossible for F)

Each X is bonded to three O's and has 3 electrons remaining - This should give a 'distorted tetrahedral' structure - the O-X-O angle will be the same between all combinations of O. Alternatively the molecule could be a trigonal bipyramid with O's expected around the middle - giving an O-X-O bond angle of 120degrees.

(see Trigonal bipyramid molecular geometry83.100.250.165 21:24, 7 February 2007 (UTC)Reply

Personally I'd look at the effect of adding one electron to the stable structure ClO₃^- - though I'd be thinking in terms of molecular orbitals - which may not be much use to you? - I'd expect the extra charge to be delocalised ie the structure would consist of resonant hybrids (see resonance (chemistry) - and I find it difficult to accurately predict a structure.83.100.250.165 22:22, 7 February 2007 (UTC)Reply

Beta particle capture surface...?

Latest comment: 18 years ago3 comments3 people in discussion

 

Would the surface shown above provide better capture of Beta particles than a flat surface and how high a voltage differential would there be between the two plates in a vacumn? (This is not a test or homework question BTW.) -- Barringa 21:40, 7 February 2007 (UTC)Reply

im not an expert on this, but I think there is really no limit (apart from leakage or vacuum breakdown) to the voltage difference that could be created.--DarkFuture 22:17, 7 February 2007 (UTC)Reply

 

Nikola Tesla's
"Lightning-Protector"
U.S. patent 1,266,175; An early type of dissipater-arrester, which purported to prevent and safely dissipate lightning strikes

Charge accumulates on sharp points (i.e. areas with small radius of curvature). See lightning rod. Nimur 19:33, 8 February 2007 (UTC)Reply

Moon east

Latest comment: 18 years ago4 comments3 people in discussion

From Wikipedia:Reference_desk/Science#Reversed West and East on the Moon?.

What direction is east on the moon - according to astronomers, spacemen, scientists etc.

83.100.250.165 21:52, 7 February 2007 (UTC)Reply

Or if east/west is not used - what system is used to define points on the moon?83.100.250.165 22:08, 7 February 2007 (UTC)Reply

Per JPL, the moon has its own system of latitude and longitude with the lunar prime meridian at the center of the near side. Presumably, the center is averaged to account for lunar libration.

Of course, there's no telling what spacemen might use for a coordinate system. — Lomn 22:53, 7 February 2007 (UTC)Reply

OK there are multiple ways.. Thanks - not knowing was really starting to irritate.87.102.2.204 09:59, 8 February 2007 (UTC)Reply

Paleozoic marine animal name

Latest comment: 18 years ago2 comments2 people in discussion

I am trying to remember a name of a Paleozoic marine animal. I'm pretty sure its name starts with "dunkleo-", but I cannot find the remainder of the name, and I do not know how one would go about doing Wikipedia- or Google-searches for partial words. The creature is very distinct-looking for its very strange layer of teeth which appear to be all one jagged structure, like a continuation of the jaw bone. 206.176.113.70 22:05, 7 February 2007 (UTC)Reply

Dunkleosteus - I searched for "paleozoic marine" on google by the way.83.100.250.165 22:10, 7 February 2007 (UTC)Reply

Orbital characteristics

Latest comment: 18 years ago1 comment1 person in discussion

In the planet infobox, (as used here and in other planet articles), under orbital characteristics, four of the parameters are for aphelion, perihelion, semi-major axis, and semi-minor axis. How/why is the first pair different from the second?

--Awesome 23:52, 7 February 2007 (UTC)Reply

The two pairs give two ways of describing the shape of the orbital ellipse. The aphelion and perihelion points are at opposite ends of the major axis, so the aphelion distance (A) and perihelion distance (P) are related to the semimajor axis (a) by 2a = A + P. The minor axis is perpendicular to the major axis and runs through the center of the ellipse (halfway between the Sun and the other focus). The semiminor axis (b) is not a very useful number for astronomical purposes, but it's related to the other quantities by (thinks a moment) a² = b² + ((A-P)/2)². --Anonymous, February 8, 2007, 01:29 (UTC).

Species and Speciation

Latest comment: 18 years ago13 comments5 people in discussion

I thought that the thing separating species was that interbreeding between two different species was either impossible, or would not result in fertile offspring. So how does a new species evolve considering that it could not be the progeny of the species it evolved from? Is my definition of species incorrect? Is it not an absolute? Have I missed something? Is this a problem for the theory of evolution?—The preceding unsigned comment was added by 129.15.131.247 (talk • contribs).

Speciation occurs gradually, and often when a population of organisms is separated into subgroups by a natural phenomenon (e.g. a landslide, or continental drift, or just gradual migration). The subgroups of the population each evolves independently, responding to the pressures of their environment. Over time, they could adapt in different ways, until eventually the genes of one group are no longer compatible with the genes of the other. Maelin (Talk | Contribs) 04:16, 8 February 2007 (UTC)Reply

First of all, there are several definitions of species. You are referring to the "Biological / reproductive" concept. New species would evolve when separate populations of the same species become separated and evolve in different ways. For example, suppose there is a species of fish in a lake, and that lake dries up, leaving only puddles with fish in them. Over time, the different puddles may evolve different types of fish. When the water levels rise again, and the fish are all together again, there will potentially be more species. − Twas Now ( talk • contribs • e-mail ) 04:17, 8 February 2007 (UTC)Reply

No, no, I understand the patric speciation and how a group of one species can be split apart for whatever reason and therefore be subjected to different environments, each requiring different adaptations, but within each of those split groups, how would the population change into a new species? Eventually, wouldn't a member of the old species have to give birth to a member of the soon to be new species? What does that member of the new species mate with to increase the population of the new species? Would 2 mutants with similar adaptations and opposite sex have to be born around the same time so that they can increase their numbers? Is there some absolute cut-off point for the possibility of reproduction, or is it instead increasingly improbable that viable offspring will be created from a mating of two different species based on the number of genetic differences, meaning that a human and monkey could in fact create fertile offspring, only that it is a gross statistical improbability?—The preceding unsigned comment was added by 129.15.131.247 (talk • contribs).

Just because organism A is "close enough" to organism B to breed and organism B is "close enough" to organism C to breed doesn't mean that A and C can breed. It's not that one generation is one species and suddenly the next generation is a different one. DMacks 05:05, 8 February 2007 (UTC)Reply

This is where the concept of species is sort of blurry. This excerpt from Richard Dawkins' The Ancestor's Tale (one of my favourites) is what you are asking, I think, but in a different way:

If species A evolves into species B, […] there must come a point when a child belongs to the new species B but his parents still belong to the old species A. Members of different species cannot, by definition, interbreed with one another, yet surely a child would not be so different from its parents as to be incapable of interbreeding with their kind. (pp.255)

− Twas Now ( talk • contribs • e-mail ) 05:06, 8 February 2007 (UTC)Reply

If you want Dawkins' subsequent explanations on this, let me know. Oh, and please remember to sign with ~~~~ after you ask questions. − Twas Now ( talk • contribs • e-mail ) 05:59, 8 February 2007 (UTC)Reply

@DMacks: Yes, I understand that not EVERY generation (and certainly not consecutive ones) will be a new species, but the problem I'm having is understanding how there will be (seemingly) new species offspring from old species parents, and how these new species, being, by definition, unable to mate with the old species, will be able to expand their population.

Speciation does not seem to occur absent an outside pressure (change in food sources or predation, environmental barriers to population mixing). In time, separate populations within a species will adapt to individual niches (perhaps plants located on windward vs leeward mountainsides or insects feeding on a specific local weed). Given enough time, these populations may diverge enough to meet our human-defined criteria for different species. -- Scientizzle 06:54, 8 February 2007 (UTC)Reply

@Twas Now: Yes, that is a more eloquent way of putting my question. Now, what is the answer? ~~~~—The preceding unsigned comment was added by 129.15.131.247 (talk • contribs).

