terça-feira, 17 de janeiro de 2017

Match

Match


a small wooden stick, usually of ash wood, with a head composed of a combustible substance and an oxidizing agent. (Matchsticks are sometimes made of cardboard.) The length of the wooden matchstick is usually 36 to 48 mm. Matchboxes contain 50 to 600 matches.
Matches that ignited from the friction caused by rubbing the match against any rough surface were first produced in the 1830’s. The composition of the match head included white phosphorus—a flammable and toxic substance. The first match factory in Russia was constructed in 1837 in St. Petersburg. Safety matches were first developed in Sweden in 1855 and, hence, were called Swedish matches. By the beginning of the 20th century, they had become the principal type of match.
A distinction is made between household and special-purpose matches. The composition of household match heads can include sulfur, potassium chlorate, potassium dichromate, pyrolusite, animal glue, and zinc oxide. Potassium chlorate, an oxidizing agent, produces combustion, and the glue binds the components of the match head together. Both the glue and the sulfur are combustible. The other components regulate the combustion processes and impart color to the head. The friction surface, usually placed on the side of the matchbox, can consist of, among other things, red phosphorus, antimony sulfide, chalk, and animal glue. Rubbing the head of the match along the friction surface causes the phosphorus, oxidized by the potassium chlorate, to ignite and kindle the sulfur.
Special-purpose matches are divided into wind, signal, and ignition matches. Wind matches have a large head whose composition is easily ignited and not extinguished by wind. Signal matches burn with a clear, colored flame (blue, green, yellow, or red). The heads of ignition matches are made of substance that upon combustion produces a high temperature. These matches are used for igniting thermal charges in welding under conditions in the field.

http://encyclopedia2.thefreedictionary.com/Match

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