There’s a good chance that this is just a crazy guy setting fires in his garage, but there’s an equally good chance that he’s teaching us something about physics. The Ruben’s Tube was invented in 1905 by a German Physicist named Heinrich Rubens. It’s purpose is pretty clear, to visualize sound waves using many small flames, though I can’t imagine how he came up with the idea.
Not only that, imagine hearing about this in 1905. Your friend tells you about some sort of mad scientist who is using fire to visualize a invisible shape that accompanies sound wherever it goes. I wouldn’t know whether to be afraid of what else this man is capable of or in awe of his super-human control of the elements. Anyways, enjoy the modern day execution of an old experiment.