Helmholtz Resonators with tuning forks and a candle

3D30.40 • B+45+51

diagram for demo

Several Helmholtz resonators are set out with tuning forks of the correct frequency to excite the cavity. When these tuning forks are stuck the sound from the tuning fork increases noticeably. A candle can be set out directly in front of the Helmholtz resonator and, when the cavity is excited, this will substantially disturb the flame. A camera is used to illustrate this effect to the class.

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. 3D30.60 Kundt's tube: Powder in tube shows standing waves.
B+45+0 Steel spring pendulum, inverted, vibrates at 10 Hz. B+45+5 Giant tuning fork, barely audible, displayed with stroboscope. B+45+10 Ultrasound transducers (40 kHz) as both sources and receivers. B+45+15 Bell ringing in a jar evacuated with pump. B+45+20 Savart's wheel: Toothed wheel and cardboard or air jet. B+45+25 Siren: large, electric motor driven. B+45+30 Compressed air jet blows through spinning disk with holes. B+45+32 Twirling Tube B+45+35 Sprockets on shaft rotate against a card to make sound. B+45+40 Caruga horn: Varigated tube to blow through B+45+42 Hoot Tube B+45+45 Galton's whistle: Compressed air whistle. B+45+50 Helmholtz resonators drive radiometer vanes, using tuning forks. B+45+55 Casio electronic synthesizer with amp and speaker. B+45+41 Feedback from microphone/speaker system. B+45+60 Applet: Vibrational Behavior of an Empty Beer Bottle B+45+65 Applet: Vibrational Modes of a Tuning Fork