What did Chinese inventors discover while experimenting with saltpeter?

Gunpowder

Chinese inventors discovered gunpowder while experimenting with saltpeter. Saltpeter is a naturally occurring mineral that is composed of potassium nitrate. When saltpeter is heated, it decomposes and releases oxygen. This oxygen can be used to fuel a fire. Chinese inventors used this discovery to create gunpowder, which is a mixture of saltpeter, charcoal, and sulfur. Gunpowder is highly flammable and can be used to create explosions.