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{{Mergefrom|Pine tar|date=September 2007}}
{{otheruses}}
[[Image:Corn Stover Tar from Pyrolysis by Microwave Heating.jpg|right|thumb|200px|Tar can be produced from corn stalks by heating in a microwave.  This process is known as [[pyrolysis]].]]

Sometimes used as a street name for [[heroin]].

'''Tar''' is a [[viscosity|viscous]] black [[liquid]] derived from the [[destructive distillation]] of organic matter.  Most tar is produced from [[coal]] as a byproduct of [[coke (fuel)|coke]] production, but it can also be produced from [[petroleum]], [[peat]] or [[wood]].

==Types of tar==
===General===
The word "tar" is used to describe several distinct substances. Naturally occurring "[[tar pit]]s" (e.g. the [[La Brea Tar Pits]] in [[Los Angeles, California|Los Angeles]]) actually contain [[asphalt]], not tar, and are more accurately known as ''asphalt pits''. [[Tar sands|Tar sand]] deposits contain various mixtures of sand (or rock) with [[bitumen]] or [[heavy crude oil]] rather than tar, as does the [[Tar Tunnel]] in [[Shropshire]]. "Rangoon tar", also known as "Burmese Oil" or "Burmese Naphtha", is actually [[petroleum]].  "Tar" and "[[pitch (resin)]]" are sometimes used interchangeably; however, pitch is considered more solid while tar is more liquid.

===Coal===
In English and French, "tar" is a substance primarily derived from coal.  It was formerly one of the products of a [[gasworks]].  Tar made from coal or petroleum is considered [[toxic]] and [[carcinogenic]] because of its high [[benzene]] content, however, [[coal tar]] in low concentrations is used as a [[topical]] medicine. Coal and petroleum tar has a pungent odor.

===Wood===
In [[Northern Europe]], the word "tar" refers primarily to a substance [[pyrolysis|derived]] from wood, which is used even as an additive in the flavoring of candy and other foods. Wood tar is [[Microbicide|microbicidial]] and has a pleasant odor.

The heating ([[dry distillation|dry distilling]]) of [[pine]] wood causes [[Pine tar|tar]] and pitch to drip away from the wood and leave behind charcoal.  Birchbark is used to make particularly fine tar (''tökötti'').  The by-products of wood tar are [[turpentine]] and [[charcoal]]. When deciduous tree woods are subjected to destructive distillation the by-products are [[methanol]] (wood alcohol) and [[charcoal]].

==Uses==
Tar is used in treatment of the skin-disease [[psoriasis]], where coal tar is the most effective. Tar is also a general disinfectant.  Petroleum tar was also used in [[ancient Egypt]]ian [[Mummy|mummification]] circa [[1000 BC]].{{ref|www.geotimes.org.feb05}}

Tar was a vital component of the first sealed, or "[[tarmac]]", roads. It was also used as seal for roofing [[shingle]]s and to seal the hulls of [[ship]]s and [[boat]]s. For millennia wood tar was used to waterproof [[sail]]s and boats, but today sails made from inherently waterproof synthetic substances have negated the need for tar.  Wood tar is still used to seal traditional wooden boats and the roofs of historical shingle-roofed churches, as well painting exterior walls of log buildings. 

In [[Finland]] wood tar was once considered a [[panacea]] reputed to heal "even those cut in twain through their midriff". A Finnish proverb states that ''if [[sauna]], [[vodka]] and tar won't help, the disease is fatal''. The use of wood tar in traditional Finnish medicine is because of its microbicidial properties.

Wood tar is also available diluted as [[tar water]], which has numerous uses:
*As a flavoring for candies (e.g. [[Terva Leijona]]) and alcohol ([[Terva Viina]])
*As a spice for food, like meat
*As a scent for [[sauna]]s. Tar water is mixed into water that is turned to steam to the air
*As an anti-[[dandruff]] agent in [[shampoo]]
*As a component of cosmetics

Mixing tar with linseed oil [[varnish]] produces tar paint. Tar paint has a translucent brownish hue, and can be used to saturate and tone wood and protect it from weather. Tar paint can also be toned with various pigments, producing translucent colours and preserving the wood texture. Because of its paint-like properties, wet tar should not be touched with bare skin, as it can dry to produce a stain, though paint thinner is effective in removing it.

Coal tar is listed at [[List of UN Numbers 1901 to 2000|number 1999]] in the [[United Nations]] list of [[dangerous goods]].

==See also==
* [[Bitumen]]
* [[Coal tar]]
* [[Pine tar]]
* [[Pitch (resin)]]
* [[Pitch drop experiment]]
* [[Tarring and feathering]]
* [[Tar Heels]]
* [[Tar pit]]

==Sources==
*{{note|www.geotimes.org.feb05}} {{cite web | title=Geotimes - February 2005 - Mummy tar in ancient Egypt | url=http://www.geotimes.org/feb05/NN_mummytar.html | accessdate=January 9 | accessyear=2006 }}
*[http://www.prices-candles.co.uk/history/HISTORYdetails.htm] - details history and uses of "Rangoon Tar".

{{Antipsoriatics}}

[[Category:Materials]]
[[Category:Chemical mixtures]]

[[cs:Dehet]]
[[da:Tjære]]
[[de:Teer]]
[[es:Alquitrán]]
[[eo:Gudro]]
[[fa:قیر]]
[[fr:Goudron]]
[[gl:Alcatrán]]
[[it:Catrame]]
[[he:זפת]]
[[nl:Teer]]
[[ja:乾留液]]
[[no:Tjære]]
[[pl:Smoła]]
[[pt:Alcatrão]]
[[ru:Дёготь]]
[[fi:Terva]]
[[sv:Tjära]]
[[vi:Hắc ín]]
[[uk:Гудрон]]
[[yi:פעך]]
[[bat-smg:Smala]]
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