This is a video of Destin Sandlin of Smarter Every Day (not me!) firing his homemade clear PVC potato cannon in ultra slow-motion to teach us a lesson about how awesome fire and explosions. Or something. HOLD ON, let me read. Actually, hold on and let me just copy/paste while I microwave a Pop-Tart (Frosted Raspberry).
During the video, Destin is trying to determine if it's better to ignite the cannon from the back end or the middle of the combustion chamber. His hypothesis is that igniting from the middle is better as it will result in a more even explosion. Along the way, he gives a primer on the basic mechanics of a combustion chamber and explains how hard it is to get good efficiency.
I love how Destin laughs after he fires the thing for the first time because he's out making loud noises at night. He's all, "It's like nine o'clock!" You wild child. When I was in high school my long-time girlfriend's dad built a potato cannon to fire off at a barbecue, which he did, but on one shot I think he may have sprayed too much hair spray or the potato was wedged in there really good because the blast actually blew the PVC screw cap off the end of the thing and f***ed his leg up pretty bad. So much blood. It's cool though, he never liked me anyways.
Keep going for the video.
Thanks to Hooby, who made a potato cannon bong to force the smoke into your lungs as fast as possible and has seriously injured everybody who's ever tried it.