gunpowder

Oldest known explosive, a mixture of 75% potassium nitrate (saltpetre), 15% charcoal, and 10% sulphur. Sulphur ignites at a low temperature, charcoal burns readily, and the potassium nitrate provides oxygen for the explosion. As gunpowder produces lots of smoke and burns quite slowly, it has progressively been replaced since the late 19th century by high explosives, although it is still widely used for quarry blasting, fuses, and fireworks. Gunpowder has high activation energy; a gun based on gunpowder alone requires igniting by a flint or a match.

It was probably first invented in China, where it was chiefly used for fireworks. It is possible that knowledge of it was transmitted from the Middle East to Europe. The writings of the English monk Roger Bacon show that he was experimenting with gunpowder in 1249. His mixture contained saltpetre, charcoal, and sulphur. The development of effective gunpowder was essential for the growing significance of cannons and handguns in the late medieval period. The Arabs produced the first known working gun, in 1304. Gunpowder was used in warfare from the 14th century but it was not generally adapted to civil purposes until the 17th century, when it began to be used in mining.