Wikipedia:Reference desk/Science
Wikipedia:Reference desk/headercfg
July 1
Why are antistatic bags pink?
Why are antistatic bags pink? Yes there are blue/silver ones too but pink I dont get. Is there a reason or not? Studying Comptia A+ and questions keep coming up like "what colors are antistatic bags" -- why pink? wikipedia link [1]
--88.105.249.208 00:30, 1 July 2007 (UTC)
- I honestly don't know the answer - but I would speculate that it's either:
- One is technically supposed to open such bags at a static-protected workstation and assemble the component into whatever it's going into in a static-safe environment. Using a pink bag instead of a clear one is an indicator to the person unpacking it that this procedure is advised. (but rarely taken!)
- It might be to make sure that the people packing the parts in the first place don't grab a non-static-safe bag by mistake.
- Hopefully someone will come up with a better answer! SteveBaker 01:24, 1 July 2007 (UTC)
- According to this, the pink is just a dye added to distinguish what would otherwise be a transparent bag from all the other transparent and not anti-static plastic bags. By contrast, black and silver colors actually come from the intrinsic colors of the materials used in those cases. Dragons flight 01:54, 1 July 2007 (UTC)
- Dragons flight is correct: the pink color is so that you can know, at a glance, that the bag alleges to have some antistatic properties. We do have an article, BTW: Antistatic bag.
re:heat and sound
hello friends..
i m currently working on effect of "sound on temperature changes".i m not getting sufficient written matters to complete my project report.kindly prescribe some e-books/wikipedia articles related to this topic.
- Could you be more specific on what you are interested in? Do you want to know if sound energy (acoustic vibrations) can make something heat up (or less likely, cool down)? It would be interesting to see someone cook food by yelling at it! Edison 04:48, 1 July 2007 (UTC)
- One classic gedankenexperiment is to calculate the speed of sound in a material from fundamental principles and its Young's modulus. I'll see if I can dig up a reference... Nimur 06:36, 1 July 2007 (UTC)
we know that when a sound source is directed in a tube(means it is kept at one end)we get compressions and rarefractions.The longitudinal wave(sound) results from successive compressions (state of maximum density and pressure) and rarefactions (state of minimum density and pressure) of the medium.change in air density changes temperature of that part of air.my project is dealing with this fact .i want to alter the frequency of the incident sound wave and control the temperature.my project aims to assist machines which involve heat transfer by gases.
kindly help now in this regard. Sameerdubey.sbp 5:18 1st july india
- It's still not overly clear, but to me it sounds like you are looking at effects of "temperature changes on sound" rather than effects of "sound on temperature changes". See Speed of sound, in particular the section on speed in ideal gases and in air for starters. --jjron 12:10, 1 July 2007 (UTC)
- They really aren't. They are asking about the effects of sound on temperature changes, as described in their summary above. They are looking at changing the frequency to get different temperatures. Skittle 20:04, 1 July 2007 (UTC)
Didn't you ask this last week? I pointed out High intensity focused ultrasound and second sound in superfluids. The latest comment sounds more like acoustic refrigeration, though. — Omegatron 12:49, 1 July 2007 (UTC)
thankyou very much ...i hope i could get something very nice out of it. Sameerdubey.sbp 8 :06 1july india
Wireless Energy
I was reading the articles Tesla Coil and Wireless Transmission of energy and I started to contimplate how feasible these devices really are. If I where to build a tesla coil could I power my house wirelessly?68.190.214.230 03:41, 1 July 2007 (UTC)
- Yes, in principle you could. In fact, there is a bunch of very active practical research at MIT and elsewhere into finding ways to recharge small portable electronic devices such as cellphones and MP3 players wirelessly - I vaguely recall hearing that practical devices are only a short way from being practical devices that may ship with cellphones in the next year or two. See Wireless energy transfer for example. Furthermore, those RFID tags that you find in things like the Speedpass are powered (briefly) in exactly this manner. SteveBaker 04:26, 1 July 2007 (UTC)
- At the same time people worry a lot about the dangers of electromagnetic fields EMF causing cancer. How hard is it to plug a cell phone or a laptop power supply/wall wart into an outlet rather than plugging the "wireless transmitter" into the same outlet and beaming the power through the air (and sometimes through the kids) to the gadget you need to power? By all indications if you move too far away or out of the beam the gadget quits working, and under the best circumstances there would be a low efficiency compared to a direct connection. I see some promise in Micropower. Edison 04:43, 1 July 2007 (UTC)
- The forementioned MIT guys have 40% efficiency at 7 feet. I must admit there is appeal to having a universal wireless charging tech so I could just put my cell phone, camera, laptop, iPod, whatever on a special shelf and have it be fully charged when I come back. Dragons flight 05:27, 1 July 2007 (UTC)
In a way, you already power your house wirelessly. There are transformers between the power plants and your house that step down the voltage. These transformer have no wire connections, only Electromagnetic connections. This is the most common form of wireless power transfer. There are many other forms of wireless power transmission, some with high theoretical efficiencies such as Microwave power transmission. --Duk 05:14, 1 July 2007 (UTC)
- Also, the Carrier wave used by FM and AM transmissions are sort of like wireless power, enough to power a simple radio. -- JSBillings 13:16, 1 July 2007 (UTC)
- I have vague recollections of a court case involving some enterprising chap who lived very close to some large, powerful radio transmitters who was able to capture enough energy to power his home (I have no clue to what degree) - thereby causing a radio black-spot downstream from his house. I don't recall enough detail to provide a reference sadly. SteveBaker 16:23, 1 July 2007 (UTC)
- I heard a similar story about a farmer who laid some coils of wire in his field, beneath the high-tension transmission lines that crossed it, and was successful enough at extracting energy that the electric company's normal monitoring noticed. The farmer argued in court that he was simply picking up "waste" energy, but the electric company brought in an expert witness who showed, convincingly, that due to inductive coupling those coils in the field weren't passive, but were actively sucking -- stealing -- energy from the power company's lines. —Steve Summit (talk) 17:20, 1 July 2007 (UTC)
- if I lived next to a transmission line or substation I would probably check into free lighting. Edison 23:12, 1 July 2007 (UTC)
Nice thank you for all the responces.67.121.105.126 00:48, 2 July 2007 (UTC)
- Re Steve, Steve and Edison. Mythbusters investigated this in an apparently not very widely released episode and essentially busted it - see here (scroll down to the first entry in the table). --jjron 09:38, 2 July 2007 (UTC)
- Incidentally, the evidence for EM fields of the wavelengths suggested for wireless electricity causing cancer is non-existent. Batmanand | Talk 11:36, 2 July 2007 (UTC)
- The best evidence (and it is still weak, inconsistent and unconvincing) for there being any link between cancer and powerline EMF comes from the analysis of the experiences of thousands of people who lived near power lines, or thousands of utility worker who spent a career near lines. Obviously any new application with a different frequency will not have had thousands of people working or living for tens of years next to it, so your statement is technically correct but not informative. In the 1890's they could have said "the evidence for X rays causing cancer is nonexistent." They were in fact pretty sure it was harmless. 5 years later there were people such as Clarence Madison Dally dying of cancer after amputation of cancerous limbs. There is no handy database showing a chart of the cancer-causing or other harmful potential and safe intensity of each possible electromagnetic wavelength, from ELF to gamma rays. As an example, a friend who worked on hawk missile battery radar during the Vietnam War noted years later how many of the 40-something year old vets of the unit had developed cataracts, such that a proper statistical study (the government wasn't interested in doing one) would probably fond a link between the microwave exposure and the eye trouble a few years later. Today I see people with celphones clamped to their ears for several hours a month, and am concerned about the possible consequences. To power a device with transmission from several feet away would require a very high field intensity, in what is effectively an air core transformer. Only selected frequencies have been studied for their harmful potential so far, because either natural observation or a lab study of a large number of rats is extremely expensive and time consuming. As for the power near a transmission line only being able to produce negligible amounts of current or voltage, Mythbusters is not always a credible source. I enjoy the show but sometimes groan at their mistakes. They and their tech people do not always approach a question in a way which would show the claimed effect. That said, people should stay away from powerlines and not attempt any such experiment. A conductor parallel to an energized conductor can have very high voltages induced in it, and the ground near a power system ground where imbalance current from a three-phase system goes through a ground rod can have a measurable and significant ground potential. Edison 15:46, 2 July 2007 (UTC)
- Except that the frequencies being proposed are already well-studied. BBC News says the proposal is for 6.4MHz frequency EM waves to be used. They are currently used frequently - by ham radio operators! They are as safe any portion of the spectrum. Batmanand | Talk 16:14, 2 July 2007 (UTC)
- Is it safe at the power levels involved? IIRC, ham radios don't usually involve power levels of more than tens of watts. --Carnildo 21:52, 2 July 2007 (UTC)
- What is the field intensity that human beings near the transmitter for the wireless power would be subject to, and where is a citation showing that it's biological effects have been studied. So far I just see proof by assertion and hand waving. Edison 22:04, 2 July 2007 (UTC)
- Doing a quick google search, it seems that laptop power supplies work at about 90W or so, in other words within the same order of magnitude as ham radios. So there is no danger. Batmanand | Talk 00:10, 3 July 2007 (UTC)
- Above mentioned MIT guys accomplished only 40% efficiency. That means wireless power source would have to emit at 225W. This number might be bigger/smaller because of other considerations, but just because wired power supply works at 90W that does not mean that wireless power supply will work at 90W. — Shinhan < talk > 13:56, 10 July 2007 (UTC)
- Doing a quick google search, it seems that laptop power supplies work at about 90W or so, in other words within the same order of magnitude as ham radios. So there is no danger. Batmanand | Talk 00:10, 3 July 2007 (UTC)
- What is the field intensity that human beings near the transmitter for the wireless power would be subject to, and where is a citation showing that it's biological effects have been studied. So far I just see proof by assertion and hand waving. Edison 22:04, 2 July 2007 (UTC)
- Is it safe at the power levels involved? IIRC, ham radios don't usually involve power levels of more than tens of watts. --Carnildo 21:52, 2 July 2007 (UTC)
- Except that the frequencies being proposed are already well-studied. BBC News says the proposal is for 6.4MHz frequency EM waves to be used. They are currently used frequently - by ham radio operators! They are as safe any portion of the spectrum. Batmanand | Talk 16:14, 2 July 2007 (UTC)
Nicotinate concentration in the blood or blood plasma
Can anyone enlighten us as to what the figure is? Thank you so much in advance, anon.
- I found this: about 80 ng/ml (= 0.66 nmol/ml). Icek 21:54, 1 July 2007 (UTC)
What is a 'stable ectotherm'?
Hi all. I know that an ectotherm is a cold-blooded animal, ie a snake or fish. Your article doesn't express what a "stable" one is, however, and I was wondering what it meant. Much help appreciated ! Xhin Give Back Our Membership! 04:52, 1 July 2007 (UTC)
- I think we need some context. Where have you come across this expression? Our ectotherm article doesn't mention their stability, and "stable ectotherm" returns zero Google hits. "Stable" simply means non-changing.--Shantavira|feed me 07:51, 1 July 2007 (UTC)
- Agreed, we need some context. At a guess, it sounds to me you'd be talking about an ectotherm whose body temperature nonetheless remained at a stable temperature. This could refer to creatures that I have heard of previously termed mass (or bulk) endotherms, and which Wikipedia redirects to gigantothermy. In short the idea is that the animal can essentially maintain a constant high body temperature simply by virtue of being so big that it takes a long time to lose heat from normal body processes such as digestion, rather than by actually controlling body temperature in the manner of endotherms. I first heard this discussed in arguments over whether dinosaurs were cold or warm blooded, in particular in reference to the real giants like the brontosaurus and brachiosaurus. --jjron 11:55, 1 July 2007 (UTC)
If a Tree Falls in the Forest MARK II
Perhaps this is a naive question, but ... how has science resolved the dilemma presented in "If a tree falls in the forest, and no one is there to hear it, does it make a sound?" ...? Thanks. (JosephASpadaro 04:33, 30 June 2007 (UTC))
- Your question was answered at inordinate length yesterday. Please see above.--Shantavira|feed me 11:26, 1 July 2007 (UTC)
Never mind that!
If a single photon passed through a double slit experiment but no one or no detector has observed it, is it behaving like a wave or a particle? 211.28.121.217 11:20, 1 July 2007 (UTC)
- Re first question, as Shantavira says, please do not repost the same question when you have received an extensive reply. Re second question, even if you are trying to be silly, the answer is that it behaves as both - see Wave–particle duality. And in case you're wondering, strange as it may sound, even single photons display the properties of this duality. --jjron 11:59, 1 July 2007 (UTC)
- Scientists make precise definitions and stick to them. It saves a lot of hassle. The rest of the world could learn this habit, it would make their unscientific pursuits much more efficient. Nimur 17:18, 1 July 2007 (UTC)
Re - first question. I never re-posted it. Some one else, for whatever reason, probably cut-and-pasted it and re-posted it. I do not have the time, energy, inclination, or interest to review the history logs and see who that "some one" might be. You are welcome to do so. In any event, please research facts before making accusations. Thanks. (JosephASpadaro 00:10, 2 July 2007 (UTC))
- Yes, upon reflection, it seems that User 211.28 was merely using my question as a preface to introduce his/her "single photon" question. His photon question took the same syntax as my tree/forest question. What 211.28 was essentially saying is, "Who cares about the tree falling in the woods question, I have a single photon question to ask that seems much more interesting!" (JosephASpadaro 00:39, 2 July 2007 (UTC))
- "I do not have the time, energy, inclination, or interest to review the history logs...please research facts before making accusations". And we do have the time, etc, to do this? What, we should research the history of all posters and how the question was created before answering their question? You must be joking! --jjron 02:38, 2 July 2007 (UTC)
- Look, it was very, very rude of 211.28.121.217 to repost JosephASpadaro's text, including his signature. If I were Joseph, I'd be annoyed, too, especially after getting scolded for a repost which wasn't mine. If Joseph's reaction wasn't just what you would have liked, let's let it ride, okay? We shouldn't let 211.28.121.217's rudeness set the rest of us against each other. —Steve Summit (talk) 03:13, 2 July 2007 (UTC)
- I agree with Steve Summit (at least, your 2nd, 3rd, and 4th sentences). As far as User 211.28, I assume good faith on his part; he was probably cutting-and-pasting simply to show the parallel between his question and mine. He was basically saying, "never mind that question posed above by JosephASpadaro ... let's take a look at my question! If you think the tree question was interesting, how about this question about photons?" I don't think he meant any harm. As far as Jjron, the answer to your question ("And we do have the time, etc, to do this?") is that the proof is in the pudding. Yes, apparently, Nimur did indeed have the time, etc, to do this. Furthermore, no, I am not asking you to research the history of all posters, etc. But, clearly, you did enough "research" to see that my original question was posted a day or so prior with extensive response. Not to mention, discussion and engagement and participation on my part in the thread. It would seem unlikely (at best) that I would engage in the extensive conversation posted a day or so earlier, only to repost the very same question the following day. Given the unlikelihood of that scenario, I would have assumed good faith. And the time that I spent researching the original post could just have easily been spent on researching who, in fact, submitted the re-post. So, yes, I will stick with my statement, which is: before you scold someone, make sure that the scolding is proper and appropriate. (Or, as I worded it, research facts before making accusations.) Bottom line: this is not a big deal, we all have bigger fish to fry, we can all move on. No harm, no foul. Thanks. (JosephASpadaro 04:01, 2 July 2007 (UTC))
- Re Steve - agree with the gist of your comment. Three people had posted replies to this requestion, two had politely asked users not to repost the same question. However, a simple 'it wasn't me' was all that required from Joseph, instead he follows that up with a rude 'do some research you jerks' comment. That is what requires a response.
- Re Joseph - I think you need to learn some real manners. Remember that the people posting answers here are unpaid volunteers giving freely of their own expertise to help out people like you. My guess is that Nimur has better things to do than research edit histories (I know I do), the fact that he did so as another favour to you should be appreciated, not met with a 'nah-nah he's got heaps of time to waste' comment. And if you cared to do your own "research", or rather just read the replies to your own questions properly, you would have seen that I posted the second response to your original question. This is where the extended discussion started - so of course I knew about the original question, I didn't have to research it. Oh, and as for doing some research, in fact I did do some research before posting my initial comment in this section and saw that you had had some run-ins before with other users on questionable use of Wikipedia, including, but not restricted to this, so in fact was suspicious that this could have been trolling on your part. Now, is that scolding "proper and appropriate" - yes, I think it is. --jjron 09:23, 2 July 2007 (UTC)
- FWIW, while Joseph's words may have been curt, they certainly didn't strike me as rude. In particular, there was no implication of "you jerks" in there, for me. —Steve Summit (talk) 11:39, 2 July 2007 (UTC)
- I agree with Steve Summit (at least, your 2nd, 3rd, and 4th sentences). As far as User 211.28, I assume good faith on his part; he was probably cutting-and-pasting simply to show the parallel between his question and mine. He was basically saying, "never mind that question posed above by JosephASpadaro ... let's take a look at my question! If you think the tree question was interesting, how about this question about photons?" I don't think he meant any harm. As far as Jjron, the answer to your question ("And we do have the time, etc, to do this?") is that the proof is in the pudding. Yes, apparently, Nimur did indeed have the time, etc, to do this. Furthermore, no, I am not asking you to research the history of all posters, etc. But, clearly, you did enough "research" to see that my original question was posted a day or so prior with extensive response. Not to mention, discussion and engagement and participation on my part in the thread. It would seem unlikely (at best) that I would engage in the extensive conversation posted a day or so earlier, only to repost the very same question the following day. Given the unlikelihood of that scenario, I would have assumed good faith. And the time that I spent researching the original post could just have easily been spent on researching who, in fact, submitted the re-post. So, yes, I will stick with my statement, which is: before you scold someone, make sure that the scolding is proper and appropriate. (Or, as I worded it, research facts before making accusations.) Bottom line: this is not a big deal, we all have bigger fish to fry, we can all move on. No harm, no foul. Thanks. (JosephASpadaro 04:01, 2 July 2007 (UTC))
- Steve Summit - thank you. Jjron - please re-read my original post in this thread. It says, quote, " ... please research facts before making accusations." You, completely of your own doing, interpreted those black-and-white words as, quote, "do some research you jerks." Clearly, you have interjected the negative tone and rudeness into the comment, fully of your own doing. And that is your issue, not mine. In other words, despite hard evidence, you are seeing only what you want to see. A second example of the same phenomenon: My statement, exactly, was (quote) "Yes, apparently, Nimur did indeed have the time, etc, to do this." And, completely of your own doing, you interpreted that black-and-white statement as, quote, "nah-nah he's got heaps of time to waste." So, once again, you yourself have interjected the negative tone and rudeness into a comment that, on its face, is 100% neutral and 100% factual. And, once again, that is your issue, not mine. And, once again, despite hard evidence, you are seeing only what you want to see. So, actually, you are making my case for me. Thanks. Let me offer you an example. In your statement to me, you said, quote, "please do not repost the same question when you have received an extensive reply." How would you like it -- and, more importantly -- how fair would it be to you ... if I subsequently asserted (from your direct quote) that in fact you said to me, quote, "hey, you stupid jerk, stop reposting the same damn question over and over" ...? I am quite sure that you would see the point that I am making here. So ... in conclusion, I am done with this thread. If you are the type of person who needs to get the last word in, go ahead. And we can call that the last word. As I said earlier, we all have bigger fish to fry than to belabor some semantic misinterpretation / misunderstanding. Also, I did notice that you offered some input on the original question (tree falls in the woods). Thanks for that. That question had been in the back of my mind for quite some time, and I found that thread interesting, informative, and enlightening. Thank you. And, to Steve Summit, thank you also. (JosephASpadaro 15:19, 2 July 2007 (UTC))
- If nobody demands a document from Dick Cheney's office, is it part of the Executive Branch or the Legislative Branch? Gzuckier 16:09, 2 July 2007 (UTC)
- That's hysterical. Next, Cheney will twist and turn words in such a way that he is in the Judicial Branch and, didn't you know, he is in fact the Chief Justice of the Supreme Court. Unreal. (JosephASpadaro 18:37, 2 July 2007 (UTC))
- I am the "type of person who needs to get the last word in." I want everybody to know that I use Wikipedia with Popups and that it takes just a few seconds to scan a page history. If you aren't using popups, you should be! Nimur 07:23, 4 July 2007 (UTC)
Fibre glass Polyster Resin
I would like to know how to make fibre glass polyster resin and its chemical ingrediants with chemical ratio.
- Sadly, our article on Polyester resin isn't very helpful. There is more information in Polyester. SteveBaker 16:10, 1 July 2007 (UTC)
Ganymede (moon) volcanic?
Hi, is Ganymede volcanic in any way? Io would be the most active volcanically, but I was just wondering. --Kjoonlee 13:03, 1 July 2007 (UTC)
- Yes. If you go to this page: [2] and scroll down to "Volcanic Landforms on Icy Satellites" where it says "This mosaic illustrates the great variety of relief-forming volcanic landforms observed on the icy satellites, including Ganymede." - also, a bit further down, it's discussing some craters on Ganymede and says "Also visible is a large, irregular, caldera-like feature that may be volcanic in origin (right of Isis).". Ganymede's surface is certainly tectonically active - there would be earthquakes that would cause cracks to form - through which it's icy mantle would ooze out. Such 'volcanoes' as there might be would be water volcanos - so 'geyser' might be a better term. You should also check out: Schenk P. (1995) Volcanic constructs on Ganymede and Enceladus. Journal of Geophysical Research, 100, 19009-19022. SteveBaker 16:05, 1 July 2007 (UTC)
Decision tables versus classification tables
While both a decision table and a classification table are based upon truth table format it appears that they are different in some respects. For instance, in a classification table there can be only one rule for each dependent variable, that is, each rule is unique per table or context whereas in a decision table there may be more than one dependent variable which has the same rule per table or context. Where can I find a list of any other such differences between decision tables and classification tables? Ugly bag of mostly water 13:14, 1 July 2007 (UTC)
- The Decision tree article mentions that "...classification tree (discrete outcome)..." but nother more and does not state the type outcome of a decision tree although the Decision table article may suggest that it is exhaustive for the condition set. There seem to be other differences bewteen a decision table and a classification table, however, which are not expressed in either article or in any article related to either topic which I could find.
- I'm not quite sure what your question is, but a decision table, easily visualized as a decision tree, can also be seen as a way to partition a many-dimensional space, where each decision splits the remaining partition in two. For the XOR problem for instance, with 2 parameters you'd first split the space in two, with a rule based on parameter 1 and then use two different rules on parameter 2, on the two parts. Alternatively, the same rule may be used twice, once in each half. So what kind of table can be used depends on how the categories are distributed in the many-dimensional space.
super tall
i'd really love to be super tall well 6ft (no bigger!) im 5ft 9 at the moment (plus im still young 16) but i read about Maria Sharapova's height and all the growth spurts she had plus i've got all the 'growth spurt' symptoms at the moment and i've always been taller than average (for a girl!) since the day i was born,so how can i put my 'growth spurt' to advantage and recieve maximum height?
- There is very little you can do to increase growth, but there is some you can do to limit inhibiting growth. Lack of exercise and malnutrition both inhibit growth. So, exercise and eat a healthy balanced diet. Your body will take care of the rest to the best of its ability. However, I should note that I've seen multiple studies that show bone thicker under stress - in other words, the leg bones of a runner are thicker and longer than those of someone who never puts stress on their legs. To my knowledge, this type of observation has never been proven or applied to the body to increase growth. -- Kainaw(what?) 18:02, 1 July 2007 (UTC)
SWIMING POOL CHEMICALS
I RECENTLY ACCIDENTALLY MIXED THE FOLLOWING TWO CHEMICALS AND THEY EXPLODED. I WOULD LIKE TO KNOW WHAT CHEMICAL EVOLVED FROM THIS MIXING.
CALCIUM HYPOCLORITE was added to ACID TRICLORO-S-TRIAZINETRIONE then water which caused the explosion.
CONTACT EDGAR ALLEN PAUL, AIA (Contact information removed)
Always add acid to water. The fact that you added water to acid is often sufficient to cause explosion. Nimur 20:19, 1 July 2007 (UTC)
- Mixing concentrated acid and water generates a lot of heat, often enough to cause localized boiling, which causes a lot of spatter. You'd rather have a bucket of water with a little bit of acid spatter all over you than the other way around, which is why you add the acid to water. Gzuckier 16:13, 2 July 2007 (UTC)
Treadmill Question
When running on a treadmill, there is some internal "calculator" that displays various data: how many miles you've run, the speed at which you are running, the number of calories you have burned, etc. Does anyone know of either a website or a mathematical formula that computes these values? Basically, I would like to calculate the answer to a question such as this (generically stated): If I weigh X pounds, and I want to set the treadmill at X miles per hour, how many minutes of running will be required for me to burn X calories?
Namely, the questions (below), as well as other variants of the same question:
If I weigh 165 pounds, and I want to set the treadmill at 4.5 miles per hour, how many minutes of running will be required for me to burn 1,000 calories?
Variant – example: If I weigh 165 pounds and I want to run for 30 minutes and I want to burn 1,000 calories, what speed (miles per hour) should I set the treadmill on?
Variant – example: If I weigh 165 pounds and I set the treadmill for 4.5 miles per hour and I run for 30 minutes, how many calories will I burn?
Etc. Etc. Etc.
Of course, I can do this through trial-and-error on the treadmill. But (a) that would be an inefficient and laborious process; and (b) I don’t have a treadmill at my disposal at home, but only at the gym. I assume that there are websites where I can plug in the numbers and the calculator will compute the answer … or I assume that there is a (relatively simple?) mathematical formula that can do this. In fact, there must (?) be some formula that does this, as that very formula must be what is programmed into the treadmill apparatus. No? Thanks. (JosephASpadaro 18:35, 1 July 2007 (UTC))
- Yes, a formula must exist if the treadmill is giving the output, but it's a "rough estimate" at best. I would not put a lot of stock in the numbers it displays for "calories burned." Nimur 20:06, 1 July 2007 (UTC)
- I will take a "rough estimate" ... any idea where to find the formula? Thanks. (JosephASpadaro 20:20, 1 July 2007 (UTC))
- This and this online calculator both use formulas in which energy burned is proportional to body weight times distance, with a proportionality constant of about 0.9–1 kCal/(kg*km). In your units, that would be (energy burned, in kCal) = (body weight, in lbs)*(speed, in mph)*(time, in minutes)*C, where the constant C is 0.0109 kCal/(lb*mph*min) according to the first site, and 0.0121 kCal/(lb*mph*min) according to the second site. This is of course all but complete BS, since the actual energy use must depend in much more complicated ways on body weight, speed, running skill, height, etc. But your treadmill is probably using a similar formula. --mglg(talk) 21:04, 1 July 2007 (UTC)
- To Nimur and mglg: why do you both put such little stock in these calculations? Isn't simply a non-controversial mathematical formula based on physics, biology, chemistry, kinesiology, whatever field of science? Why the skepticism and cynicim? Why is the formula not reliable? (JosephASpadaro 00:44, 2 July 2007 (UTC))
- There are two problems: (1) measuring the mechanical work output of the treadmill user, and (2) figuring out how many of the calories the user is burning are going into that mechanical work.
- Theoretically, the treadmill could measure the mechanical work you're putting into it fairly accurately. But I tend to doubt it does this, because it would be harder (for the manufacturer, that is), and given all the other uncertainties, it probably wouldn't be worth it. So my guess is that they make a simple estimate based on your speed.
- The big problem is the connection between the calories you burn and the mechanical work you're doing. I'm pretty sure humans (like most animals, and most machines, for that matter) are about 25-30% efficient. That is, for each unit of energy (i.e. food energy) you burn, you can produce 1/4 to 1/3 of a unit of actual, usable mechanical energy. The rest of the energy you're burning is lost as waste heat (again, just as for machines). But the actual efficiency figure will probably vary widely for different people.
- Finally, for weight-loss purposes, the amount of calories you "burn" while exercising is most usefully computed as the difference between the calories you're burning while exercising, minus the calories you'd be burning just sitting on a couch watching TV or editing Wikipedia (that is, your basal metabolic rate). But different people's basal metabolic rates vary all over the place.
