What you need

• An empty fizzy drink can
• Some water

Instructions

1. Pour about 100ml of water into an empty fizzy pop can
2. Tip it slightly to one side and balance it so that the two parts of the bottom rim are touching the table
3. Once the can is stable, give it a gentle push and it will pirouette!

Results and Explanation

For something to balance, its centre of mass has to be above its point of support. Water can flow which means that as the can pirouettes, the water moves and the centre of mass always stays above where the rim touches the table.

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.