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Doppler Ball
# 3B40.10

320x240 456K
160x120 326K
Description: A buzzer and battery are in a tennis ball at the end of a long string. Whirl the buzzer in a horizontal circle over your head. Point out the difference in sound between the moving and stationary buzzer.

Purchased/Built: built

Setup Time: none

Quant. in Demo Room: 1

Demo References
The Video Encyclopedia of Physics Demonstrations Disc 10-21 Mount two speakers on a rotating frame and attach to an audio oscillator through slip rings.
Freier and Anderson Si-3 A battery operated oscillator drives a speaker mounted on a 3' turntable.
The American Journal of Physics AJP 41(5),727 Attach a Sonalert to a 2 m string and the shift is almost a minor third. MORE: interference and radiation resistance.
The American Journal of Physics AJP 29(10),713 Mount a buzzer and a battery on opposite ends of a meter stick and rotate about the center of mass.

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