- So it's a hard problem. And, cynically speaking, there's no incentive for the treadmill manufacturers to work very hard at solving it. The people using the machines will certainly want some indication of "how many calories they're burning", but they're in no position to verify the numbers the machine gives them. So as long as the machine displays some vaguely-plausible number, which goes up the faster you run, everybody's happy.
- The numbers probably aren't complete BS. But the fact that it's hard to find concise formulas in the open literature is suggestive. I'd guess that the various manufacturers guard their own formulas as trade secrets, and (as is the case for lots of trade secrets) not so you can't snitch them, but just so that you can't see how lousy they are. —Steve Summit (talk) 01:13, 2 July 2007 (UTC)
- Treadmill (and those elliptical machines) are actually rather accurate if used properly. The formulas were not just made up. They are based on the "work" (from a physics standpoint) of moving your weight a specific distance. It doesn't matter if you run on your hands or legs - your body is putting the same amount of work into moving your body over a certain distance. In fact, treadmills are more accurate than running because, on a treadmill, you are not working against or with the wind (unless you use your treadmill outdoors - but that is ridiculous. Why would you even suggest taking a treadmill out to the park to run on?) The fault in treadmills is that they are normally NOT used properly. The person doesn't enter their weight properly (yes, the treadmills COULD weigh you when you hopped on). Also, most people hold the rails when they run. If you do this, you are not working to move your weight forward. You are just hopping a little and sort of bouncing in place. -- Kainaw(what?) 01:25, 2 July 2007 (UTC)
Thanks to all for your input. This thread was certainly enlightening and informative. Kainaw -- are you saying that, when the user holds the rails on the treadmill, that is essentially "cheating" (i.e., lessening the work load)? I have been using them all along, assuming (since the rails are there) that that (hands on rail) was the proper way to use a treadmill. Aaaarrrggghhhhh! So, what's the proper form? Hands swinging by your sides? Thanks. (JosephASpadaro 02:25, 2 July 2007 (UTC))
- Correct. According to our physical therapy people, you use the rails to maintain balance when starting and stopping. While exercising, do not hold on to them. As one of the ladies put it, you don't get any effective exercise if you just hold on to the back of a bus and let it drag you ten miles. You have to let go and run it yourself. -- Kainaw(what?) 12:13, 2 July 2007 (UTC)
- Kainaw -- yes, what you said makes perfect sense. Thanks. The bus example is a great parallel. But -- on a bad note -- you are effectively telling me that these past two months of me running/ sweating on a treadmill have all been for naught! Aaaaaarrrrrrrgghhhhhh! (JosephASpadaro 15:29, 2 July 2007 (UTC))
- If you've been working up a sweat, then you've been exercising! Holding the rails on a treadmill is not the same as being towed by a bus: you are still working your leg muscles, your arms are taking some of the weight of your upper body, but by no means all. Some people find it hard to balance on a treadmill, so holding on to the rails could be a sensible safety precaution. DuncanHill 15:36, 2 July 2007 (UTC)
Business model
What is the name of the business model Microsoft uses to sell copies of its personal computer operating systems - providing an OS with a specific version number or name who's content is upgraded continuously until the version can no longer be updated to match current technology or is otherwise outdated and support can be justifiably removed following replacement by a new version name or number? What businesses have used or developed this business model prior to Microsoft? Ugly bag of mostly water 19:28, 1 July 2007 (UTC)
- This probably does not belong on the science reference desk. Anyway, business plans tend to be proprietary and confidential. Needless to say, any software provider will try to optimize the frequency that it sells new versions, based on how often people will buy it and how rapidly it can be developed. Nimur 20:08, 1 July 2007 (UTC)
- Business plan and business model are entirely different. Why do you keep guessing at answers to the questions I've asked? Stop doing it. Ugly bag of mostly water 07:38, 2 July 2007 (UTC)
- The business model you describe sounds like planned obsolescence. The article has some history. --HughCharlesParker (talk - contribs) 14:25, 5 July 2007 (UTC)
What did Surrealists like Andre Breton and others think about Zionism?
As much as I know Andre Breton and his surrealist group in Paris appreciated the foundation of Israel in 1948. But I really wasn´t able to find reliable sources for that. Can anybody help? 77.2.106.24 22:24, 1 July 2007 (UTC)
- This belongs at the Humanities desk. Nimur 22:55, 1 July 2007 (UTC)
- The link, for those looking for the answer. WP:RD/H#What_did_Surrealists_like_Andre_Breton_and_others_think_about_Zionism.3F Skittle 16:02, 2 July 2007 (UTC)
July 2
Red light.
I'm doing a research project on Chambered Nautilus and in my local aquarium they nautilus are stored in a tank with dim red lighting. I know Nautilus are known for living in very deep and dark waters. Also, I heard somewhere that in very dark areas the first color to disappear is red light. Would this be a reason why they chose this color? --Agester 00:47, 2 July 2007 (UTC)
- You're right in saying red is the first colour to disappear from shadowed areas. This is because it diffracts less than blue, which is better at illuminating areas not in direct light. In the sea, shadowed areas are not the issue, but absorption of light by water as it passes through. In this case, the opposite happens, and blue light is the first to be absorbd, so underwater environments are in fact much redder. Light in the aquarium doesn't pass through as much water as in these habitats, so I'm guessing the red lighting is a way to make the nautilus feel at home. Bendž|Ť 10:48, 2 July 2007 (UTC)
- Your statement that blue light is absorbed more than red in water is very counterintuitive, and these references say blue is least absorbed ([3], [4], [5]). Do you have any references that it's redder in the briny deeps? Perhaps due to scattering, as in a sunset? Thanks! --TotoBaggins 21:02, 2 July 2007 (UTC)
- Since red light is almost nonexistant at the depths involved, I wouldn't be surprised if the nautilus is unable to see it. In that case, the red light is both a way of keeping the nautilus dark enough for comfort, but lighting it enough for people to see. --Carnildo 22:01, 2 July 2007 (UTC)
- Red light is also good if you want a dim light that will keep people's eyes dark-adjusted. I've seen it used (I think) in situations such as lighting the sound mixing board in an otherwise dark auditorium. So one reason for using it in a public aquarium might be to give just enough light for the human visitors to see by so they don't run in to each other, but keep their eyes adjusted so they can see the weird deep-water fish in the almost-dark tanks. --Steve Summit (talk) 23:12, 2 July 2007 (UTC)
skin -kojic acid;azelaic acid;bearberry, mullbery, vitamin c
a cream or exfoliant containing the ingredients in the heading are suppossed to improve and brighten the appeareance of the skin... are they dangerous or harmful at all?
can you tell me of any over the counter product of a respectable brand that contains the former compounds?
thank u.
- You could read our articles on kojic acid, azelaic acid, bearberry, mulberry and vitamin C. The berries are edible, so those are presumably safe. As for the exfoliant as a whole, it is generally safe to presume that anything sold in at pharmacies in the United States is safe to use, and likely underwent animal testing. Barring any allergies, and of course obeying the manufacturer's suggested amount and frequency of use. I don't know of any in particular that have these chemicals, but like i said before, if you see it in a pharmacy, do what the bottle says and you probably won't have problems. Ask your dermatologist if you're worried. Don't buy chemicals over the internet...</rambling> Someguy1221 04:14, 2 July 2007 (UTC)
- If it is marketed as an herbal supplement it might not have been tested; the FDA does not regulate herbal supplements with any regularity (it treats them as food, not as drugs). --24.147.86.187 12:47, 2 July 2007 (UTC)
Heat Shield
I read an article once in Popular science about sending payloads into space with a magnetic launcher, mass driver. I was wondering though how much shielding would be needed for traveling through the air at escape velocity? [6]
- Why would this be any different from any other spacecraft? See especially the 'Thermal control' section in spacecraft subsystems. While a magnetic launcher may mean the spacecraft doesn't need to be able to handle the heat produced in a fuel based launch, it doesn't alter it's requirements for withstanding the heat produced by passing through the atmosphere. See also atmospheric reentry. --jjron 03:17, 2 July 2007 (UTC)
- There is a difference between the two situations. On re-entry a spacecraft is deliberately trying to slow down by dissipating its kinetic energy as heat energy, so it is trying to generate as much drag as possible. In the launch situation, however, you want to minimise energy loss, so you want low drag, with a streamlined profile. Contrary to intuition, a streamlined profile actually requires more heat shielding than a blunt profile - see Blunt Body Theory. However, this difference is probably immaterial - because escape velocity is over 20 times the speed of sound at sea-level, a spacecraft launched by a mass driver, with no on-board engines, would have to travel at hypersonic speeds at launch. Because of this, I doubt that an Earth-based mass driver is a practical launch mechanism unless the payload travels in a vacuum - in a space fountain for example. Gandalf61 09:19, 2 July 2007 (UTC)
- There's a *huge* difference between the two situations: a chemical rocket is at its slowest near the ground where the atmosphere is at its densest, and picks up speed as it goes; a launcher-fired projectile is at its fastest near the ground, and loses speed as it goes. --TotoBaggins 20:06, 2 July 2007 (UTC)
- Bah! Passimists! Yes you are going insanely fast through the densest air...not good! But the temperature conduction through your heat shield isn't immediate - the mass-driver vehicle isn't in the dense atmosphere for very long. Crunch the numbers guys/gals (sorry, I'm in a hurry - these numbers are from memory): At launch your projectile is heading out at maybe 12km/second - that's escape velocity. The troposphere (~75% of the mass of the atmosphere) lies below ~20km altitude at the equator...and below ~10km at the poles. So bury your mass driver in the ice at the South pole and shoot your projectile vertically up at escape velocity. It'll be subject to atmospheric heating for rather less than a second!! So you need an insulator that conducts heat just slowly enough to protect the skin of your craft for just ONE second! Remember...Thermal conductivity is heat transferred though some area in some amount of time. We don't need a really low conductivity if the time is short enough...and it is. Then you may discarded the heat shield before the heat on it's surface is conducted through to the payload. It's short - violent - but possible. The real problem with mass drivers is finding some interesting payloads that don't mind a few tens of g's of accelleration during launch! SteveBaker 00:36, 3 July 2007 (UTC)
- I don't think heat shielding is the biggest obstacle here. Problem 1 - launch acceleration. Let's assume the launch tunnel is as deep as the Kola Superdeep Borehole - thats 12km. To reach a terminal speed of 12 km/s over a distance of 12km requires an average acceleration of 6 km/s2 - that's about 600 g. Problem 2 - drag. A bullet fired horizontally loses one third of its muzzle velocity over the first 500m of its range (see External ballistics) - and that's at supersonic speeds, not hypersonic. Even assuming drag is no worse at hypersonic speeds, you will need a terminal velocity (on leaving the launch tunnel) many times higher than escape velocity. This then compounds the launch acceleration problem, as average launch acceleration is proportional to the square of the terminal velocity. As a certain Chief Engineer once said "A canna' change the laws of physics". Gandalf61 10:47, 3 July 2007 (UTC)
- Absolutely - I agree entirely. However, the questioner was asking about the heat shield - not about the overall practicality of these gizmos. You're absolutely correct in saying that the ballistic drag on the payload would be phenomenal - so the muzzle velocity would have to be much more than 12km/s. However, that only serves to further reduce the amount of time the object is within the atmosphere. These 'mass drivers' might be useful for things like launching large chunks of ice to a colony on the moon - or lumps of metal ores to orbital refineries turning out space station components. Bulk materials that won't suffer from 600g accellerations - and which need to be launched cheaply and at high payload capacities without generating too much air pollution from rocket exhausts and such. It's still not obvious that it can be done - but I maintain that the reason it's tough has nothing to do with heat shielding. Ice makes a pretty good insulator - if we were shooting thousands of tons of water to a lunar colony - we probably wouldn't bother with shielding at all. Just cast the water into the right shape - use a metal sabot to get the thing accellerating and even if half of the ice melted and boiled away on the way up (which I doubt it would), you're still onto a winner. SteveBaker 12:21, 3 July 2007 (UTC)
- Won't 600 g's cause massive heating throughout the slug, not just at the surface ? StuRat 02:54, 11 July 2007 (UTC)
WOOT cool thanks for the answers.68.120.85.164 05:26, 4 July 2007 (UTC)
Are all Neoptera holometabolic?
Are there any Neoptera outside Endopterygota? If you know the answer, it may be helpful to include it in those articles. If it is already there and I somehow missed it, I apologise for wasting your time. Wikipeditor 02:34, 2 July 2007 (UTC)
- Sorry, but doesn't the taxobox at Neoptera answer this question? It seems to list the superorder Exopterygota and 11 other orders outside Endopterygota. --mglg(talk) 02:45, 2 July 2007 (UTC)
- According to our articles Neoptera is an infraclass, Endopterygota is a superorder within that infraclass, therefore indicating that all Endopterygota are Neoptera. --jjron 03:03, 2 July 2007 (UTC)
- My question was whether it is the other way round, but thanks nevertheless. Wikipeditor 03:11, 2 July 2007 (UTC)
- D'oh! It seems I had only checked the German article on Neoptera and somehow misunderstood all Neoptera to belong either to Endopterigota = Holometabola or to a paraphylic group of Exopterigota.
- The English article is much clearer. Thank you! Wikipeditor 03:11, 2 July 2007 (UTC)
- Sorry, I had misread your question, but my answer stands. You are correct, the articles could perhaps be clearer on this. However, what you say in your 'doh' still doesn't sound right - there's the Superorders Endopterygota and Exopterygota, plus eleven other orders outside these two superorders within the Neoptera. --jjron 03:32, 2 July 2007 (UTC)
Development of the water tank
Hello Wikipedia, I am looking for some rather specific information which I have had some difficulty in finding. I am looking for dates of significant technological developments of the water tank (specifically, the backyard rainwater tank) which would help me put together a good picture of it's history. I have information like the dates of introduction of technologies like hot dip galvanization (helped produce a metal tank which was less susceptible to corrosion) and the dates of development of technologies that facilitated industrial polyethylene and fiberglass production which are also used extensively in tanks. Any information or assistance would be greatly appreciated. Dates of milestones, breakthroughs and innovations is what I am aiming to find out.
Thank you, --Waynekruse 02:55, 2 July 2007 (UTC)
- Whatever you find vis a vis the history of galvanized or plastic tanks, be aware that in the 19th and early 20th century (if not earlier) it was common to have a rainbarrel of wood sited to catch runoff from the roof, which women could use to wash their hair. Since it had no minerals in it like well water, simple laundry soap worked better with the soft rain water. Cisterns served much the same function plus serving as a well substitute. Edison 03:12, 2 July 2007 (UTC)
Name of Flower
Can someone help me identify a particular flower? I used to know the name, have been searching through my books, but some of my books are missing. I've also tried searching the "net" but haven't had much success yet. The flower is roughly 12" tall. It has green leaves that are somewhat pinnate and which are not smooth to the touch. It has clusters of purple/violet colored flowers at different sections of the main stem. The stem is somewhat squarish--as if it might be in the mint family. The flowers individually are perhaps the size of a nicket (+ or -), but are bunched together around the stem at various intervals. Thanks so much if you cfan identify it or set me in the right direction. My mind wants to think the name began with a "v", but I cannot find any flowers that start thus and look like the plant I am describing. I might be able to upload a picture is someone needs it. . . . Thanks for any help! Rfhallock 05:55, 2 July 2007 (UTC) Email removed to minimize spam
- Have you looked at Hyacinth (flower), Grape hyacinth, crocus, iris (plant), and violet (plant)? Nimur 07:07, 2 July 2007 (UTC)
- Bracted Vervain perhaps? --TotoBaggins 20:37, 2 July 2007 (UTC)
Sounds like a form of Polemonium. Hardyplants 22:24, 2 July 2007 (UTC)
- How about Veronica? --Eriastrum 19:14, 3 July 2007 (UTC)
Moisture transmissivity of Aluminium.
Hey all, I've found some papers that discus the water transmissivity for an Al film of given thickness. I'm wondering if you would expect the ingression rate to be proportional to the thickness of the coating? I can't find any solid data on this. I have some data for other plasticy materials which suggest a linear relationship. Would this be the same for metals? 213.48.15.234 09:35, 2 July 2007 (UTC)
- At diffusion equilibrium, the rate of transmission through a barrier is approximately proportional to its thickness. The time required for the equilibrium rate to be established is roughly proportional to the square of the thickness, so roughly speaking a barrier twice as thick prevents noticable seepage for 4 times as long. Dragons flight 10:30, 2 July 2007 (UTC)
- Thanks, great answer. Can you find any sources? I've been looking all morning. 213.48.15.234 10:37, 2 July 2007 (UTC)
- I was thinking that for a thin film of aluminium it would be linear, as grain boundaries might be present through the whole thickness. But as you get to thicker films (thicker than the grainsize) it would become non-linear, as there is no longer a single grain boundary. Any thoughts? 213.48.15.234 14:12, 2 July 2007 (UTC)
Future of Technology Ten Years From Now
Can someone list approx 10 technological advances would affect us (in everyday life) ten years from now? whether it is medicine, entertainment, etc. —Preceding unsigned comment added by Juliet5935 (talk • contribs)
Um..10? I'll list as many as I can think of, the others can come up with better ones..
- Credit cash (literally credit cards, no cash)
- Virtual machines that shows you a vacation spot you like. Use it in the office to get some stress off. Size like normal sunglasses.
- There's an "Aroma Jockey" in Amsterdam, which couples music, sight, and smell together.
- Bloomframe, a very sassy window and balcony. Push a button, it pops out like a shelf into a balcony; push a button, it pulls back into a big window.
That helps? Cheers!!! (Most information adapted from Reader's Digest) -Zacharycrimsonwolf 14:02, 2 July 2007 (UTC)
- Sorry if I'm being overly-suspicious, but this sounds exactly like the sort of thing that is asked as homework, to try to make a student think. I cannot think of a reason someone would want this sort of list if it wasn't homework. If you look for a ready written list, or ask other people to do it for you, you get none of the benefit and miss the point. There won't be a right or wrong answer for this homework, and it's probably meant to be fun, so just think! Skittle 15:58, 2 July 2007 (UTC)
- I suspect homework as well. Here's a competition to build a flying car. Nimur 16:26, 2 July 2007 (UTC)
You are correct, SKITTLE and NIMUR, in that you are being overly-suspicious. I am a 35 year old woman who had an innocent request for other people's opinions. What I am overly-suspicious of is that it appears a LOT of the answers to all of the questions in the Wikipedia Reference Desk contain the following phrases: "Do your homework!" "I am not going to answer that as it appears to be a honework question", etc. If that is the response that people are going to get when they ask a question, then why bother having this Reference Desk anyway?!
......oh and by the way, Crimsonwolf, thank you very much for contributing!
Skittle, skedaddle with your stumbling block! Nimur, no more of your nuisance!—Preceding unsigned comment added by 209.0.0.29 (talk • contribs)
- Some editors might like to try assuming good faith and even being nice to newbies. DuncanHill 19:48, 2 July 2007 (UTC)
- "Prediction is hard, expecially the future." Ten years is a very long time in today's world. Some people think that change will be so fast in the next decade that the world will be unrecognizable. Please see Technological Singularity. Another interesting idea: look back at 1997. -Arch dude 21:18, 2 July 2007 (UTC)
- Ten years ago feels like the extended present. I do not see anything like the pace of technological progress there was in an equivalent ten year period 100 years earlier, considering progress then in aviation (the Wright Brothers) made the first powered flight, radio (Marconi claimed to have sent a transatlantic radio signal), the widespread exhibition of motion pictures and medicine (the X ray became useful). Genomics (published genomes, functions of genes) and astronomy (discovery of numerous exoplanets, evidence of water on Mars and the moon, Mars rovers) would be the most dramatic science/technology things in the last 10 years. Otherwise for the past decade I see creeping incremental progress. Smaller celphones, better DVDs, faster PCs. Big whoop. I hope things which make life better come along at a faster pace in the next ten years: cures for more diseases, robocars to reduce the 35,000 vehicular deaths a year in the US, better batteries to make electric cars practical, and maybe something which helps world peace fall into place before nuclear proliferation adds nukes to the terrorists' toolkit. Edison 22:09, 2 July 2007 (UTC)
- Nevertheless the reference desk is NOT a soap box: It's not for asking people's opinions and having a discussion about it. --antilivedT | C | G 22:21, 2 July 2007 (UTC)
- In just 10 years...tricky. We can't go with nanotechnological assemblers or space elevators or human minds transferred into software - those are 40 or 50 years away. Over ten years, it's reasonably safe to predict that no really radical technology will come along AND make it into mainstream life. All of the things we marvel at right now are technologies that were basically around 10 years ago - but not as cheap/fast/small or whatever. We can shoot for some easy ones: I guess we'll have computers that are about 100 times faster (if Moore's law doesn't crap out on us first) - and it should be possible to store every book and every piece of music in existance on your 2017 model iPod with room left over for every movie you own...but without some radical changes in the way copyright law works - it's really not going to help you much. I'll be seriously upset if we don't have a majority of cars and light trucks doing 60+ mpg in 2017. Perhaps the RepRap project will really take off - that could make a MASSIVE difference to our lives - being able to make a huge range of plastic and metal objects in a box the size of a refrigerator from plans you can download for free from the Internet and using easily recyclable materials. That would be fairly earth-shattering. (Hint: Don't hold on to shares in WalMart if this happens!). As other have said - look back at what has changed since 1997. Not a whole lot actually. We have things like MP3 players and tiny, ubiquitous telephones. We have digital cameras. But all of those things were around in 1997 - they were just big clunky things that cost a lot of money and didn't perform all that well. 2007's versions of those things aren't materially different - it's just that we can all have them if we want - and they are immensely capable. We had the Nintendo 64 game console in 1996 - and now we have the PS-3 - but the games are rather similar, a bit nicer looking - more realistic - but not radically different. We had DVD's in 1997 - and in 2007 we're just starting to switch to Blu-Ray...which is a little better - but not earth-shattering. Stuff like HD television has been around since the 1980's - but only now is it getting some serious market share. It's really too late to start thinking about putting men on Mars by 2017. Nope - my prediction is more of the same - smaller, cheaper, faster, more energy efficient...but nothing really dramatic. Go on - I'll give you a free replay - ask again, but for 50 to 100 years! SteveBaker 00:15, 3 July 2007 (UTC)
- Phrasing your question in that case to make it sound like homework (IMO) when you could have made it more conversational / discussion sounding isn't then really the best idea :) 194.168.231.2 11:18, 3 July 2007 (UTC)Wes
Maybe I have been out of school for some time, but why must we "re-phrase" questions anyway. The question I posted is exactly how I wanted it phrased. I do not have to change the way I ask questions for anybody. It is ridiculous that we cannot answer the question at hand without defending the validity of the actual question. Focus on finding the answer to the question itself instead of where it has originiated from!
- But thing is, if someone was trying to cheaply use the Reference Desk as a homework service, then he would not gain anything, and it would be contrary to our objective. We're not trying to attack you, just that, as in real life, the way you express a question can be interpreted in different ways. Splintercellguy 19:09, 3 July 2007 (UTC)
- I apologise for those who are creating this fuss - they clearly haven't read the helpdesk guidelines properly (WP:AGF and perhaps also WP:BITE would be good starting points!). Assuming Good Faith means not accusing someone of asking a homework question unless you have solid evidence. In the absence of strong evidence, one must assume good faith on the part of our questioners. Sadly, we really can't control who answers questions. You don't need to rephrase anything - your question was perfectly valid. What triggered this was probably the specificity with which you asked for TEN things - this is suggestive of someone who just typed in the question at the top of their homework assignment and hoped we'd do it for them. Most people who were merely curious would probably have asked for "some" predictions of the future. However, one must assume good faith on the part of questioners - and for all we know you are writing a "Top 10" piece for a newspaper - or perhaps you are even setting homework for some kids and wanting some interesting answers of your own to give. This is what it means to assume good faith. Like I said - please try to ignore the hot-heads. SteveBaker 19:15, 3 July 2007 (UTC)
- With all due respect, I did provide a civil and useful response, even though I questioned the motives of the original poster. As with other instances when I suspected homework, I merely identified my suspicion, and provided a "reference" instead of a "solution." I think this is the best course of action for the reference desk. If anybody feels that they have been sleighted, I apologize; but I don't think my responses have been disrespectful. Nimur 03:13, 4 July 2007 (UTC)
Oh, everyone, just know that no one is wrong. The questioner (I shall call him/her Annonymous for now) came here to ask for an answer; Nimur and Skittle just wanted him/her to be creative and try to find an answer him/herself. No grudges! Cheers!!! -Zacharycrimsonwolf 14:14, 8 July 2007 (UTC)
- Here are some changes possible on cars:
- 1) Use of cameras to supplement, or in place of, side-view and rear-view mirrors.
- 2) More hybrids and more electric cars.
- 3) More use of regenerative breaking.
- 4) Widespread GPS technology.
- 5) Internet access from cars, integrated with software, say to find the cheapest gas available at the next highway stop.
- 6) More use of all-wheel drive, speed sensitive steering, adjustable suspension systems, etc.
- 7) More use of heads-up displays.
Re:Lava lamps and chemical lights
What exactly are lava lamps made of? And chemical lamps? -Zacharycrimsonwolf 13:45, 2 July 2007 (UTC)
- Did you look at the article on lava lamps? I found this on Light Sticks which is probably what you're looking for. Donald Hosek 21:50, 2 July 2007 (UTC)
- Our article on Glowsticks has a good diagram showing how all the reactions work. Laïka 10:31, 3 July 2007 (UTC)
- I'm glad to see that the article at Lava lamp is back again. It was gone there for a while. Corvus cornix 16:12, 3 July 2007 (UTC)
- Yeah. I tried the article, but all there is was a "this page is protected" template and nothing else. Blank. Anyway, thanks to you!!! Cheers!!!! -Zacharycrimsonwolf 14:01, 8 July 2007 (UTC)
A list of Hispanic scientists?
Hi. I need to find a list of Hispanic scientists (past and present) and their achievements. Thanks. Xiner (talk) 14:19, 2 July 2007 (UTC)
- Did you see List of notable Hispanics from the United States#Sciences? I can't find anything else right now. 213.48.15.234 14:25, 2 July 2007 (UTC)
Membrane potential
hi i want to know is there difference in voltage between epiderm and hypoderm? —Preceding unsigned comment added by 221.223.44.101 (talk • contribs)
- Voltage in epidermis and hypoderm? I don't think those things carry appreciable amounts of "voltage", if you connected a copper wire between your epidermis and your hypoderm I can't see how it could generate any current flow. Vespine 22:52, 2 July 2007 (UTC)
protein/protein interaction
What are prey and bait in protein/protein interactions?. could you please give me a link that explains the basics of log2ratio and how it is used for measuring the reactions?.
- Perhaps a more detailed question would be easier to answer. Someguy1221 06:07, 3 July 2007 (UTC)
- I'm guessing you may be referring to protein microarrays or yeast two hybrids, both methods for determining protein-protein interaction. In a yeast two hybrid, if you have protein X and you wish to know what other proteins bind to it, then protein X is referred to as the bait and whatever binds to it is the prey.
- A log2 ratio as a way of representing a difference between the readout values in a baseline (control) and an experiment. A log2 ratio of 1 is the same as a fold change of 2. Rockpocket 18:05, 4 July 2007 (UTC)
rigveda, translation bij Griffith
LS I'ld like to know if the translation bij Griffith : "Rigveda V1", edited by Kessinger, contains the full text. What does the V1 mean? [volume? there is no V2 etc]. Contact with Kessinger is hardly/not possible. Thanks, Ruud Lensen, the Netherlands 193.172.24.226 16:23, 2 July 2007 (UTC)
Help Needed
Is energy material? I couldn't find the direct answer to the question in the article. -PatPeter 17:17, 2 July 2007 (UTC)
- No. Energy is "the ability to do work"; in other words, energy is a capability. It is a property of matter, like charge or mass. It is not itself material. Batmanand | Talk 19:18, 2 July 2007 (UTC)
- Well, yes and no... This is the general view of classical physics. You may want to read about Mass–energy equivalence, if you are looking for more advanced materials. Michel M Verstraete 21:40, 2 July 2007 (UTC).
