No one knows exactly when gunpowder was invented. It was invented and used in China by9 centrys for firecrackers and incendiary devices thrown by a catapult.
Gunowder is basically a fuel, and an oxidizer to make that fuel burn VERY quickly. As it burns, it produces gasses that are very hot- due to the heat, they expand rapidly. These expanding gasses can...
The only invention that could be argued as the single "greatest" of all time are the very first tools that humans created; simple axes and knives that were forged from shards of stone. This invention...