- published: 12 Jan 2016
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Combustion ( /kəmˈbʌs.tʃən/) or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame. Fuels of interest often include organic compounds (especially hydrocarbons) in the gas, liquid or solid phase.
In a complete combustion reaction, a compound reacts with an oxidizing element, such as oxygen or fluorine, and the products are compounds of each element in the fuel with the oxidizing element. For example:
A simple example can be seen in the combustion of hydrogen and oxygen, which is a commonly used reaction in rocket engines:
The result is water vapor.
Complete combustion is almost impossible to achieve. In reality, as actual combustion reactions come to equilibrium, a wide variety of major and minor species will be present such as carbon monoxide and pure carbon (soot or ash). Additionally, any combustion in atmospheric air, which is 78% nitrogen, will also create several forms of nitrogen oxides.
A girl is any female human from birth through childhood and adolescence to attainment of adulthood when she becomes a woman. The term may also be used to mean a young woman.
The English word girl first appeared during the Middle Ages between 1250 and 1300 CE and came from the Anglo-Saxon words gerle (also spelled girle or gurle). The Anglo-Saxon word gerela meaning dress or clothing item also seems to have been used as a metonym in some sense.
Girl has meant any young unmarried woman since about 1530. Its first noted meaning for sweetheart is 1648. The earliest known appearance of girl-friend is in 1892 and girl next door, meant as a teenaged female or young woman with a kind of wholesome appeal, dates only to 1961.
The word girl is sometimes used to refer to an adult female. This usage may be considered derogatory or disrespectful in professional or other formal contexts, just as the term boy can be considered disparaging when applied to an adult man. Hence, this usage is often deprecative. It can also be used deprecatively when used to discriminate against children ("you're just a girl").
They took a hot-rod motor and they put it in her heart
It's a dream location but she's tearing it apart
Tounge-tied and twelve
Staring up at perfect pearls
He's 13, she's 13
She's a teenage girl
Teenage girl
Skin the surface like a Mach 5 flower
Fibreglass shakin' and it shatters from the power
It's crush and blow
When the engine overflows
That motor's pride
Just say goodbye to Water World
Teenage girl
Tounge-tied and twelve
Staring up at perfect pearls
He's 13, she's 13
He's 13 teenage girl
He's 13, she's 13