(adjective) Refers to a chemical compound, mixture, device etc. that is capable of exploding. Example: "Gasoline forms an explosive mixture with air." (noun) An explosive is a compound or mixture susceptible (by heat, shock, friction or other impulse) to a rapid chemical reaction, decomposition or combustion with the rapid generation of heat and gases with a combined volume much larger than the original substance. Explosives can be broken into two general categories that reflect the rate of the transformation. 1.High explosives are capable of detonating and are used in military ordinance, blasting and mining etc.. These have a very high rate of reaction, high pressure development, and the presence of a detonation wave that moves faster than the speed of sound (1,400 to 9,000 meters per second). Examples include primary explosives such as nitroglycerin that can detonate with little or no stimulus and secondary explosives such as dynamite (trinitrotoluene, TNT) that require a strong shock (from a detonator such as a blasting cap). 2. Low explosives change into gases by burning or combustion. These are characterized by deflagration (burning rapidly without generating a high pressure wave) and a lower reaction rate than high explosives. The overall effect ranges from rapid combustion to a low order detonation (generally less than 2,000 meters per second). Gun powder (black powder) is the only common example.