Description: The Rubens' tube was invented by German physicist Heinrich Rubens in 1905. It is a tube that is sealed at both ends in includes a flammable gas like propane. A speaker is attached to one end of the tube so sound waves can be transmitted thought the air/gas mixture. Small holes are drilled in the top of the tube and when the air/gas mixture emerges it creates a flame. As sound is played standing waves are created in the flames that change as the frequency of the waves is changed.
Web Resource: Rubens’ tube - Wikipedia