physicist call

[Suicide Junkie]

We have a propane-powered PVC cannon at the cottage. 2 meters long, with a fat combustion chamber at the bottom and a skinny barrel for more velocity. There's also a remote ignition system, so we can take cover

Kaaa-FOOM. Then, a few seconds later, a splash far across the lake

We even made a silencer for it out of metal, which works surprisingly well. Cuts the noise level way down, and dosen't seem to affect the power.