Ruben's Flame Standing Wave Tube
Safety Warnings
Warning: Open Flame / Gas Hazard
Warning: Speaker Cooling Required
Purpose
Visualizes standing acoustic waves using a propane-filled tube with rows of small flames that respond to pressure variations. Students directly observe nodes and antinodes as differences in flame height, connecting frequency, wavelength, and resonance concepts.
Figure 1:
The Ruben's tube in operation in a darkened room. The row of flames along the tube becomes a standing wave pattern when driven at resonant frequencies.
Figure 2:
Speaker end of the tube showing the signal generator, propane supply, and barbecue lighter for ignition. Small blue flames are visible along the tube.
Figure 3:
Water cooling connection at the sink end. Clear tubing connects the faucet to the copper cooling tube that runs through the speaker housing.
Figure 4:
Full setup on the lecture bench showing the tube length, signal generator, propane supply, and water cooling lines.
Equipment
- 1
Demo Apparatus
- 1