(when signing, don't include the nowiki tags...) -- Scientizzle 06:58, 8 February 2007 (UTC)Reply

The answer is that "speciation" is a human construct, and mother nature has done quite well without confining herself to human rules for several millenia. -- Scientizzle 06:58, 8 February 2007 (UTC)Reply

Perhaps she has done so for even longer than several thousand years! Whammy! Blammy wowie zowie! − Twas Now ( talk • contribs • e-mail ) 07:07, 8 February 2007 (UTC)Reply

Quite right, but even young-earthers can agree on "several millenia" :) -- Scientizzle 07:15, 8 February 2007 (UTC)Reply

Yes, I believe it was October 23, 4004 BCE? − Twas Now ( talk • contribs • e-mail ) 08:11, 8 February 2007 (UTC)Reply

Dawkins explains, that we should "allow for the possibility that an individual might lie half way between two species, or a tenth of the way from species A to species B" (pp.256). He goes on:

Are there sharp discontinuities between species, or do they merge into each other like first-class and second-class exam performances [referring to bell curve grading]? If we look at surviving animals, the answer is normally yes, there are sharp discontinuities. […] People and chimpanzees are certainly linked via a continuous chain of intermediates and a shared ancestor, but the intermediates are extinct: what remains is a discontinuous distribution. The same is true of people and monkeys, and of people and kangaroos, except that the extinct intermediates lived longer ago. Because the intermediates are nearly always extinct, we can usually get away with assuming that there is a sharp discontinuity between every species and every other. […] When we are talking about all the animals that have ever lived, not just those that are living now, evolution tells us there are lines of gradual continuity linking every species to every other […] in lines of smooth unbroken continuity. (pp.258-9)

In other words, an essentialist view of species is a mistaken view. But a fresher concept of "species" is not what you want to know—so let me take you through some hypothetical steps that would cause two lines of the same species to diverge into distinct species. However, remember to keep in mind this "continuous" view of species.

1. The two populations are separated somehow (often, but not necessarily, geographically separated). For example, one population (A) lives where conditions are moist and fertile, and the other population (B) lives where the climate is dry and barren.
2. Selective pressures on the two populations are different. For instance, members of population A may have selective pressure to evolve water-absorbent skin, while members of population B will have selective pressure to evolve water-retentive skin.
3. Other factors, such as sexual selection are likely to have an effect.
4. After sufficient time, the two species have changed genetically (from their initial species) to such a degree that they can no longer interbreed.

You may want to look up cladogenesis (splitting of one species into two) and anagenesis (change of one species from its ancestral to modern form). I hope this helps—and it should! − Twas Now ( talk • contribs • e-mail ) 08:03, 8 February 2007 (UTC)Reply

Distinct species are unlikely to interbreed, not unable to interbreed. Very often the barrier between two sister species starts of behavioural rather than genetic - ie, they could interbreed, they just don't because they don't recognise each other's breeding display or breed at slightly different times. The Apple maggot is considered a case of incipient speciation - the flies that lay their eggs on apple flowers are still considered the same species as their cousins who lay their eggs on hawthorn, having developed a taste for apples in only the last few hundred years since Europeans introduced apples to North America. Because apples and hawthorn flower at different times, populations which specialise on one or the other need to emerge at different times and be attracted to different scents. Since they emerge at different times, they tend to breed at different times, so mixing is unlikely, but possible (there is no genetic reason that they can't). If you have one parent of one variety and one parent of the other, you might be lucky and inherit the right set of genes that makes you emerge at the right time and go searching for the right flower, or you might get the wrong combination of genes (and be looking for hawthorn flowers despite the fact that you emerged when apples were in flower). If you have the right pair, you merge seamlessly into that population (introgression). If you have the wrong pair, you're dead. So there is selection that favours keeping the two populations separate. In the future there might be more changes that gradually become established in one population or the other, resulting in populations that we might call different species. Guettarda 17:42, 9 February 2007 (UTC)Reply

Vocal Octet

Latest comment: 18 years ago5 comments4 people in discussion

Greetings... I searched the wikipedia pages for the vocal octet. What I got was not what I wanted... Isn't the english vocal octet something "do re mi fa so...." I do not remember the whole octet but on the pages here this octet is not talked of. Could someone complete it for me?

The Do Re Mi page is a good starting point. DMacks 05:47, 8 February 2007 (UTC)Reply

You are referring to solfege:

Do Ré Mi Fa Sol La Si

Do Ré Mi Fa So La Ti

− Twas Now ( talk • contribs • e-mail ) 05:57, 8 February 2007 (UTC)Reply

Or perhaps you have confused 'octet' with 'octave', which in the vocal tradition is sometimes divided into 8 notes and sung with the syllables you mentioned. --bmk

Well, an octet is any group of eight things, so technically "Do Ré Mi Fa Sol La Si Do" is an octet. It is an octet of the eight Ionian mode intervals of an octave. This discussion might belong at the humanities desk. − Twas Now ( talk • contribs • e-mail ) 07:18, 8 February 2007 (UTC)Reply

I think a "vocal octet" would be a group of eight singers. Duet = two singers, quartet = four singers, sextet = 6 singers, so octet should be eight singers. On the other hand, "vocal" can mean "outspoken." A group of eight articulate single-issue citizens forcefully expressing their opinion at a town meeting would be a "vocal octet." -Arch dude 01:14, 9 February 2007 (UTC)Reply

Thanks for the response... 203.187.238.139 05:06, 9 February 2007 (UTC)Reply

A question I can't get out of my head

Latest comment: 18 years ago9 comments7 people in discussion

Hypothetically, if all humans are incapable of feeling/experiencing pain then will we (humans) ever deduce that animals can feel pain? 211.28.131.148 11:08, 8 February 2007 (UTC)Reply

You mean capable (not incapable) I think.

I already have deduced that animals can feel pain - when I stood on a dogs foot (by accident) the noise it made (yelp) coupled with knowledge of what I had just done made it clear that dogs can feel pain.87.102.2.204 11:32, 8 February 2007 (UTC)Reply

Are you asking: If humans were incapable of feeling pain, would they ever deduce that animals can feel pain? The swapping of would and will makes a big difference in this case.

• Humans (most of us) cannot use echolocation but we know microbats can.
• Humans can only hear in the frequency range of 20 Hz to 20 kHz, whereas dogs can hear from about 16 Hz to 45 kHz and cats can hear from about 20 Hz to 64 kHz, etc.
• Humans can not see infrared, but some animals can.

Of course, my examples might be different than the hypothetical situation you have proposed, since humans at least have that sense, only less sensitive. Humans can hear and know of other frequencies of sound, so it wouldn't be a great leap to deduce these things about bats, cats, and dogs. Humans can see and know of other wavelengths of light, so they could also deduce how animals can see infrared. However, it is a completely different thing to say that humans would be able to deduce that animals can feel if humans had no sense of touch whatsoever!

Just my thoughts. − Twas Now ( talk • contribs • e-mail ) 11:38, 8 February 2007 (UTC)Reply

I don't think we would be able to deduce that animals can feel pain. However, we would be able to notice that animals had the mechanisms for feeling pain (and also realize that we didn't have them). So for example, we may be able to find pain receptors, and deduce that animals can feel something through them which we can't. However, if humans all humans are incapable of feeling pain, then the concept of "pain" would not exist in our soceity. We wouldn't understand what it was, and we wouldn't really be calling it "pain". And there the question starts getting philosophical... --`/aksha 12:06, 8 February 2007 (UTC)Reply

Yes. Possibly we would call it thigmotaxis (or invent a name for it), seeing that animals move away from pain but without realising why (the actual feeling). It is something like how some of the animals are able to sense impending natural disasters but we humans are not able to -- WikiCheng | Talk 13:25, 8 February 2007 (UTC)Reply

Me, I'd say that if humans were incapable of feeling pain, then no, they would never deduce that animals can feel pain, because the humans would not exist.

Pain is a vital mechanism; no animal can fail to experience it in some way. It's a tremendous survival advantage: animals which experience pain can (usually) move away from or otherwise eliminate the source of the pain before their body is fatally damaged. An animal which is in pain due to an injury can take steps to care for itself while it heals. An animal which didn't experience pain wouldn't last long.

There was a long discussion in Stephen Pinker's book How the Mind Works about whether non-humans can "feel" pain, which I thought was silly: of course they can. The only difference is that they don't call it "pain", but then, they don't usually call anything anything.

There was great line in Terminator II where John Connor asks the Terminator, "Do you feel pain?" (I think this is while the Terminator is having bullets picked out of his back.) The Terminator thinks for a moment and says, "I experience what you would call pain", which I think sums the condition up perfectly. —Steve Summit (talk) 01:32, 9 February 2007 (UTC)Reply

Acctually I have done an experiment myself, and using an electric charge monotoring system of sorts, one is able to measure the amont of pain felt by a plant: when i inserted two probes into the stem of the plant, then broke a leaf in half it registered, therefore, we would, and can measure the pain flet by other species, plants, animals ect.

So what did you measure with your electric charge monitoring system of sorts? How much pain do you deduce that plants feel? Why would you believe that electrical currents in a plant would indicate pain? Why not pleasure? Or humor? Or dark current? --User:bmk

Scientifically, pain is separate and distinct from nociception. We can be certain animals experience the latter, but since the former is a subjective experience its open for debate whether animals "feel pain" as we do. See Pain and nociception for an overview. Rockpocket 06:56, 9 February 2007 (UTC)Reply

Huh! "Nociception". Whouda thunkit. So my speculations above about animals (and robots) "obviously" experiencing pain were misguided, or at least underinformed.

