Properties of Matter

Psychedelic Milk

At home for 5-11 11-14

What you need

  • Shallow bowl
  • Milk
  • Food colouring
  • Washing up liquid


  1. Pour a couple of centimetres of milk in to the bowl
  2. Add a couple of drops of food colouring at even spaces around the edge of the bowl
  3. Add a drop of washing up liquid to the centre of the bowl

Results and Explanation

The colours start to mix and churn! The washing up liquid reduces the surface tension of the milk causing swirls and eddies as the detergent spreads through the liquid.
What happens if you use skimmed or full fat milk? Does warming the milk first make any difference?

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.



Matter and Nuclear CPD videos

Our new set of videos gives teachers and coaches of physics a preview of the training we offer ahead of this term's live support sessions.

Learn more