Forces and Motion


Enrichment Activity for 5-11 11-14

What you need

  • An old CD
  • A sports cap from a drinks bottle
  • Blu Tack
  • A balloon


  1. Place the sports cap in the centre of the cd and fix it in place with the Blu Tack
  2. Blow up the balloon and, making sure the sports cap is closed, pull the open end of the balloon over the cap
  3. Place your hovercraft on a flat surface and open the sports cap. Give it a quick tap and watch your hovercraft go!

Results and Explanation

The air rushes out of the balloon and through the cap, lifting the CD up on a cushion of air. The air reduces the friction between the CD and surface it’s on so the hovercraft can travel a surprising distance before stopping.

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.

is a special case of Force
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