EXPLOSION may be defined as the sudden or extremely rapid conversion of a solid or liquid body of small bulk into gas or vapour, occupying very many times the volume of the original substance, and which in addition is highly expanded by the heat generated during the action.
This sudden or very rapid expansion of volume is attended by an exhibition of force which is more or less violent, according to the constitution of the original body and the circumstances of the explosion.
Any substance capable of undergoing such a change on the application of heat or other disturbing cause is called an "explosive."
Explosive Force.—Explosive force is directly proportional to the heat of combustion and the volume of gas, and inversely to the specific heat of the mixed products.
Explosive effect is directly proportional to the volume of gas produced and the temperature of the explosion, and inversely as the time required for the change to take place.
Explosive Effect and Force compared.—Explosive effect depends upon the rapidity with which the conversion is effected, while the same amount of explosive force may act suddenly or gradually.
As before stated, explosions are more or less violent according to the circumstances under which they take place. These may be considered as follows:—
1.—The physical state of the explosive substance.
2.—The external conditions under which the explosive body is fired.
3.—The mode of firing.