What You Need:
- Bowl of cold water
- Coin (bigger than the bottle opening)
- Any glass soft drink bottle
- Fill a bowl with some cold water.
- Place the bottle neck and coin in the bowl of water to chill them. This helps to make an airtight seal when you place the coin on the top of the bottle.
- Now place the coin on top of the bottle and wrap your hands around the bottle. Wait for several seconds.
Why does the coin jump? When you hold the bottle with your hands, the air inside the bottle heats up. The warm air pushes harder than the cool air that is outside the bottle so it forces the coin up. When the air inside the bottle cools down the coin will stop jumping.