What could be more entertaining than fire and good music? How about fire that will dance to that music? The following will not only cause flames to pulse to a beat, but it will also allow you to see different wavelengths of audio frequency. The following is my first Instructable, and my entry to the Instructables Science Fair contest. In addition to documenting the build steps to create something called a Rubens' Tube, I'll also go over some of the basic concepts and science involved with sound waves. From the moment I discovered what a Ruben's Tube was, I wanted to build one... and considering I was in a physics class at the time, there couldn't have been a better excuse than extra credit.
http://www.instructables.com/id/The-Rubens_-Tube%3a-Soundwaves-in-Fire!/