I'm reminded of this little ditty:

There once was a thinker of zeal

Who said, "Although pain is not real

  When I sit on a pin

  And I puncture my skin

I dislike what I fancy I feel."

--Steve Summit (talk) 16:32, 9 February 2007 (UTC)Reply

Well, when you cut a part of a living organism, the feeling, if at all there is one, would be of 'pain' (or agony), unless the living organism enjoys it. So the electric charge measured when a leaf is broken can be classified under pain and not under pleasure. Obviously, the plant doesn't enjoy it's leaf being cut? -- WikiCheng | Talk 08:47, 9 February 2007 (UTC)Reply

Trichobezoar

I'd be interested to know how much (approximately since I realise there is probably no definite answer)hair would an adult have to consume in order to develop a trichobezoar which would pose some risk to their health? Thanks, if anyone has any idea.

chemistry

Latest comment: 18 years ago4 comments3 people in discussion

I need to find the chemical formulas and names and how many atoms are in the following chemicals. CH4, C2H4O2, CaCO3, NH4NO3 do you think that you can get some answers?

Well you've already given the answer to the first query: the chemical formulas are CH₄, C₂H₄O₂, CaCO₃, NH₄NO₃. − Twas Now ( talk • contribs • e-mail ) 14:20, 8 February 2007 (UTC)Reply

CH₄

• Methane
• 5 atoms (one C atom and four H atoms)

${\displaystyle {CH}_{4}=\underbrace {C} _{1}+\underbrace {H+H+H+H} _{4},}$ 

C₂H₄O₂

• Acetic acid
• 6 atoms

CaCO₃

• Calcium carbonate
• 5 atoms

NH₄NO₃

• Ammonium nitrate
• 9 atoms

− Twas Now ( talk • contribs • e-mail ) 14:42, 8 February 2007 (UTC)Reply

Molecular formulas are not very specific for organic molecules, many of which can have the same composition of atoms, but different structures. For example, glycolaldehyde is also C₂H₄O₂. --Spoon! 21:08, 8 February 2007 (UTC)Reply

And methyl formate, methyl dioxirane, acetaldehyde oxide, and also a host of less stable isomers. DMacks 21:27, 8 February 2007 (UTC)Reply

arun singh bagh

Latest comment: 18 years ago5 comments5 people in discussion

can I die if I lick pure diamond?

• Well, it might be sharp and cut you, but otherwise no ... it's just carbon, which isn't toxic. WilyD 15:15, 8 February 2007 (UTC)Reply

(Note I guess Arun Singh Bagh is your name - it helps if the section title relates to the question eg "Are diamonds poisonous" or something like that - most people put their name at the end of the question.)83.100.158.135 15:17, 8 February 2007 (UTC)Reply

No. Never. Well, maybe if you lick it thousands of times until your tongue becomes swollen, causing you to asphyxiate; or after the thousands of licks, if it is cut, and you get an infection. − Twas Now ( talk • contribs • e-mail ) 15:23, 8 February 2007 (UTC)Reply

no, as in times gone by people would lick diamond to check whether or not they were genuine, a real diamond's (as opposed to a piece of glass or other rock) surface acts much like oil and does not get wet.

I bite lick and nibble on jewels all the time and none of them are poisonus. all i know is that i can tell the diffrence between a real jewel and a fake one by licking it . (yes i guess its kinda gross but hey I get and give that peace of mind when you know you got the real deal instead of the fake plastic or glass ones) Maverick423 16:05, 8 February 2007 (UTC)Reply

Nonsense - you will certainly die if you lick diamond. In fact you'll die anyways. We all die. (groan) --bmk

How do you know everyone will die, it hasn't happened yet:) Licking doamonds could make people live forever for some reason, but there is no proof:]HS7

Diamonds are the hardest naturally occurring things known to science. It takes another diamond to make any impact on its surface. That means you could lick one 24/7 for 50 years and you'd still never get any of its substance into your body at all. All you'd ingest is whatever dirt happened to be on its surface. As WilyD says, swallowing one whole could be a hazard, but that's nothing to do with poison. JackofOz 02:20, 9 February 2007 (UTC)Reply

Does it snow at sea?

Latest comment: 18 years ago4 comments4 people in discussion

Many thanks, --194.176.105.40 15:51, 8 February 2007 (UTC)Reply

Yes. (but it doesn't lay obviously)83.100.158.135 15:54, 8 February 2007 (UTC) It would be more likely to snow nearer to the poles. Apologies I haven't provided a very good answer.83.100.158.135 16:11, 8 February 2007 (UTC)Reply

I had the opportunity to ride the Alaska Marine Highway [14] during a blizzard[15] in November 2006. Indeed it does snow at sea. Other interesting phenomenon of snow-at-sea: water retains its temperature due to its high specific heat, so the ocean (sound, bay, etc) may be several degrees warmer than the snowing air. This provides a consistent thermal updraft of air which starts at the surface of the water and flows upwards, convecting with the snowy air. This means that it is very difficult for snowflakes to actually land on the water! In fact it appears to be snowing upwards. Nimur 19:41, 8 February 2007 (UTC)Reply

Cool! Now I want a video of this! — Kieff | Talk 22:33, 8 February 2007 (UTC)Reply

Boric Acid

Latest comment: 18 years ago4 comments3 people in discussion

Hello

On your page about Boric Acid, it is mentioned that "boric acid can also be used as an acne treatment (see directions for solution at bottom.)"

I cannot find the "directions" for the solution and would like help or directions for this?

I hope someone can be of assistance.

Thanking anyone in advance.

Gavin

I've removed that info for now as I can't find an adequate reference - however it is true that boric acid can be used as an antiseptic - the proportions were 1 part Boric acid to 4 (boiling) water to dissolve the boric acid. I can't guarantee this is correct.

If you intend to use boric acid for this purpose - I would suggest either - following any instructions on the package OR following the instructions given to you by a pharmacist (it is usually bought at a pharmacist and a pharmacist should be able to give you instructions on it's correct use.)83.100.158.135 16:21, 8 February 2007 (UTC)Reply

Note also that repeated use of boric acid/borates can cause poisoning - specifically when it comes in contact with a wound eg broken skin.83.100.158.135 16:23, 8 February 2007 (UTC)Reply

It is a leftover from an old edit. Have a look at the MSDS sheet for this substance too. − Twas Now ( talk • contribs • e-mail ) 16:27, 8 February 2007 (UTC)Reply

...like this one, courtesy of the SIRI MSDS index. Or check out the ICSC. Although the toxicology reports may be more relevant here; the MSDS and ICSC are for the concentrated stuff, and mostly just say you should be careful when handling concentrated acids (even weak ones like H₃BO₃). Just for comparison, here are the corresponding MSDS, ICSC and toxicology reports for acetic acid. —Ilmari Karonen (talk) 14:13, 9 February 2007 (UTC)Reply

Genetics of Neurospora

Hello, When you want to calculate the distance between 2 linked genes in Neurospora Crassa, if you don't know the number of crossing-overs, when do you use the non-corrected formula (RF = 0.5*T + NPD) and when do you use the corrected one (RF = 0.5*T + 3*NPD)? Thanks in advance!! -- Max

Voltage Coefficient

Latest comment: 18 years ago3 comments2 people in discussion

Hello... Could someone pleae precisely define Voltage Coefficient??? It is a specification mentioned in data sheets of carbon filmed resisitors... Bhavikmehta2685 17:33, 8 February 2007 (UTC)Reply

This is when a change in the physical characteristics of a component are changed somewhat due to a change in the voltage across the component. See [16] − Twas Now ( talk • contribs • e-mail ) 17:41, 8 February 2007 (UTC)Reply

Thanks a lot Bhavikmehta2685 05:08, 9 February 2007 (UTC)Reply

Current problem

Latest comment: 18 years ago11 comments5 people in discussion

I have a problem, I have to generate 30 Amps across a resistance of less than one milliohm. Basically, I want to find a way to convert a dc voltage to about .01 volts. I can't find a dc to dc converter that can do this. Any ideas?

