The '''mesomeric effect''' or '''resonance effect''' in [[chemistry]] is a property of [[substituent]]s or [[functional group]]s in a [[chemical compound]]. The effect is used in a qualitative way and describes the electron withdrawing or releasing properties of substituents based on relevant [[resonance structure]]s and is symbolized by the letter '''M'''. The mesomeric effect is negative ('''-M''') when the substituent is an electron-withdrawing group and the effect is positive ('''+M''') when based on resonance the substituent is an electron releasing group.
[[Image:Beach Towel (occupied).jpg|thumb|300px|A beach towel in use]]
A '''towel''' is a piece of [[absorb|absorbent]] [[cloth|fabric]] whose chief use is for drying objects, by drawing [[wiktionary:moisture|moisture]] (usually [[water]]) from the object, into the fabric, through direct contact, with either a blotting or rubbing motion.
*Examples of -M substituents: [[acetyl]] (UPAC ethanoyl) - [[nitrile]] - [[nitro]]
==Types of towels==
*Examples of +M substituents: [[alcohol]] - [[amine]]
* A ''bath towel'' is used for drying one's body after bathing or showering. It is typically rectangular, with a size somewhere around 30"×60" (75×150 cm).
The net electron flow from or to the substituent is determined also by the [[inductive effect]]. It's important to note that the mesomeric effect as a result of p - orbital overlap (resonance) has absolutely no effect on this inductive effect, as the inductive effect is purely to do with the [[electronegativity]] of the atoms and their structural chemistry (which atoms are connected to which).
* A ''beach towel'' is usually a little bit larger than a bath towel. Although it is often used for drying off after being in the water, its chief purpose is to provide a surface to lie on. Beach towels often have colourful patterns printed or woven into them.
The concepts of mesomeric effect, '''mesomerism''' and '''mesomer''' were introduced by [[Christopher Kelk Ingold|Ingold]] in 1938 as an alternative to the [[Linus Pauling|Pauling's]] synonymous concept of [[resonance effect|resonance]] <ref>''If It's Resonance, What Is Resonating?'' Kerber, Robert C. . J. Chem. Educ. '''2006''' 83 223. [http://www.jce.divched.org/Journal/Issues/2006/Feb/abs223.html Abstract]</ref>. Mesomerism is in this context is often encountered in German and French literature but in English literature the term resonance dominates.
* A ''hand towel'' is significantly smaller than a bath towel (perhaps 30x60 cm), and is used for drying one's hands after washing them.
== External links==
* A ''[[paper towel]]'' is a piece of paper that can be used once as a towel and then be disposed of. A perforated roll of paper towels is normally mounted on a wall-mounted horizontal rod a little longer than the width of the roll, or in an alternative type of hanger that has indentations on ears, the indentations fitting into the ends of the paper towel roll. Paper towels can also be found as individual folded sheets.
* IUPAC [[Gold Book]] [http://www.iupac.org/goldbook/M03844.pdf definition]
== See also ==
* A ''tea towel'' ([[British English]]) or ''dish towel'' ([[American English]]) is a cloth which is used to dry dishes, cutlery, etc., after they have been washed.
* [[List of publications in chemistry#Organic chemistry|Important publications in organic chemistry]]
== References ==
Confusingly, the term ''kitchen towel'' can refer to a dish towel or to a paper towel, the latter usage being primarily British.
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==Alternative uses==
[[Image:Towel3.jpg|thumb|right|250px|Fibres in a tea towel]]
Towels are often used for purposes other than drying things.
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* Wrapped around one's body, a towel acts as a make-shift [[garment]] (also for changing clothes on the [[beach]] etc.).
* Removing sand from the body or things on a sandy beach.
* To sit, lie and stand on, to avoid direct contact with the ground, rock, chair, etc. This may be to avoid getting dirty or sandy, because it is more comfortable, and in the case of partial or full [[nudity]], to avoid making the chair dirty.
* In order to prepare the skin for [[shaving]], [[barber]]s use steamed towels.
* To reserve seats, for example sunloungers, by the side of swimming pools or similar locations, and this is a source of amusement to some, and annoyance to others.
* In extreme cases, a towel may be used as a blanket to preserve heat.
==Cultural significance==
Towels have long been thought of as nothing more than utilitarian objects that everybody has, but about which nobody really thinks twice. [[Douglas Adams]] challenged this when ''[[The Hitchhiker's Guide to the Galaxy]]'' attained cult status in the [[1980s]]. He described his characters travelling around his universe, often as hitchhikers, finding that towels were the most "massively useful" objects they could carry. The fictitious time/space traveller and Guide Researcher [[Ford Prefect (character)|Ford Prefect]] uses the idiom "a [[frood]] who really knows where his towel is" to mean someone generally alert and aware, someone who in [[1960s]] Earth slang might have been called "with it".
In Adams' universe, a hitchhiker who carries a towel can always find a ride, because if someone is carrying a towel, it is assumed (however illogically) that they also have a toothbrush, a bathroom kit, shower shoes, hair nets, maps, a toolbox, tickets to the opera, finely lapped silicone wafers, a set of encyclopedias, an astonishing array of credit cards, travellers checks, etc. For this reason, hitchhikers were directed by the Guide to always carry a towel to maintain the appearance that they would make a good guest.
In addition, a towel can be used as a [[hammock]], a [[blanket]], or a [[cape]]. The corners of the towel can be soaked in vitamins, and useful bits of wire can be woven into the towel. The corners of a towel can also be tied together to make a bag. If wet, the towel can even be used in [[melée]] combat. You can use it to hide from the [[Ravenous Bugblatter Beast of Traal]] (a mind-bogglingly stupid animal, it assumes that if you can't see it, it can't see you -- daft as a brush, but very very ravenous).
Fans of Adams' books have seized on this idea, and towels are now considered a symbol of one's devotion to the Hitchhiker books, [[radio]] series, [[television|TV]] series, [[H2G2|website]], etc.
In the cartoon [[South Park]] a character named [[Towelie]] is a walking, talking towel that was artificially created in a lab for military/subversive purposes. All he really does is get high, and is intentionally the worst character ever.
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