The song is "Haro Strait" by the Battlefield Band. The sound is funneled into a Rubens Flame Tube which allows you to visualize the sound waves in flame as Mr. Alasdair White of the band plays the tune. Some notes are of too high a frequency to be resolved by the tube, which makes it appear still for certain portions of the song. Unfortunately, the camera battery died after the fiddle solo, but still a great piece of music to be rendered by the tube.