Rubens tube demo

This outreach rig is built around a classic Rubens tube, transforming invisible sound waves into a vivid, unforgettable display. The system consists of a long, sealed metal tube perforated with evenly spaced holes along its length and fed by a regulated gas supply.

When ignited, a line of small flames forms above the holes, creating a steady baseline pattern. An integrated audio driver—connected to a function generator, microphone, or music source—introduces sound into the tube.

As pressure waves reflect inside, standing waves develop, causing distinct variations in gas pressure along the tube. These pressure differences translate directly into flame height: taller flames mark pressure antinodes, while shorter flames reveal nodes. By changing the frequency or playing music, the flames dance in real time, allowing audiences to see resonance, wavelength, and harmonics.

Designed for public engagement, the rig emphasizes safety and clarity: sturdy mounting, clear flame shields, simple controls, and bold visual contrast make it suitable for classrooms, science fairs, and stage demonstrations. The result is a dramatic, multisensory experience that bridges physics and art—turning sound into fire and abstract wave behavior into something instantly intuitive.