Latin explosion-, explosio act of driving off by clapping, from explodere
- Date: 1667
- 1 : the act or an instance of exploding <injured in a laboratory explosion>
- 2 : a large-scale, rapid, or spectacular expansion or bursting out or forth <the explosion of suburbia> <an explosion of red hair>
- 3 : the release of occluded breath that occurs in one kind of articulation of stop consonants
An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive". Subsonic shock waves are created by low explosives through the slower burning process known as deflagration.
The generation of heat in large quantities accompanies most explosive chemical reactions. The exceptions are called entropic explosives and include organic peroxides such as acetone peroxide. It is the rapid liberation of heat that causes the gaseous products of most explosive reactions to expand and generate high pressures. This rapid generation of high pressures of the released gas constitutes the explosion. It should be noted that the liberation of heat with insufficient rapidity will not cause an explosion. For example, although a pound of coal yields five times as much heat as a pound of nitroglycerin, the coal cannot be used as an explosive because the rate at which it yields this heat is quite slow.