Kundt’s Tube

Demo:

This demonstration shows the locations of pressure wave nodes and antinodes of a pressure wave through the interaction of the medium of which the pressure wave propagates with another medium, typically crushed Rice Krispy Treats or cork dust.

Equipment:

• Plastic Tube
• Speaker ( the one used for the Ruben’s Tube Demo)
• Signal Generator
• 3 Jack Stands
• Crushed Rice Krispy Treats or Cork Dust

Set Up:

1. If there is no available cork dust, finely crush Rice Krispy Treats into a powder. Place this evenly across the plastic tube.
2. Place the plastic tube filled with Rice Krispy Treats powder on 2 jack stands. This allows the tube to be easily aligned with the speaker.
3. Place the Speak on a jack stand, and attach the speaker to the signal generator.
4. Align the level plastic tube to the center of the speaker, with the end of the plastic tube touching the speaker.
5. Turn on the function generator. Tune the frequency to around 180 Hz. Increase the amplitude until the Rice Krispy Treats powder begins to condense into segments due to pressure wave nodes and antinodes.

Written by Ryan Dudschus