Wednesday, July 13, 2011

Ruben's Tube!

Just wanted to make a few notes about my latest project - a Rubens' Tube!  This is a simple apparatus that should be in every high-school physics class, as it involves music/sound, fire, and awesome visualizations!

Though the interaction of pressure waves in and fire predates Heinrich Rubens' experiment in 1904, he is credited with bringing it all together in a great package!  Here's a simple diagram, thanks to the folks at

I was inspired and helped by my friend, DB, who has made a few tubes of varying sizes already!

Here's my tube.  It's 12' long, 6" diameter, aluminum pipe with a 1/8" wall thickness
Here's the boring end of the setup -- just a cap to seal in the propane on the end of the tank.

Here's the business end of the pipe, with a 1/2" ring attached (JB weld) to the pipe, a diaphram of Buna-N rubber (1/32nd -- would prefer thinner) sandwiched tightly to prevent propane leakage, and a 6" speaker.

The 1/32nd inch diameter holes are each spaced about 1/2" apart, along the entire length of the pipe except for 6" at each end.
 Here's our propane entry nozzle.  We thought it would be artistic to insert propane halfway down the tube, but really it just makes the flames larger there, and its distracting.  We may move it down to the "cap" end of the pipe (far from speaker).

And finally, here's our Rubens' Tube, playing Imogen Heap's "Hide and Seek", 

Here are snapshots showing three different notes that occur in the song:
4 nodes
5 Nodes
13 Nodes