Gunpowder, also called black powder, is a low explosive, the only one known from its discovery in the West in the thirteenth century until the mid-nineteenthth century. It consists of about 75% potassium nitrate (saltpetre) or sodium nitrate, 10% sulfur, and 15% charcoal. When ignited, it expands violently due to the almost instantaneous conversion of the solid ingredients into gases such as carbon dioxide, carbon monoxide, nitrogen, nitrogen oxides, sulfur oxides, and steam. The sudden release of enormous volumes of these gases gives the reaction its explosive force.
Gunpowder was used in fireworks in tenth-century China, as a propellant for firearms from the fourteenth century in Europe and for blasting since the late seventh century. After about 1900 it was replaced in firearms by smokeless powders such as cordite. It is now used mainly as an igniter, in fuses, and in fireworks.