ok this one is pretty cool. we all know that air travels in waves, but because they are waves we have a pretty hard time actually seeing said waves. the Rubens Tube is a way to easily visualize these waves... WITH SCIENCE.
what is happening is, when a note is played on the speaker, the sount travels through the tube in its usual wave pattern. the wave contracts in some parts and expands in others thus creating the alternating heights of the flames.
the wave compresses the propane in some parts of the tube while expands in others, where the gas is compressed we see a smaller flame, where it is expanding, we see a higher flame.
this beats the crap out of the music visualizer on iTunes

btw, you might want to turn down your volume for this one

excuse me god... i'd like to report a bug in your system

how the hell is this possible? it is either the most amazing form of balance i have ever seen or pure shenanigans.
the two ends of the fork and spoon must provide enough torque to cancel each other out. the stick is only there for the balance point. it is amazing that all that weight can balance on just a few cm of wood.
so either the spoon and fork each provide enough torque to cancel out eachother and keep the whole system balanced, or the burning stick created a super sticky resin that has such a high Coeff of friction that it is able to cancel out the outward and downward forces of the fork and spoon. either way, the system is at complete equilibrium.