Charge is a term often used for explosive content, usually contained in explosive devices (e.g. bombs, grenades, etc.), but can also refer to applications such as ammunition, artillery and various firearms.
An explosive material, also called an explosive, is a substance that contains a great amount of stored energy that can produce an explosion, a sudden expansion of the material after initiation, usually accompanied by the production of light, heat, sound, and pressure. An explosive charge is a measured quantity of explosive material.
The energy stored in an explosive material may be
- chemical energy, such as nitroglycerine or grain dust
- pressurized compressed gas, such as a gas cylinder or aerosol can
- nuclear, such as fissile isotopes of uranium-235 and plutonium-239
Explosive materials may be categorized by the speed at which they expand. Materials that detonate (explode faster than the speed of sound) are said to be high explosives and materials that deflagrate are said to be low explosives. Explosives may also be categorized by their sensitivity. Sensitive materials that can be initiated by a relatively small amount of heat or pressure are primary explosives and materials that are relatively insensitive are secondary explosives.