What you need

• Bouncy ball or ball of Plasticine
• Piece of paper
• Sticky tape
• Scissors

Instructions

1. Cut the bouncy ball in half
2. Roll the paper into a column around the top of the ball and hold it in place with sticky tape
3. If you flick the column of paper, it will fall over.  Cut off bits of paper until when you flick it, it rights itself again

Results and Explanation

The wobbler is self-righting because its centre of mass is very low. As the wobbler leans over, its centre of mass rises but gravity pulls the wobbler back upright before it can topple over.

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.