Gunpowder

Gunpowder, known since the late 19th century as black powder, is a mixture of sulfur, charcoal and potassium nitrate. Because it burns rapidly and generates a large amount of heat and gas, gunpowder has been widely used as a propellant in firearms and as a pyrotechnic composition in fireworks. In ancient China, gunpowder and gunpowder-based weapons were invented and widely used by military forces to dispel invasion at the borders. The prevailing academic consensus is that gunpowder was discovered in the 9th century by Chinese alchemists searching for an elixir of immortality. Wujing Zongyao, written by Zeng Gongliang and Ding Du in the Song Dynasty (960－1279), is the earliest treatise recording three formulas for making gunpowder.