Try holding one end in each hand, you might be able to produce a small amount of electricity that way:]HS7

Wouldn't you know it: DC to DC converter. -- mattb @ 2007-02-08T19:56Z

The 1 milli-ohm resistance will do almost nothing to your circuit if you add it in series to an ideal current source. You can probably create a current source which is "ideal" compared to a 1 milliohm resistance with a simple battery and resistor. I don't know if a standard lantern-battery can provide 30 amps, even at 12 volts; this is a lot of juice. But if you have a dc power supply, it should be no problem. One final question: are you sure you need to put 30 amps across 1 milliohm? This may not really be what you want, and you might smoke some components :) Nimur 19:57, 8 February 2007 (UTC)Reply

We used to use these types of batteries (9.6 volt toy-racecar batteries) to drive current through some tinfoil - specifically for the purpose of igniting matches during science projects. You'll quite probably do the same, if you're driving 30 amps into a short circuit. Nimur 20:05, 8 February 2007 (UTC)Reply

Perhaps I should restate everything I've said above in one sentence: your task is generating 30 Amps, then attaching that into your circuit. The voltage will appear across your resistor - you don't need to generate it. But (in dc circuits) you can't get 30 amps unless your battery can supply it... Nimur 20:13, 8 February 2007 (UTC)Reply

what he said ^^ anyways the only other way that i can see you generating more ampage is by using conductors (the little ones that look like tiny batteries) and connect them to resistors to reduce the charge to .01 i used to do this when i made small battery powered robots so as to not fry the main processing unit but to provide enough power to the wheels and stuff.Maverick423 20:42, 8 February 2007 (UTC)Reply

If you explain why you need to do this we may be able to advise you better. Not knowing your age or qualifications to work with electricity, I must caution you strongly against experimenting with high current (which I consider this to be) or high voltage, on the account of the danger of shock, fire, explosion, burns, or eqiuipment damage, which can occur in an instant even if you do not accidentally hook something up wrong. A qualified teacher or a qualified adult should be present and supervise all work and assure that all proper safety procedures are followed. If you or they do not know what those procedures are, then do not attempt to do the experiment and keep as a "thought experiment." I have worked out how to do it, but will reserve details until I hear more about why and how you want to do this, and what your age and qualifications are.Edison 23:00, 8 February 2007 (UTC)Reply

Yes. Perhaps we should make it very clear that this much current can be very dangerous. Even if you are "experienced," you can burn yourself, electrocute yourself, damage your equipment, and otherwise cause harm. Nimur 00:38, 9 February 2007 (UTC)Reply

And despite those things, the experiment can fail to be amusing. Electricity does not make exceptions for age, inexperience, misunderstanding, or give second chances.Edison 00:43, 9 February 2007 (UTC)Reply

Hello, sorry about the delay. I am trying to create a magnetohydrodynamic pump actually, and as it turns out quite a bit of current is necessary to drive the fluid medium I desire, liquid gallium. Unfortunately, the resistance across this small gap of liquid gallium (between two graphite electrodes) is extremely small. I was hoping to find a way to shrink the voltage down considerably, but most of my ideas seem to have run into issues, as I would need such an incredible rheostat to generate this many amps. I have been considering using a car battery and a self built variable resistor from carbon rods, but as you said I'd be afraid some part of the system would smoke. I am a senior student who is working on a science fair project, and I have sought out help from a few teachers and engineers. All of whom are glad to supervise me for this project.

Eep. First of all, I would avoid using a car battery. Lead-acid batteries of that size can pack enough punch to be fatal if you screw up. Next, I think you may have hit on several of the engineering issues with a magnetohydrodynamic pump already. For something as viscous as gallium, you will probably notice that mechanical and fluid forces are significantly stronger than any electromagnetic force you can produce. This is why few (probably zero) commercial pumps operate on this principal. Danger aside, I doubt you will be able to make this thing work - magnetohydrodynamics is an advanced area of physics, so you will probably have difficulty with the theory; it also has numerous practical issues, so you will probably have difficulty with the implementation. There are many options, though!

• You can come up with a complete report and theoretical diagrams of how you would build this device. Mention the practical engineering limitations (need high current, high voltage, and where in the heck will you get that much gallium! Certainly not your school's chemistry lab, I don't think it's very common in such settings! You can probably order a few ounces at exorbitant prices from science supply warehouses...$40 for 5 grams!) Talk about how all of science and engineering are fundamentally dominated by practical considerations. It is not a failure to determine something is infeasible. In fact, it would be much more of a failure to pursue something that is beyond your capacity, and then not deliver it.
• You can also try switching to some other similar experiment- such as an electric ion pump. You can use this technique to dissociate ions in solution (i.e. extract sodium and chloride from salt water). This will be an interesting chemical reaction and you can discuss a lot of the science behind it. Or you could try to build a simpler mechanical pump. You can discuss the difference between a rotary pump and an internal combustion engine. You can discuss practical uses of these pumps, and explore why few applications rely on magnetohydrodynamic pumps.

Hope this helps, Nimur 02:10, 9 February 2007 (UTC)Reply

MHD principles are a lot more frequently applied on micro scales, such as in MEMS (and in some theoretical applications, but that's not my area). The high magnetic field density required makes this a non trivial effort on the macro scale. I also wouldn't bother with the wikipedia article on MHD. It's poorly written, has poor topical coverage, is vague, etc. All you need for a simple MHD pump is a conductive fluid and a sufficiently large magnetic field. If you've really set your heart on an MHD pump, at least change the fluid you're attempting to flow to something that will make your construction job easier rather than harder.

Also, I must respectfully point out to the above poster that a car battery is not likely to kill you unless you drink its contents or allow it to fall off a ladder onto your head. In addition, I think there may be some confusion as to the nature of an MHD device, since one need know nothing more than the Lorentz force equation and basic math to understand how it works. Plasma physics only apply if you're trying to manipulate a plasma, which doesn't seem to be the intention here. -- mattb @ 2007-02-09T03:13Z

Better to err on the side of caution :) Anyway, I've only ever seen MHD applied in two areas: stellar physics, and fusion reactions. I've never to MEMS or pumps or anything else. Are you sure you don't mean Microfluidics? Those tend to make use of electric fields for moving around microdroplets of water or chemical, but I've never heard of them using magnetics. 171.64.91.48 05:16, 9 February 2007 (UTC)Reply

I meant what I said. Electrostatics are much more common, but MHD has been used as well. -- mattb @ 2007-02-09T05:40Z

OK, To cause 30 amps to flow across .001 ohms requires that you supply a voltage of .03 volts, from E=IR. This will dissipate 0.9 watts in the .001 ohm resistance, from P=EI. A 6 volt lantern battery cannot supply this much current, nor can D cell flashlight battery. It is practically a dead short. For a test circuit, what physical form might your .001 ohm resistance take? From American wire gauge, the resistance of number 10 copper wire (the smallest size usually rated to carry 30 amperes) is .9989 ohms per thousand feet, so 1.001 foot of the wire will have the desired resistance of .001 ohms. You will find that the contact resistance between the battery or other source and the wire will greatly increase this resistance. I find that the leads of my digital multimeter have about .2 ohms resistance, for example. To measure the current you may connect a voltmeter across the approximately 1 foot of number 10 wire, and then use Ohm's Law again, but in the form I=E/R. where R=.001 ohm. If you had a battery capable of producing more than 30 amps, such as a 12 volt car battery. you MUST NOT just connect the 1 foot of number 10 wire across the battery, because that would be a short circuit. It would draw far more than 30 amps (perhaps hundreds of amps) and might cause the battery to explode or the wire to heat up red hot. If the battery produces 12 volts exactly and you wanted to reduce the current to 30 amps, you must have a dropping resistor in series with your .001 ohm resistor, to drop the voltage from 12 volts to .03 volts. This works out by Ohm's law to (11.97 volts)/(30 amperes)= .399 ohms. Even if your MHD cell were shorted, with the stated dropping resistor, the current would not increase much. It is acting something like a current source. Again from the wire table article, for number 10 copper wire, this equals (1000 feet) times(.399/.9989)=399.4 feet of number 10 copper wire, or an equivalent resistor. The power dissipated in the dropping resistor will be 30 squared times the resistance or 359 watts, so such a resistor would be very hard to find, and the wire will heat up, so the current should be only briefly applied. The car battery would discharge, and the car alternator would be overloaded, if this current drain were sustained. So in the case cited, an improvised dropping resistor could be the stated amount of number 10 wire. You could measure the current with an ammeter in series, or with a voltmeter across the dropping resistor and use Ohm's law. A second way would be to use a stepdown transformer which steps down the household voltage (such as 120 or 240 depending on your ___location) to a high current at a low voltage. An electric welder has this characteristic. Some arc welders produce DC output, although it will be pulsating rather than smoothed DC. Others produce low voltage high current AC, which could be rectified with diodes to produce DC. A filter might be used to smooth the ripple, with capacitive filtering. You of course must assume all risk in such experiments. [17] discusses a home-made arc welder, starting with a transformer of the required KVA and replacing the original secondary with a low voltage-high amperage secondary of one or a few turns. This would also require high amperage rectifiers and capacitive filters to produce smooth DC, and would also have all the risks associated with experimenting with electricity, such as death, injury, or property damage. Edison 05:18, 9 February 2007 (UTC)Reply

If I were doing this "professionally", I would do what someone suggested above: Consider operating a switching regulator as an "ideal current source". It would be pretty efficient, compact, and safe. But such parts aren't readily available to be bought "off the shelf".

