Find out how to make an anti-gravity biscuit tin.

For this experiment you'll need...

  • A blob of plasticine
  • A round biscuit tin
  • A slope

To find out how to make the anti-gravity biscuit tin just watch the short animated video below or follow the instructions underneath the video.


  1. First roll up the plasticine into a ball.
  2. Take the lid off your biscuit tin and put it on its side.
  3. Stick the ball of plasticine inside the biscuit tin.
  4. Position your biscuit tin half way up a slope, but position the biscuit tin so the blob of plasticine is at the top.
  5. Let go of the tin and watch the magic! The tin should defy gravity and roll up the slope!

Science behind the experiment:

Gravity is pulling everything down, into the centre of the Earth. So why doesn’t the tin roll down the ramp?

By attaching the plasticine at the edge of the tin you are changing the tins centre of mass, this would normally be in the middle of the tin. Because the plasticine is heavier than the tin the centre of mass is now around this area. Gravity is therefore going to pull the plasticine down.

When you place the tin on the ramp with the plasticine at the top of the tin (but just off centre towards the top of the ramp), gravity will pull the plasticine downwards resulting in the tin rolling up the hill. If you don’t position your tin correctly, gravity will still pull the plasticine downwards, but this might result in the tin rolling down the ramp instead.

Key Terms:

  • Gravity: is the force by which a planet draws objects to its centre.
  • Centre of mass: the single point of which the weight of an object is acting at.

Activities and Questions:

Does the angle of the ramp alter the experiment?

What weight could be attached to the side of the tin instead of plasticine?

Why does the tin only do a half turn and not keep going to the top of the ramp?