Black powder is an explosive that is made by mixing ground charcoal, sulfur, and potassium nitrate, also known as saltpeter. Until the middle of the 19th century, it was the primary explosive used for firing guns, making fireworks, and blasting in mines and quarries. It has since been supplanted by more efficient and stable explosives, although it is still used by enthusiasts of antique guns and some special effects specialists. Black powder is available through several manufacturers, although this easily combusted substance is dangerous enough that ownership and transport of it is restricted in some regions.
The earliest black powder was developed by the Chinese in around the ninth century CE. The Chinese used it for firearms and fireworks, along with other applications, and it slowly spread into the West. As firearms grew more sophisticated, the use of this explosive grew more widespread, until the development of other explosives like smokeless gunpowder and nitroglycerin.
A basic black powder recipe has 75% potassium nitrate, 15% charcoal, and 10% sulfur. These ingredients are ground to create a uniformly textured powder, which will have a varying burn rate, depending on the size of the grains of powder. One of its major flaws is that, when combusted, these ingredients create particulate pollution and the sulfur tends to break down into a corrosive compound that can be hard on the weapons it is used in.
One of the most classic uses of black powder is in firearms, where it is used to propel the bullet. It burns very rapidly, and in the confined environment of a gun barrel, it produces an explosion of hot, rapidly expanding gases that force the bullet out. Modern bullets incorporate their explosive charges into their casings, but traditional weapons must be packed with powder, wadding, and shot in a painstaking process that could be dangerous in the chaotic conditions of a battle.
In fireworks, black powder can be mixed with various colored substances. It has also historically been used as an explosive charge in mining and to roughly shape stones for masonry, although this use has since been abandoned in favor of safer, more reliable explosives. Modern enthusiasts of antique weapons sometimes gather together for black powder shoots and other events which celebrate the heritage of this weaponry. Many modern formulations are designed to produce less residue and pollution, making them more pleasant to use.