Kundt's tube: Powder in tube shows standing waves.

3D30.60 • B+55+25

diagram for demo

Kundt's Tube: resonant frequency of a stroked rod causes nodal patterns in dust in a tube. The apparatus is clamped to a table. Plunger A is adjusted. The rod of Plunger B is stroked with a cloth impregnated with resin, causing the rod to resonate loudly (at first harmonic = 2,470 Hz). This excites powder in the glass tube to form patterns in the nodal regions. The frequency f of the resonating rod B can be determined,knowing the distance between the nodes. [f = (speed of sound divided by ) = (344m/sec)/.14m = 2457 Hz.]. Plunger B: Rod is clamped at midpoint. Plunger A: Rod is slid into tube, with black mark positioned under metal holder.

Related Demos

3D30.35 Twirling Tube 3D30.70 Hoot Tube 3D30.40 Helmholtz resonators drive radiometer vanes, using tuning forks. 3D30.50 Ruben's tube: Standing sound waves in flames along a large pipe. 3D30.40 Helmholtz Resonators with tuning forks and a candle
B+55+0 Film loop: "Vibrations of a metal plate", 3:45 min. B+55+1 Film loop: "Vibrations of a drum", 3:25 min. B+55+5 Chladni's disc: Bowed disk forms patterns in sprinkled salt. B+55+10 Large glass bowl with ping pong balls and violin bow. B+55+15 Young's modulus rod: Hammer and rod with nodes marked. B+55+20 Longitudinal wave apparatus: Ball bounces off end of stroked rod. B+55+7 Chladni's Figures: Vibrational modes of a metal plate B+55+30 Applet: Vibrational Modes of a Circular Membrane B+55+35 Applet: Hotel webcam of pool during California Eartquake 2010 B+55+40 Applet: Vibrational Modes of a Rectangular Membrane