- If a 5 ton truck acceleraates from 0 to 70 miles/hour, its mass increases an infinitessimal and unmeasurable but calculable amount due to the added kinetic energy. If a subatomic particle accelerates to an appreciable fraction of the speed of light in an atom smasher, its mass increases dramatically. Edison 22:16, 2 July 2007 (UTC)
- Would it still have the same amount of matter? -PatPeter 18:39, 3 July 2007 (UTC)
- Well, yes and no... This is the general view of classical physics. You may want to read about Mass–energy equivalence, if you are looking for more advanced materials. Michel M Verstraete 21:40, 2 July 2007 (UTC).
- Yes, it would still contain the same amount of "matter", in the sense that the number of atoms etc. would remain the same. When we say that it an object that has gained energy (by, say, being heated a few degrees) is "increasing in mass", we mean only that its inertia has increased (i.e. it has become harder to accelerate or decelerate the object) and that its gravitational mass has increased (it would register as having a very slightly larger mass, if weighed on a hypothetical, ideally sensitive scale). But the number of atoms, and the nature of each atom, is exactly unchanged. --mglg(talk) 03:53, 4 July 2007 (UTC)
- The deal is that a very small amount of mass is equivelent to an enormous amount of energy (E=mc2 - and 'c' is a HUGE number!) - and in everyday experience, we don't see mass turning into energy because it takes reasonably extreme circumstances to make that happen (nuclear reactors and such). Conversely - the amount of energy that's out there in a 'normal' situation corresponds to an utterly microsopic amount of mass - so (as User:Edison points out) you don't notice that something like a truck that's moving fast (in human terms) is a teeny-tiny bit heavier. So this mass/energy duality thing doesn't fit with our normal range of experience. SteveBaker 19:02, 3 July 2007 (UTC)
White teapot or black teapot
Has any experimental work been done to see in which sort of teapot the tea cools down more slowly? I would have thougt the white teapot if just considering radiation, but Im not sure. Any answers? —Preceding unsigned comment added by 88.110.40.127 (talk • contribs) 22:52, 2 July 2007
- That's probably true, but I think the infrared emissivity would be more important than visible light at teapot temperatures. — Omegatron 22:57, 2 July 2007 (UTC)
- I would also be interested in any data relating to metal vs. ceramic teapots too. (I am partial
to a cuppa). DuncanHill 23:00, 2 July 2007 (UTC)
- Metal is a better conductor of heat than ceramic - so the metal teapot will cool much faster than the ceramic teapot. The colour of the teapot is a tricky matter - what it's made of is vastly more important - and you can't change the colour without changing what it's made of so it's not even really possible to compare purely the colour. SteveBaker 01:20, 3 July 2007 (UTC)
- Well you CAN change the colour of ceramics without much affecting their other properties; and if you go for metal cans you have to paint it either black and white anyway, so it's just a painted can, differing in the colour of the paint. --antilivedT | C | G 09:29, 3 July 2007 (UTC)
- You may want to choose a white cearmic teapot over a black ceramic. You'll notice that most water heaters are painted white. While a black object absorbs more light, it also emits heat as radiation more readily, the same process in reverse. Source: recent posting in the "last word" section of New scientist. (www.newscientist.com) EverGreg 10:34, 3 July 2007 (UTC)
- Would a highly polished metal teapot radiate less heat than a metal teapot painted white? (Or should I just get a tea-cosy? DuncanHill 10:38, 3 July 2007 (UTC)
- The answer by Omegtron seems to make sense. So its not the actual visible color, but what it looks like in the infra red. I seem to remember someone who had done some experiments with black and white painted metal strips in sunlight and measured the temperature difference. Surprisingly (?) he found very little differnce. I think he said it was because the emissivities of all paints was about the same.--88.110.40.127 11:21, 3 July 2007 (UTC)
- How things look in Infrared is pretty counter-intuitive. I used to work in military flight simulation where my specialty was the accurate simulation of infrared cameras - so I have quite a bit of knowledge in this area. A while back, I was looking at video from an IR camera - watching cars driving along a black tarmac road at night. I was initially puzzled that the cars seemed to be casting shadows on the road...at night...! It turned out that the camera was set up in 'black-is-hot/white-is-cold' mode (most military IR cameras can switch between 'positive' and 'negative' images) - so the dark patches that I was seeing were hot spots under the cars as they drove along - a kind of 'anti-shadow'. It was clearly impossible for the road to heat up and cool down again fast enough to account for these short-lived hot-spots. It turns out that tarmac - whilst being pretty black (ie non-reflective) in visible light - reflects IR pretty strongly. What I was seeing was a reflection of the underside of the hot engine bay of the car in this mirror-like tarmac! If there is one lesson I definitely learned from that and other similar findings, it's that it's very dangerous to make any assumptions about the properties of a material in IR versus visible light. If this surprises you, think about this. Something that appears to be bright red in visible light is strongly reflecting red light - yet strongly absorbing green light. Red and green are much closer in frequency than (say) red and the medium-range infrared that's the cause of most heat loss. However, even that is misleading - we're more interested in how IR energy is emitted by an object than we are about how much it reflects (which is what we mean when we talk about an objects' "colour"). The IR emissivity and visible spectrum reflectance of a surface are not really closely correlated. So whilst you can do experiments with a particular pair of colours of the same object and perhaps get the same result for a particular material - that is very far from being proof that this is true for all materials that differ (seemingly) only in their colour. Short answer: You don't know for sure just by looking at the colour without having a heck of a lot more information about the substance(s) involved. SteveBaker 12:09, 3 July 2007 (UTC)
- Sorry I should have been clearer. What I meant by 'looks like' was how an object (at a known absoulute temperature with no external source of infra red shining on the object) would look to you if you had infra red vision. This I believe to be a measure of its emissivity. See Wein's Law, Stephan-Boltzmann law, Stephan's Law, (when thay are written) and Black body radiation--88.110.40.127 12:57, 3 July 2007 (UTC)
- OK. The amount of IR light emitted depends on the 'emissivity' (which I guess you'd describe loosely as 'the ability to radiate') and the temperature. So, yeah - if you have two objects with the same surface temperatures and you pointed an infrared camera at them then they will appear with different brightnesses in the camera if their emissivities are different. An IR camera doesn't measure temperature directly because it's not measuring the frequency of the light - only the amount of it that's within it's range of sensitivity. To measure temperature remotely, you need a Bolometer. Hey! I know a poem about bolometers. "Sam Langley invented the Bolometer - which is really a kind of thermometer - that can measure the heat - from a polar bears feet - at a distance of half a kilometer." - Feel free to applaud at any time. Any time at all. Now would be good. SteveBaker 16:16, 3 July 2007 (UTC)
- Sorry I should have been clearer. What I meant by 'looks like' was how an object (at a known absoulute temperature with no external source of infra red shining on the object) would look to you if you had infra red vision. This I believe to be a measure of its emissivity. See Wein's Law, Stephan-Boltzmann law, Stephan's Law, (when thay are written) and Black body radiation--88.110.40.127 12:57, 3 July 2007 (UTC)
Tea cosies
There is an article on tea cosy but it doesnt say how they work. They certianly keep your head warm if you pull them right over your face (as I remember from childhood), but from the above comments it seems that they would not block the IR from your head. My assumption is that they prevent conduction to the air and cooling convetion currents. Maybe some one could find a ref and add to the tea cosy article.--88.110.40.127 13:22, 3 July 2007 (UTC)
- Exactly, they work like clothes. They keep a layer of air trapped which warms up and cannot escape. This prevents convection, and reduces conduction. 213.48.15.234 14:13, 3 July 2007 (UTC)
Off-topic joke posts.
- This is merely a theory advanced by liberals in order to control everybody. The heat of teapots is much too complex to model. In fact, the reason teapots keep warming is undoubtedly because of an increase in solar output. Mars is also warming. Gzuckier 14:52, 3 July 2007 (UTC)
- Since we seem to be tightening policy on the reference desk, we should remind all contributors that deliberately useless joke posts are usually not appropriate; especially since we don't know how the original questioner will interpret them (i.e. they may think you are being serious). Nimur 03:19, 4 July 2007 (UTC)
- I don't even understand why it's funny. 213.48.15.234 06:37, 4 July 2007 (UTC)
- Gzuckier was satirising those who claim that global warming is a myth. For example, Michael Crichton in State of Fear. Skittle 15:10, 5 July 2007 (UTC)
- I don't even understand why it's funny. 213.48.15.234 06:37, 4 July 2007 (UTC)
- Since we seem to be tightening policy on the reference desk, we should remind all contributors that deliberately useless joke posts are usually not appropriate; especially since we don't know how the original questioner will interpret them (i.e. they may think you are being serious). Nimur 03:19, 4 July 2007 (UTC)
- This is merely a theory advanced by liberals in order to control everybody. The heat of teapots is much too complex to model. In fact, the reason teapots keep warming is undoubtedly because of an increase in solar output. Mars is also warming. Gzuckier 14:52, 3 July 2007 (UTC)
July 3
The Sun on the Horizon
Can anyone tell me why the sun apprears larger on the horizon when it sets?
Poplargrovegirls 00:31, 3 July 2007 (UTC)marpro123
- I believe it's quite similar to the Moon illusion. You'll find a number of theories in that article. —Steve Summit (talk) 00:38, 3 July 2007 (UTC)
- Yeah - I agree - it's very, very slightly distorted by the thicker atmosphere - but not enough that you could detect by eye alone. It's an optical illusion - the only serious debate is WHY it's such a good illusion. SteveBaker 01:02, 3 July 2007 (UTC)
thanks, links were very helpful. Always assumed it was the atmosphere but was told not so had to check out for myself. Poplargrovegirls 13:26, 3 July 2007 (UTC)
Itchy nose at dentist
Just been to dentist. Got itchy nose whilst lying there. Mentioned it to dentist. She said a lot of people get an itch nose whilst in the chair and she hadnt worked out why. Does anyone have any idea? —Preceding unsigned comment added by 88.110.40.127 (talk • contribs) 00:47, 3 July 2007
- I've heard sunlight can make people sneeze. Maybe the bright lights at the dentist get you halfway there? -- Beland 01:01, 3 July 2007 (UTC)
- THe itch was on the outside., but I suggested the lights. —Preceding unsigned comment added by 88.110.40.127 (talk • contribs) 01:07, 3 July 2007
- I believe this is a psychological issue, that is Ionlywantodothisthingwhenicant Syndrome. It's the same thing that causes your underwear to bunch up the second you leave the house, that gives you gas when you're in polite company, and that makes you hungry thirty minutes after your nonstop cross country flight departs --ʇuǝɯɯoɔɐqǝɟ 02:12, 3 July 2007 (UTC)
- Interesting, I never really thought about it like that. Is there a psychological term for this broad experience? And an article, hopefully? Someguy1221 02:33, 3 July 2007 (UTC)
- Well, besides the scientific Ionlywantodothisthingwhenicant Syndrome, there is the common name: Sourgrapsitis. --ʇuǝɯɯoɔɐqǝɟ 03:03, 3 July 2007 (UTC)
- This might also be related to bread always landing buttered side down, see Buttered cat paradox for the sum of Wikipedia's knowledge on that topic --ʇuǝɯɯoɔɐqǝɟ 03:08, 3 July 2007 (UTC)
In addition to the factors mentioned above, I suggest that the dental work itself stimulates nerves in the face: the various bits of powered equipment tend to vibrate, and the dentist's hands are moving close to your skin. A mild stimulation could easily be felt as an itch. --Anonymous, July 3, 2007, 04:18 (UTC).
- So could this be the same thing as only needing to rub your itchy eyes when you have your glasses on? Or is it that you do these things normally unconsciously, but when you cant or shouldnt, you start to notice it?
--88.110.40.127 11:28, 3 July 2007 (UTC)
- Yes, I think that hits the nail on the head. Normally, when you have an itch ... you scratch it. It is such an inconsequential and trivial event, that you don't even think twice about it. It is almost a reflex. However, when you cannot scratch the itch or you are prevented from doing what would be a natural relfex, then you notice the "event" that much more. (JosephASpadaro 22:04, 3 July 2007 (UTC))
Space tracking networks
Does anyone know what the difference is between SPACETRACK and the United States Space Surveillance Network? -- Beland 00:52, 3 July 2007 (UTC)
Negative buoyancy
Is it true that some people have what is known as Negative buoyancy (ie they do not float in water). there doesnt seem to be a page on this. —Preceding unsigned comment added by 88.110.40.127 (talk • contribs) 01:06, 3 July 2007
- I don't remember if this is the actualy term, but yes, many people cannot attain a "natural" floating position in the water. A lot of it depends on your body height and shape and your fat content (muscle and bones are going to be less buoyant than fat). A lot of people simply cannot achieve an "ideal" floating position on top of the water--instead, they will have shift their body position (for example, raising the hands up slightly). –Pakman044 02:36, 3 July 2007 (UTC)
- If one is more dense than water (as the question suggests "they do not float in water") then limb position or other shape-changes won't help. However, muscle/bone/fat composition differences can explain why certain body parts sink vs float for various people. Further, since one's body is all joined together, one can take advantage of different buoyancies of the parts to raise or lower other parts by bending etc. From experience, "sinkers" are often not that far from being able to float—a deep breath is enough, kinda like swallowing a life vest. DMacks 05:17, 3 July 2007 (UTC)
- Some of us Wikipedians are pretty dense, as should be obvious from our posts...169.230.94.28 03:11, 4 July 2007 (UTC)
- When an object sinks, it is because it is more dense than the fluid it is in. This would still be called buoyancy, since it operates on the same principle (i.e. differences of density between an object and a fluid). That is why we do not have (and should not have) an article called negative buoyancy. Nimur 03:41, 4 July 2007 (UTC)
I believe that there is a term for "negative buoyancy" — sinking. --69.177.208.125 23:39, 8 July 2007 (UTC)
Dimples on back of thighs
My girlfriend ( White,37,3 children,good health) is upset with what appears to be "dimple's" on the back of her thighs (1 ea. side) about mid point slightly to the outside of the muscle.To me it looks as if a tendon or maybe sinew is holding that part of the muscle back, thereby giving it a dimpleing effect is that possible? -shredder0288
- Cellulite? DMacks 05:18, 3 July 2007 (UTC)
- Sounds similar to dimples of Venus. If there's only one on each side, and they're symmetrical, it's unlikely to be cellulite. --TotoBaggins 06:00, 3 July 2007 (UTC)
rays that reflect by bones
Neel shah556 06:21, 3 July 2007 (UTC)
hi i would like to know which rays get reflected specifically by bones only and not reflected by metals as well gases Neel shah556 06:21, 3 July 2007 (UTC)neel shah556
- Xrays can be scattered from bones, but metals are going to reflect or scatter these too. Bones contain Calcium which is a metal of moderate density. You may be able to find a nuclear magnetic resonance frequency for something in the bone, but this is hardly a ray. GB 09:54, 3 July 2007 (UTC)
- Gamma rays of around 10.3 Mev are absorbed and reemitted by Ca40 neclei. This should be very specific for detecting calcium, and should penetrate through other meterials very deeply. The frequency will have to be controlled to about 1 part in a million to actually work. see Nuclear Resonant Absorption of Gamma Rays by Ca40. However this is quite hazardous to living things nearby! Another method is to irradiate with neutrons and observe the gamma ray emmissions: eg 48Ca(n,y)49Ca, emits 3.084 MeV y-rays. This too would be hazardous. GB 01:41, 5 July 2007 (UTC)
- Yet another technique is to use X-ray diffraction to detect tha apatite crystals in bone. The object is irradiated by a thin beam of xrays at a particular frequency. The crystal planes in the minerals in the bone will reflect the X-rays at particular angles that are characteristic of the mineral content. The 002 plane produces the biggest reflection. See [7] for an experiment.
- X-ray fluorescence is another way to go. Kα1,2 at 0.3359 nm for Calcium, Kα3,4, or Kβ1,3are names of spectral lines that could be used. GB 02:35, 5 July 2007 (UTC)
Denoting Free radicals
I noticed that Wikipedia just uses a full stop in chemical equations to denote a free radical. I have always seen the dot central and right of the atom. As long as it is right, does it really matter where the dot is placed? Thanks in advance. GizzaDiscuss © 06:29, 3 July 2007 (UTC)
- It seems that both is used. In TeX a full stop is used: , but in text a dentral dot is used: 2Cl·→ Cl2. Infact in that TeX both are used, a . and a superpostioned .
- Are these different or should it be fixed? 213.48.15.234 08:23, 3 July 2007 (UTC)
- Thank you for your response! Just wondering, how did you type the central dot? I can now Copy & Paste it when I need it but I'm still curious. Incidentally, I want to add a couple of equations where radicals are involved to some Chemistry-related pages on Wiki. GizzaDiscuss © 08:58, 3 July 2007 (UTC)
- Copy and paste is exactly how i did it *hides*. Windows Character map says you can make it with Alt+0183. ··. Yup it works! I believe that it's also emboldened in the article, otherwise it's faint. ·. There we go :) 213.48.15.234 09:10, 3 July 2007 (UTC)
question
i have this bio quiz i have to answer i got from a pal.i eat with my head upside down.my mouth held horizontally beaneath the water.what am i? 2.i got a pirated cd of hitman 2 silent assasin.i reached the second last level of the mission.which is st petersburg revisited.the problem is that my gun is firing blanks.it has no effect when i shoot someone.is it possible that that is a defect because i got a pirated disc.or that the guy who made the cd edited it so that someone doesnt complete the game.
- 1. A Flamingo? 2. We can't help you with pirated games. I doubt that the guy you bought it off of "programmed" the bug into the game. Buy the game from a reputable store if you wish to avoid these issues and recieve support form the publishers/developers. 213.48.15.234 08:20, 3 July 2007 (UTC)
- My job is as a game developer - playing pirated ("stolen") games is a bad thing - it makes it harder for me and my colleagues to make a living - there are fewer jobs out there and they don't pay as well because of people like you. My family is worse off because of you and that hurts. We games programmers are just regular guys - you'd like me if you met me - and I KNOW you appreciate the work that we do - because without people like me, you'd be playing one of the 60 different OpenSourced versions of Tetris or something. So why are you making my life worse? I feel pretty strongly about this - and I now know your IP address because you handily left a record of it when you posted your question. I have a clear confession of guilt from you - so this is going to be an open-and-shut court case. I have pretty good computer skills - you are a self-confessed criminal - how about I see if I can trace your account and find a way to have a policeman knocking at your door tomorrow morning? I'd tell you how much you can expect to pay in fines - and how much jail time you might serve - but we're not allowed to give out legal advice here on the Wikipedia help desk.
- No - I'm not really going to do that - but then you're going to promise me you won't play pirated games anymore. Or maybe I'll just figure out your parent's email address. SteveBaker 11:49, 3 July 2007 (UTC)
- Steve, while you're at it, port something to linux so I have something to play other than 60 different open source versions of Quake. Or hell, anything that isn't an FPS. Can we get a platformer or an action puzzle game (Zelda/Metroid style), pretty please? --ʇuǝɯɯoɔɐqǝɟ 13:01, 3 July 2007 (UTC)
- I'm a huge Linux enthusiast - heck, I'm the guy who wrote TuxKart. I also wrote "Tux the Penguin - A quest for Herring" - which was the first 3D game ever designed for Linux. It was a platformer - but sadly, not enough people wanted to help out on it (actually, aside from a guy who contributed some music - I got zero help on either project). A 3D platformer is a big project for just one person - so it didn't really get properly finished. TuxKart was much easier and is a really fun go-kart racing game. But to answer your question - commercial games companies just can't afford to do Linux ports - there is no money in it. Too many Linux users have dual-boot machines and they tend to rush out and buy the Windows version of a new game before there is time to port them to Linux - as a result, on the rare occasions when people like ID and Loki produced Linux ports, they sold really badly. It doesn't help that in the months it takes to do the port, the Windows version has fallen from gamer favor and can be found in the $10 outcast bin right at the time when the Linux version is selling for $40. The only way to avoid that and to create a market for Linux ports would be to release the Linux version on the very same day as the Windows version - but that would require serious investment in time and money at the very point in the game's development when both things are at a premium. Right before a typical launch, the entire game team are likely to be working 'crunch time' - 60 to 80 hours a week - typically without overtime pay. To expect them to crunch the Linux port at the same time is asking too much. It's a hard problem to fix - for Linux games to be cost-effective there has to be a large pool of dedicated Linux-only gamers...but that can't happen because there aren't enough good Linux games out there. SteveBaker 16:04, 3 July 2007 (UTC)
- Steve, while you're at it, port something to linux so I have something to play other than 60 different open source versions of Quake. Or hell, anything that isn't an FPS. Can we get a platformer or an action puzzle game (Zelda/Metroid style), pretty please? --ʇuǝɯɯoɔɐqǝɟ 13:01, 3 July 2007 (UTC)
- The OP/thief doesn't have to take Steve's word for it, either: take it straight from MC Double Def DP, the Disk Protector. --TotoBaggins 16:20, 3 July 2007 (UTC)
- For the second question, it's the game design. The rifle is filled with blanks for a reason... Splintercellguy 18:58, 3 July 2007 (UTC)
jeez steve.first of all i wasnt scared one bit.its seems u have a really cool job and that my buying pirated games really pisses u off.only thing i can tell u is that its a tough world.survival for the fittest.as for getting my parents ip address,i dare u.am a software engineer student and unless telepathy is a course u took i think ur bluffing.but seriously al try and buy more genuine software next.just because u seemed so offended
- Well, if you are a software engineering student (I was a Computers & Cybernetics student - essentially the same thing) - you should be more aware than most of how this problem will eventually hurt you, personally. You may not end up being a games programmer - but you will almost certainly be be spending a large chunk of your life writing software - and the odds are good that people will be pirating whatever it is you write. That's going to have a direct effect on how much money you'll earn - how hard it'll be to find a job - how interesting that job will be - how secure that job is going to be. The games business isn't the massive money making machine most people think it is - games programmers work longer hours than most software engineers - and we don't typically get paid overtime for doing it. Sure, it seems a pretty glamourous activity - but most of the time it's not (I spent the last two days tracking down a shader compiler bug in nVidia's 8800GTX graphics drivers - it doesn't get much less glamorous than that!). But to find that many of our biggest fans are prepared to screw us out of our (rare!) well-deserved successes is REALLY frustrating. You're right about survival of the fittest - and in a world with much piracy that means that the companies that churn out large quantities of low grade junk are going to be the ones that make it. Survival under this kind of pressure means not aiming aiming high. So if people continue to pirate at the rate they are, the best people will move out of the industry - and those that stay will have less time and resources. Game quality will suffer first.
- It's not like the music business. It costs almost the same amount of money to record, produce, advertise and distribute a crappy piece of music as it does a great one - and only a very tiny share of the cost of a music CD is actually paying the musicians - so the record companies don't respond to falling income by reducing quality. Not so with games - our costs are in a hundred or more people working for two or three years on one single title. You can produce a crap game with a much smaller team in much less time so if we don't make enough profits to support that large team - that's exactly what you'll get.
- Anyway - this is as much about your future as it is mine. (And if you don't think an old school hacker can find you from your IP address and contextual clues...you need to take some more networking courses!) SteveBaker 17:05, 4 July 2007 (UTC)
- Nameless IP guy, I couldn't tell a TCP from a UDP, but I could still easily track you down. Steve knows his crap very well, I wouldn't tempt him. You'd do well to follow his advice, as well. I know how nice it feels to get all the games you want for free, but you're really just screwing yourself out of future jobs, not to mention there's a ton of free games out there, and I'm not talking about the above mentioned open source tetris variants. If you want some links to free games, leave a note on my talk page, and I'll get back to you --ʇuǝɯɯoɔɐqǝɟ 21:34, 4 July 2007 (UTC)
- First question looks like a whale that eats plankton.Polypipe Wrangler 00:39, 6 July 2007 (UTC)
- Steve while I appreciate how you feel, bear in mind it's not a criminal offence in every country to simply use a pirated copy of a product. It may simply be a civil matter. (IP 62.24.99.165 [8] appears to be Kenyan, no idea what the legal situation there is) Also, at least you get to use a GeForce 8800GTX... :-P I'm still stuck with my 6600GT. Also the one person I know who took software engineer (who was a top student) in Malaysia career has been in the consultancy (implementing various projects for others) and large company IT department areas. While there is software programming going on I believe, it's not so much the kind of stuff that is sold. I would presume this is fairly common in Malaysia since there are AFAIK few local companies who write marketed software product. While piracy will still have numerous effects, I'm not so sure whether's your description accurately encompasses the work that many software engineer graduates end up doing (but then again, I don't really understand the field well) Nil Einne 00:02, 11 July 2007 (UTC)
radiology
is there any frequency of x-ray that is not refleced by metals203.187.197.27 09:49, 3 July 2007 (UTC)
- No, unless the metal is beryllium. 213.48.15.234 10:18, 3 July 2007 (UTC)
- Light metals will have little imapct on X-rays, because there are few electrons in each atom. Lithium and sodium magnesium and aluminium are other light metals, with lithium by far the lightest, floating on water. GB 05:48, 4 July 2007 (UTC)
- I wonder if this this question is related to the "rays that reflect by bones" question from earlier today. Is there some more general problem you're trying to solve here (i.e., what's the context for the question)? DMacks 05:56, 4 July 2007 (UTC)
- No. Part of what makes a metal a metal is the large (~1023/cm3) concentration of relatively free electrons. An incident electromagnetic wave causes these electrons to oscillate at its frequency, and reflection is observed at the angle at which all of these oscillations add constructively. Within a few skin depths, essentially no intensity is transmitted. X-ray reflectivity needs some work, but it does show how reflectivity depends on electron density. Higher frequencies and lower electron concentrations lead to greater penetration, and many devices have a thin "beryllium window" which contains the sample but is essentially transparent to high frequency x-rays. Of course, if this is related to that earlier question, one must consider that beryllium is toxic. -Eldereft 06:15, 7 July 2007 (UTC)
Interconnectivity of Earth's Food Web between Oceans and Land
Perhaps this is speculation more than science, per se, but how dependent are Earth's Oceans on land based life? If, say, all life on land including plant and animal were wiped out completely by something other than nuclear warfare or cosmic impacts(That is to say, no nuclear fallout or dangerous amounts of dust in the atmosphere or anything like that to factor in) how would Earth's oceans fare? I once heard that Earth's oceans produce and consume about the same amount of oxygen, and I can't think of many oceanic lifeforms that would require a food source from land. One problem I would see would be rampant erosion of huge rivers of mud rolling into the oceans. Perhaps problems could come from estuaries where land-based food for oceanic-life causing some kind of domino effect? Or would Earth's oceans be more or less uneffected? --Demonesque 09:50, 3 July 2007 (UTC)
- Clearly there would be some niche species that would suffer greatly - there must be some that rely on nutrients washed out of river esturies and such. The balance of some populations might swing wildly due to lack of predation from birds, penguins, seals, etc - and that would undoubtedly start a number of boom/bust cycles that would probably kill off some populations - but boost others. But other than that, I think ocean life would survive quite well. After all, life on earth started in the oceans - at that time, the land was completely barren. The lack of human activity - pollution and over-fishing in particular would clearly be of immense benefit to species that are in steep decline right now. So I think the oceans would change - but not drastically. SteveBaker 11:30, 3 July 2007 (UTC)
- The Oceans need nutrients from the land masses to sustain life, much of those nutrients come from life forms living on land or on their effects on the nutrient cycles, two factors greatly limit oceanantic life Iron and nitrogen. Only bacteria and maybe some fungus can free up nitrogen for use by other life forms. Land plants also have an effect of global temperature, higher air temperature would result in higher ocean temps resulting in a change in water chemistry.Hardyplants 02:18, 4 July 2007 (UTC)
Geodesic distance
I am trying to find out, what the geodesic distance in a Robertson-Walker-metric is. I came across comoving distance and proper length and I wonder if one of them is the thing I am looking for. The proper length looks quite nice but unfortunately the definition does not seem to be restricted to geodesics. (I wonder if such an arbitrary looking definition makes sense anyway.) I just found that it says "For instance, if one measured the distance along a straight line or geodesic between the two points, one would not be correctly measuring comoving distance." in comoving distance. So it looks as if both of them do not help me, do they? Anyway, can I use Riemannian normal coordinates to calculate the geodesic distance? Or would you propose another ansatz? -- 217.232.40.21 16:13, 3 July 2007 (UTC)
- This may get better responses at the Mathematics desk... Nimur 16:35, 3 July 2007 (UTC)
- Have you read Friedmann-Lemaître-Robertson-Walker metric? SteveBaker 18:52, 3 July 2007 (UTC)
- Yes, I have. I would not ask if I was satisfied with the information provided there. It is kind of vague in this point, talking about "physical distance to a point in space at an instant in time" which says nothing about what the meaning of this distance is. As there are different notions of "distance" I did not assume this "physical distance" identical to the geodesic distance. -- 217.232.40.21 19:54, 3 July 2007 (UTC)
- Have you read Friedmann-Lemaître-Robertson-Walker metric? SteveBaker 18:52, 3 July 2007 (UTC)
welding..........
can we arrange the welding processes ; smaw,fcaw,gtaw,gmaw & saw according to criteria;
- quality
- field welding
- energy efficiency
- automation&
- out of position welding
i tried based on knowledge of books but could arrange for few criteria that too not all processes.59.92.11.37 16:18, 3 July 2007 (UTC)
- For reference, we have articles on SMAW, FCAW, GTAW, GMAW, SAW, and welding. Nimur 17:00, 3 July 2007 (UTC)
breathing a bug accidentally
hi guys, i just breathed a bug...it may be inside my lungs... uh...besides it being gross...is it really dangerous? should i b worried?
