Clickety-Clackety Coin

coin experiment

What You Need:

  • 2-liter plastic soda bottle
  • A quarter
  • Water


  1. Place the empty uncapped bottle in the freezer for 10 minutes.
  2. Dip the coin in water.
  3. Remove the bottle from the freezer and immediately place the wet coin on the top of the open bottle.
  4. Wait and watch the coin move! As it moves, it will make a clickety-clackety noise.


When removed from the freezer, the cold air inside the bottle expands and tries to rush out of the bottle. This air flow causes the coin to move!