Alright, this might be a dumb question.. my friend and I are in a little debate. I have built two kinds of "potato cannons": one uses the force of a acetelyne gas + oxygen reaction for the energy (single explosion, flings it far). The other uses actual compressed air: I would pump air into a chamber to about 60 PSI, hit a valve, and it would decompress out with the object. He says that TECHNICALLY, both can be considered "compressed air" cannons. Any thoughts?