TABLE OF CONTENTS When a loud, sharp bang is heard similar to a grenade or a bomb exploding it is known as detonation. If the noise is not as loud as that produced by a detonation and is longer in duration and sounds like a hissing sound ( i.e. the sound of a rocket motor) it is classed as deflagration. In many cases these effects are preceded and accompanied by fire. If a fire is not accompanied by a thundering noise and blowing up of a building, it is classed as either burning or combustion. Some explosive materials will burn relatively slowly (a few millimetres or centimetres per second) if spread on the ground in a thin line. The rate of burning will increase and sometimes develops into deflagration or detonation if these explosive materials are confined.
Combustion is a chemical reaction which takes place between a substance and oxygen. The chemical reaction is very fast and highly exothermic, and is usually accompanied by a flame. The energy generated during combustion will raise the temperature of the unreacted material and increase its rate of reaction. An example of this phenomenon can be seen when a matchstick is ignited. The initial process on striking a match is to create enough friction so that a large amount of heat is generated. This heat will locally raise the temperature of the match head so that the chemical reaction for combustion is initiated and the match head ignites. On ignition of the match head, heat...