So for a science fair, I'd take a different approach. I'd probably take a car battery and mount it safely in an insulating container along with five or six automotive headlamps. I'd wire the headlamps in parallel and connect one end of that parallel circuit securely and safely to the battery. I'd provide heavy wire leads from the other end of the battery and the other end of the headlamp circuit. Then, when you connect those external leads together, you'll get a lot of light and about 30 amps of current flowing in the circuit. The exact resistance of the external part of the circuit won't matter much because the lamps are safely limiting the flow of current. The circuit is also limited to 12 volts (the open-circuit voltage of the battery). Packaged up nicely (with no external access to the junction between the battery and the lamps), the device would be quite safe. You could add a circuit breaker as protection and to provide a convenient on/off switch.

Two notes:

• Incandescent light bulbs have very low resistance when the filaments are cold, perhaps 1/10 of the resistance they have when the filaments are hot. So my proposed circuit will put out a brief pulse of much higher current. This probably doesn't matter (and might help get the gallium moving), but please be aware of that effect and consider it.

• The circuit breaker probably wouldn't be rated to break DC and so it probably wouldn't last a huge number of operations, but it would probably be fine for "science project" duty.

Atlant 13:56, 9 February 2007 (UTC)Reply

Purpose of a manned space flight program ...?

Latest comment: 18 years ago9 comments7 people in discussion

Given the fact that if you could cram 200 people onboard a space shuttle and thereby limit the number of space shuttles required to put the Earth's population into Earth orbit to 32,875,406 in the event a wayward asteroid headed this way what is the purpose of a manned space flight program besides the E-ticket ride? 71.100.10.48 21:19, 8 February 2007 (UTC)Reply

I'm not sure what the question is. There are not 33 million shuttles, nor will there ever be. By the time such an event will happen, who knows how many people will live on Earth? Even if there were 33 million shuttles, that would not be enough, since you would also need to fit enough food, oxygen, and fuel, and you would have to figure out the logistics of rallying billions of people into all of the shuttles. − Twas Now ( talk • contribs • e-mail ) 23:02, 8 February 2007 (UTC)Reply

The chance that if life on earth was to end the possability that it can still exist elsewhere Maverick423 22:49, 8 February 2007 (UTC)Reply

To quote Sam Seaborn: "‘Cause it’s next. For we came out of the cave, and we looked over the hill, and we saw fire. And we crossed the ocean, and we pioneered the West, and we took to the sky. The history of man is hung on the timeline of exploration, and this is what’s next." - Akamad 23:05, 8 February 2007 (UTC)Reply

Or to quote Arthur C. Clarke who was quoting Konstantin Tsiolkovsky, "The earth is the cradle of humankind, but one cannot live in the cradle forever." --81.230.70.70 00:05, 9 February 2007 (UTC)Reply

The purpose of the manned space flight program is because there are some tasks which are best performed by humans (as opposed to robots, computers, or anything else you might put in space). The purpose of a space program, in general, is many-fold, and includes science, politics, exploration, and many other details. I don't think it's correct to say that any present-day manned space program exists with the intent to "save our population" or "colonize other worlds." Perhaps you can take a look at NASA's Strategic Mission objectives from 2006: [18], which clearly explains exactly why we have a manned space program in the United States. (I mean, in all truth - the buck stops here. This report is what is given to federal government decision makers to explain why we have a space program, and why it should be funded). Nimur 00:43, 9 February 2007 (UTC)Reply

Here's my cynical summary (for those who don't want to read all 44 pages:)

1. Kill space-shuttle program within four years
2. Kill the funding for International Space Station as soon as we've met our contractual obligations
3. Focus on ground-based science, which is cheaper
4. Introduce a new space transportation system with no long-term commitment (per-mission funding)
5. Outsource as much as possible to private contractors
6. Initiate a hypothetical and entirely implausible moon exploration directive which will veil the previous objectives until the space program deteriorates beyond a salvageable enterprise.

But, this is just my opinion. You should read the report yourself. Nimur 01:09, 9 February 2007 (UTC)Reply

The purpose of the manned space program was, originally, to prove that we had a bigger dick than the Rooskies. Now, it is primarily a corporate welfare program operated to transfer American tax dollars to a small set of investors in the military-industrial complex. Nearly everything we do through manned "exploration" could be done by our robots at a much lower cost.

Atlant 14:07, 9 February 2007 (UTC)Reply

What about in the case of nuclear war? Wouldn't a manned space flight program at least prepare Americans for orbital evacuation? That would only require 1,492,221.07 space shuttle flights at 200 Americans per trip... and who needs food? They could dine on each other. 71.100.10.48 17:23, 9 February 2007 (UTC)Reply

Essential amino acid

Latest comment: 18 years ago1 comment1 person in discussion

I am looking for lists of essential amino acids required by various animals. In particular, I'm interested in domesticated animals e.i. cattle, cats, chickens...

Know of any source for this information? ike9898 21:36, 8 February 2007 (UTC)Reply

Rubbing Alcohol

Latest comment: 18 years ago1 comment1 person in discussion

what will happen if a person consumes 1 fl oz. of rubbing alcohol? it's 70% isoproyl alcohol

Probably a seriously upset upper GI tract, followed by some vomiting. Isopropanol is not for human consumption. See below comment. -- mattb @ 2007-02-08T22:39Z

We're not qualified to answer questions about medical problems here at the Reference Desk. You should contact your local poison control center or your physician to receive reliable, thorough answers to these types of questions. TenOfAllTrades(talk) 22:48, 8 February 2007 (UTC)Reply

Brain vomiting mechanism

Latest comment: 18 years ago4 comments4 people in discussion

A few years back I read a story in which a man died after receiving a "sherry enema", which raised his BAC to something like 0.47. (If you don't believe this, google "sherry enema".) But if one was to drink a bottle or two of wine, it's likely the brain would decide the body needs to vomit to get rid of the toxins.

The question is: When alcohol is involved, does the brain tell the body to purge the contents of the stomach because the alcohol/blood ratio is too high (regardless if the stomach is full of alcohol or not...the brain just "assumes" that's where it is), or because the alcohol simply irritates the stomach?

I.e. if someone became drunk through means other than traditional oral consumption, would they still vomit?

This may sound like a sophomoric question, but it is really a question about how the brain may be "tricked" into doing something that is, in this case, essentially useless in helping to solve the problem.

Thanks.

Darnoc 22:27, 8 February 2007 (UTC)Reply

This is presented as information or observation, and not as medical advice. Drinking a large quantity of wine is just as likely to cause the person to go to sleep as it is to cause them to throw up. Deaths from frat initiations often occur when the person passes out or falls asleep, and their "buddies" put them in bed to sleep it off. They never wake up. If they vomit in their sleep they may aspirate the fluid and die from the effects on the lungs. Edison 00:49, 9 February 2007 (UTC)Reply

I don't think it's sophomoric at all! According to Vomit#Vomiting_center, there are several sensory inputs to the vomit response mechanism. We would hope that the first-pass "poison sensor" is in the stomach, to induce vomiting before any has a chance to be absorbed. It does not appear that there is any "toxin" sensor there, though - only other assorted nerves. This seems in agreement with a normal situation - the vomiting does not begin immediately (sometimes it may take hours), I can only imagine that the perception of "poison" occurs after alcohol or other toxin has already entered the bloodstream. In that case, vomiting may do very little to eliminate poison (depending on how much is left in the stomach). Maybe a qualified biologist knows more about this. Nimur 00:50, 9 February 2007 (UTC)Reply

More speculation: my impression is that fatal alcohol intoxication is usually the result of consuming massive quantities of hard liquor. For anything with a lesser alcohol content (e.g. beer or wine), you can't physically get enough of it into your stomach to then get a fatal amount into your bloodstream.

(But this begs the question of where the vomit response is triggered and why it's delayed. The explanation usually given in cases of fatal alcohol intoxication is that the victim drank too much too fast for his body to protect itself from, but this does suggest that a reaction involving organs other than the stomach is involved.) —Steve Summit (talk) 01:02, 9 February 2007 (UTC)Reply

"Lake Overturn"

Latest comment: 18 years ago4 comments3 people in discussion

I was searching for some information regarding most lakes' seasonal "overturn," or the event where the top layers of water mix with the bottom layers of water in a lake every spring and fall (or something like that). However, I have forgotten the name of this event. I figured it was like "Lake Overturn" or something like that, but that only redirects me to Limnic Eruption. If anyone knew the exact name of this event, could you please tell me the name, and if possible, the page? Thanks a lot!

