Potato launchers are simple. Two tubes–one large, one small–some propellant, a potato, and a spark. You can build one in a day and start spraying spuds into the sky. What’s not so simple are the physics happening inside the barrels. But to see those, you need a powerful camera (and neighbors willing to endure midnight potato explosions).
In the latest video from the fantastic and educational SmarterEveryDay, Destin is bringing us inside a potato launcher in order to figure out the best way to fire one. He always assumed that igniting the combustion chamber from the center would be the best bet — a symmetrical expansion of gases could be the most powerful. However, when looking at the 20,000 frames per second footage, Destin finds that chemistry may be the limiting factor.
Most people assume that you can just light something flammable, like gasoline, on fire. Nope. Not even gasoline will combust unless it has the correct oxygen-to-fuel ratio. That’s why gasoline in your car has to be vaporized before it can explode, and why you can’t blow up a bucket full of gasoline by just lighting the top.
You’ll have to watch the video above to find out whether igniting a potato launcher from the middle or from the back is best, and why, but know that Destin has captured some of the coolest combustion footage I have ever seen. It’s reminiscent of the gorgeous “sewer explosion” footage that the MythBusters captured a few years back.
What do you think? Does this make you want to craft your own transparent potato gun? Because I’ll be right back…