Gunpowder, or Black Powder, an explosive mixture of fine grains of charcoal, sulfur, and saltpeter. The saltpeter (potassium nitrate) supplies oxygen, while the charcoal and sulfur act as fuel. Placed in a container such as a paper tube or the barrel of a gun, and touched off by a flame or spark, gunpowder explodes. Spread thinly in an open space, gunpowder merely burns rapidly.

Gunpowder is used in fireworks, certain kinds of coal mining and stone quarrying, and seismographic prospecting for oil. In firearms, mining, and construction work, it has been largely replaced by more powerful explosives.

For centuries, gunpowder was the only practical explosive known. It was first used by the Chinese during the 900's A.D. for simple rockets, bombs, and grenades. Gunpowder was introduced in Europe in the 13th century and first used in firearms there in the 14th century. It was first used to blast rock in the 17th century, when the French built the Languedoc Canal. Later, gunpowder was used extensively—and dangerously—in mining. The safety fuse, invented in 1831, made the handling of gunpowder less hazardous. In the late 19th century, gunpowder was replaced in firearms by smokeless powder and in rock-breaking operations and mining by dynamite.