According to Explosions Their Anatomy and Destructiveness (1944) and explosion consists of the very sudden production of large quantities of gases, usually hot, from a much smaller amount of a solid, a liquid, or a gas. This is usually accompanied by a loud noise or report?. According to The Chemistry of Powder and Explosives (1984) an explosive is a material, either a pure single substance or a mixture of substances, which is capable of producing an explosion by its own energy. There are three different types of explosions: I. propellants or low explosives, II. primary explosives or initiators, and III. high explosives.
Propellants are combustible materials, containing within themselves all oxygen needful for their combustion, which burn but do not explode, and function by producing gas, which produces an explosion. Explosives of this class [type] differ widely among themselves in the rate at which they deliver their energy? (The Chemistry of Powder and Explosives p.2). Some examples of these are: black powder, smokeless powder.
Primary explosives explode when they are heated or subjected to shock. They don't burn; sometimes they do not even contain the material needed for combustion. The materials are what explode, and the explosion happens whether or not the materials are contained or not. The sensitivity to heat, the amount of heat the explosion gives off, and the shock that is produced from the explosion depends on the materials that are used. Some examples of these are: fulminating silver, mercury fulminate, lead azide, and many more.
High explosives detonate with the shock of an explosion from a primary explosive. The materials don't burn, most aren't combustible, but a flame can ignite most. This type of explosive differs from the primary explosives because they don't explode readily with heat or shock and they produce a more powerful and larger shock. This type will also have a damaging effect on anything that is around it, even if the explosive is confined or not.