--70.48.177.87 23:50, 8 February 2007 (UTC)Reply

Sorry, I found the information after a little while. Thanks anyways though! --70.48.177.87 00:05, 9 February 2007 (UTC)Reply

Where did you find it? I am also interested. --Spoon! 01:58, 9 February 2007 (UTC)Reply

The best term I found was 'seasonal lake turnover', as explained here: [19] However, this would make a great article! --Zeizmic 02:48, 9 February 2007 (UTC)Reply

If this happens twice a year, the lake is dimictic. If it never fully turns over (true of some deep lakes), it's meromictic (I do like that word!); if permanently frozen, amictic. Search on this page for other "mictic" words in this family. --Anonymous, February 9, 2007, 23:16 (UTC).

DRY ICE questions

Latest comment: 18 years ago7 comments5 people in discussion

Does carbon dioxide burn?

is carbon dioxide gas heavier or lighter than normal air?

thanks, anon

Consider reading the Carbon dioxide article, or the CO2 Fire Extinguisher section. Nimur 01:15, 9 February 2007 (UTC)Reply

Sort of depends on your definition of "burning". See [20]. DMacks 01:30, 9 February 2007 (UTC)Reply

(Wow! Cool. Thanks. I have never heard of that reaction. —Steve Summit (talk) 01:39, 9 February 2007 (UTC))Reply

Also, if you touch dry ice to your skin for very long, you will freeze your skin and get what is usually called a burn (because it hurts just like one, and involves subcutaneous tissue damage just like one, even though it's caused by extreme cold rather than extreme heat). —Steve Summit (talk) 01:38, 9 February 2007 (UTC)Reply

The density of carbon dioxide at 100 kPa and 0 °C is 1.6 kg/m³, where has air a density of 1.2 kg/m³ at sea level at 20 °C. So 1 m³ of carbon dioxide will be heavier than 1 m³ of air under similar conditions. But note that air contains carbon dioxide. - Akamad 01:47, 9 February 2007 (UTC)Reply

Burning almost always means oxidizing, and it's not common to oxidize a stable oxide (like CO2). Nimur 02:55, 9 February 2007 (UTC)Reply

Aw man i love dry ice every hollows eve the lunch lady would always drop a peice of dry ice in my drink and it would fog and carbinate and taste kinda like coke! you should try it once its fun and gets ya alot of attention. also i experimented with it using bubbles (i was very bored) and i noticed that the ones that didnt pop would get stuck on the ice and freeze (as a bubble) and it look really cool. i miss my youth Maverick423 14:37, 9 February 2007 (UTC)Reply

February 9

Hottest Temp...

Latest comment: 18 years ago6 comments6 people in discussion

Amigo of mine said that it hasnt been above 100 Farenhiet in the U.S. in February of '07, is this true? I just read a NASA article that said Death Valley, CA, USA is the hottest place on the Earth...for real?

Cheers, 72.70.4.120 02:02, 9 February 2007 (UTC)moe.ronReply

Since it's barely a week into February, and February being in the winter, I highly doubt the U.S. has had areas reaching 100 F, which is already not too common during the summer. But yes, I believe Death Valley is the hottest place on earth. --Wirbelwindヴィルヴェルヴィント (talk) 02:11, 9 February 2007 (UTC)Reply

I always thought the Atacama Desert in Chile had the highest recorded temperature, near 130 degrees F. I should check my numbers, though... Nimur 02:56, 9 February 2007 (UTC)Reply

Google says El Azizia in Libya, hottest temp was recorded in 1922. --Peta 03:51, 9 February 2007 (UTC)Reply

The Atacama Desert in Chile is the hottest desert in the world, Death Valley is the hottest in the United States and El Aziza is where the hottest temperature was ever recorded (some say Aswan), the top spots for that are all in the Sahara somewhere. [Mαc Δαvιs] X (How's my driving?) ❖ 04:33, 9 February 2007 (UTC)Reply

also check out Marble Bar, claimed to be the hottest town. It is located in Australia. But the most extreme here is 119.8F. Its consistently hot for months at a time. GB 06:24, 9 February 2007 (UTC)Reply

Sound coming from tv to computer speakers

Latest comment: 18 years ago4 comments3 people in discussion

I've noticed that sometimes when I put my hand against my tv screen, which is right by my computer speakers, a sound comes out of my computer speakers. They aren't hooked up in any way so I was wondering how this could be. Thanks. Imaninjapirate^{talk to me} 02:22, 9 February 2007 (UTC)Reply

My guess is that you get a lot of static 'sparkles' when you put your hand on a CRT screen in dry humidity. This could be picked up by the speaker wires, especially those amplifying ones, that are powered on, but not connected directly to a computer. --Zeizmic 02:51, 9 February 2007 (UTC)Reply

Ah, I see, I do feel those static sparkles. Thanks for the response! Imaninjapirate^{talk to me} 03:10, 9 February 2007 (UTC)Reply

Perhaps it's Electronic voice phenomenon? :) Nimur 05:30, 9 February 2007 (UTC)Reply

Pressure treated lumber splinter under the skin...?

Latest comment: 18 years ago2 comments2 people in discussion

I know that pressure treated lumber has arsenic and copper compounds, etc. to prevent insects from attacking the wood. So what happens if one gets a splinter when carrying pressure treated lumber? Is there enough toxic chemicals in a splinter if left under the skin to get into the blood stream and cause death? -- Barringa 03:32, 9 February 2007 (UTC)Reply

Not cause death, no. If the preservatives were that toxic to humans, you wouldn't be able to buy the wood just anywhere, and you wouldn't carry it bare-handed ever, and you wouldn't build decks out of it that you would then walk on barefoot or casually eat spilled hamburgers off of.

With that said, though, the chemicals are pretty nasty. I've noticed that if I saw pressure-treated wood, I feel a raspy sensation in my throat that I certainly don't get when sawing regular wood. (Yes, I should probably wear a dust mask more often.)

I don't think I've heard of splinters from treated wood being hazardous. (If anything the chemicals might help kill the germs that might otherwise infect the puncture wound.) But I'd certainly pay extra attention to a nasty puncture from treated lumber, and seek medical attention if my skin turned a funny color or anything. —Steve Summit (talk) 03:49, 9 February 2007 (UTC)Reply

Electronic voice phenomenon

Latest comment: 18 years ago10 comments5 people in discussion

Hello, I think I have stumbled upon an absurd situation at this article. I have tried to place a tag alerting editors that content policies may not be followed there. There is original research, and non-objectivity. For example, the article divides points of view into "paranormal" and "non-paranormal." The scientific point of view is referred to as "non-paranormal," rather than scientific. Also, scientists are referred to as "skeptics," rather than scientists, as if believing in extraterrestrials communicating via magnetic tape were the majority viewpoint, and there were some minority "skeptics." I believe it is the other way around, there is a minority which believes in this, and the scientific majority does not. Scientists are scientists, not skeptics and non-paranormals. Also, the article contains a self-published purported recording of a paranormal voice, which is original research, I believe, since it was recorded and published on a website by the same people, not by a reliable third party. an editor keeps removing the tag I have placed. I am not sure what to do.-MsHyde 05:12, 9 February 2007 (UTC)Reply

Yikes. At least posting it here will get more eyes on it, and hopefully that will help build a majority consensus. Nimur 05:19, 9 February 2007 (UTC)Reply

I've read through the article. They make very few falsifiable claims, so I don't know if you can truly cite them on inaccuracy (though it's certainly not a science article). I guess it's difficult to accept, but people will believe what they wish to believe. In its present form, the article clearly states that there are alternative, simpler explanations than the "supernatural" - but if people choose to conclude otherwise, no amount of proof can convince them. Nimur 05:28, 9 February 2007 (UTC)Reply

It's fascinating how one paranormal wiki-page can lead me onto a goose chase of paranormal stuff. If EVP infuriates you, check out Shadow people - there's all KINDS of awful science there! Anyway, it looks like there's some consistency among these pages. They all list Paranormal vs. Non-Paranormal explanations. Honestly, I'm content with that level of consistency. Though you and I may choose to believe the scientific explanation, assume good faith and let people think what they will. It doesn't harm us to allow them to live in ignorance. Plus it makes for entertaining television. Nimur 05:33, 9 February 2007 (UTC)Reply

Yes, but this is an encyclopedia. Neutrality is important. The original research policy looks like it was developed precisely to keep crackpot theories in check. That is fine if people want to privately believe that science is "non paranormal," but it is not appropriate to label it that. The majority definition of science is science, not "non paranormal." And the audio recording is, frankly, ridiculous. It was published on a website by the same people who recorded it. It could be a recording of their vacuum cleaner.-MsHyde 06:33, 9 February 2007 (UTC)Reply

