The world of warfare was revolutionized by the development of black powder, fireworks, cannons, and the like. You don’t need any of that chemical nonsense to just have fun, though, as this compressed air cannon from [OtisLiu153] demonstrates.
This is a companion discussion topic for the original entry at https://hackaday.com/2024/01/01/building-a-simple-compressed-air-cannon-is-easy/