Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products.[1] Slower oxidative processes like rusting or digestion are not included by this definition.
There may be a great fire in our hearts, yet no one ever comes to warm himself at it, and the passers-by see only a wisp of smoke.
Vincent Van Gogh
Fire is hot because the conversion of the weak double bond in molecular oxygen, O2, to the stronger bonds in the combustion products carbon dioxide and water releases energy (418 kJ per 32 g of O2); the bond energies of the fuel play only a minor role here.[2] At a certain point in the combustion reaction, called the ignition point, flames are produced. The flame is the visible portion of the fire. Flames consist primarily of carbon dioxide, water vapor, oxygen and nitrogen. If hot enough, the gases may become ionized to produce plasma.[3] Depending on the substances alight, and any impurities outside, the color of the flame and the fire's intensity will be different.
| Content categories | Flow content |
|---|---|
| Permitted content | An optional <caption> element; zero or more <colgroup> elements; an optional <thead> element; an optional <tfoot> element; |
| Tag omission | None, both the start tag and the end tag are mandatory |
| Permitted parent elements | Any element that accepts flow content |
| Normative document | HTML5, section 4.9.1 (HTML4.01, section 11.2.1) |
Fire in its most common form can result in conflagration, which has the potential to cause physical damage through burning. Fire is an important process that affects ecological systems around the globe. The positive effects of fire include stimulating growth and maintaining various ecological systems.
"Glossary of Wildland Fire Terminology". National Wildfire Coordinating Group. November 2009. ↩︎
Schmidt-Rohr, K (2015). "Why Combustions Are Always Exothermic, Yielding About 418 kJ per Mole of O2". J. Chem. Educ. 92 (12): 2094–99. ↩︎
Helmenstine, Anne Marie. "What is the State of Matter of Fire or Flame? Is it a Liquid, Solid, or Gas?" ↩︎