Still don’t quite get the whole sound = wave thing? Check out the video below, which contains a demonstration of a classic physics experiment: the Ruben’s Tube. Flammable gas is circulated through a perforated tube and ignited. Then, music is projected through the tube, which creates points of higher or lower pressure, and causes the gas flames to mirror the properties of the sound. This one was constructed by Jeff Ryan at the University of Portland. A beautiful visual example of sound waves in action!