- You seem to have survived well enough to type the question. Generally, an insect of average size should not be dangerous if swallowed or inhaled, but if you feel any weird symptoms, you might consider getting it checked out by a doctor. ◄Zahakiel► 18:46, 3 July 2007 (UTC)
- Well, we aren't allowed to give medical advice - but my best guess is that if you aren't coughing and choking really hard then you probably swallowed it - so it's in your stomach - not your lungs. Bugs make perfectly good food - so you should be OK. But if you are in any way concerned or distressed - consult an expert - not Wikipedia. SteveBaker 18:48, 3 July 2007 (UTC)
- You should check out the article on eating insects. They are an excellent source of protein. Lanfear's Bane
If it was inhaled, I'd suggest risk of Bronchopneumonia. See Pulmonary aspiration and consult your GP. --Seans Potato Business 20:39, 8 July 2007 (UTC)
How do we know the universe is expanding/accelerating if red shift increases with distance (time)?
Something that has always confused me is Hubble's explanation of red shift observations. The fact that distant objects were moving away from us more quickly than near objects is used as evidence of an accelerating expansion of the universe. This seems to me to be evidence of the exact opposite - that expansion is slowing. Looking at an object 2 billion light years away is looking at light that is 2 billion years old. This suggests that: a) we are now moving quickly away from the point where that star was 2 billion years ago, and/or b) the star 2 billion years ago was quickly moving away from the spot we are at now. These are, of course, equivalent propositions.
What confuses me about this being used for an accelerating universe is that it tells us nothing about how we are moving relative to that object now. In fact, relativity demands that I can know nothing at all about that object now, including its current speed relative to me. For all I know, in the 2 billion years since the light left that object, gravity could have slowed and/or reversed that expansion.
Could someone please help me to understand this better? Kurt 21:18, 3 July 2007 (UTC)
- Part of the article on Hubble's law addresses this. You might also find Olbers' paradox interesting in relation to a finite / infinite universe and redshift. Lanfear's Bane
- The problem is that it's hard to visualize the 3D space. So simplify it and think of the surface of a balloon. All the stars are on the surface. It starts inifinitely small and starts to inflate. There is no "center" or "spot" on this perfect inflating balloon. All the stars are moving away from all the other stars. At any given time, the farthest stars have moved away the farthest amount in the same time. By moving farther in the same time, they are moving faster. therefore the farthest stars are moving away the fastest. Turn it around and the fastest stars are the oldest and furthest away. --Tbeatty 05:26, 4 July 2007 (UTC)
- In fact this even works in one dimension. If you draw some equidistant points on a line, then assume this line is being stretched at a constant rate. Choose one of the points as Earth, and you'll see the other points move away with speed proportional to their distance. Move to another point, calculate the speeds and you'll see the same thing. This also demonstrates the point that although things are expanding in all directions from Earth, that doesn't mean there is anything special about our place in the Universe. Cyta 07:06, 4 July 2007 (UTC)
- Note that the red shift just tells us that we're moving away from the object (or vice versa). It doesn't say anything about acceleration. To ascertain that you'd have to see if the amount of red shift changes. See also Accelerating universe. DirkvdM 10:11, 4 July 2007 (UTC)
- Yes, but we already have that information. Or rather, the theory gives us that information. The objects furthest way, and the most primordial objects, have the most red shift. The furthest objects are moving away the fastest. --Tbeatty 09:03, 7 July 2007 (UTC)
- Kurt - you have asked an excellent question, which highlights some on the inconsistencies in the standard simplified explanation of the cosmological redshift. Here is a more "sophisticated" explanation. When measuring cosmological redshifts of distant galaxies, it is not the redshifts themselves that are of interest - it is what they tell us about the Hubble paramater, which measures how space itself is expanding. The amount of the redshift is determined by how much the Universe has expanded since the light that we observe now was emitted by the distant galaxy. This is, in turn, determined not just by the value of the Hubble parameter now, but by how the Hubble parameter has changed while the light was travelling. Accurate measurements of redshifts at different distances tell us how the Hubble parameter has changed over time, a change which can be measured by a value called the deceleration parameter (note that cosmologists always expected the Hubble parameter to change over time - they expected it to be getting smaller, as the expansion rate of the Universe slowed down). These accurate measurements are complicated by the following factors:
- You need to measure redshifts of many galaxies at similar distances in order to average out the redshift components due to peculiar velocities, which we are not interested in.
- You need a measure of distance that is independent of the redshift measurements themselves - otherwise you have a circular argument.
- Recent measurements have shown that the deceleration parameter is negative, so the expansion rate of the universe is, contrary to expectations, accelerating. Gandalf61 11:23, 4 July 2007 (UTC)
July 4
Identify this lizard
We saw this lizard in Galveston, TX. It is approximately 3 to 4 inches in length, and we've seen it several times at night. Does anyone know what it is?
anonymous6494 02:10, 4 July 2007 (UTC)
- Mediterranean House Gecko, Hemidactylus turcicus [9] [10]? --mglg(talk) 02:33, 4 July 2007 (UTC)
dealcoholize alcohol?
I love the tastes of certain beers, but I don't want to get drunk. (I'm extremely easy drunk.) Is there something I can do to the alcohol to keep the original flavour and fizziness but remove all or some of the alcoholic content?--Sonjaaa 03:49, 4 July 2007 (UTC)
- I feel really terrible for suggesting this, but if you insist on drinking beer for the flavor, it might be better to try to get your tolerance up. Sadly, the near beer article doesn't say how dealcoholization is done, but judging from the terribly reception that near beers get, it cannot possibly be good for the flavor! See Effects of alcohol on the body, Ethanol#Metabolism and toxicology and Hangover for more information that you could possibly need. My personal recommendation is to drink slower, and alternate a glass of water between each glass of beer. Eat something, too! Finally, check the label! Great beers are not necessarily high in alcohol! --Mdwyer 04:51, 4 July 2007 (UTC)
- Easy drunk = cheap date. Yah, per what Mdwyer said, drink a lot and soon your liver will be like a chunk of concrete, and you will have a huge tolerance for alcohol, and you will literally be able to drink your peers under the table. However, this does not bode well for your longevity. Edison 05:22, 4 July 2007 (UTC)
- I feel really terrible for suggesting this, but if you insist on drinking beer for the flavor, it might be better to try to get your tolerance up. Sadly, the near beer article doesn't say how dealcoholization is done, but judging from the terribly reception that near beers get, it cannot possibly be good for the flavor! See Effects of alcohol on the body, Ethanol#Metabolism and toxicology and Hangover for more information that you could possibly need. My personal recommendation is to drink slower, and alternate a glass of water between each glass of beer. Eat something, too! Finally, check the label! Great beers are not necessarily high in alcohol! --Mdwyer 04:51, 4 July 2007 (UTC)
- Huh? Drinking low-alcohol beers and drinking slower are bad for your liver? Sorry, Edison, you're not living up to your name here. For centuries, Europeans have drunk beer in stead of plain water because it was less disease-ridden. But it was also extremely light beer. I don't know if such beer is still made. Also, judging by Sonjaaa's post, she's never going to be able to drink others under the table. Some people have a lower tolerance for beer than others. I wonder if that also affects how much damage the same alcohol-consumption will do to the liver (if any). DirkvdM 10:00, 4 July 2007 (UTC)
- I thought I read somewhere before that in medieval times the "beer" that they have are a lot stronger than what we have nowadays... --antilivedT | C | G 22:56, 4 July 2007 (UTC)
- See Small beer. Also, unless Edison has edited his comments since you replied Dirk, you seem to have drawn the opposite conclusion to that which his words suggest to me :-) Skittle 14:54, 5 July 2007 (UTC)
- Getting back to the original question, it's an interesting problem in physical chemistry. Distillation and freeze distillation/fractional freezing come to mind immediately, but distillation is no good because the CO2 would come out of solution before you could boil off a significant amount of ethanol (leaving you with flat beer), and freeze distillation is no good because most of the flavor compounds would remain in the alcohol-rich liquid portion and the solid would be almost pure water ice.
- There seem to be two major commercial methods of adjusting the alcohol level of wine (which should be applicable to other alcoholic beverages as well). Both methods involve first separating the color and flavor components ("retentate" or "essence"), then decreasing the alcohol level of the remaining alcohol-water fraction, then re-adding the flavor components. Vinovation's method involves reverse osmosis, and ConeTech's method uses some complicated apparatus to achieve something similar to steam distillation (please correct me if that's wrong).
- Anyhow, those are both large-scale industrial process that would be difficult to recreate in your kitchen, so if you like the taste of a certain beer, you'll have to either live with the alcohol content, or hope they produce a light version. —Keenan Pepper 02:43, 5 July 2007 (UTC)
Need to identify soundfile
- I need to identify which of the four goldfinch articles this belongs to. Original clip came form here. Borisblue 05:22, 4 July 2007 (UTC)
Planet of the Apes
I was watching the old Planet of the Apes, specifically the second one Beneath the Planet of the Apes and in the movie the doomsday device is an atomic bomb with a cobalt casing. How does the cobalt casing affect the efficency of the bomb?68.120.85.164 05:33, 4 July 2007 (UTC)
- See cobalt bomb for a full explanation, but the idea is that the cobalt casing would be turned into the extremely nasty isotope cobalt-60, which would be spread as fallout, and remain lethal for a couple of decades. --Bob Mellish 07:13, 4 July 2007 (UTC)
Thank you.67.121.105.12 02:02, 5 July 2007 (UTC)
Humming Bee?
I saw the strangest animal the other day. It looked like a cross between a bee and a humming bird. It was about an inch long (2.5cm) had a brown body, and a small fan tail, like a bird. It's wings looked slightly like bird's but were moving so quick it was hard to tell. It also had a long 'beak' which it was using to suck stuff out of flowers, and two 'antennae' on top of it's head, also long and thin like the 'beak'. It hovered while sucking, moved about quickly, and was the only thing of it's kind, in a patch of flowers with many bees. This was in central Europe. Any ideas what sort of creature this was, I am clueless? Cyta 08:07, 4 July 2007 (UTC)
- Take a look at Sphingidae. --Mdwyer 08:55, 4 July 2007 (UTC)
- Thanks a lot, that's definitely the one. What a crazy animal! Cyta 09:11, 4 July 2007 (UTC)
- The article doesn't say where they live, but a friend in the Netherlands spotted one in his garden. Nor did the article mention that this is a nice example of convergent evolution, so I added that. DirkvdM 09:50, 4 July 2007 (UTC)
- Your description was spot on for http://en.wikipedia.org/wiki/Image:Bee_hawk_moth_newspaper.jpg . They look pretty interesting. Lanfear's Bane
- The article doesn't say where they live, but a friend in the Netherlands spotted one in his garden. Nor did the article mention that this is a nice example of convergent evolution, so I added that. DirkvdM 09:50, 4 July 2007 (UTC)
Here in south eastern ontario, canada the larval forms/caterpillars are called "hornworms". They use thier large size, colour patterns and the biotoxins from the very specific plants that they eat to ward off would be predators. Sadly, most people who love to see the adult kill the larval forms! OOPS, forgot to sign. I'm a newbie, mea culpa. Rana sylvatica.
- The article on Macroglossum stellatarum mentions their distribution. What it doesn't mention is that these critters are on the increase now in places such as southern England and the Netherlands. People are blaming global warming.--Shantavira|feed me 13:27, 4 July 2007 (UTC)
Earth Natural Satellites
Completely by chance I came across the article 6R10DB9. It says that further study will be avaliable around 14 June 2007. As i'm sure you're all aware this date has passed. Do we have any more information about this object? Can we expand the article? 213.48.15.234 11:10, 4 July 2007 (UTC)
- The article has a link to the Great Shefford Observatory's page about this object, which includes an update from 16th June. I feel sure that this could be used to expand the article, however lack the aastronimical knowledge to do this myself. DuncanHill 11:20, 4 July 2007 (UTC)
- I've tagged it with an {{update}} request.--Shantavira|feed me 13:22, 4 July 2007 (UTC)
- Great, i'm new to all this :) 213.48.15.234 13:29, 4 July 2007 (UTC)
Jar lid motion on counter top
Hi - My wife has challenged me to see if there is a formal name of the oscillation/rotation motion that a jar lid makes when dropped onto a counter top. Any suggestions? ````Cavermedic
No. There isn't.For more information on this phenomenon see Euler's disk. 213.48.15.234 12:22, 4 July 2007 (UTC)- Scrap that, a manufacturer of the disk [11] uses the verb "spoll" as a portmanteau of spin and roll. I can't find it in any dictionary though. I don't think it's a real word. 213.48.15.234 12:30, 4 July 2007 (UTC)
- I would go with Precession. The lid is acting kinda like a gyroscope. SteveBaker 16:16, 4 July 2007 (UTC)
- Hmm, I'm not sure. The contact point of the disc isnt fixed, it's rolling/slipping. 80.229.228.229 18:45, 4 July 2007 (UTC)
- Well, yes - that's why I said kinda' like a gyro, however, precession is still the right word. SteveBaker 22:08, 4 July 2007 (UTC)
- I don't believe that the motion is the same, though. If you watch it, The disc is hardly spinning. You always get that funny bit at the end where the coin doesnt look like it's vibrating at all, it's just hovering and turning slowly. I think this (and the similar movement before that when you can see the oscillation) is what they refer to as "spolling" and is what the OP is looking for. It's certainly a very interesting phenomenon. 213.48.15.234 06:41, 5 July 2007 (UTC)
- I googled 'spolling' and I only see a handful of relevent hits (most are typo's for spelling or spooling) - all but one of them come from www.eulersdisk.com and that one comes from a patent filed by that same company. I don't find the word in any of the four dictionaries I have at hand right now. So, no - spolling is a neologism at best - most likely it's a word that one guy made up that hasn't been taken up by the worlds of physics and mathematics. The rate of wobble of the axis of rotation is not equal to the rate of rotation around that axis - that's what precession is - and that's what the lid is doing. What's happening with the lid is certainly interesting though. SteveBaker 14:43, 5 July 2007 (UTC)
- I'm aware that it's a made up word :). The precession that's happenning with the lid is certainly happening at a very different rate to what I would normally consider to be precession. The resultant motion is quite different. Capuchin 06:46, 6 July 2007 (UTC)
- I'm unaware of any definition of the word 'precession' that specifies any limits on the rate of the motion. SteveBaker 13:49, 6 July 2007 (UTC)
- I'm aware that it's a made up word :). The precession that's happenning with the lid is certainly happening at a very different rate to what I would normally consider to be precession. The resultant motion is quite different. Capuchin 06:46, 6 July 2007 (UTC)
- I googled 'spolling' and I only see a handful of relevent hits (most are typo's for spelling or spooling) - all but one of them come from www.eulersdisk.com and that one comes from a patent filed by that same company. I don't find the word in any of the four dictionaries I have at hand right now. So, no - spolling is a neologism at best - most likely it's a word that one guy made up that hasn't been taken up by the worlds of physics and mathematics. The rate of wobble of the axis of rotation is not equal to the rate of rotation around that axis - that's what precession is - and that's what the lid is doing. What's happening with the lid is certainly interesting though. SteveBaker 14:43, 5 July 2007 (UTC)
- I don't believe that the motion is the same, though. If you watch it, The disc is hardly spinning. You always get that funny bit at the end where the coin doesnt look like it's vibrating at all, it's just hovering and turning slowly. I think this (and the similar movement before that when you can see the oscillation) is what they refer to as "spolling" and is what the OP is looking for. It's certainly a very interesting phenomenon. 213.48.15.234 06:41, 5 July 2007 (UTC)
- Well, yes - that's why I said kinda' like a gyro, however, precession is still the right word. SteveBaker 22:08, 4 July 2007 (UTC)
- Hmm, I'm not sure. The contact point of the disc isnt fixed, it's rolling/slipping. 80.229.228.229 18:45, 4 July 2007 (UTC)
efficiency?
hey friends ..
can anyone help me
regarding increasing the efficiency of an ic (2-stroke) engine by temperature variations.
- Have you looked at heat engine or carnot cycle ? Nimur 16:43, 4 July 2007 (UTC)
i have read that article ,it is clearly stating that increasing temperature of source(inlet/atmospheric air in case of 2-stroke engine) or decreasing the temperature of sink(exhaust gas in case of 2-stroke engine) would increase the efficiency.so ..a freak but why dont we increase the temperature of inlet gases using some heaters or decrease the temperature of exhaust gases by some coolers.please comment that why?/why dont? we use those procedures. Sameerdubey.sbp
- In short form, because you can't get that energy for free. Where does the heat energy come from? Another engine. Does that engine use less energy than the energy saved on the initial engine? No. Entropy increases. — Lomn 13:24, 5 July 2007 (UTC)
- I disagree. Firstly, I'm surprised that heating the inlet would help - it certainly doesn't on a 4-stroke engine. In fact, most cars run significantly more efficiently in cooler air because there is more oxygen present and that allows a more efficient fuel burn and less energy goes into driving the coolant around and providing energy to the radiator fan. I've actually dyno'ed my MINI Cooper S and found that I get about 10% more horsepower in winter than in summer (that's in Texas). Note also that we do in fact employ special 'engines' to compress (and thereby heat) the air on the way into car engines - we call them 'Turbochargers' and 'Superchargers'. In fact, they heat the air up so much that some cars use a secondary radiator called an Intercooler to try to drop the temperature back to ambient again before the air gets into the cylinders. The Turbo is powered by the waste energy in the exhaust gasses (the fact that they are emitted at higher than ambient pressure means that the exhaust gas can spin a little turbine to power the pump that pushes the extra air in. The Supercharger is powered from a belt taking power directly from the engine - the supercharger produces more extra efficiency than it consumes - so this is a worthwhile thing to do. So clearly you can do something to help without invoking Entropy and saying "it's impossible" - millions of cars out on the roads today prove conclusively that this is true! SteveBaker 14:31, 5 July 2007 (UTC)
- You're correct; I was looking at the question in terms of "why don't we go above and beyond present engine technology", assuming that turbos, etc, were assumed as integral where appropriate. Heat engines are more or less as efficient as they're going to get from a conceptual standpoint, and hooking up an air conditioner to cool the exhaust is a net loss. — Lomn 15:34, 5 July 2007 (UTC)
- Well, if cooling the exhaust helped (and I honestly don't see how it could!) you could simply provide a big expansion chamber somewhere shortly after the engine - the exhaust gas is under pressure - so letting it expand out into a big chamber would certainly cool it down - and at zero energy cost. But aside from the issue of back-pressure (which is actually somewhat advantageous in some cases), once the exhaust is outside of the engine block, who cares what temperature it's at?! SteveBaker 19:29, 5 July 2007 (UTC)
- SteveBaker, the idea of the heat engine is that the action of cooling has the ability to perform work. You could "waste" that work by allowing the gas to cool adiabatically, as you mention. If a hypothetical method to use the remaining heat existed, that energy could be used by the engine (powering the drive shaft, or something). That is why cooling the output would make the "theoretical" engine more efficient. In a practical scheme, I don't know that it's so trivial to harness excess energy outside the combustion chamber just by refrigerating the exhaust gas. On the other hand, a more efficient engine would inherently yield cooler exhaust gases. Nimur 04:35, 6 July 2007 (UTC)
- Yeah - I agree entirely - if you can capture some of the heat from the exhaust (and thereby cool it) but use that heat to do more work - then for sure, it's a win/win situation. But forcably cooling it with refrigeration is nuts! The idea that a heat engine that happens to have a cooler exhaust is more efficient than one with a hotter exhaust is also true - but we're turning that around and saying that cooling the exhaust of a hot-exhaust heat engine makes it more efficient - and that's just nuts! FWIW, BMW have been playing with using the exhaust heat to do some work - they've demonstrated a small steam engine (powered by engine exhaust heat) that would have enough power to run the cars' A/C and recharge the battery - thereby relieving the main engine of that work and resulting in a more efficient car overall. Since the exhaust gasses will have been routed through those pipes which are full of cold water, the exhaust gasses are indeed cooled by doing this. But that's not refrigeration. As I also mentioned earlier, lots of cars have Turbochargers that extract power from the exhaust gasses in order to get more engine efficiency. So this is a well-understood phenomena. SteveBaker 13:46, 6 July 2007 (UTC)
- SteveBaker, the idea of the heat engine is that the action of cooling has the ability to perform work. You could "waste" that work by allowing the gas to cool adiabatically, as you mention. If a hypothetical method to use the remaining heat existed, that energy could be used by the engine (powering the drive shaft, or something). That is why cooling the output would make the "theoretical" engine more efficient. In a practical scheme, I don't know that it's so trivial to harness excess energy outside the combustion chamber just by refrigerating the exhaust gas. On the other hand, a more efficient engine would inherently yield cooler exhaust gases. Nimur 04:35, 6 July 2007 (UTC)
- Well, if cooling the exhaust helped (and I honestly don't see how it could!) you could simply provide a big expansion chamber somewhere shortly after the engine - the exhaust gas is under pressure - so letting it expand out into a big chamber would certainly cool it down - and at zero energy cost. But aside from the issue of back-pressure (which is actually somewhat advantageous in some cases), once the exhaust is outside of the engine block, who cares what temperature it's at?! SteveBaker 19:29, 5 July 2007 (UTC)
- You're correct; I was looking at the question in terms of "why don't we go above and beyond present engine technology", assuming that turbos, etc, were assumed as integral where appropriate. Heat engines are more or less as efficient as they're going to get from a conceptual standpoint, and hooking up an air conditioner to cool the exhaust is a net loss. — Lomn 15:34, 5 July 2007 (UTC)
- I disagree. Firstly, I'm surprised that heating the inlet would help - it certainly doesn't on a 4-stroke engine. In fact, most cars run significantly more efficiently in cooler air because there is more oxygen present and that allows a more efficient fuel burn and less energy goes into driving the coolant around and providing energy to the radiator fan. I've actually dyno'ed my MINI Cooper S and found that I get about 10% more horsepower in winter than in summer (that's in Texas). Note also that we do in fact employ special 'engines' to compress (and thereby heat) the air on the way into car engines - we call them 'Turbochargers' and 'Superchargers'. In fact, they heat the air up so much that some cars use a secondary radiator called an Intercooler to try to drop the temperature back to ambient again before the air gets into the cylinders. The Turbo is powered by the waste energy in the exhaust gasses (the fact that they are emitted at higher than ambient pressure means that the exhaust gas can spin a little turbine to power the pump that pushes the extra air in. The Supercharger is powered from a belt taking power directly from the engine - the supercharger produces more extra efficiency than it consumes - so this is a worthwhile thing to do. So clearly you can do something to help without invoking Entropy and saying "it's impossible" - millions of cars out on the roads today prove conclusively that this is true! SteveBaker 14:31, 5 July 2007 (UTC)
hymen
Can the hymen of a girl ruptutred, if her vigina is contacted(not penetrated) by a finger strongly even if she wears a trouser or under pant.
- I don't think you know what vagina means. But, yes, hymens are damaged quite frequently by things other than penetration. Friday (talk) 17:29, 4 July 2007 (UTC)
- Horse riding was frequently blamed in less enlightened days. Corvus cornix 23:34, 4 July 2007 (UTC)
- Or maybe the secret lover's name was "Horst" and she didn't enunciate. Edison 14:41, 5 July 2007 (UTC)
- Horse riding was frequently blamed in less enlightened days. Corvus cornix 23:34, 4 July 2007 (UTC)
- You should see Hymen#What might damage the hymen. — Laura Scudder ☎ 14:44, 5 July 2007 (UTC)
vagina
who can tell me the size of the viginal opening?
- We can. Welcome to Wikipedia. You can easily look up this topic yourself. Please see vagina. 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. .
Determining the proper pump for a water fountain.
I have a question regarding matching the right pump for a specific purpose. I have a water pump that is 40gpm and it has 1 1/2" intake and outlet. The pump will be set below the water level by 24". I will divide the outlet into 3 seperate lines that will push water up. I have a trough that contains 11 inches of water included in the overall height to push the water. The goal is to have the water bubble above the surface of the water in this trough bu no more than 12". Do I have the right pump and how do I accomplish the task. This is also in the exterior environment.
Accuracy of Weather Forecasting
This is a rather difficult question, and although I think I read something on it several years back, I have been unable to find any statistics.
The question, in its simplest form, is something like this: as a function of time (edit: where time is defined as the time between the forecast and the event), how accurate are the modern weather forecasting computer models?
The problem is how we define accuracy, and although I have a few ideas, none of them are perfect. Can anyone find me information on this subject? Any kind of relevant statistic will be very helpful.
Thanks a lot. 69.255.38.193 19:21, 4 July 2007 (UTC)
- One example I know of where long systematic studies have been done is in the accuracy of hurricane landfall locations. This image is a good summary. Dragons flight 21:32, 4 July 2007 (UTC)
- http://www.forecastadvisor.com will show you the accuracy of a range of different weather services for a particular US zipcode - and also how one particular weather forecast has changed over the five days prior to the actual day of the forecast. You can use this to see how the prediction homed in on the final value. There is a scientific-looking study of forecasting accuracy here http://www.customweather.com/accuracy/2003study.html. Here is another www.omninerd.com/2007/02/08/articles/69. Our article on the WxChallenge explains the criteria that are used for judging weather forecasting competitions. SteveBaker 22:05, 4 July 2007 (UTC)
How could I engineer weather inside my house?
