Mysterious coin

Material List:

1. 2 liter plastic soda bottle
2. small coin
3. water

Procedure:

Be sure the coin is big enough to fit over the opening of the bottle. Wet the coin with water before placing it on the 2-liter bottle. The water will enable a good seal around the top. Place both hands around the sides of the 2-liter bottle without squeezing the bottle.

Scientific Principle:

The warmth from the hands will warm the air inside the bottle. When the air inside warms, the air will expand causing the coin to flip up to release the build up. This demonstrates that hot air expands its molecules causing them to become more active and less dense than the colder air.

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Air Density