Materials Required:
l Small, glass soda bottle
l Freezer
l Water
l Coin
Procedure:
- Wash out an empty glass soda bottle and place it in the freezer.
- After several hours, remove the bottle and moisten the top with water. Set a coin over the opening. The coin should make a seal at the mouth of the bottle.
- Cup both hands around the sides of the bottle. Soon, the coin will jump up and down, tapping out a fascinating rhythm on the glass surface.
This Is What Happens:
Cold air is trapped inside the bottle. As it begins to warm up, the air expands and forces the coin up. A little bit of air escapes and the coin falls back down. The process is repeated until the air inside the bottle reaches the same temperature as the air in the room.