I wish to satisfy my God complex. Vitriol 22:39, 4 July 2007 (UTC)
- Central heating and air conditioning should take care of the temperature. Fans will provide wind. To obtain rainfall, you will have to increase humidity dramatically, consider a paraffin heater (they produce a remarkable amount of water vapour). DuncanHill 22:44, 4 July 2007 (UTC)
- Or consult our article on humidifiers. Root4(one) 22:57, 4 July 2007 (UTC)
- If you built your "house" large enough, like the size of a gigantic aircraft hanger. You can have precipitation occurring inside your "house". Especially if you use technological devices to change the humidity and temperature inside your "house". 202.168.50.40 04:44, 5 July 2007 (UTC)
- Would God need to ask? :) DirkvdM 06:33, 5 July 2007 (UTC)
- One of the crucial aspects of weather is convection between air masses. You will want to make sure that you have a source of hot air and a source of cold air, and allow them to swirl around and such. If you have sufficient temperature differences, you can induce condensation (imagine leaving a bathtub full of hot water near the open freezer - as the warm moist air rises and hits the cold freezer air, it will form a steam cloud and will almost certainly drop some precipitate water). If you're lucky, the rapid condensation may even make some ice crystals and you can call it snow. Using a fan will move air, but it won't be "wind" (at least not to my satisfaction). Wind is the natural flow of air masses as a result of pressure differences. You'll get a more realistic wind effect with the bathtub-freezer mash-up. In summary, you should seek to provide sources and sinks for pressure, humidity, and heat, and the natural air motion will take care of the rest. You might want to read about Biosphere 2; their engineered indoor weather was quite expensive. Nimur 07:16, 5 July 2007 (UTC)
- The Vehicle Assembly Building may have its own internal weather system, with reports of clouds forming inside the building on humid days. Gandalf61 10:17, 5 July 2007 (UTC)
- I heard that happened in some of the larger sports arenas too. SteveBaker 14:20, 5 July 2007 (UTC)
Some original research - if you go to an indoor pool with warm water and cold weather outside, opening the doors to the outside will cause a cloud, and eventually precipitation, to form. It's actually quite remarkable -- Sturgeonman 23:54, 8 July 2007 (UTC)
Map of the North and South Magnetic Hemispheres
Campasses are made for both the North and the South Hemispheres. Where can I find a map of the dividing line between the two magnetic hemispheres? Ugly bag of mostly water 23:26, 4 July 2007 (UTC)
- Compasses always point to Magnetic North, in both hemispheres. If you're talking about compass balancing, that's not essential because you can always compensate for the inclination of the magnetic field by tilting the plane of the compass away from horizontal. There's definitely no such thing as a "dividing line" such that you need one specific kind of compass to the north and a different kind to the south. Compasses work anywhere on Earth. —Keenan Pepper 01:57, 5 July 2007 (UTC)
- Not if you're on the actual magentic poles themselves... :p --antilivedT | C | G 02:14, 5 July 2007 (UTC)
- Sure they do! You just notice that the needle is trying to tilt away from horizontal, so you tilt the plane of the compass until the needle becomes perfectly vertical. Then you know you're at the magnetic pole. The magnetic field isn't zero at the poles; it just points straight up or down. —Keenan Pepper 02:45, 5 July 2007 (UTC)
- Compass#Compass balancing describes geographic "zones" - compasses are calibrated for the strength of the vertical component of the magnetic field, not the direction of the horizontal component. The compass always points towards magnetic north/south. As far as the dividing line between the "hemispheres", I don't believe there is much use for such a distinction. You could draw a great circle centered at either pole and set its equator. Finally, you may be interested in a map of magnetic declination, which I have added to this section. Nimur 03:04, 5 July 2007 (UTC)
While agreeing with both Keenan Pepper and Nimur that there is not much use for it in terms of compasses, the line that separates north from south is the line of zero inclination (not declination, although declination is much more important for actual navigation). An inclination similar to the one already posted for declination exists: [12] and shows that the line of zero inclination is a wavy line grossly sub-parallel to (but by no means coincident with) the geographic equator. Cheers Geologyguy 04:12, 5 July 2007 (UTC)
vitamin B12 and vivid dreams
I've had extremely vivid and surreal dreams the past few days, and I think it's because I've been taking 1.5 mg of vitamin B12 (orally) as a dietary supplement before sleeping. I've found some anectodal evidence and new age-y stuff on the internet that seem to confirm my suspicions, but I've found no actual medical information. Have there been any scientific studies dealing with this phenemonon? --Krsont 23:46, 4 July 2007 (UTC)
- I don't know of scientific studies, but it is widely accepted that B12 can increase vividness/lucidity in the Lucid Dreaming community. As well as a few other things like Nicotine patches. You might be interested in reading people's experiences on ld4all.com, and if you ask around there you might also find some studies on the matter --ʇuǝɯɯoɔɐqǝɟ 00:08, 5 July 2007 (UTC)
- Interesting... I've had a few lucid dreams in the past, but they didn't last very long. Maybe I should take the chance to experiment further with lucidity :) --Krsont 00:35, 5 July 2007 (UTC)
- I highly recommend it. I really enjoyed doing it. I stopped doing when I started getting depressed, since those dreams were very lame anyway, and I'd rather just relax when I go to sleep than MILD myself --ʇuǝɯɯoɔɐqǝɟ 01:27, 5 July 2007 (UTC)
- Interesting... I've had a few lucid dreams in the past, but they didn't last very long. Maybe I should take the chance to experiment further with lucidity :) --Krsont 00:35, 5 July 2007 (UTC)
- Vitamin B12 is usually considered safe with very few side effects. A quick search in PUBMED (Database for published medical literatures) did not reveal any such association. Consult your doctor and see if you can take tablets in the daytime.--Countincr ( T@lk ) 00:31, 5 July 2007 (UTC)
- Why would I want to take them in the daytime? I guess I wasn't clear: I like the dreams, I just want to know more about it ;) --Krsont 00:35, 5 July 2007 (UTC)
July 5
SpaceShipOne Orbit Style
Could Rutan's method of lifiting spacecraft then launching them into space be used to achieve orbit? Does his engines, if scaled up, a bit meet the requirement for reaching orbit or would diffrent kind of engines be needed?67.121.105.12 02:04, 5 July 2007 (UTC)
- No physical law precludes that approach. It has yet to be seen whether the engineering and financial challenges can be feasibly and safely overcome. Among the major challenges are control and stability, and carrying enough fuel. Nimur 03:06, 5 July 2007 (UTC)
- The idea has been floated a number of times, both in science fiction and real life. Using an airplace in lieu of a first stage makes reusing the first stage quick and easy (in principle) and it means that your rocket will start out with significant speed and altitude, as well as above much of the atmosphere and weather. (The idea of using a balloon to get above a lot of the atmosphere has also been proposed; it was even used for suborbital sounding rockets in the 1950s: see rockoon.)
- This page has a list of air-launched rocket craft (proposed and flown). The Soviet Union developed and tested an air-launched spaceplane (called MAKS), but the program ended with the Cold War, and it never reached orbit: [13]. TenOfAllTrades(talk) 13:23, 5 July 2007 (UTC)
- Some of the X-planes were launched that way - and many of them reached "the edge of space", so SpaceShip One was hardly the first. Rutan certainly claims to be able to reach orbit with a similar approach to his first effort - and he's a pretty smart guy, so I'm inclined to believe him. My best guess is that his approach to re-entry is his biggest problem. SpaceShip One only just got out of the atmosphere - so that on re-entry it was moving rather slowly and managed to cope without needing fancy heat tiles or ablative coatings. When you re-enter from orbit, you've been falling for a long time without air resistance by the time you hit atmosphere - so your speed is much greater and slowing down becomes a major problem. SteveBaker 14:16, 5 July 2007 (UTC)
- The Pegasus rocket from Orbital Sciences is a commercial satellite launch system that is launched from a modified commercial airliner. They have launched quite a few satellites. -Arch dude 02:53, 6 July 2007 (UTC)
- Wow! Interesting! They do say though that the primary reason for the air launch has nothing to do with getting the thing up high and going fast at the point of the launch - they do it to save on the cost of ground-based launch failities and to avoid launch delays due to bad weather. That's a fascinating thing! Thanks for the link. SteveBaker 20:23, 7 July 2007 (UTC)
ultrasound???
hey friends is anyone having idea about the ultrasound machine: 1.consumption according to a particular frequency generation. 2.minimal space requirement for specifc 20,000hz machine.
please help
in urgent need
- SameerDubey, with all due respect, I can't tell what you are asking. You might be interested to know that 20 kHz is probably not ultrasound, since it is approximately in the range of human hearing (on the high end, so it may be barely out of audible range for many people). A machine would consume energy (probably electrical energy), and would most likely be an ultrasonic transducer. Nimur 06:50, 5 July 2007 (UTC)
- Agreed - Ultrasound is more often in the MegaHertz (MHz) to GigaHertz (GHz) range - but unless we know what it's for - we can't answer either question. It's not just about the frequency - the power required and the way it's going to be used and the way that results are collected and displayed at much more relevent! The ultrasound units used for checking the health of unborn babies are totally different from the units used to detect cracks in welded steel which in turn are completely different from the ultrasonic cleaning bath I have at home for cleaning gunk off of old car parts. SteveBaker 14:06, 5 July 2007 (UTC)
- Even ~30 or 50 kHz is usually called ultrasonic, but 20 kHz is probably not. Nimur 17:31, 5 July 2007 (UTC)
- Hmmm - well I wouldn't have said so - but our article on Ultrasound says 20kHz. Weird. SteveBaker 19:12, 5 July 2007 (UTC)
- Short of an ANSI or ISO standard, there's not going to be a well-defined border for the nomenclature. But if professional audio is anything to gauge, it is extremely common to have 44.1 kHz and 48.0 kHz recordings - which would indicate a folding frequency at 22.05 and 24 kHz, respectively. That, to me, suggests that there must be some audibly discernible signals at those frequencies. I worked with a SONAR system for a while that operated at 34 and 70 kHz, and it was most certainly ultrasonic; but it also produced some unwanted harmonics (undertones?) that could be heard as mild, faint buzzing. (The system was operating at 100+ dB in the ultrasonic range...) Nimur 21:15, 5 July 2007 (UTC)
- Hmmm - well I wouldn't have said so - but our article on Ultrasound says 20kHz. Weird. SteveBaker 19:12, 5 July 2007 (UTC)
- Even ~30 or 50 kHz is usually called ultrasonic, but 20 kHz is probably not. Nimur 17:31, 5 July 2007 (UTC)
- Agreed - Ultrasound is more often in the MegaHertz (MHz) to GigaHertz (GHz) range - but unless we know what it's for - we can't answer either question. It's not just about the frequency - the power required and the way it's going to be used and the way that results are collected and displayed at much more relevent! The ultrasound units used for checking the health of unborn babies are totally different from the units used to detect cracks in welded steel which in turn are completely different from the ultrasonic cleaning bath I have at home for cleaning gunk off of old car parts. SteveBaker 14:06, 5 July 2007 (UTC)
Satisfaction of Swallowing
Why is it that we must swallow food to enjoy it? I tried "eating" ice cream by savoring the food, then spitting it out and chasing it with a spoonful of rice. My stomach picked up on the bait-and-switch and I was not satisfied. Why does swallowing the food complete the satisfaction effect? If this weren't the case, it would be much simpler for people to not gain wait brought on by heavy foods. HYENASTE 05:03, 5 July 2007 (UTC)
- Evolutionarily, we want to swallow food because only then can we begin the digestion process to extract nutrients and fat from it. It's only in the modern world that we eat so much high fat foods that we want to lose weight, our body systems havent caught up with the modern world. We get very little nutrients from food we don't swallow. 213.48.15.234 06:46, 5 July 2007 (UTC)
- It is our stomach that tells us when we are satisfied. Check out the articles on hunger and appetite.--Shantavira|feed me 10:38, 5 July 2007 (UTC)
- Yes, but the OP asked why they couldn't spit out ice cream and substitute rice. This should satisfy the stomach, while the ice cream satisfies the tongue. The Question is "why didn't this work?" I would say that most likely, the ice cream contains something which your body craves that the rice does not. For instance, plain rice is low in fat. I would suggest that you try eating just a little bit of ice cream maybe a couple of spoons to fool the stomach then starting the bait and switch with the rice. Let us know how it works for you. - Czmtzc 15:02, 5 July 2007 (UTC)
- I guess the problem is that enjoying the taste of something - and having your hunger satisfied are two completely independent sensations. What we want from food is a combination of both things. It's possible to taste ice cream without swallowing it (well, technically: "you can if your willpower is a lot stronger than mine"!) - but I think it would be hard to swallow enough rice without tasting it along the way. So I think the reason you aren't happy with the experiment in an overall way was not that the rice didn't satisfy your hunger - but that it was boring to eat and even the occasional mouthful of ice cream didn't help that. It's a hard experiment to do well because the only reasonable way to get the bland food into your stomach is going to involve tasting bland food. I wonder about chewing gum though...hmmm. I admire your efforts to employ good scientific methodology though - everyone should do more to experiment with the things around them! SteveBaker 15:16, 5 July 2007 (UTC)
Food For The Homeless and $1,000,000
I have been discussing a question with a friend of mine for quite some time (~1 month). I have my ideas, he has his; I wanted to see what the Wikipedia Refernce Desk community could come up with. This is in no way a ultra-precise or "nit-picky" question.
- Let us imagine that you have $1,000,000 cash.
- You want to feed the maximum number of American homeless people possible using this money.
- What should you buy? White Rice? Cans of Meat and Beans? "For Maximum Value"-Brand Cheerios?
- What is the healthiest, but cost effective (read: dirt cheap) food to buy?
- About how much of it would you be able to purchase? How many people would it feed?
- The costs of delivery to the homeless people is not a factor - they must come TO your food stockpile to recieve the food.
- Just to add onto the question above, would it be more effective to buy land and seed and fertilizer and to grow the food? 213.48.15.234 06:48, 5 July 2007 (UTC)
- One million dollars isn't really a lot of money. But first, you should evaluate some philosophical choices - is it better to feed a small amount of people for a small number of meals ( ... buying a full lunch for a million people), or to feed a few people many times (buy a year's supply of food for 500 people)? What level of cost-nutrition tradeoff are you willing to accept?
- In any case, it may be easier to imagine the cost-per-meal. If you are an effective negotiator, you can probably buy bulk ingredients at cost. How "raw" you go will determine how much preparation and labor you need to turn it into a meal. But if you could get the ingredients down to ~$1 per meal, (say, a peanut butter sandwich on two pieces of bread; a carrot, and a glass of juice), you could feed 1,000,000 people one small meal. It is not even clear that there are this many homeless people near enough to walk to your sandwich depot, but census numbers vary wildly for that demographic (these statistics indicate that 13 million Americans (7.4%!) self-identify as having been homeless at some time, while conservative estimates place the number much much lower).
- But this leaves you with a nasty predicament. This hypothetical solution has fed a million people one meager sandwich, and now they are off again on their own. The contribution to their health is debatable; only a very minuscule percentage would have starved if not for your sandwich contribution. Those who would have starved may not be much better off anyway, because you have only given them one meal (enough food to last another few hours?)
- It would make significantly more sense for you to prioritize how hungry people have to be, and give them aid based on that level. But that will require a bureaucracy, a lot more labor on your part, and you may have to make a few gut-wrenching decisions between who gets to eat and who may not. Nimur 07:02, 5 July 2007 (UTC)
- You could invest the million dollars, reinvest enough of the profits to keep up with inflation, and spend the rest of the profits on food. This way you would have a steady inflow of money. —Bkell (talk) 07:11, 5 July 2007 (UTC)
- Surely what the homeless need is housing. Anyway, the best investment would be to buy lots of fishing rods and teach them to fend for themselves.--Shantavira|feed me 07:43, 5 July 2007 (UTC)
- The problem is much more complicated. Firstly, you need to think about transportation. There is very often excess food produced in the more fortunate parts of the world that could be had for $0 (I was listening just this morning to an NPR report that European grape growers are being paid to destroy part of their crop because of the effect that over-production is having on price) - but getting those excesses into the right place is a big issue - perhaps your best use of that $1,000,000 is to pay for transportation instead? Secondly, over what time-period are we talking? If you take the $1,000,000 and invest it wisely, you'll get a 5% or so return on it - which means that you have $50,000 per year FOREVER. After 20 years, you'll have helped the same number of people as with $1,000,000 spent all in one lump today - but after 100 years, you'll have done much more good. Invest the money as micro-finance loans to people in the area and you'll be doing good while you are making that money. Thirdly, simply giving people food doesn't solve anything over the long term. If you give them food, they might stop farming and live on the food you provide - that means that when you run out of your $1,000,000 - they may be worse off than when you started. It would be better to invest that money in improving their food production infrastructure than to provide direct food aid. (Although, clearly there are emergency situations where immediate short term food aid is both necessary and beneficial). In the end, to take the ultimate 'long view', the problem is that much of Africa's climate and soil conditions simply doesn't allow it to produce enough food for all of the people who live there - the solution is to have less people. There is merit in providing funding for long term population control. To answer your actual question - the answer is Rice. SteveBaker 14:01, 5 July 2007 (UTC)
- Not to mention those pesky civil wars that keep blowing up all the infrastructure that endemic corruption even allow to be built in the first place. As for the OP - white rice is less nutritious than the whole stuff, but SteveBaker I believe is correct in suggesting rice as *the* answer for a single staple to feed the masses, although I seem to recall that bananas put in a pretty good showing if you do not have to worry about spoilage. Consider the rolling population explosion across southeast Asia as rice cultivation spread, and then factor in all the breeding and other genetic modifications (e.g. golden rice) that have happened since. As for pricing your solution, a lot depends on how much volunteer labor you can mobilize to cook for you, as processing adds to food costs. -Eldereft 07:48, 7 July 2007 (UTC)
Re:Protons, Electrons, Neutrons and such
What produces these charges? Does heat produce electron? If it does, then what does cold produce? How do you know if something is positively charged (protons) or negatively charged (electrons)? And secondly, does lightning come from the ground? Finally, if a car produces a large number of electrons, and the road produces an equal number of static charge, will the car be pushed away from the road? -Zacharycrimsonwolf 13:05, 5 July 2007 (UTC)
- Lightning travels most commonly from cloud to cloud, however what most people think of when you refer to lightning is from cloud to ground. The article does indicate that lightning can also travel from ground to cloud . Lanfear's Bane
Okay. Thanks for that! Cheers!!! -Zacharycrimsonwolf 13:28, 5 July 2007 (UTC)
- We don't really know what creates charges, they are just a quantum number, an intrinsic property of particles, which determines how strongly they interact with photons, i.e. the electromagnetic field. I'm not sure what you mean does heat produce electrons? Heat in itself doesn't no, but the energy from heat can ionise atoms, that is remove a negative electron, leaving a positive ion. Cold is simply an absence of heat energy, not an opposite so produces nothing. Positive/negative charges can be deduced from the direction of curvature during motion in a magnetic field, or the direction of force in an electric field. Which is positive and which negative is simply a matter of convention, we could equally well swap the names round. The important point is they are opposite charges. Lightning has been covered above. The car question has me confused again! Maybe the simplest thing to say is that electrons are not really produced, simply moved around. If the car gains eletrons from the road somehow (static electricity in effect) it will leave behind a positive road and be attracted to it, not repelled. Charge is conserved, basically moved around not created. Cyta 13:32, 5 July 2007 (UTC)
- Electrostatics may also be helpful to you. DuncanHill 13:33, 5 July 2007 (UTC)
- Let's break this up for more manageable answering:
- What produces these charges?
- The charge on these fundamental particles is just an innate property of the particle - nothing 'produces' it - it's just a property - like their mass. SteveBaker 13:43, 5 July 2007 (UTC)
- Does heat produce electron? If it does, then what does cold produce?
- Heat is just the measure of how fast (on average) the molecules are moving/vibrating. Heating some substances may cause them to emit electrons - see Thermionic emission. SteveBaker 13:43, 5 July 2007 (UTC)
- To clarify, heating something can cause it to release electrons as opposed to creating electrons. — Laura Scudder ☎ 14:51, 5 July 2007 (UTC)
- How do you know if something is positively charged (protons) or negatively charged (electrons)?
- You bring something whose charge you know to be (say) positive close to the unknown thing and see if it is attracted or repelled by it. Like charges repel, unlike charges attract. SteveBaker 13:43, 5 July 2007 (UTC)
- The mathematical and moral definitions of the terms positive and negative don't apply to positive and negative charge, they're just arbitrary polar descriptions of a property. -- JSBillings 14:21, 5 July 2007 (UTC)
- That's true - but we needed a pair of names with opposite meanings! Physics is full of arbitary names for things - that's how we ended up with Strangeness, Charm, Bottomness and Topness. One certainly cannot garner extra meaning from the names chosen. So you can tell whether two electrical charges have the same sign by whether they attract or repel each other - but is you don't have a 'known-to-be-negative' or 'known-to-be-positive' object handy then there is no 'absolute' way to tell (that I'm aware of). SteveBaker 14:52, 5 July 2007 (UTC)
- You could look at how the charged object interacts with other EM things...throw it through a magnetic field of known direction and see which way it curves or throw it past a compass and see which way the compass points. But still, need some known starting point. DMacks 17:03, 5 July 2007 (UTC)
- Or apply a magnetic field to a conductor through which current is flowing and measure curvature via the Hall effect. -Eldereft 08:04, 7 July 2007 (UTC)
- Right - there are plenty of ways to determine this - but (I believe) that all of them depend on you having something with known polarity (either a positive or negative charge/potential-difference or a current whose direction of flow you know or a magnet for which you know which end is north and which is south). Since we know the polarity of the earth's magnetic field, then a compass needle is one way to get that with certainty. But how would you tell if you didn't have anything like that? SteveBaker 14:18, 7 July 2007 (UTC)
- Or apply a magnetic field to a conductor through which current is flowing and measure curvature via the Hall effect. -Eldereft 08:04, 7 July 2007 (UTC)
- You could look at how the charged object interacts with other EM things...throw it through a magnetic field of known direction and see which way it curves or throw it past a compass and see which way the compass points. But still, need some known starting point. DMacks 17:03, 5 July 2007 (UTC)
- That's true - but we needed a pair of names with opposite meanings! Physics is full of arbitary names for things - that's how we ended up with Strangeness, Charm, Bottomness and Topness. One certainly cannot garner extra meaning from the names chosen. So you can tell whether two electrical charges have the same sign by whether they attract or repel each other - but is you don't have a 'known-to-be-negative' or 'known-to-be-positive' object handy then there is no 'absolute' way to tell (that I'm aware of). SteveBaker 14:52, 5 July 2007 (UTC)
- The mathematical and moral definitions of the terms positive and negative don't apply to positive and negative charge, they're just arbitrary polar descriptions of a property. -- JSBillings 14:21, 5 July 2007 (UTC)
- And secondly, does lightning come from the ground?
- See Lightning#Leader_formation - it's rather complicated. SteveBaker 13:43, 5 July 2007 (UTC)
- Finally, if a car produces a large number of electrons, and the road produces an equal number of static charge, will the car be pushed away from the road?
- Well, if a static charge were being built up on the car by virtue of the tyres rubbing on the road, you'd maybe get electrons building up on the car - and left-over protons on the road (or vice-versa) - this would result in the car being attracted towards the road - not pushed away from it. However, the force would be very tiny indeed and in any case, I'm pretty sure that the static charge that builds up on cars comes from friction with the air - not the road. SteveBaker 13:43, 5 July 2007 (UTC)
- Many thanks, all! To tell the you truth, its my teacher who told us that heat (somehow) produces electrons. And if you remove the tires of a car while its moving, leaving only the rim, the rims will produce electrons (because of heat). The road produces electrons as well (because of friction, which produces heat), and because of that, the car will (literally) 'fly' because the electrons repel each other. -Zacharycrimsonwolf 13:47, 8 July 2007 (UTC)
Facial hair (from Humanities)
What is record of earl facial hair and late facial hair? --Vess 07:29, 5 July 2007 (UTC)
- I don't understand your question. Have you read facial hair and Earl "Facial Hair" Derby?--Shantavira|feed me 08:05, 5 July 2007 (UTC)
- I think they meant early facial hair. WAFFLESOAP 09:28, 5 July 2007 (UTC)
I meant early and late facial hair. --Vess 10:03, 5 July 2007 (UTC)
- Pituitary adenomas can cause the growth of ancillary and facial hair at virtually any age. These are hormonal variations, and therefore there wouldn't really be a "record." Instead, there would be various disease states, and those with either the lack of facial hair despite functional male gonads or the presence of facial hair despite the lack of mature male sex hormonal organs would suffer from other symptoms and would be distinctly suffering. Geogre 11:55, 5 July 2007 (UTC)
- NO! Pituitary adenomas are extremely unlikely to produce facial hair-- not one in 10,000 cases. This is all nonsense offered by an editor who should know better. alteripse 19:25, 6 July 2007 (UTC)
- A condition of very early precocious puberty in boys causing early growth of facial hair – possibly as early as from age 1 – is testotoxicosis. Delayed puberty, possibly indefinitely delayed, can be caused by a variety of conditions, including Klinefelter's syndrome and androgen insensitivity syndrome. By the way, a more appropriate spot for this question is the science section of our reference desk. --LambiamTalk 12:38, 5 July 2007 (UTC)
- Not facial hair by itself. Advanced precocious puberty may be associated with beard growth in a boy, but only after advanced maturation of the genitalia and bones. alteripse 19:25, 6 July 2007 (UTC)
- I suspect the original poster may have meant early and late in a historical sense - that is to say, changes in styles of facial hair through history. DuncanHill 12:45, 5 July 2007 (UTC)
I meant without disease. Howewer, by the way, what was the known historical period in which men had early facial hair and what n which they had late facial hair? --Vess 14:47, 5 July 2007 (UTC)
- Even at birth there is a fine 'peach fuzz' of hair on babies faces - it's just a matter of degree - you're not going to find "WOW! A boy born in transylvania in 1796 had a full beard at age 3." (I just made that up OK!)...because it's just not a clear-cut thing. SteveBaker 14:59, 5 July 2007 (UTC)
- Closer but still not quite. There are several types of facial hair that are being confused in these answers, and the difference IS generally a "clear-cut thing". The two main categories are vellous and androgenic. Vellous hair is not hormone dependent and is normally present all over the body at all ages but in widely varying densities. There are genetic differences in heaviness, color, and density in healthy people, and sometimes it distresses people from a cosmetic perspective. There are extremely rare cases of defective control of this type of hair growth due to single gene mutations, sometimes familial, resulting in generalized hypertrichosis,-- someone who might get a job as a "wolfman" in a carnival. This condition becomes apparent in early infancy. Exaggerated growth of fine vellous facial hair can also accompany some chronic non-hormonal diseases in childhood (like chronic renal failure), and this too can appear before 5 years of age. This also can occur in chronically malnourished adolescent girls with anorexia nervosa. Lanugo hair is a type of fine hair present in fetal life and would qualify as the earliest facial hair. Androgenic hair is what normally grows at puberty as a result of rising testosterone levels in both males and females. It can occur in childhood as a result of any form of androgen excess but is an advanced, rather than an early manifestation: pubic hair is the first place androgenic hair grows in conditions of androgen excess. alteripse 19:36, 6 July 2007 (UTC)
Valence electrons
In most metals (I assume all, but I know someone will find one counter-point) there are electrons that float on the surface of the metal, giving it the metallic luster. Are these electrons called valence electrons or is there another more exact name for them? The article claims that valence electrons are in the outer-most shell and the ones on metal are not really in any shell. They just float on the surface - or is that just an apparent floating from outer shell of one atom to another? -- Kainaw(what?) 16:17, 5 July 2007 (UTC)
- I'm no chemistry expert, but this is what I figure: That each atom of the metal has its valence electrons, in the outer most shell. But then, between metal atoms, metallic bonding exists, so that metals are held together so to say by a 'sea of electrons', delocalised electrons floating that broke off from valence shells?
- See the Metallic Bond article, if it helps.74.102.89.241 16:37, 5 July 2007 (UTC)
- The electrons aren't just "floating on the surface" of the metal, but can move throughout the whole piece of metal (see the metal article for more details about this bonding picture). There are indeed surface effects on metallic materials and other conductors, but the idea of valence electrons is in relation to each atom, not bulk material. DMacks 16:57, 5 July 2007 (UTC)
- Thanks - conduction electrons is what I was looking for. -- Kainaw(what?) 17:16, 5 July 2007 (UTC)
UDDERS
What happens to wild cows and goats (and the like) when their udders are full? I know this is a dumb question but it has been torturing me for some time now.
- They stop producing milk. The reason milking cows and goats produce so much milk is because they are milked regularly. It is an adaptive reaction. The more they are milked, the more milk they produce. They less they are milked, the less milk they produce. By the way, humans function the same way. See breastfeeding. -- Kainaw(what?) 17:18, 5 July 2007 (UTC)
- In the long term, (scale of days to weeks), they adapt as Kainaw mentions. Over the scale of a few hours, a full udder is a discomfort for the animal. Nimur 17:35, 5 July 2007 (UTC)
- Plus, remember domestic breeds have been selectively bred for generations to produce huge quantities of milk, and to keep producing it. Wild breeds would not have a problem to the same extent as a domestic (dairy) breed. Skittle 21:31, 7 July 2007 (UTC)
- Domestic dairy cattle are fed and watered in huge quantities; this helps produce vast quantities of milk. Nimur 02:07, 9 July 2007 (UTC)
Hooking up solar panel to appliance
Hi all,
The computer in my apartment is probably the most energy-consuming appliance have. I'd love to be able to hook up a solar panel to it and have it run off of green energy. However, obviously it isn't as simple as that.
I am renting, so have little ability to change the wiring in my apartment or sell back to the grid or anything. And if I just hooked up the panel to my computer, I might get a little power in the day (or I might not, this is Boston), and would certainly get nothing at night.
Is there any system I can use whereby the solar power just suppliments the energy I'm drawing from the grid? Ideally I'd like to be able to instal a solar panel on my roof and attach some kind of large battery (so that it's always charging even when I'm not consuming electricity), and then, when I start consuming electricity, it jumps in and supplies as much electricity it can and lets the grid take up the rest of the slack.