The original research policy also keeps you from using your own beliefs to determine the validity of an article. However bunk EVP may be, it is notable. The article, in its current state, makes no claims as to its validity, and nothing about the article is the least bit against Wikipedia's policies. Furthermore, just to cover the complaints, skeptics is a perfectly appropriate term. By definition, those who do not believe in something are skeptical of it. Finally, the audio recording is also fine. Regardless of how valid it may be, it is still an example of EVP. – Someguy0830 (T | C) 06:41, 9 February 2007 (UTC)Reply

It is claimed to be an example of EVP, but not by a reliable source. It is the original research of two people who make money off of EVP, and self-published it on their website. Skeptics is not the appropraite term for scientists. Per due weight, even in an article about something, an extreme minority view should be represented as such. That means, science is the majority view, not the "skeptical" view, or "non-paranormal" view. The article as written is heavily slanted towards the view that EVP exists.-MsHyde 08:38, 9 February 2007 (UTC)Reply

It is not. The thing is a blow by blow history and a possible causes section, with equal weight given to both. The article does not exist to disprove or prove EVP. It only exists to detail the phenomenon. – Someguy0830 (T | C) 09:08, 9 February 2007 (UTC)Reply

I haven't read the EVP article (if for no other reason than that I don't have time this morning for "wild goose chase of paranormal stuff", as Nimur so nicely put it), but I'm prepared to believe that the article needs work. Thanks, MsHyde, for trying to do something about it. With that said, this Reference Desk probably isn't the best place to figure out how to better apply Wikipedia's NPOV policy to that article -- I'd also try its talk page and the Village Pump. —Steve Summit (talk) 13:24, 9 February 2007 (UTC)Reply

Any unpublished recording is definitely original research, and should not be considered as a source to support the claimed EVP. I could make a tape with mysterious voices on it very easily. To be used in an article, it would need to be published by a "reliaable source," and in a scientific dispute it should have been published in a respected peer reviewed journal. Questionable evidence should not be used to create a Wikipedia article which can then be cited as "proof" that the claims are valid. No home-made flying saucer photos, no personal diaries of time travel or UFO abduction, no claims that one had a dream forecasting some publicized disaster. No claims that one is Elvis's love child. No personal bigfoot sitings. No claims of having invented a miracle cancer cure or perpetual motion machine. Edison 15:59, 9 February 2007 (UTC)Reply

immune system

Latest comment: 18 years ago3 comments3 people in discussion

Hello, i was just wondering when "B cells" inside our body is trying to fight off "invader cells" and there are also body cells there aswell how the the "B cell" tell teh difference beetween teh two other cells?

thankyou very much, i really apreciate it :D. 24.68.136.43 05:50, 9 February 2007 (UTC)Reply

Our articles on Adaptive immune system and B cell answers your question. Rockpocket 06:46, 9 February 2007 (UTC)Reply

I agree with Rockpocket that the articles linked to answer your question. However, they contain a lot of information if you know little about this beforehand, so here's a simplified version:

In most circumstances, it isn't the B-cells that tell the difference between self and non-self. It's the helper T cells. Both B and T cells have antigen-specific receptors that are generated randomly by somatic DNA recombination when the cells develop. One clone of T or B cells has one receptor, which recognizes one single antigen only. B cell receptors (≈immunoglobulin) can arise that recognize just about anything. T cell receptors, however, are designed to recognize major histocompatibility complex (MHC) molecules, which are cell surface molecules found on most cells of the body, and which always have a short peptide bound. The peptide is put there when the MHC molecule is assembled, before it goes to the cell membrane, and may be derived from either the degradation of one of the cell's own proteins, or from a virus, or from bacterial proteins that the cell has "eaten". Because of the random process that creates the receptors, auto-reactive receptors are generated both for T and B cells. Auto-reactive T cells, however, are eliminated in the thymus, and never reach maturity. The T cells that reach maturity are those that recognize your own MHC molecules, with a foreign peptide in them. Those B cells that happen to be reactive towards the same foreign protein as a given helper T cell clone, will have MHC molecules that are loaded with peptides derived from that foreign protein, because recycling of their B cell receptors ensures that some of the material is internalized, degraded, and displayed on their surface bound to MHC molecules. When a helper T cell encounters a B cell with the right combination of MHC molecules and peptides, it signals to the B cell that now is the time to launch an attack against the invader. --NorwegianBlue ^talk 13:43, 9 February 2007 (UTC)Reply

eutrophication

Latest comment: 18 years ago1 comment1 person in discussion

how can a eutrophied lake be rescued — Preceding unsigned comment added by Bates g (talk • contribs)

Welcome to Wikipedia. You can easily look up this topic yourself. Please see eutrophication. For future questions, try using the search box at the top left of the screen. It's much quicker, and you will probably find a clearer answer. If you still don't understand, add a further question below by clicking the "edit" button to the right of your question title. --Shantavira 13:02, 9 February 2007 (UTC)Reply

Heat Sink Formulae

Latest comment: 18 years ago3 comments3 people in discussion

Given the fin surface temperature of 68 degree Celsius and resistor temperature of 100 degree Celsius what would be the heat sink design?? This is in context of a convection cooled RF Load of 60W operating at 1 GHz frequency. What would be the fin height, no. of fins and cross sectional area of fin??? The base of the heat sink is at a temperature of 87 degree celsius?

Are you the same person who was asking this before? I suspect you're not going to get the precise, detailed answer you need here. You might want to try asking your instructor, or hiring a knowledgeable consultant, depending on the context of your problem. Good luck! —Steve Summit (talk) 13:28, 9 February 2007 (UTC)Reply

Among other factors you'll need to consider: What fluid is the heat sink immersed in, at what temperature does the fluid enter the system, is the fluid freely convecting or being forced to flow, how much turbulence occurs at the heat sink fins/pins, etc.

Atlant 14:14, 9 February 2007 (UTC)Reply

Before didn't you say 600 watts? It would take a while to heat up say a gallon of oil or silicone fluid with 60 watts of heat. Engineers who miss decimal points tend to design things which do not function up to expectation. I seriously mean this. The bridge falls down or the plane crashes. I had a professor who would take half off an answer for an "oops error' on that ground. Again, seriously consider a cooling fan, and look at a space heater as a model. You must consider the ambient temperature and the air flow. Perhaps a fan could blow room air in at the bottom, so the fan is spared the heat, and the hot air come out at the top or side. You need to spare your cable and connectors from the heat. I still suggest a thermometer or thermocouple (with a design which will not be affected by the RF emission) to make sure the oil is not too hot, and a design which makes sure the resistor is not partially out of the oil. Transformers sometimes have a float switch inside ot a level indictor with a float, or in the old days, a sight glass like on a big coffee pot. You must also allow for the expansion of the oil, so you do not have a pressure buildup which ruptures the can. Detailed design goes beyoond what I or most people here have attempted. There are probably specialized programs to be used with graphical mathematical analysis programs for such heat flow calculations. Good luck. Edison 15:50, 9 February 2007 (UTC)Reply

Uranium refinement

Latest comment: 18 years ago1 comment1 person in discussion

According to the Uranium article, the production of uranium metal from uranium ore involves using uranium halides. Are there any simple ( but not necessary quick or efficient ) ways to produce uranium metal direct from ore ( such as using electrolysis or reducing agents ? Robmods 11:17, 9 February 2007 (UTC)Reply

How many protons, neutrons and electrons is in the average in human body

Latest comment: 18 years ago4 comments4 people in discussion

Hallo, I´d need to know, how many protons, neutrons and electrons is on the average in human body? How many is it for one cell? Thank you

You can make a rough estimate from four assumptions.

1. Essentially all of the mass in your body comes from protons and neutrons (electrons are so light that their contribution is negligible for now; the masses of each particle are in the linked articles).
2. Your body will contain roughly equal numbers of protons and neutrons, as the most common elements and isotopes (oxygen-16 and carbon-12) in your body contain equal numbers of protons and neutrons. (For bonus points you can account for the contribution due to hydrogen, which mostly contains one proton and no neutrons; these tables have the relative contributions of each element to the body's weight: [21], [22]).
3. The number of electrons is equal to the number of protons—your body has no net charge.
4. Finally, the human body contains roughly 100 trillion cells: see Cell (biology).

That should get you started. TenOfAllTrades(talk) 16:25, 9 February 2007 (UTC)Reply

Don't even need to know how many cells...just how much total mass. DMacks 19:09, 9 February 2007 (UTC)Reply

He also wants to know how many are in a single cell... --Neo 19:13, 9 February 2007 (UTC)Reply

Ah yeah. DMacks, Friday-afternoon moron.

