What you need

• A metal coat hanger
• A pound coin
• A file

Instructions

1. Carefully pull the coat hanger out of shape until it forms a square. Bend the hook so that it points towards the newly-formed corner and file the end flat
2. With the coat hanger on one finger, balance the coin on the hook. This might take some patience!
3. Once the coin is in place, start swinging the hanger back and forth. Can you get the hanger to swing in a complete circle without the coin falling off?

Results and Explanation

The circular motion of the hanger means that a centripetal force acts to keep the coin firmly in place while you’re swinging.

These experiments have not been specifically safety tested for home use but we believe them to be safe if the instructions are followed. Adult supervision or direction is recommended as appropriate. All experiments are carried out at your own risk.