Coin and feather tube
Put a coin and a feather (or a piece of paper and a golf ball) in a plastic tube. When the tube is opened, the feather will fall more slowly than the coin (or the paper will fall more slowly than the golf ball). When the tube is evacuated, the feather and coin fall at the same rate.
|Plastic tube with feather and coin (or a piece of paper and a golf ball) that can be sealed||021-15B|