Is there any system remotely like that? And what kind of price would you figure would be on it?
Thanks! --Mike. 17:05, 5 July 2007 (UTC)
- There are many systems for it, but they are not as "green" as you may like. You need a collector (such as a solar panel and a windmill propped out your window). You can hook up a stationary bike if you like also. Anything that produces electricity is fine. Then, you need an electronic device that uses the electricity collected to charge batteries. It limits incoming electricity (in case of, say, a lightning strike) and stops charging when the batteries are maxed out. You obviously need batteries - a lot of them. That is the least "green" part of the process. Batteries are rather nasty, but are slowly being replaced with greener ones. Then, you need a power regulator to manage supplying power from the batteries. Unless you want to hack your computer, you will be converting the DC in the batteries to AC and then the computer will convert the AC back to DC for you. A good regulator will let you connect your wall outlet to supplement power when necessary. Now, that is a lot of electronics you will need. Electronic production requires a lot of chemicals and power. So, you are trading the electricity production from the power company for the electronic production of your "green" system. -- Kainaw(what?) 17:24, 5 July 2007 (UTC)
- As a renter, green energy possibilities are limited. You're not going to get anything really cost-effective in terms of generating your own power as a renter. Your best bet instead is to move towards conservation. Don't leave your computer on at all times, for example. Switch to a laptop model (laptops are designed to be very power efficient). Put as much of your electronics as possible onto power strips and turn off the power strips when they're not in use. Use compact fluorescents in all your light fixtures. When you purchase anything new (say a TV or refrigerator), look for something that's power efficient. Note that a plasma TV will use more power than the same size LCD TV. Incidentally, it's actually your fridge which is the highest power user in your apartment. Finally, if your local power party offers it as an option, sign up for green power. If they don't offer it, pester them about it until they do (or they block your phone number from calling). Donald Hosek 17:47, 5 July 2007 (UTC)
- I VERY much doubt that your computer is the biggest energy user. Lets examine the facts: According to Energy use in the United States:
- 32% space heating
- 13% water heating
- 12% lighting
- 11% air conditioning
- 8% refrigeration
- 5% electronics
- 5% wet-clean (mostly clothes dryers)
- So all of your electronics (including TV, VCR, Satellite, radio, phone, etc) is only 5% of the total - your computer is probably 1% or maybe 2% of your total usage. Your best bet is to turn down the heat/A.C - since heat is eating a third of your budget, saving even 10% of the cost of heating will more than compensate for the PC! Then you can take shorter showers and fewer baths (and share with a *close* friend!) - turn off lights when you aren't truly, honestly using them and switch to compact florescent bulbs. If you can do even slightly better at even just one of those things, it'll wipe out the cost of running your PC. Next time you buy a refrigerator/oven/microwave/dishwasher/A.C/water-heater/freezer - look at the energy consumption and cost of ownership numbers. SteveBaker 18:53, 5 July 2007 (UTC)
- It all depends on individual circumstances -- you can't just take a statistical summary and declare that everyone follows that. For example, that "32% space heating"? It doesn't apply to me: I've never run the baseboard heaters in my apartment. Likewise, the A/C only gets a day or two of use each year. And there's no clothes dryer in my apartment. I prefer dark environments, so "12% lighting" is a massive over-estimate in my case. For me, it would look more like:
- 30% water heating
- 30% computer (always on, and reasonably busy)
- 25% refrigeration
- 10% oven/stove
- 3% lighting
- 1% air conditioning
- 0% space heating
- --Carnildo 22:52, 5 July 2007 (UTC)
- It all depends on individual circumstances -- you can't just take a statistical summary and declare that everyone follows that. For example, that "32% space heating"? It doesn't apply to me: I've never run the baseboard heaters in my apartment. Likewise, the A/C only gets a day or two of use each year. And there's no clothes dryer in my apartment. I prefer dark environments, so "12% lighting" is a massive over-estimate in my case. For me, it would look more like:
- I think you are over-estimating your computer(s), as the average computer's power supply is only rated at less than 500W, it usually uses around 200W at full power for a pretty average computer on high load, plus 50W for a 17" LCD monitor that's just 250W for your "average" computer. On the other hand, Water heating, stove/microwave and fridges are count in kilowatts, and although they may not be always on, I doubt they are used less than say 2 hours a day. --antilivedT | C | G 00:07, 6 July 2007 (UTC)
- I agree he's probably overestimating his computer, but you're overestimating everything else! Not everyone uses electric heating (and a good thing, too, as it's horribly inefficient). If you have natural gas or fuel oil heating, and a gas stove, and a gas water heater, and no air conditioner, your electricity cost for heating/cooling is 0. And refrigerators are a relatively small load, nothing like a kilowatt. (Off the top of my head, I think a typical refrigerator draws 4 amps or so, and of course it's not -- or shouldn't be -- on all the time, either.) So the other big draws are lighting, and major appliances such as dishwashers, microwave ovens, washing machines, and clothes dryers. (For that last, there's obviously another huge difference in electricity load between the gas and electric models). --Steve Summit (talk) 00:21, 6 July 2007 (UTC)
- See [14] for some typical consumption figures. Donald Hosek 00:24, 6 July 2007 (UTC)
- OK - so you're telling us that this 'oksolar' site is reliable? Let's examine what they said. Firstly, they don't seem to understand the difference between kWatts and kWatt/hours which is a red flag right away for a company that's selling solar panels!! But we'll forgive that. They claim that your computer uses 240 Watts and consumes 1248kWatt(/hours) in a year. For that to be true, the computer would have to be pulling 240 Watts 24 hours a day for 216 days out of the year - or 14 hours a day 365 days of the year!! Who are these online junkies?! Even if you forget to turn off the PC, when it's idle, the power drops way below 240 Watts when the computer isn't working hard. Even if you are leaving it on 24/7 to run a website or something, turning off the CRT monitor or letting it powersave properly will get you way below 240 Watts. 240 Watts is when the PC is working hard with graphics and CPU running something really heavy duty - probably with with the hard drive and CD-ROM drive both spinning and the monitor lit up. Even 500W power supplies don't deliver 500W continually - that's a peak number for when absolutely everything is going at full power at the same time. The number they give has to be the very most a dedicated net junkie can rack up. My (really high end) laptop runs from a 24V/4.5A supply - that's AT MOST 108 Watts and typically more like 30 Watts - it runs for maybe 6 hours a day, 356 days of the year. So the number for me ought to be something like 44kWatt/hrs - not 1248kWatt/hrs. If they produced such a ridiculous set of numbers for the computers - I don't trust them to get the other things right either. Last month my apartment used 513kWatt/hrs (air conditioning - Texas!) - of which maybe 3.6kWatt/hrs was my laptop - much less than 1%. SteveBaker 01:37, 6 July 2007 (UTC)
- See [14] for some typical consumption figures. Donald Hosek 00:24, 6 July 2007 (UTC)
- I double-checked against last month's electric bill, and if anything, I'm underestimating. Assuming that my computer (actually, one new high-power computer, one very old low-power computer, one router, one cable modem, one KVM switch, and one CRT monitor) draws an average of 250 watts, and is on 24/7/30, then my computer makes for 45% of my monthly electric bill. My apartment is wired for electric baseboard heating, but I don't use it. My stove is typically used for 20 minutes every other day (I live alone, so I cook for two days at a time), and the microwave for less than five minutes a day. Since there's only one of me, and clothes washing is done at a laundromat, I use far less hot water than "average", and I don't have a clothes dryer. --Carnildo 22:49, 6 July 2007 (UTC)
- Sure - it's possible for the PC to be that big a share of your bill - but you must surely recognise that you are one the very extreme end of the bell-curve here! (I actually don't believe your 45% figure even so - don't you have a refrigerator? It'll easily out-consume your PC collection.) You have two computers (one old and therefore inefficient), you have lots of peripherals, you have a CRT monitor rather than an energy-efficient LCD - and you don't use electricity for much else. You obviously live in an extremely mild climate. But is it reasonable to answer a question like this on the basis of your (extreme!) situation? It is vastly more likely that our questioner is in the middle of the range of users - for which the number is around 5% for all electrical items (including TV's which are typically a big chunk of it). Taking an extreme statistical anomaly isn't the way to answer this question in a helpful manner. For almost everyone, the best policy is to cut down on heating/AC, turn off unneeded lights, switch to compact flourescent lightbulbs, use the microwave more than the stove, set washing machine and dishwasher onto the cooler settings, take showers rather than baths, shower quickly, hand clothes out to dry naturally instead of using a drier, unplug the TV/DVD/Satellite/Cable-box when it's not in use ("Turninng it off" probably doesn't really turn it off), turn off your PC when not in use (or at the very least, turn on all of the power saving settings and turn off the monitor whenever you walk away from the keyboard for a few minutes or more. Unless you are a VERY anomalous electricity consumer or already very diligent about these things - then doing any ONE of those things will save more electricity than it takes to run your computer. SteveBaker 20:36, 7 July 2007 (UTC)
- I double-checked against last month's electric bill, and if anything, I'm underestimating. Assuming that my computer (actually, one new high-power computer, one very old low-power computer, one router, one cable modem, one KVM switch, and one CRT monitor) draws an average of 250 watts, and is on 24/7/30, then my computer makes for 45% of my monthly electric bill. My apartment is wired for electric baseboard heating, but I don't use it. My stove is typically used for 20 minutes every other day (I live alone, so I cook for two days at a time), and the microwave for less than five minutes a day. Since there's only one of me, and clothes washing is done at a laundromat, I use far less hot water than "average", and I don't have a clothes dryer. --Carnildo 22:49, 6 July 2007 (UTC)
- Although not effective use of money, solar panels could be carefully connected into the power supply of the computer, somewhere where there is DC; probably close to large capacitators. This would reduce the computers usage of mains power a little bit. Easy to burn out things though. Could be dangerous. Polypipe Wrangler 00:52, 6 July 2007 (UTC)
- This is dumb - this is INSANELY DUMB advice. It's a stupid thing to do your PC. Of all of the appliances in your home - the PC is by FAR the most vulnerable to power supply glitches. If you have solar cells - connect them up to your refrigerator, use it to charge a 12v battery and use an inverter to drive a table lamp or your TV - it doesn't give a damn if the sun goes behind a cloud or a pidgeon lands on the panel and casts a shadow over the cells. Truly - it is not thinking at all logically to pick the PC as the thing to improve. Literally every other thing you own that consumes electricity can be addressed as a source of power savings that will be easier and more effective than messing around with what is probably the most expensive, delicate and precise appliance you own! WHAT ARE YOU THINKING?!?!?!? SteveBaker 01:37, 6 July 2007 (UTC)
- There's nothing to do but second this. Trying to use a solar panel in an apartment, and especially to power your computer, will probably cost you more than it saves, especially when your PC blows up --ʇuǝɯɯoɔɐqǝɟ 02:00, 6 July 2007 (UTC)
- Modern computers are actually quite robust when it comes to power. As long as your solar panels are supplying enough power to keep the computer running, or you've got a battery to take up the slack, there's nothing wrong with hooking your computer up to them. A light bulb is about the worst possible thing you can hook up to a solar panel: since you usually don't need artificial light during the day, you must have a battery to store the power, and batteries use an incredible mix of toxic chemicals. --Carnildo 22:53, 6 July 2007 (UTC)
- There's nothing to do but second this. Trying to use a solar panel in an apartment, and especially to power your computer, will probably cost you more than it saves, especially when your PC blows up --ʇuǝɯɯoɔɐqǝɟ 02:00, 6 July 2007 (UTC)
Ok, if you're doing this for environmental reasons, check out http://terrapass.com/ - it will help far more than a solar panel ever will. If you're doing it for cost reasons... it would be best to just buy cheaper appliances. The 200$ maximum your PC might possible cause you in costs if you run it constantly is not worth any solar panel powerful enough to offset it. --ʇuǝɯɯoɔɐqǝɟ 02:05, 6 July 2007 (UTC)
Klinefelter's syndrome and homosexuality
Is there any links between Klinefelter's syndrome and homosexuality? Are there any scientific proof that Klinefelter's syndrome may cause homosexuality? Has there ever been any (non-scientific) speculation about the possible connections? ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 17:33, 5 July 2007 (UTC)
- A cursory examination of the relevant literature indexed by PubMed reveals very little work that looks at homosexuality in the context of Klinefelter's. Ratcliffe S. (1999) "Long-term outcome in children of sex chromosome abnormalities" PMID 10325742 Arch. Dis. Child. 80(2):192-5 failed to identify a link, though the study was relatively small (19 XXY boys, none of whom demonstrated homosexual tendencies).
- Worth bearing in mind is that the incidence of Klinefelter's is about 1 in every 700 men, whereas the fraction of the male population that is homosexual is on the order of 1 in 10—so even if all Klinefelter's individuals were homosexual, it would make a relatively small contribution to the total number of homosexual individuals. TenOfAllTrades(talk) 19:04, 5 July 2007 (UTC)
- Oh ok, I see. Thanks for the info! ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 22:37, 5 July 2007 (UTC)
- Where does that one in ten figure come from, I hear it a lot, but in my personal experience (I know, not statistically significant) I wouldn't think it was even close. Are there really 6 million homosexuals in the UK? Cyta 07:00, 6 July 2007 (UTC)
- I don't have a source to hand, Cyta, but expect I can find one soon with some digging. I used to be on the Equalities group of a community regeneration company, and that is the figure we worked with. One thing to remember is that you almost certainly know many more gay people than you think you do - it's just that some will not be "out" at all, others will only be out with certain people or in certain circumstances. DuncanHill 09:28, 6 July 2007 (UTC)
- I think the actual number is about 3% from the last peer reviewed study I've seen with some varations in rural and urban settings. --Tbeatty 17:26, 7 July 2007 (UTC)
- I don't have a source to hand, Cyta, but expect I can find one soon with some digging. I used to be on the Equalities group of a community regeneration company, and that is the figure we worked with. One thing to remember is that you almost certainly know many more gay people than you think you do - it's just that some will not be "out" at all, others will only be out with certain people or in certain circumstances. DuncanHill 09:28, 6 July 2007 (UTC)
- Where does that one in ten figure come from, I hear it a lot, but in my personal experience (I know, not statistically significant) I wouldn't think it was even close. Are there really 6 million homosexuals in the UK? Cyta 07:00, 6 July 2007 (UTC)
- Oh ok, I see. Thanks for the info! ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 22:37, 5 July 2007 (UTC)
- I read somewhere that no-one is completely defined as homosexual ro heterosexual or whatever. They said that some people are only more straight or gay than others. I guess that there are fewer more-gay people than there are bisexuals and straight people. ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 09:18, 6 July 2007 (UTC)
- The article Kinsey scale is relevant to the theory of a continuum of human sexual orientation. DuncanHill 09:21, 6 July 2007 (UTC)
- Obviously in order to quote the '1 in 10' concept we would have to get our terms better defined. As others have mentioned the term 'homosexual' leaves the field rather open to include people that may define themselves as straight/heterosexual in society but are nonetheless somewhat homosexual. Even the word 'homosexual' can mean anything from a) a person that identifies themselves as homosexual, to b) a person that is attracted to the same sex, to c) a person that engages in sexual activity with members of the same sex but not necessarily exclusively (e.g. bisexuals, curious, etc), to d) people that exclusively or predoiminantly engage in sexual activities with only members of the same sex, etc. Indeed a rainbow. My point is, that I don't agree with the "1 in 10" statement at face value. I don't believe that 1 in 10 people are predominantly gay. I would accept the 3% rule, however. But if you change it around to include c) a person that engages in sexual activity with members of the same sex but not necessarily exclusively, then maybe it's more accurate. Rfwoolf 12:29, 8 July 2007 (UTC)
- The article Kinsey scale is relevant to the theory of a continuum of human sexual orientation. DuncanHill 09:21, 6 July 2007 (UTC)
- I read somewhere that no-one is completely defined as homosexual ro heterosexual or whatever. They said that some people are only more straight or gay than others. I guess that there are fewer more-gay people than there are bisexuals and straight people. ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 09:18, 6 July 2007 (UTC)
An unusual application of tack adhesive
Would it be even theoretically possible to use tack adhesive to hold a shelving unit full of books to a wall? NeonMerlin 18:17, 5 July 2007 (UTC)
- Theoretically - yes - practically - no! Well, there are two issues here:
- What area of shelf is in contact with the wall via the adhesive? Every square inch of tack will require a certain amount of force to pull it off the wall - the more square inches there are, the more force it'll take - so the more weight it can support. If the area is large enough - it should hold. So your best chance is to fix (using nice strong screws/nails) a large 'back board' to the back of the shelf - then cover that with tack adhesive.
- Shear forces. The weight of the shelf+books (which are insanely heavy BTW!) is acting downwards, parallel to the wall - but the tack adhesive is also resisting pulling forces at 90 degrees to the wall. The complicating factor is that if it more or less resists the shearing force, the front edge of the shelf is trying to move down - while the back of the shelf is staying stuck. That's causing a rotation - so what's going to happen is that the tack behind the bottom of the shelf will be squashed while the tack at the top of the shelf is being pulled - the tack that's being squashed is doing some work in resisting the shear forces - but the tack at the top of the shelf is being pulled off the wall at more or less 90 degrees...AND resisting the shear forces. This suggests that you want to have more area of tack above the shelf than below it in order to better resist that force.
- But no - it's bloody obvious that it's going to fall down! Duh! SteveBaker 18:37, 5 July 2007 (UTC)
- If you're in an earthquake zone (like me!) you might want a sturdier shelf than that. I recall a statistic (probably from this book) that most earthquake injuries are due to falling books and bookshelves, and falling glass from lights and windows. (Specifically, they cite "For example, in the 1994 magnitude 6.7 Northridge earthquake, 55% of quake-related injuries were caused by falling objects, such as televisions, pictures and mirrors, and heavy light fixtures." Nimur 21:24, 5 July 2007 (UTC)
- Excuse a poor Englishman... what is tack adhesive? DuncanHill 22:39, 5 July 2007 (UTC)
- Blu Tack. Also, you should consider that if the wall is painted, it's not the wall that will be holding up the shelf, but the paint. Paint has a nasty habit of peeling right off if you pull too hard. —Bkell (talk) 22:47, 5 July 2007 (UTC)
- That's not a problem so long as the adhesion between paint and wall is better than between paint and tack adhesive. So that if something is going to give, it'll be the adhesive, not the paint! It is an important property of Blu Tack that it does NOT pull paint off the walls - it's the single property that it has that makes people use it! So unless the walls are in terrible shape (such that even tacking up a poster with blu-tack would pull off the paint), it doesn't matter how much weight you try to hang off of it - the tack will give up before the paint does. SteveBaker 13:32, 6 July 2007 (UTC)
- Blu Tack. Also, you should consider that if the wall is painted, it's not the wall that will be holding up the shelf, but the paint. Paint has a nasty habit of peeling right off if you pull too hard. —Bkell (talk) 22:47, 5 July 2007 (UTC)
Burning wood = carbon neutral??
On the Terrapass.com site there is a list of FAQs about energy consumption. Link (though it's a php page, so not certain if you'll see the FAQs without further navigation). The last FAQ is this:
= What about my wood stove? = Technically, the burning of wood is carbon neutral. Of course there are many other downsides to it, and we're not recommending it as a substitute for gas or other more traditional energy sources.
Really? I had understood that combustion of wood releases all the carbon that was stored in the wood out as carbon dioxide into the air. Is that not correct? The wood and combustion articles don't help much, except that I see that CO2 is indeed often on the right side of the chemical equation.
Maybe by "technically carbon neutral" they mean that no new CO2 got created, because it was in the air before the tree consumed it? If so it seems that the wording is a little silly -- after all, the carbon in fossil fuels may well have been CO2 before it went into the fossils...
Thanks! Mike. 18:53, 5 July 2007 (UTC)
- The idea is that if you want to use wood as a fuel, you're going to have to keep growing new trees. Burning any plant that you've grown from scratch is carbon neutral, in that you pulled all the carbon in the plant out of the air in the first place. The key difference between burning wood and burning oil is that we actually can grow new trees (on a non-geological timescale). TenOfAllTrades(talk) 19:27, 5 July 2007 (UTC)
- Do all of the carbon in the wood go into the air though? Because, what is that black stuff (ash) that remains after you burn wood? Isn't that like the left-over carbon? ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 22:41, 5 July 2007 (UTC)
- If the fire is properly oxygenated, and you let it burn to completion, the stuff left has almost no carbon content. --Carnildo 22:56, 5 July 2007 (UTC)
- So long as there is no deforestation being caused by people cutting down trees for firewood - then we're carbon-neutral. The important thing is that new trees are being planted and looked after until maturity. If this really bothers you - dig a deep hole in your back yard - every time you burn a log - toss another one into the hole and bury it. That way you're not only carbon neutral - you're actually 'sequestering' carbon. SteveBaker 01:03, 6 July 2007 (UTC)
I hope it's carbon neutral. That means burning oil is carbon neutral, since it came from plant matter. Points out the silliness of "carbon neutral" though. --Tbeatty 17:22, 7 July 2007 (UTC)
- I thought oil was algae and zooplankton, not plants? It's coal that's plants. Anyway, burning fossil fuels would be carbon neutral if you burnt them at the same rate as, or slower than, the rate they are being made at. Skittle 21:25, 7 July 2007 (UTC)
Terminal shoot - English botanic name?
Hello, please does anyone know the term of "Terminaltrieb" (German) in English, it is the main shoot of a tree and determinates the direction of its growth (in contrary to the offshoots). Many thanks in advance, --birdy (:> )=| 20:44, 5 July 2007 (UTC)
- You have it perfectly in the title of your question, unless I have misunderstood you. The english term is indeed 'terminal shoot'. Lanfear's Bane
Try Apical Shoot. Hardyplants 00:02, 6 July 2007 (UTC)
- Thanks a lot! So terminal shoot and apical shoot are synonyms? --birdy (:> )=| 12:03, 6 July 2007 (UTC)
- I'm not sure about horticulture but in botany you're probably looking for either the apical meristem (most likely) or the shoot apex which is properly the shoot apical meristem plus the leaf primordia. KP Botany 04:00, 7 July 2007 (UTC)
dimmer switch efficiency
I want to buy a dimmer switch for an incandescent, not cfl, bulb. I understand that modern dimmers are more efficient than old variable resistor style. My question is: Are some brands or models of dimmer more energy efficient than others? I notice that one manufacturer markets what looks like the same switch at the same price with two different styles of packaging, one of which says it is 1/4 more efficient (but does not specify what this means).
- Modern dimmer switches work because they are powered off an AC circuit; as a result, they can take advantage of the fact that the voltage varies by only allowing a current to pass when the voltage is high enough; as a result, they waste less energy as heat than an old-fashioned resistors (no energy is needed by circuit that doesn't flow). Presumably the more efficient one is of a lower resistance (as dimmers no longer rely on internal resistance to work); check whether the back of the box gives either resistance or heat output (both would be good indicators of efficency). Laïka 23:17, 5 July 2007 (UTC)
- You could call what a dimmer does PWM, though it's sort of a poor-man's simulation; I've usually heard it called "chopping". But it does still have the property that the dimmer is always either "on" or "off", and hence (theoretically) there's no loss, and the process is perfectly efficient.
- If there are efficiency variations between models, they're bound to be slight.
- What people here are calling "old-fashioned", resistive dimmers are more than just old-fashioned, they're positively obsolete. I've never seen one, and I doubt anyone reading this (at least, if they're in the U.S.) has, either. As far as I know, all dimmers have been choppers, for decades now. --Steve Summit (talk) 00:13, 6 July 2007 (UTC)
- My college still had one in one of it's original buildings. It had this monstrous heat sink attached to it. It just looked like such an obviously bad idea. — Laura Scudder ☎ 01:11, 6 July 2007 (UTC)
- I think the correct term for the circuitry in a dimmer switch is triac, which is similar to PWM in concept, but not in implementation. The article elaborates on the details. Nimur 04:42, 6 July 2007 (UTC)
- "Triac" is the name of the principal component in those dimmers. You can (and many people do) call it "a triac circuit", but that's an imprecise term, as there are of course other circuits that also use triacs. (That is, saying that "the" name for the circuitry in a dimmer is "Triac" is like saying that the name for the circuit inside a radio is "transistor", or that the name for the circuit inside a computer is "microprocessor".) —Steve Summit (talk) 05:08, 6 July 2007 (UTC)
- I have definitely seen resistive dimmers. At a motion picture theater built in the 1920's which had been a vaudeville palace in bygone years, the dimmer system had a bank of resistive dimmers, which could be gang-operated by a motor. The resistance element could have been nichrome wire, but in earlier years it could have been iron wire. It could be set up to dim individual lights or groups of lights, much like present-day theatrical lighting systems. Edison 04:16, 7 July 2007 (UTC)
- "Triac" is the name of the principal component in those dimmers. You can (and many people do) call it "a triac circuit", but that's an imprecise term, as there are of course other circuits that also use triacs. (That is, saying that "the" name for the circuitry in a dimmer is "Triac" is like saying that the name for the circuit inside a radio is "transistor", or that the name for the circuit inside a computer is "microprocessor".) —Steve Summit (talk) 05:08, 6 July 2007 (UTC)
To answer the original question, all phase control dimmers are very efficient. The triac (the power switching element) drops less than a volt when switched "on" and dissipates no power when switched off, so even on a 120 volt circuit, less than 1% of the voltage is dropped in the switch; on a 230 volt circuit, less than 0.5% of the voltage is lost in the power switch. Because of this, I think we can safely call the efficiency of the dimmer >99%. Even a perfect dimmer would only improve that efficiency by 1% (120 vac) or 0.5% (230 vac).
The big improvement that's coming is sine wave dimming instead of phase-control dimming. By replacing the slow triacs with high-speed power MOSFETs, the dimmers will be able to preserve the sine wave shape of the power voltage. This, in turn, will eliminate the problem of lamps "singing" and fan motors "buzzing" when dimmed down.
Atlant 13:48, 8 July 2007 (UTC)
hi , my guestion is about c++
hi , i have some guestions about c++ programing language they are very important for me i didn't find the answer for these guestions ,, i will be delighted if someone help me in this field (c++) and answer my questions first which is difficult for me to know how to make it in matrix - i want to make the size of the array is variable , which is entered by the user or the size depends on variables . or there is no way to make the size of the array variable ,,,it should be the size constant(value).
i.e :
int main ()
{
int b;
cout<<"enter the size of the array ";
cin>>b;
int a[b];
}
return 0;
please help me in this matter , it means a lot to me .....
