Talk about a hot beat!
With the help of a "pyro board," Sune Nielsen, a masters student in physics at Denmark's Aarhus University, uses fire to represent music visually. The result, displayed in the video above, is absolutely mesmerizing.
Exactly what is this pyro board? It's a sealed metal box that allows flammable gas to mix with sound waves. Atop the box, gas flowing out of 2,500 perforations creates 2,500 individual flames that pulsate in time to the music produced below. At certain frequencies of sound, the device reveals standing waves, which appear as an unmoving pattern of flame resembling a sine wave.
This particular device was created by Fysikshow, a physics outreach program for students in Denmark.
In a demonstration for the science video blog Veritasium, Nielsen explains that the pyro board was inspired by a simpler device called a Rubens' Tube. Unlike a pryo board's matrix of perforations, Rubens' Tubes feature a single line of perforations.
A Mythbusters" video from 2008 offers a primer on Reubens' Tube physics:
[When a tone is played] through the speaker, the sound wave enters the tube, and the confined space creates reflections and interference, which combine to create a standing wave. The standing wave affects the air pressure inside the tube, which affects the amount of gas coming out of each perforation, which affects the size of each individual flame.
WATCH the pyro board in action, above. The video opens with an explanation of how the board works. Skip to 3:88 to "see" the music.