Yesterday, I was lucky enough to spend some time with my friend Larry, a man with enough patience to teach science to 12-year-olds. Here’s one of the tools he’s going to use in the upcoming school year — a vortex cannon! Okay, so it’s basically a trashcan with a hole cut in the bottom and a shower curtain stretched across the top, but it’s mega-cool. Basically, when you slap the shower curtain you send a surprisingly strong blast of air through the hole, demonstrating the fact that air takes up space and can be displaced. If you pick up a fog machine, you can fill the trashcan with smoke and blast out rings. Here I am shooting rings of fog out into the woods!