3C20.43 - Coin in a Balloon

Code Number:
Demo Title:
Coin in a Balloon
Frequency of Sound Waves
Area of Study:
Oscillations / Acoustics
Balloons, Quarters or Dimes.

Put a dime or a quarter in a balloon.  Blow the balloon up and tie it off.  Rotate the balloon so that the coin starts to travel in a circle inside the balloon.  The edges of the coin on the balloon will create a sound whose frequency depends on the velocity of the coin inside the balloon.

  • Bobby Mercer, "Rubber Maraca", Junk Drawer Physics, p. 69.

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