We've all played around with vortex air cannons when we were younger, using the powerful air gusts to attack our friends' hair or send papers flying. But what happens if you replace the air with propane and increase the size of the cannon tenfold? You end up with an epic video of a vortex cannon shooting fire rings across a backyard. I cannot stress this enough. Do not try this at home.
According to Popular Science: "A vortex cannon is a simple device. With a flexible, airtight membrane on one end and a tapered opening on the other, a person can pull back on the cannon and send a surprise gust of air at an unsuspecting passerby."
According to Popular Mechanics: "In this video for GoPro, the Backyard Scientist, Kevin Kohler, makes a giant vortex cannon using a wooden frame, a trash can, and a little bit of plastic to launch toruses of propane across his yard and into a pilot light. This might not be a great thing to fire at coworkers, but it sure would be a fun way to spice up a bonfire."