So that would be slightly more than 8x10^26 of each per kg:)Hidden secret 7 19:48, 9 February 2007 (UTC)Reply

So how many atoms is that:]HS7

Fundamental Tissues

Latest comment: 18 years ago2 comments2 people in discussion

I am aware that there are the four primary tissues- neural, connective, epithelial and muscle- and that most(all?) tissues fall under these, but where would specific tissues of the organ fit, say liver or kidney...

It depends. Most organs contain a mix of the four 'classical' tissue types. Taking the heart as an example, it contains:

• Neural tissue: The heart is innervated by (among others) the vagus nerve.
• Connective tissue: The heart circulates blood, the pericardial sac is lubricated by adipose tissue. The fibrous pericardium and epicardium are both mostly connective tissue.
• Epithelial tissue: The endothelial cells which line the blood vessels of the heart are epithelial tissue.
• Muscle: The heart is mostly muscle.

In other words, you have to look at the organ in detail. TenOfAllTrades(talk) 16:37, 9 February 2007 (UTC)Reply

What about say specific cells like hepatocytes, kupffer cells etc. Do they have to fit into the 'primary' tissue classification? (cells do make up the tissue after all- they only seem to fit into the connective tissue group...)

In the histological schematic you are talking about, hepatocytes are endothelial, they form sheets with clear lumina (is that the plural for lumen?); and kupffer cells are connective tissue (they are really just special macrophages). Remember that connective tissue falls into two categories, mobile (like plasma cells, mast cells etc.) and resident (fibroblasts, adipocytes, etc.). As stated above, these cell types interact metabolically and structurally to make the tissues we call organs. I can't personally think of any epithelial cells which appear without nearby connective tissue, nor muscle which occurs without neural tissue either connected (as with skeletal muscle) or somewhat nearby (though with the muscular conduction in the heart, cardiac tissue is something of an exception).^tucker/_rekcut 22:51, 9 February 2007 (UTC)Reply

Goldfish floating upside down

Latest comment: 18 years ago5 comments4 people in discussion

Ever since I got a couple of goldfish (the typical big-eyed kind that you can get in any pet store), one of them has spent a lot of time floating upside down at the top of the water. The first time I saw it do it, I thought it was dead. But a few minutes later it was swimming around fine. I've had it now for about six months and nearly every day it does this playing-dead upside down thing. Sometimes it even swims around the tank upside down for several minutes. Is this unusual behavior? Is my fish sick? Or is it just a weird fish? Deli nk 15:31, 9 February 2007 (UTC)Reply

Try googling swim bladder problems in goldfish. Apparently fancy goldfish are prone to problems like that. Guettarda 16:13, 9 February 2007 (UTC)Reply

FYI, you probably have comets; they're a very common kind of "fish store" goldfish. And yes, it's quite uncommon for a healthy fish to be completely inverted, although they certainly do momentary headstands, tailstands, and the like when feeding.

Atlant 17:05, 9 February 2007 (UTC)Reply

quick question about the comet gold fish

whats the max temprature range they can survive in Maverick423 18:44, 9 February 2007 (UTC)Reply

There seems to be quite a bit of info out there on swim bladder problems, as Guettarda suggested. After reading a bit, it's pretty clear that's the problem. Thanks all! Deli nk 19:16, 9 February 2007 (UTC)Reply

how much force does it take to propel a body the size of one of mars's moons or even earths moon

Latest comment: 18 years ago2 comments2 people in discussion

how much force to propel an object of this size???...or to change its current direction of motion??? and could humans ever achieve such a thing as propelling such large objects...??? how much does it take to fight the suns gravity and drive such a large object out of the solar system???...can the gravity of other planets be used to make it easier?? yet what would the initial force have to be like???...perhaps its easier to work with objects out near pluto???...could pluto and another object out that way be set into orbit around eachother on course heading out of the solar system???...(from a biologist)(its been a while since college physics class someone else can answer this quickly)...Benjiwolf 19:10, 9 February 2007 (UTC)Reply

F=ma, therefore the force needed to move an object would be the mass of the object, (in kg) multiplied by its acceleration, which is the same as the combined forces of gravity acting on it (in m/s^2):) Gravity varies with the square of distance from an object, so away from a planets surface, most of it would come from the sun:) Therefore it would decrese as you got further from the sun, but the masses and therefore gravities of other planets also needs to be considered:( So to find the forse you would have to work out the effect of gravity, and its direction, and then use this to find the force pulling the moon &c away from where you want it to go, and then multiply this by its mass:)Hidden secret 7 19:45, 9 February 2007 (UTC)Reply

Keeping raccoons alive

Latest comment: 18 years ago3 comments3 people in discussion

For my project at uni, we have to argue why we should keep raccoons alive as we are to debate with a group that says that they should be made extinct etc. Any help people?

You could start with the general arguments on why extinction of any species is bad. Then you explain what happened when the wolf was hunted to extinction in many parts of the world, and why it is being reintroduced. --Zeizmic 20:56, 9 February 2007 (UTC)Reply

I'm not sure if this would be what the moderator of the debate or whatever wanted, but costs versus benefits always works well; if you can show that it would be a lot cheaper to, for instance, buy everyone garbage cans secure against Racoon attack, than to exterminate them, then that is surely a point in your favour. --Neo 21:04, 9 February 2007 (UTC)Reply

More importantly: If you decide to keep them alive, but change your mind next year, you could deal with them then. But if you exterminate them now, and ever change your mind in the future, there would be no way to ever get a single living raccoon back. Extinction is forever. --mglg_(talk) 21:34, 9 February 2007 (UTC)Reply

Some Biology Questions

Latest comment: 18 years ago4 comments2 people in discussion

1. Of the three types of RNA, which is the primary transcript of eukaryotic genes?
2. An image of a mitochondria is presented, and the question is what does it have in common with chloroplasts, the choices being DNA is present, ATP is produced, and Ribosome presence, or A and B, or all three?
3. A nucleotide may contain: Ribosomes, Nucleic Acid molecules, AMP, ADP, ATP?

Any ideas as to the above, I disagree with the answer key on the above. ST47Talk 20:28, 9 February 2007 (UTC)Reply

How about telling us what you think the answer is and why so someone can see how/if your logic is wrong. Just being told the answer is no way to get an education... DMacks 21:34, 9 February 2007 (UTC)Reply

OK. #1 my response was mRNA, assuming that since they are limited-use, they would need transcription more often than re-usable ribosomal subunits and tRNA. The given answer was rRNA. #2, I knew both produced ATP, and I know both have their own DNA, I do not think either have ribosomes, so my answer was D: A and B. The Key said A, B, and C. #3, I put Nucleic Acid molecules, which is just plain wrong, but nucleotides don't contain any of those - AMP IS the Adenine nucleotide of RNA, so I suppose that was the reasoning, as that was the given answer on the key. ST47Talk 21:56, 9 February 2007 (UTC)Reply

1: see our articles on mRNA, tRNA, and rRNA. Yeah, seems like mRNA would be a reasonable answer assuming we're talking about nuclear genes. 2: visit the "structure" section of our pages about mitochondria and chloroplasts. That third question is pretty confusingly worded indeed. DMacks 23:04, 9 February 2007 (UTC)Reply

Flame test

Latest comment: 18 years ago2 comments2 people in discussion

In the flame test why do you see different colours from different salts? How is this colour made? Thanks for your help! --Flying Canuck 21:49, 9 February 2007 (UTC)Reply

Well, um, as our flame test article explains, this is due to "an element's characteristic emission spectrum." And as our emission spectrum explains, the colors are based on "the frequency of the light [electromagnetic radiation] the element emits when it is heated". Were you looking for more than that? --Steve Summit (talk) 22:38, 9 February 2007 (UTC)Reply

Why is that....?

1) When you take out earrings it feels like there's a little ball inside your earlobe? 2) What is the function of yawning and stretching - and why is it catchy? 3) What actually happens when you have 'pins and needles' or your leg is 'asleep'?

Thanking you,

San 23:18, 9 February 2007 (UTC)23:18, 9 February 2007 (UTC)23:18, 9 February 2007 (UTC)23:18, 9 February 2007 (UTC)23:18, 9 February 2007 (UTC)~

Stop Global Warming !

Latest comment: 18 years ago1 comment1 person in discussion

Why hasn't more attention been given to simply shielding the earth from sunlight? A series of thin, mirrored panels between the earth and sun would be more effective than trying to clear greenhouse gases from the atmosphere.

The costs for that would be huge, and it wouldn't really work since Earth rotates around itself and the Sun. Also, we'd lose so much of the visible sky that anyone involved in astronomy (that is, anyone who'd be involved in such a project) would reject the idea as preposterous. — Kieff | Talk 00:33, 10 February 2007 (UTC)Reply