This is a sound wave, as represented by fire. Making it the most metal oscilloscope in history.
To be exact, it’s called a Ruben’s Tube. And it’s playing the start of the chorus to Journey’s Any Way You Want It. It must be closing time in the clubs, that’s the only reason they play Journey.
Sound is just air vibrations, as the air vibrates it creates sections of high density air and low density air. The more air, the higher the flame can be. So it translates the sound wave for us. Also fire is pretty.
See how it briefly lapses into a sine wave? That happens when Steve Perry’s dulcet tones occasionally hit one of the harmonics of the pipe, making a standing wave. Which is cool.
This loses something without the sound, so please, go listen to the video here
In case you missed it
This is why I studied physics.
This is also why I freaked out whenever people wanted to play with random lab equipment late at night.