- Go to the computing reference desk --ʇuǝɯɯoɔɐqǝɟ 23:31, 5 July 2007 (UTC)
- Future computing questions are best asked at the computing desk. In this case, you should read about malloc. Wikipedia is an encyclopedia, not a tutorial service; you might be interested in the C++ wikibook. Nimur 00:37, 6 July 2007 (UTC)
- Almost. C++ typically uses (well emphasizes) new and delete instead of malloc/free, although the latter are still available. Look at dynamic memory allocation in any beginning C++ book. But yes, the Computing Desk will probably be more open to these sorts of questions. --Bennybp 00:45, 6 July 2007 (UTC)
- Just replace 'int a[b];' with 'int *a = new int[b];' - when you are finished with the array, run 'delete [] a;' SteveBaker 00:57, 6 July 2007 (UTC)
- Also the C++ Standard Template Library (STL) has lots of useful containers, for example in this case a std::vector<int> which have variable size. [15] is a good guide. Not sure if it's possible to set an upper size limit, so it may not be what you want now, but these containers are useful and have a series of preprogrammed functions (such as .size() which tells you the size of the vector) which can come in handy. Cyta 07:07, 6 July 2007 (UTC)
- Just replace 'int a[b];' with 'int *a = new int[b];' - when you are finished with the array, run 'delete [] a;' SteveBaker 00:57, 6 July 2007 (UTC)
- Almost. C++ typically uses (well emphasizes) new and delete instead of malloc/free, although the latter are still available. Look at dynamic memory allocation in any beginning C++ book. But yes, the Computing Desk will probably be more open to these sorts of questions. --Bennybp 00:45, 6 July 2007 (UTC)
- Future computing questions are best asked at the computing desk. In this case, you should read about malloc. Wikipedia is an encyclopedia, not a tutorial service; you might be interested in the C++ wikibook. Nimur 00:37, 6 July 2007 (UTC)
Voltage to Current converter (2A)
Is there a way to simply generate a 0-2 A current source proportionally to a 0-5 V or 0-10 V control voltage signal. I would like to replicate the functionality of this device. --Jcmaco 00:46, 6 July 2007 (UTC)
- That would be an amplifier. Do you intend to design the circuit, or are you hoping to buy a commercially available one? In either case, you will need more thorough specification of requirements (what load will the 2 amps be driven into? How much variation can you tolerate?) 2 amps may be a lot of juice, so be careful if you try to build it yourself. Nimur 00:51, 6 July 2007 (UTC)
- The load is variable (4-8 ohm). I intend to design and built the circuit myself since the available commercial solutions are too expensive. Could a high current Op-Amp (like the OPA548) be used if I were to control the current limit? --Jcmaco 01:02, 6 July 2007 (UTC)
- See current source to start with--Tugjob 01:29, 6 July 2007 (UTC)
Yes, you want a voltage to current converter. see Voltage-to-current converter and this for some ideas. --Duk 05:54, 6 July 2007 (UTC)
Spherical mirror
After seeing the result of what happens when two mirrors face each other, I wondered what things would look like inside a spherical mirror. Then I began to wonder about the physics of such a situation. Imagine you are inside a spherical object or room where the inner surface is a highly reflective mirror. If you turn on a flashlight for a brief moment and turn it off again, how long would you be able to see, since most of the energy is constantly being reflected? Some of the energy would be absorbed by the mirrored surface, some by your body, some would impact the eyes and be absorbed by the retina, etc. but surely most of it would be reflected many times before being absorbed. Or would the shape of the spherical mirror focus the light on the center of the sphere? Suppose you turned the flashlight on and left it on. Would the trapped light significantly raise the temperature inside the sphere? 152.16.59.190 07:23, 6 July 2007 (UTC)
- Don't forget that conservation of energy still applies, so it won't get much warmer, at least not quickly. About focusing: See curved mirror - a perfectly focusing mirror is actually paraboloid, not spherical. A small segment of your sphere, at which the light from the flashlight hits the surface nearly at an angle of 90 degrees, can be viewed as an approximation to a paraboloid, but then the distance from the surface to the focal point is half the radius of the sphere. Icek 09:01, 6 July 2007 (UTC)
- Even the very best telescope mirrors absorb 5–10% of the energy (each time the light is reflected), so it wouldn't take long for almost all the energy to be absorbed.--Shantavira|feed me 09:29, 6 July 2007 (UTC)
- Even if you ignore everything inside the mirror, the light won't last for long. Say the mirror was 99.9999% reflecting (that's about the absolute best possible mirror you can make, but in reality such a mirror would only reflect that well over a narrow band of wavelengths and reflection angles - we'll ignore that for now). So the mirror reflectivity is R=0.999999. After N bounces of the light from the mirror, the intensity of the remaining light is I = I0 * RN, where I0 is the light's starting intensity. Now say the sphere is such a size that light travels an average of 1 metre between each bounce. So the time taken to make N bounces is just N/speed of light. Now work out those numbers; after 50 milliseconds, the light has made 150 million bounces, and the intensity of the light is 1/(30 millionth) of what it started at. So only 50 milliseconds after you turn off the light, the remaining light bouncing inside the sphere is essentially undetectable. --Bob Mellish 09:36, 6 July 2007 (UTC)
- I don't think that a flashlight left on would increase the temperature significantly. In every reflection, only a part of the energy is being absorbed (and the remaining reflected). At the end of all reflections, the mirror would have absorbed all the energy. This energy absorbed would be equal to the energy absorbed by a black body (without any reflection). I don't expect a (non reflecting) black spherical mirror to become very hot due to a torch light left inside it and hence a reflecting mirror would be even less hotter -- WikiCheng | Talk 12:30, 6 July 2007 (UTC)
- "Black mirror". What? Capuchin 13:07, 6 July 2007 (UTC)
- No matter what - all of the heat energy that's created during this process came from a couple of little batteries inside the flashlight. The total amount simply cannot be more than that. Even if the outside of the sphere is exceedingly well insulated, the amount of heat gained won't be all that much. The situation is similar to the parallel mirrors case in that the light would bounce around forever if it were not for the fact that no mirror is perfect - and anything you place between the mirrors/within the sphere such as yourself and your flashlight - will inevitably absorb light themselves. However, small the imperfection is, it'll eventually end up absorbing all of the light and turning it into heat. SteveBaker 13:24, 6 July 2007 (UTC)
- I have measured a flashlight with 2 D alkaline cells to produce and consume .35 amps at 3 volts, which is 1.05 watts, or about 1 Joule/second. Now take the mass and specific heat of the air and any person inside the sphere, plus the sphere itself, and figure how fast it would heat up, even if it were insulated and no heat left it. Compare that to the heat evolved from the observer, which might be 60 to 80 watts. The flashlight would be a negligible addition. Edison 14:20, 6 July 2007 (UTC)
- ... similar to the parallel mirrors case in that the light would bounce around forever ... -- Actually, it's my understanding that light would fall to the ground in the perfectly-reflecting parallel mirrors case. [16] --TotoBaggins 14:32, 6 July 2007 (UTC)
- Hah! I guess that depends on how you define parallel. If the mirrors were aligned perpendicular to spacelike geodesics, then sure, the light would fall. But if they were aligned perpendicular to null geodesics, the light would go back and forth along the same path, because light always follows null geodesics. One could argue that that's a better definition of parallel. In practice, the only way to align the mirrors that accurately is by interferometry... and it's obvious what definition that leads to. —Keenan Pepper 18:05, 6 July 2007 (UTC)
Missing diffraction spikes
In the picture at right exhibiting diffraction spikes, the spikes seem to be proportional to the brightness of the star. However, in today's Astronomy Picture of the Day (see here), the effect seems to be either off or on, with nothing in between, and not depending strictly on brightness. Explanations I can think of are 1) the image was composed of shots from different telescopes, or 2) the spikes that are there are photoshopped in for effect. Is there some more compelling explanation? Thanks. --TotoBaggins 16:28, 6 July 2007 (UTC)
- I have mentioned before that I believe many of these astronomical photographs use digital effects for artistic purposes, and that it can blur the distinction between "scientific data" from "art." I cannot think of a good reason why those diffraction spikes should only appear selectively, as you mention. Nimur 19:09, 6 July 2007 (UTC)
In fact, the source of that image specifically states:
| “ | Separate black and white exposures through clear, red, green and blue filters are digitally combined and stretched, using Adobe Photoshop and other image processing software, to create full color pictures. --Cosmotography |
” |
.
It is difficult to know "how much" post-processing is used. Nimur 19:11, 6 July 2007 (UTC)
- I wrote to the photographer, and he replied with a very helpful and friendly response which read in part:
- "Diffraction spikes are proportional to the brilliance of the star that causes them. Only a handful of stars had sufficient brightness in this particular image.
- Interestingly, the diameter of stars in astronomical images are usually perceived as a metaphor for their relative brightness to one another. In the case of this photograph, some of the brighter stars were digitally reduced (their were diameters decreased) so that would not appear distracting. You can spot these fairly easily- they are the ones with diffraction spikes. Notice that they also have a colorful halo- those halos give a good indication of their original size in the raw data. I purposely left the halos surrounding each star (and their diffraction spikes) as a way of showing the true size of the star and as an substitute metaphor for brightness.
- This is a fairly common approach used in astronomical photography, by the way...
- Significantly, nothing was artificially added to this image- the diffraction spikes were not drawn onto the picture."
- So I guess the answer is not that spikes were added to a few of the stars, but that they were subtracted from a bunch of them. Thanks for the replies, Nimur. --TotoBaggins 20:38, 6 July 2007 (UTC)
- Well, no, spikes were neither added nor subtracted. The brightest stars were dimmed. Diffraction spikes are indeed "proportional to the brightness of the star" as you wrote initially, and in this image noticeable spikes occurred only at the very brightest stars. Because the apparent brightness of these stars was artificially dimmed, the expected proportionality between star brightness and spike brightness was thrown off. Thus you were right to sense that something was strange. --mglg(talk) 23:53, 6 July 2007 (UTC)
- And if you look at the APOD photo again, you will see that the diffraction spikes on the two bright blue stars to the right of the galaxy are longer than the others, although not by much. --Anonymous, July 6, 2007, 21:45 (UTC).
Nasty Bread
Can potentially deadly types of mold (or other gross stuff) grow on artisan bread if it's left out for a wicked long time?
- This source (and my mycologist sister-in-law) say that it is unsafe to eat moldy bread. "Deadly" is relative, of course, as people have survived arsenic and died from peanut butter. The bread being "artisanal" is unlikely to have an effect, as mold doesn't know how lovingly and authentically and with how much integrity its delicious substrate was prepared. --TotoBaggins 20:31, 6 July 2007 (UTC)
- It's generally not safe to eat anything moldy. "Deadly" is definitely relative. People have died from water. Bart133 (t) (c) 22:02, 6 July 2007 (UTC) (Link changed --Anon, July 6, 23:00 (UTC)).
Killroy filter
I'm no electrical engineer, but isn't this a band-stop filter? —Keenan Pepper 18:11, 6 July 2007 (UTC)
- Correct. To be painfully precise, it is a parallel resonant band-stop filter. -- Kainaw(what?) 18:23, 6 July 2007 (UTC)
- It depends where you take the output, doesn't it? Nimur 19:15, 6 July 2007 (UTC)
- I'm assuming that the missing part of the circuit (the left/right ends that go off the edges) loop back and connect to some sort of source. See http://www.eng.cam.ac.uk/DesignOffice/mdp/electric_web/AC/02127.png for an example. -- Kainaw(what?) 19:18, 6 July 2007 (UTC)
- As shown here
-
High Pass Filter -
Low Pass Filter
- Identical components, in the same topology, function as either a pass- or a stop- filter depending on where the input and output are placed. Nimur 19:21, 6 July 2007 (UTC)
- The circuits you have shown are not "parallel resonant" circuits like the one asked about (with the inductor and capacitor in parallel). To turn this into a "pass" filter, the load resister is also put in parallel (see http://www.eng.cam.ac.uk/DesignOffice/mdp/electric_web/AC/02125.png for an example of a parallel resonant band-pass filter). I must make a disclaimer that I only work with common circuits. I'm sure someone knows how to get these circuits to do things they are not intended to do. However, if you are taking an AC electronics test and they show you an RLC circuit with the cap/inductor in parallel and ask if it is a stop or pass filter. If the load resister is in series, it is stop. If the load resister is in parallel, it is pass. -- Kainaw(what?) 23:26, 6 July 2007 (UTC)
- I thought someone was having a little fun. Look in the trivia section of Kilroy was here, which was the first thing I thought of when I saw this. Lanfear's Bane
- The circuits you have shown are not "parallel resonant" circuits like the one asked about (with the inductor and capacitor in parallel). To turn this into a "pass" filter, the load resister is also put in parallel (see http://www.eng.cam.ac.uk/DesignOffice/mdp/electric_web/AC/02125.png for an example of a parallel resonant band-pass filter). I must make a disclaimer that I only work with common circuits. I'm sure someone knows how to get these circuits to do things they are not intended to do. However, if you are taking an AC electronics test and they show you an RLC circuit with the cap/inductor in parallel and ask if it is a stop or pass filter. If the load resister is in series, it is stop. If the load resister is in parallel, it is pass. -- Kainaw(what?) 23:26, 6 July 2007 (UTC)
- It's Chad! DuncanHill 10:27, 7 July 2007 (UTC)
- Oddly - it's Chad in the UK, Kilroy in the USA. Having said that - when I lived in UK - I saw plenty of Chad's adorned with the words "Kilroy woz 'ere" - so it is perhaps not that clear-cut! SteveBaker 14:01, 7 July 2007 (UTC)
- It's Chad! DuncanHill 10:27, 7 July 2007 (UTC)
Enthaply Change
how do i calculate the mean molar bond entalpy of Br-F bonds in Bromine Pentaflouride.
I have th following figures: molar bond enthalpy F-F-159, Br-Br 193
the overall enthalpy change is -429
many thanks
- ΔH = ΣBonds broken - ΣBonds formed. So, you have the equation 1/2Br2 + 5/2F2 --> BrF5.
- Figure out how many bonds of each there are, and use algebra to find out what you want. 74.102.89.241 22:05, 6 July 2007 (UTC)
Shaking arm
Why is that when you flex your arm, or any other body part, it begins to shake, even if it is at rest on a table? Imaninjapiratetalk to me 21:28, 6 July 2007 (UTC)
- See Muscle contraction. A brief perusal of the article leads me to believe it may have something to do with frequency summation (apparently only approx 30% of the fibers are firing at any given time), but muscular contractions are complex processes so I am sure there is more to it than that. Is there a doctor in the house? 161.222.160.8 22:35, 6 July 2007 (UTC)
- It is not clear what you mean by "flex your arm". You may mean that you are activating both flexors and extensors at the same time and trying consciously to hold the limb in a particular position. This creates a feedback problem for the muscles and nerves, a problem that is not solved efficiently without practice. --JWSchmidt 04:15, 7 July 2007 (UTC)
Black olives...
Why do black olives taste nice to me on a pizza when combined with other flavours (tonight's topping was cheese, tomato, doner meat and olives), yet taste absolutely foul when eaten by themselves? --Kurt Shaped Box 00:15, 7 July 2007 (UTC)
- Maybe because it was masked by the other flavors? Black olives taste like vulcanized rubber to be, regardless of whether it's by itself, on pizza, or with other toppings. bibliomaniac15 BUY NOW! 01:39, 7 July 2007 (UTC)
"Black" olive is a loose term for a huge number of styles, marinades, and flavors of olive. Some indeed taste like rubber. Quality black olives are a delicious treat by themselves or with other food. I recommend Kalamata olives, instead of the canned junk you probably tasted. You can get them at a Greek, Middle Eastern, or other grocery store. Nimur 05:27, 7 July 2007 (UTC)
- Yeah, but the stuff you get on a pizza is almost always the California black olive, which is an unfermented Mission olive, with pretty much no character (and, I think, still some remnant flavor of the lye, but I may be imagining that.) --jpgordon∇∆∇∆ 15:22, 7 July 2007 (UTC)
- And thank you for the link to doner meat. I didn't think it had anything to do with the Donner Party but I liked having the link to verify that. :-) Dismas|(talk) 15:35, 7 July 2007 (UTC)
- The thing about donner meat is that you can never be entirely sure by look and taste what manner of flesh you are consuming - it's just, well, slabs of 'generic meat'. Still, it tastes good when you're drunk and it doesn't poison you - so you don't say anything. --Kurt Shaped Box 21:57, 7 July 2007 (UTC)
- And thank you for the link to doner meat. I didn't think it had anything to do with the Donner Party but I liked having the link to verify that. :-) Dismas|(talk) 15:35, 7 July 2007 (UTC)
- Thanks for the tip, Nimur. I don't know what type of olives I had on the pizza but the ones I tried to eat by themself were from a jar of 'black olives in brine' from the supermarket (no other information specified). Yes, they did taste like how vulcanized rubber smells. --Kurt Shaped Box 22:02, 7 July 2007 (UTC)
- Personally, I'd blame the brine, which probably contributed as much to the flavour as the olives themselves. Confusing Manifestation 09:35, 8 July 2007 (UTC)
RNA/DNA pills
Browsing a local bulk food and health food store, I came to find the vitamin aisle. I was looking to buy a daily vitamin, but a bottle caught my eye. I didn't buy it, nor did I want to/do I think I have a need for it. Out of curiosity, what benefit would it be for someone to take a supplement pill containing DNA and RNA of some random animal or plant? Vitamins and minerals and what not are in foods and other vitamin pills, so what good is the DNA of some other organism? 74.102.89.241 01:08, 7 July 2007 (UTC)
- It's not going to be bad for you (we eat DNA & RNA in, well, basically everything.), but a pill of nucleic acids is wasted money. Completely. — Scientizzle 02:26, 7 July 2007 (UTC)
- Yep - that's a scam for sure. Every cell of every living thing contains DNA and RNA - every plant or animal you eat (which is indeed pretty much everything) is stuffed full of the stuff. So this stuff is just a scam. They can get away with this because 'food supplements' are not vetted by government agencies like drugs - and notably there is no requirement for them to actually do what they claim to do. SteveBaker 03:01, 7 July 2007 (UTC)
- Now you might think, we need more DNA and RNA "building blocks" all the time, for all the new nuclei in all the cells of ours that are dividing, and all the RNA that's being used in expressing metabolic reactions. And you might think, what better place to get those necessary building blocks than from a jar specifically full of the stuff?
- However, if you're building new DNA, the essential building blocks are not adenine, guanine, cytosine, and thymine, but rather, carbon, hydrogen, oxygen, and nitrogen -- and we can, of course, get those raw materials from anywhere. [Well, okay, it's not quite that simple, because of course we can't fix our own nitrogen, but the point remains, we construct new DNA from generic organic building materials, not DNA-specific building materials.] —Steve Summit (talk) 03:53, 7 July 2007 (UTC) [augmented 03:58, 7 July 2007 (UTC)]
- We don't digest nucleic acids down into the constituent atoms and build them back up when we need them, it is possible for the body to absorb those water-soluble molecules. Also, keep in mind, the molecules used in DNA are also used in other organic reactions in the body. For example, Adenosine is used in nearly every energy transfer cycle your body uses to convert fuel into energy. -- JSBillings 12:26, 7 July 2007 (UTC)
- That adenine used to be considered "vitamin B4" is new and interesting to me... — Scientizzle 05:08, 7 July 2007 (UTC)
preventing pregnancy
Last night i made a sex with my girl friend using a condom. However, the condom ruptured while we made sex. We don't have a plan to have a child at this time. What we have to do now inorder to prevent the pregnancy?
- Go see a doctor, he'll probably prescribe a morning after pill. - Dammit 07:29, 7 July 2007 (UTC)
- And after that, review condom handling instructions. Generally speaking condoms should not break very often if used correctly. --24.147.86.187 11:39, 7 July 2007 (UTC)
- That's wise advice - but to emphasise, they DO break occasionally even when used correctly. Our article on the condom says that even if you use them correctly, you still have a 2% per year chance of getting pregnant - and if you don't use them right, the chance is 10 to 18% which is definitely getting a little high! For the "Morning After" pill to work, you need to get to a doctor fast - you don't literally have to get there the next morning - but 72 hours is the utter, utter limit beyond which the doctor should not prescribe them. SteveBaker 13:55, 7 July 2007 (UTC)
- But those are statistics over the whole population, and don't tell you about individual odds at all. If you use them right and they are not, say, out of date, then you should have almost no chance for pregnancy at all. A few people who use them wrong and etc. throws the whole sample off. --24.147.86.187 15:25, 7 July 2007 (UTC)
- Those stats are probably based on a very large study group. So how would "a few people" throw the data off that much? Dismas|(talk) 15:32, 7 July 2007 (UTC)
- Note that the 2% (for "perfect" use) pregnancy rate doesn't have anything to do with failure or misuse of the condom - I recommend you read the article - paying special attention to the Condom#Causes of failure section. This has nothing to do with a few misusers spoiling the sample - it's just a fact of the way these things work. Anyone using condoms for regular sex needs to be well aware that they don't work 100% of the time. SteveBaker 20:15, 7 July 2007 (UTC)
- Those stats are probably based on a very large study group. So how would "a few people" throw the data off that much? Dismas|(talk) 15:32, 7 July 2007 (UTC)
- But those are statistics over the whole population, and don't tell you about individual odds at all. If you use them right and they are not, say, out of date, then you should have almost no chance for pregnancy at all. A few people who use them wrong and etc. throws the whole sample off. --24.147.86.187 15:25, 7 July 2007 (UTC)
Vegetarian vs Non-Vegetarian
I have always had this doubt.....People who prefer Non-Vegetarian, are more physically fit, healthy and stronger than people who go for Vegetarian. Is it True ?
- With a balanced diet, I don't see how there would be any difference between a vegetarian and non-vegetarian diet. As a matter of fact because vegetarians are more conscious of what they eat and more concerned about their health I think the "average" vegetarian would be more physically fit than the "average" omnivorous people. --antilivedT | C | G 10:25, 7 July 2007 (UTC)
- Several studies have suggested that vegetarians are healthier. See vegetarian nutrition for more details.--Shantavira|feed me 14:25, 7 July 2007 (UTC)
- Heavyweight boxer Peter Hussing is said to have been vegetarian, as well as football legend Stanley Matthews. Unfortunately we don't seem to have a list of famous vegetarians, though we do have a list of vegans which includes several athletes.--Shantavira|feed me 14:34, 7 July 2007 (UTC)
- And there are so many versions of vegetarianism, it can be hard to make a direct side-by-side comparison. Nimur 15:50, 7 July 2007 (UTC)
- All of the vegetarians I know are so skinny they look like ethiopians. I think vegetarians tend to be less healthy because it is harder to organize a healthy vegetarian diet compared to eating meat and people don't do it right, but if done right it can be more healthy.
- Wrong. Vegetarians actually care about their diets, compared to the average meat eater who will shove down whatever they see --ʇuǝɯɯoɔɐqǝɟ
- It's more like the average eater period, not the average meat eater. By restricting one's diet one by nature has some care of what one eats. Someguy1221 06:51, 8 July 2007 (UTC)
- Wrong. Vegetarians actually care about their diets, compared to the average meat eater who will shove down whatever they see --ʇuǝɯɯoɔɐqǝɟ
- All of the vegetarians I know are so skinny they look like ethiopians. I think vegetarians tend to be less healthy because it is harder to organize a healthy vegetarian diet compared to eating meat and people don't do it right, but if done right it can be more healthy.
- Like all diets, a vegetarian diet can be harmful if one does not receive adequate nutrition from it. Many prominent examples show that one can be healthy and eat a strictly vegetarian diet. However, the more one restricts what one will eat, the more likely that nutritional deficits will develop if one is not mindful to such things. This is true for both vegetarians and omnivores (imagine eating nothing but red meat!). There are common potential problem with vegetarian nutrition, such as deficiencies in vitamin B12 or copper, that can be managed either with supplements or explicitly eating plants rich in those nutrients. Our article on veganism, for example, has a large section of precautions for managing such risks. In extreme cases, people have been convicted of child abuse for forcing highly restricted diets on children without concern for the resulting nutritional deficits. So, like many things, a vegetarian diet can be healthy or not depending on how it managed and the details of what one is eating. Dragons flight 20:11, 7 July 2007 (UTC)
- Exactly. Vegetarianism is just as healthy as eating meat- which is, if you're reckless, you will hurt yourself. --ʇuǝɯɯoɔɐqǝɟ 20:19, 7 July 2007 (UTC)
Contrasting Colour Pallette
I have posted this on the Computer reference desk, but I'd like to see what the science-people think...
I am looking for a palette of colours (preferably with their hex codes (eg. 0xFFFFFF)) and they must be CONTRASTING COLOURS so that users can easily distinguish between them.
The highest number of colours I could get was 16 here: List_of_palettes#Microsoft_Windows_default_16-color_palette
I will be using thse colours in a chart, and I need the viewer to be easily able to distinguish the colours.
Rfwoolf 16:03, 7 July 2007 (UTC)
- Web colors might be useful. --jpgordon∇∆∇∆ 17:16, 7 July 2007 (UTC)
- You can do this mathematically. If you pick any really bright/vivid colour, and you have the hex representation, you can find the most contrasting colour very easily: Take the six digits in the hex code - break them up into three groups of two digits - then subtract each of the three resulting hex numbers from 0xFF (if you don't have a calculator that can do hex - you might want to convert to decimal notation first!). The result will be the complementary colour. Hence, if you take a bright green (0x00FF00) then the complement is 0xFF00FF - which is magenta. Of course for very subtle colours, such as a very subtle green (0x7F8F7F perhaps), you'll get a very subtle pink (0x807080) as the complement which won't be easy for users to distinguish. For very dark green (0x002000 maybe), you'll get a very bright colour as the complement (0xFFDFFF). SteveBaker 20:09, 7 July 2007 (UTC)
Effects of electricity and magnetism on humans
Are there any known effects that electricity and magnetism may have on human beings' bodies? I've read that magnetism doesn't have any effects on a person, but maybe electricity does? Does it cause cancer or does it have any other effects? Has there ever been any scientific proof of this? ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 16:58, 7 July 2007 (UTC)
- Well, I'm assuming you mean an electric field? Because there are a lot of ways you could interpret "effect of electricity" if you aren't specific! (Toaster in a bathtub?) --24.147.86.187 17:07, 7 July 2007 (UTC)
- The effects can be shocking. --Tbeatty 17:17, 7 July 2007 (UTC)
- Electric currents, whether direct current, alternating current or radio frequency current passing through human beings can cause burns, can cause traumatic effects on the functioning of the brain (as in electroshock therapy) and can cause death by stopping the heart. It only takes a few milliamperes to cause pain,and a little more can cause the muscles of the hand to contract on a wire and be unable to let go. Magnetic effects on the body are harder to prove. In MRI scans the human body is exposed to extraordinarily high magnetic fields without apparent effects, although there have been some studies which showed effects of magnitic stimulation of the brain on mental states such as depression. For decades there have been assertions that much weaker magnetic and/or electric fields from power lines and from wiring and appliances in the home cause cancer. These effects cannot be immediately and directly demonstrated in the laboratory (in the same way that electric shock can be immediately demonstrated to have an effect). They require large databases looking statistically at whether the rare occurrence of cancer is statistically related to exposure to electromagnetic fields (EMF). The results have sometimes come down as a slight tendency for EMF to cause cancer, and other equally careful studies have found no effect. Several public utility commissions have adopted a philosophy of "prudent avoidance ," which calls for avoiding unnecessary exposure to large EMF, by such means as routing a power distribution line so it does not go next to a school building, when another route is available. This policy in the absence of sound scientific proof of a link between cancer and EMF has been criticized as a waste of resources which could be spent in other ways to reduce illness.[17] If 100 studies are done to see if there is a statistical relationship between X and Y, 5 of the studies should find a significant effect at the usual .05 level, just because of random variation. The evidence is still only suggestive of a link [18] [19] [20] , but evidence suggests a biological effect of powerline frequence EMF or radio frequency EMF is quite possible [21] [22] , that prudent avoidance is justified, and that more research is needed. There should not be any supposition that EMF is the only cancer causing agent, and it should not receive an unjustified portion of public health funding, since exposure to sunlight and pollutants in air, food and water probably cause far more, and failure to use seat belts causes far more deaths per year. In recent years there has also been concern about Mobile phone radiation and health. Clearly there is nothing like the strength of association between Xrays and cancer, or smoking and cancer, or sunlight exposure and cancer. Edison 17:21, 7 July 2007 (UTC)
- I agree with Edison - there are a bazillion problems with electric fields and essentially zero with magnetic fields. Just one little addition to that - there was a piece on Mythbusters (gotta love that show for all it's flaws!) that mentioned that old-fashioned tattoos were done with iron-based pigments and that the intense magnetic fields gemerated by an MRI machine could cause a tremendous amount of heating in the ink causing severe burns and such. Modern tattoos generally don't have that problem. SteveBaker 19:59, 7 July 2007 (UTC)
- See Transcranial magnetic stimulation for the effect of magnetism on the brain. --Heron 20:34, 7 July 2007 (UTC)
- Hey, thanks a lot for all your help. If you have anything to add, please do so! I appreciate all of your help. ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 21:32, 7 July 2007 (UTC)
- There's also this Microwave Auditory Effect, which I believe may be dubious. However, academic peer reviewed papers have investigated it, and an earlier Science Reference Desk query suggested that high intensity electromagnetic waves might have unusual effects. You can also see Active Denial System for a less-lethal electromagnetic weapon. Nimur 03:37, 8 July 2007 (UTC)
- I find it interesting that there are a "bazillion problems with electric fields and essentially zero with magnetic fields" when either can induce the other... Aaadddaaammm 04:38, 8 July 2007 (UTC)
- Or more accurately a change in each can induce the other. You could also always consider getting hit by a laser beam an effect of electricity and magnetism. Someguy1221 06:10, 8 July 2007 (UTC)
- I find it interesting that there are a "bazillion problems with electric fields and essentially zero with magnetic fields" when either can induce the other... Aaadddaaammm 04:38, 8 July 2007 (UTC)
history of emission control standards in automobiles
can i get the details of the various emission control standards set up worldwide chronologically and the organisations which ensure their implementationDeepu rdy 19:28, 7 July 2007 (UTC)
Voltage drop
I was debugging the network of electric cables in an old caravan and started to wonder if the voltage drops I seemed to have in the cables were reasonable. For example, there is one set of six lights in parallel, using about of power each. I connected this set to the battery that powers it all, and found that the battery voltage settled on . Then I measured the voltage over one of the lights and got only . :-( Isn't this difference quite large? —Bromskloss 20:07, 7 July 2007 (UTC)
- Yes. Your cables are too thin. You are losing nearly 9 watts in them! --Heron 20:26, 7 July 2007 (UTC)
- You're right. :-( Is it likely that connections between cables degrade over time (or never were any good) with a large resistance as a consequence? —Bromskloss 20:41, 7 July 2007 (UTC)
- That's seems an awfully large drop. If that's true - then you should be able to feel the wires getting warm. But yeah - car lamps do pull quite a bit of current - so heavy wires are required. SteveBaker 20:50, 7 July 2007 (UTC)
- You're right. :-( Is it likely that connections between cables degrade over time (or never were any good) with a large resistance as a consequence? —Bromskloss 20:41, 7 July 2007 (UTC)
- It is very likely that the connections do degrade over time and Ill bet that that is where most of your power is being disippated. My advice: clean up/ replace all connectors for full lamp briteness!--Tugjob 22:47, 7 July 2007 (UTC)
- If you do the math, the resistance of your cable+connection is 2 ohms. The lights in parallel are about 4 ohms (28 ohms each). --Tbeatty 15:29, 8 July 2007 (UTC)
- The voltage drop sounds way too high, if the battery was in fact still putting out 12 volts. In an old rustbucket car the ground connection from a light can also corrode and cause a voltage drop. It is common to carry wires from the battery positive through switches to a terminal of a bulb, and to achieve the other battery connection through the car body. If there is a lot of rust around the light, the resistance may be in the negative return path. On really old cars, the polarity was sometimes reversed. A supplemental ground connection can sometimes help. In troubleshooting, you can also start at the bulb terminal where you see 8.5 volts to the battery negative, and check the voltage at points further back (closer to the battery positive) to see where the voltage drop is. Of course you should not tinker with electricity unless you are fully conversant with safety procedures. Edison 19:06, 8 July 2007 (UTC)
RPM and car control
Why does downshifting, and running your engine at a higher RPM give you more steering control of the car?
