Gunpowder, or black powder, is the world's first chemical explosive. The gunpowder formula mixes sulfur, charcoal and potassium nitrate. Gunpowder is generally used as an explosive, but it has also had some rather unusual uses throughout history: for sterilization on ships, for lack of salt when there was no other food available. , for tattoos when ink was not available and for fireworks and firecrackers.