The Chemistry of Explosives

Explosive devices may be mechanical, chemical, or atomic. Mechanical explosions occur when a closed system is heated—a violent pressure rupture can occur. However, this doesn’t make a heated can of soup an explosive. An explosive substance is one which reacts chemically to produce heat and gas with rapid expansion of matter. A detonation is a very special type of explosion. It is a rapid chemical reaction, initiated by the heat accompanying a shock compression, which liberates sufficient energy, before any expansion occurs, to sustain the shock wave. A shock wave propagates into the unreacted material at supersonic speed, between 1500 m/s and 9000 m/s.