> Considering we never took the cap off and lit it off with the spark, wouldn't the amount of energy in the bottle go up with the pressure? I have been playing

> Considering we never took the cap off and lit it off with the spark, wouldn't the amount of energy in the bottle go up with the pressure? I have been playing a bit with a potato/hairspray cannon. If you don't have a good seal (that's why you use a potato), you get no boom. I tried to shoot snow, but it would just go hsssst. I'm thinking the initial combustion raises the pressure enough for the fuel mixture to detonate, and if the seal is't good enough, the fuel will just burn gradually.