- Does it? I don't see why it would. Is it something you have actually experienced yourself? —Bromskloss 11:06, 8 July 2007 (UTC)
- It gives you greater control over the speed of your car - engine braking means you can slow down just by lifting your foot off the accelerator. A slower speed then gives you more steering control. Gandalf61 12:45, 8 July 2007 (UTC)
- Your power steering pump is incorrectly producing more hydraulic pressure at higher RPM? Generally, systems are designed to either produce a steady pressure or, often, less pressure at high speed when there's less need to overcome the enormous static friction of tires when you're stopped.
- Also, by slowing down, your car will 'dive', putting more weight on the front wheels, so they are less likely to slip.
- It sure does feel like it, doesn't it? I suspect, however, that it is just an illusion from aforementioned control over speed and improved control at lower speeds. Properly done, the downshift also puts you well into the "preferred" (there is almost certainly a proper term for this, but I do not know it) range for the engine, where it can supply plenty of power and either accelerate or decelerate while maintaining responsiveness. There is a related argument for not dropping into neutral to coast down hills, but that is more about maintaining control of you speed. With the engine engaged, even in a high gear, your acceleration will be slower, providing more control. Furthermore, there is also the quality of life issue - accelerating around turns is just plain fun. -Eldereft 21:40, 8 July 2007 (UTC)
- Race drivers and drifting and autocross enthusiasts most certainly do rely on the 'weight transfer' (terrible choice of words!) effect of braking to get more down-force (and therefore more grip) at the front wheels - and they sometimes to deliberately weaken the grip at the back. That certainly has an effect on steering because it allows you to turn sharper without the front wheels skidding and/or to allow the rear wheels to 'drift' outwards and thereby induce over-steer. This is also beneficial for front wheel drive cars in that you have a brief window of opportunity for stamping on the gas and getting more accelleration without wheel-spin (a major reason why I love front wheel drive cars - and loath rear wheel drive cars!). But that's only going to be noticable at extremes of driving when you'd probably skid off the road entirely if you hadn't done that. Stamping on the brakes also causes weight transfer - and heel/toe driving where the gas and brake are operated together can take advantage of this. For ordinary street driving, I'd be surprised if this effect was anything other than an illusion. SteveBaker 03:24, 9 July 2007 (UTC)
Wet Hair
What could happen to you if you sleep with wet hair? Thanks in advance.
- Your pillow gets damp. DuncanHill 12:40, 8 July 2007 (UTC)
- ...and you wake up with *really* messy hair. --Kurt Shaped Box 12:49, 8 July 2007 (UTC)
Off-topic joke posts.
- And the hair fairy gets herpes. 12:51, 8 July 2007 (UTC)
- I have hidden this anonymous comment. See the Reference Desk guidelines. Nimur 18:10, 8 July 2007 (UTC)
- And the hair fairy gets herpes. 12:51, 8 July 2007 (UTC)
- In hot humid weather, the hair and/or pillow might mildew. Edison 19:00, 8 July 2007 (UTC)
- My mother used to tell me that going to bed with wet hair would give me a chill (or something).
- My cat won't sleep on my bed when I have wet hair. Weird thing. JoshHolloway 22:32, 8 July 2007 (UTC)
science / jupiters moons
how do jupiters moons stay in orbit around jupiter?
Re:Lucid dreaming
Does lucid dreaming make you exhausted? And how do you actually invoke that dream? -Zacharycrimsonwolf 14:18, 8 July 2007 (UTC)
- Lucid dreaming has a lot of interesting information, including how to initiate one, though I didn't see anything on whether the quality of sleep is lower. Someguy1221 16:17, 8 July 2007 (UTC)
Zachary, check out Wikibooks, one of our sister projects, they have a rather good guide to it. Also see ld4all.com, a good Lucid Dreaming community site. As far as making you exhausted- no, not at all. Well, it could be mentally draining, but it doesn't affect your sleep at all. Like, if you have a lucid nightmare, you could very well be out of it the next day like you hadn't slept well, but in general no. Lucid Dreaming takes place during REM sleep, which is what really counts anyway, so you will be just as rested in the morning as you did when you fell asleep. Unless of course your dream is a nightmare which causes you to wake yourself up, but most lucid dreams aren't nightmares unless you want them to be. --Laugh! 19:22, 8 July 2007 (UTC)
One small step for man, one giant leap for mankind
I know who said it! But who wrote it? Armstong or NASA PR?
Thanks for any help.
- The article on Neil Armstrong and a cited reference say that he came up with it an hour or two before saying it. Weregerbil 14:39, 8 July 2007 (UTC)
- I believe it was recently corrected to be "One small step for a man, one giant leap for mankind." The a is inaudible in the original. --Tbeatty 15:15, 8 July 2007 (UTC)
Thank you all for your help. But...do you really think NASA and the government would have let him go up without first deciding on what to say on an occasion they knew would be historic?
- In a sense, that particular "instant" became historic because that was the moment of most memorable dramatic effect after the fact. That's sort of hindsight analysis, though. Many historic first "instants" occurred during the entire mission - the first time a spacecraft touched down on the moon was marked with the (less memorable?) quip, "The Eagle has landed." NASA would have a hard time pre-planning every single historic occurrence and it's sort of arbitrary that the first "step" is any more historically important than the first "breath" or first "landing," or first golf game. Nimur 18:04, 8 July 2007 (UTC)
- In recent bios of Armstrong, he says that he made this up not long before the landing. See First Man by James Hansen (2005) and One Giant Leap by Leon Wagener (2004). I don't have the books right here, but I read them not too long ago. As I recall Armstrong says that he planned to say "one small step for a man" (which makes more sense), but accidentally omitted the "a" when he actually stepped on the surface of the moon. So the first version "one small step for man" is correct.--Eriastrum 18:17, 8 July 2007 (UTC)
- He has at various times said that he either was or was not aware of having omitted the 'a' - to be honest, I doubt that he knows - after all, he knows for sure that he INTENDED there to be an 'a' in there - it makes no sense without it. There is information out on the Internet someplace (I really can't be bothered to track it down) that says that very careful analysis of the available recordings show that he did say "a" - but something related to the fans and such in the suit masked it out. Something like that. The bottom line is that the odds are extremely good that he DID say "One small step for a man, one giant leap for mankind." - and that's without doubt what he intended to say. SteveBaker 20:41, 8 July 2007 (UTC)
Has anyone ever heard of this fish disease?
I've been trying to assess and clean up the vet med articles here on wikipedia, and I ran across Rotting nose disease. I can not find anything on a google search about this disease that is not wikipedia-derived, or about its potential cause, a type of protozoa called Ocimita. I've also tried a few variations in the spelling of Ocimita, but with no luck. The symptoms and treatment of rotting nose disease seem remarkably similar to hole in the head disease, making me think that it is someone's made up name for the same disease. Before I proceed with any type of deletion effort, I wanted to see if anyone had heard of this disease or the elusive Ocimita species that may or may not cause it. --Joelmills 16:36, 8 July 2007 (UTC)
- Sounds like either a hoax or a good faith duplicate of HITH. Either way, it should be prodded. Rockpocket 01:08, 9 July 2007 (UTC)
Question concerning Fourier
In Heat conduction there's a chapter called Conductance. In this section, there's an alternative statement of Fourier's law. In fact, I couldn't find this statement anywhere else in the internet. I wonder, whether it is true, I would need it for a paper. Could anybody please check this law? Lskywalker 18:20, 8 July 2007 (UTC)
- If it is true, it's very badly written. None of the symbols he's chosen (apart from 'U') are defined. My text books on this subject are 180 miles away - I won't be able to check on it until late tonight or tomorrow. SteveBaker 18:34, 8 July 2007 (UTC)
- Well, all the symbols are defined above (A, Δx, ΔT are defined, k is standard). I use other's, too, but I think that would be ok. But it would be great if you could look it up. Lskywalker 18:39, 8 July 2007 (UTC)
- The problem is that in the lead section, the symbol Q is used to denote thermal energy transfered (in Joules), but in the following sections the same symbol Q is used to mean energy transfer rate (in Watts). That is an error and should be corrected. Apart from that, the alternative statement of the law is the same as the integrated form of the law stated earlier, but with the definition of U substituted in. --169.230.94.28 18:59, 8 July 2007 (UTC)
Error in myeloid article?
The myeloid article says: In describing hematopoiesis, the terms "myeloid" and "lymphoid" are often used to discriminate between cells originating from the marrow and from lymph tissue, respectively. - but this doesn't make sense because lymphoid cells originiate from the bone marrow (where B cells mature while T cells mature in the lymph nodes). Should someone correct the article? --Seans Potato Business 19:33, 8 July 2007 (UTC)
Black hole production
Is it possible to produce a BH on earth using current technology? If we did produce one, how would we control it?
- (a) No. No chance, not even close. (b) In principle, we could feed it some electrons to charge it up, and suspend it in a vacuum chamber using electric fields. We would have to do that at the same time as we created it. Making one would be a really bad idea, however, because the first time some klutz dropped it, the black hole would fall into the Earth and start slowly engulfing it. To avoid turning our whole planet, and ourselves, into a black hole, we would be forced to keep this electric-field trap setup in continuous glitch-free operation forever, or try to get rid of the darned thing by launching it into space. --169.230.94.28 20:32, 8 July 2007 (UTC)
- Correction to (a): In some non-standard theories, it is conceivable that tiny black holes could be produced in particle accelerators. These, however, would evaporate through Hawking radiation faster than they could accrete new mass, and would therefore disappear in a fraction of a second. The European particle physics lab CERN has done a safety study on this, which concluded "We find no basis for any conceivable threat." --169.230.94.28 21:03, 8 July 2007 (UTC)
- There was some discussion about whether RHIC could produce a black hole which might then eat the Earth, but it was decided that it was unlikely and the collider was allowed to operate.
- The answer to the first question is 'very probably not'. There are some variants of string theory (and some more exotic physics models) that suggest that creating micro black holes might be just within the reach of our largest existing or planned particle accelerators. Note that such black holes, if created, would have a very short lifetime—talking about storing or controlling one wouldn't be meaningful. TenOfAllTrades(talk) 20:58, 8 July 2007 (UTC)
Night sky
I´m looking in the southern direction and in front of me there is a particularly bright planet (? - I think) not far above the horizon (about 45º up). What is it? Thanks. --AlexSuricata 20:35, 8 July 2007 (UTC)
- Where are you, and what time is it? (Or rather, when did you observe this planet?)
- If you're looking at a point on or near the ecliptic and it's not too long after sunset, then Venus should be about 40 degrees above the horizon and very bright: [23]. Jupiter is also high and bright right now, thought not as bright as Venus. TenOfAllTrades(talk) 21:12, 8 July 2007 (UTC)
I´m in Andalucía and it´s 23:45, if you look south but at little towards south-west, and then up about 40º up above the horizon - it´s very bright, is it Venus then? --AlexSuricata 21:57, 8 July 2007 (UTC)
- I think that you are probably seeing Jupiter. Venus is usually closer to the horizon unless it is close to sunset. There are a number of websites that will automatically generate a skymap given your ___location and time; here's one: [24]. TenOfAllTrades(talk) 22:16, 8 July 2007 (UTC)
Yep, it must be Jupiter. Great link btw - thanks! --AlexSuricata 22:26, 8 July 2007 (UTC)
Cleaning pen from whiteboard
What would remove felt-tip pen from a whiteboard? DuncanHill 21:39, 8 July 2007 (UTC)
- Methylated spirits or alcohol on a paper towel, or use a normal whiteboard marker to scribble over the top and then rub that off. GB 21:46, 8 July 2007 (UTC)
- Isopropanol (isopropyl alcohol) will also work; it's sold as 'rubbing alcohol' in the drugstore. TenOfAllTrades(talk) 21:52, 8 July 2007 (UTC)
- Acetone has worked for me for permanent markers; it is a pretty common gentle solvent. If you are at a school, the chemistry department almost certainly has some. Failing that, many nail polish removers are acetone-based. If you are not at a school, ethanol is another readily available solvent. Actually your friendly neighborhood chemists probably have some of this too, though perhaps not in the form I just linked. -Eldereft 21:54, 8 July 2007 (UTC)
- I tried meths already - no joy. I'll get some acetone tomorrow and try that. DuncanHill 21:55, 8 July 2007 (UTC)
- Try using a normal whiteboard market to scribble over the top and then rub it off, as GB suggested :). Has worked every time in the past for me JoshHolloway 22:29, 8 July 2007 (UTC)
- Thanks - never thought of that before! DuncanHill 22:31, 8 July 2007 (UTC)
- Here's a comparative test of a bunch of different cleaning options and techniques. A word of caution about acetone, though—I'd test it on a small area in the corner of the board before you go crazy with it, because it might damage the surface. Acetone also dissolves many plastics and synthetics, so be careful how you handle it. TenOfAllTrades(talk) 23:05, 8 July 2007 (UTC)
- I don't think I would call acetone a "mild" or "gentle" solvent - I've seen it dissolve some pretty dense plastics! It's selective about what it will react with and dissolve, but it will probably take the ink off the board. Test on a corner to make sure it doesn't take the board down with it (more realistically, the worst it would probably do is just destroy the glossy finish, but who knows what variant of "standard" whiteboard material you have on hand...). Nimur 00:57, 9 July 2007 (UTC)
- If all else fails, fire will cleanse your board. Forever. --Tbeatty 01:49, 9 July 2007 (UTC)
I had a whiteboard that someone wrote on once with a permanent marker, and a commercial whiteboard-cleaning product didn't remove the mark at all... but ordinary dishwashing liquid, that we used in the kitchen sink, did. Of course everything depends on the particular ink formulation. --Anonymous, July 9, 2007, 03:01 (UTC).
- Are you talking about dry-erase markers scribbles that have been left too long on the board and baked themselves in to the point where you can't get them off? Or are you talking about the situation where someone brought a permenant marker - and wrote on the board mistaking it for a dry-erase marker? In the former case, I would definitely go and buy a bottle of whiteboard cleaner - most office supply companies have them and they work very well - they aren't generally too much of a health hazard - and it's worth keeping some in your desk drawer because this does happen quite a lot. In the latter case - you'd need to resort to some stronger chemicals - and all kinds of organic solvents are worth trying. Acetone and Isopropyl alcohol would be good things to try. However, many of those are dangerous - so beware! Vodka works moderately well in an emergency with at least one brand of permenant marker. (you don't want to know how I found this out!). SteveBaker 03:06, 9 July 2007 (UTC)
Supposing that we were to accidentally create a black hole on earth...
What would an observer on the ground actually see during the minutes before the whole planet was torn apart and consumed? I remember seeing a dramatization of the event on some 'end of the world'-type documentary some time ago. As I recall, everything within thousands of miles of 'ground zero' immediately ignited, then collapsed into a swirling vortex of energy within seconds (with the BH at the centre). All over the rest of the world, gigantic thunderstorms raged, winds of several hundred mph battered the surface and the horizon glowed white. --Kurt Shaped Box 22:27, 8 July 2007 (UTC)
- What one sees would depend a lot on the mass. A very low mass black hole, which would presumably be the only kind we might "accidentally" create, would evaporate via Hawking radiation and pose no threat to the Earth. You see some sort of flash as it disintegrated, if you were looking at it. The other issue is that even Earth mass black holes would be very small. The Schwartzschild radius of the Earth is ~1 cm. At that size, and even if you could feed it would a continous stream of matter moving near the speed of light, it would take ~100 million years to force a volume the size of the Earth to fit through a surface area as small as the event horizon of the black hole. A micromass blackhole, i.e. something say the mass of a mountain, could well take longer than the remaining life of the solar system to eat the Earth. In other words, you might not see much of anything in your lifetime. Dragons flight 23:00, 8 July 2007 (UTC)
- Depends on the mass of the thing. Look at it like this: The gravity field of a black hole is no stronger than the thing it's made of.
- So I guess the worst case would be if we took the largest thing we can imagine that's handy and nearby - suppose we could take the entire moon and maybe "accidentally" turn it into a black hole using who-knows-what weird science (tsk, tsk - these scientist are so careless!). Well, that wouldn't do much - the moon-sized black hole would continue to orbit the earth - suckinging in microscopic amounts of gas...we'd hardly even notice! But I guess we're asking about a black hole on the surface of the earth. If the moon-sized hole were somehow brought to the surface of the earth...now THAT would be the kind of apocalypse you have in mind. The black hole would have the same gravity as the moon - except you could get much closer to it than you can get to the real moon. The moon has a radius of 1700km - so at 1700km from the black hole, it would be attracting with the force of 1/6th of a g - enough to collapse buildings maybe - but not directly dangerous. At 800km, we're up to 2/3rd of a g, at 400km, we're looking at 2.6g, at 200km, 10g, at 100km, 40g...there isn't much that can withstand a force of 40g - so the hole that a moon-sized black hole would immediately dig would be a few hundred kilometers across! Since nothing can support a moon-sized black hole - it would immediately fall towards the center of the earth - it would fall towards the center of our planet - gaining speed as it did it - then oscillate back and fourth within the earth carving out massive tunnels. The planet would rapidly hollow out from the inside out until the mantle would not be strong enough to support the weight - then the earth would collapse inwards - all in slow motion. It would take a long time to fall that far!
- But for a much smaller black hole, nothing much would happen. If you took 1000kg of matter and made a 1000kg black hole - it wouldn't exert any measurable g-force at one meter - you car weighs more than that - and it doesn't exert much gravity a meter away! The hole it would burrow in the earth might only be a tiny fraction of a millimeter across. It would still fall to the center of the earth - probably weighing a little more by the time it got there. But then it might eat out a hollow area in the middle a few centimeters across - but it's gravity would be pretty pathetic - but it's not exerting enough force on the earth's liquid iron core to excavate a huge cave - it might take thousands or millions of years for it to accumulate enough mass to be really dangerous to us.
- If you made a black hole out of 1kg of stuff - the hole it would drill might be of the order of the diameter of an atom - at which point you wouldn't ever know it was there.
- Really? I smell original research.... Nimur 00:51, 9 July 2007 (UTC)
- That moon mass black hole is only 200 microns across. While 40g may seem like a lot, it's not really from a structural prospective, it would take ~3000g to pull apart a 1 m^3 slab of rock with a typical yield stress of 100 MPa, further the ability to pull things apart depends of the difference in force between the two ends on object. The end result is that you have to be within 500 m to break rock, and much much closer to actually be consumed because of the very small surface area. Dragons flight 00:37, 9 July 2007 (UTC)
- In total, there is not enough experimental evidence with close-up black holes to say for sure with any kind of certainty. There's going to be lots of speculation, artistic license, and mishmash theories of classical and quantum and relativistic effects; but since we have no prior experience it is all speculation (no matter how rigorous the math may be, who knows if our models would break down in unforeseen ways?) Nimur 00:54, 9 July 2007 (UTC)
An insect to identify
Butterflies have two pairs of large wings, dragonflies two pairs of equal-sized slender, transparant wings. At the banks of the Soča river, near Bovec, Slovenia, I have seen several of the beautifully coloured kind of insect depicted to the right. It has dark blue-black wings with white spots, slender like a draginfly's, but seemingly only one pair. The body has a prominently yellow-coloured ring, and I think that I've seen one with an additional blue ring. What is this? TIA. Simon A. 22:48, 8 July 2007 (UTC)
Butterfly with spotted compound eyes
In the hope that my previous question already caught the idea of any professional or amateur entomologists roaming the Reference Desk, I ask a second one: I took the photo to the right at more or less the same ___location, again at the banks of the Soča near Bovec, Slovenia. When looking at the photo on my computer screen at maximum zoom, I was amazed to note a funny detail: The wings' colouring pattern, dark brown markings on amber background, seems to continue onto the butterfly's compound eyes. Two questions arise: (a) Is it common for butterflies to have coloure eyes? (ii) Given that wing colours are produced by scales tinted by thin film interference or pigments, how can a compund eye have the same colours although it does not have scales? Simon A. 23:24, 8 July 2007 (UTC)
Political views of Scientists
Obviously scientists (defining scientist however you want) have a broad range of political beliefs. However taking all scientists, how do you think their views compare to the general public in their country. ie More conservative or liberal in social policy?, more left wing or right wing economically? More religious or aethiest than the general public? etc.
- Over the earth or over first world countries?
- I'll presume you mean the U.S. and PhD scientists. More liberal in social policy. More capitalist economically. More religious than the general public. --Tbeatty 01:57, 9 July 2007 (UTC)
Presume the U.S if thats where you are Willy turner 02:19, 9 July 2007 (UTC)
- Of course you should use a scientific approach regarding the answer to this question! Note the distinction between correlation and causation. Also note the exceptions to the general trends. And finally, evaluate whether your initial criteria are valid to begin with (is "liberal/conservative" a good way to measure political affiliation and belief?) Nimur 02:03, 9 July 2007 (UTC)
liberal/conservative is one way. feel free to answer the question with regards to any other measure of political beliefs you like Willy turner 02:19, 9 July 2007 (UTC)
- I would vote for less religious than the general public. More sceptical of everything. Aaadddaaammm 02:05, 9 July 2007 (UTC)
Thats what i would have thought. Willy turner 02:08, 9 July 2007 (UTC)
- In fact, it is fairly well established that US scientists are much less religious than the general US public, and that this difference becomes dramatic if one restricts the comparison to those top scientists that are members of the National Academy of Science. 169.230.94.28 02:17, 9 July 2007 (UTC)
- One thing that is distinctive about good scientists is that they have open minds until they see proof. This tends to make conventional political distinctions hard for them to make. Democrat/Republican, Left wing/Right wing...these are statements of a belief in a bundle of policies. To pick two issues at random - traditionally, in the USA, Republicans are anti-abortion and pro-guns - Democrats are pro-abortion and anti-guns. A scientist can't simply fall into one demographic or the other. A scientist has to examine the issues - and may well decide that they are pro-abortion and pro-guns (for example). Taken over dozens of issues, this will result in someone who probably sides mostly with the views of one side - but may be very extreme on the opposite side for other views. On the whole, I think most scientists tend to be "left of center" in a majority of their views, wildly leftist on others and wildly rightist on yet others. The whole idea of "joining a club and mindlessly promoting all of their views" is an anathema to most of us. SteveBaker 02:53, 9 July 2007 (UTC)
- If the interface of science and politics is something that interests you, Chris Mooney's The Republican War on Science is an essential read (or just wait for the upcoming documentary). As SteveBaker says, scientists tend to be less ideological than the average member of the electorate, and thus harder to pigeonhole in such broad strokes. So while scientists, as a group, are probably on average somewhere left-of-centre on their personal politics, the perception as scientists as overwhelmingly and actively liberal is no more than a political tactic. Indeed, painting politically unconvenient research as junk science and policy friendly research (usually from industry) as sound science has become remarkable common in the US, and is extensively by the Bush administration to justify forming policy against the scientific consensus. Indeed Karl Rove sums this up best with his definition of a Democrat as, "somebody with a doctorate." Rockpocket 03:26, 9 July 2007 (UTC)
Creationism Questions
Firstly, how do creationists explain how plants and fungi and protists (and everything else alive at that time) survived the flood? There are indeed many living things that would survive a forty-day flood, but there are some that would not. The bible only mentions animals going on the ark. Also, does anyone recall whether the bible mentions the depth of the water? This would have a large impact on the survival of photosynthetic creatures.
Secondly, I have studied the "exact proportions" (according to the bible) of the ark that god commanded Noah to build, and I doubt that two of every species of animal would fit on something of that size.138.87.213.224 02:20, 9 July 2007 (UTC)
- The first one could be answered by an evolutionist too- what we see now are the surviving plants. The second one would probably get you two answers- an apologist saying you shouldn't take it literally, and someone who's dead set in their ways telling you that it was a miracle, or some such --Laugh! 02:32, 9 July 2007 (UTC)
- Your questions are addressed at Noah's Ark#Biblical literalism and the Ark. Specifically, the apparent conundrum is usually explained by the fact that the Ark contained representatives of "created kinds" rather than species known today. This belief has spawned the pseudoscientific discipline known as "Baraminology". Rockpocket 02:33, 9 July 2007 (UTC)
- Asking the science desk how creationists explain this is not likely to end well! Since creationism is about as far from science as it's possible to get - it's unlikely that many of them are here to answer your question. It goes deeper if you want to get picky - how do you feed all of those animals for 40 days? Particularly since a good fraction of them only eat other animals. Where did the water come from? Where did it go to? How come we don't see any evidence of a world-wide layer of sediment? When the dove returns to Noah with the olive branch - we have to ask ourselves what Olive trees had survived 40 days underwater. If it rained freshwater - then the level of dilution of the oceans required in order to get the water depth up to the top of Mt.Everest would kill most saltwater plants and animals - if it rained saltwater - then ditto for freshwater lifeforms. The questions and obstacles that a sceptical mind can throw into the path of this rather nice childrens' story are truly endless. However, if you believe in a being with literally unlimited powers - then no story is falsifiable. All a creationist has to say is "God arranged it so it all worked out using his magical abilities" - and you can't take the argument any further. Any hypothesis that includes such a being is unfalsifiable - and the whole of science, engineering, history and anything else humans have done becomes irrelevent. SteveBaker 02:39, 9 July 2007 (UTC)
July 9
I actually am seeking a peer picture review in hopes of finding someone who knows what this flower is. I planted it last summer but for the life of me cannot remember what its name. I've been told that it's some type of carnation but I'm not sure. I think it's a good photo to be included in an article once I find out what the flower's name is. - AutoGyro 02:34, 9 July 2007 (UTC)
Comments:
- Looks like Sweet William to me. David D. (Talk) 03:35, 9 July 2007 (UTC)
- (why is this transcluded onto the ref desk from Picture peer review?)
- Yup, go ahead, rename as "Sweet William Dwarf" (reference: [25]) and add it to the article. Bendž|Ť 17:52, 9 July 2007 (UTC)