Marbled Milk

4-6 year olds | half hour

An example of the potential for science to be beautiful. Everyone will marvel at this simple experiment.

What You'll Need

  • Flat dish or saucer
  • Milk (ideally with a high fat content)
  • Food colouring (the more colours the better)
  • Washing-up liquid


All you need is a saucer or a flat dish and pour some milk in it, and then add a few drops of food colouring. The magic happens when you simply add one drop of washing-up liquid or liquid soap.

What happens is that there’s fat in milk (using homogenised milk rather than 1% or 2% milk is going to give you even more dramatic results), the food colouring sits on the fat that’s found in the milk and when you add the soap it breaks the fat apart and starts moving, and you get the marbled effect.

It’s also great evidence for showing how the grease gets washed off our dishes by using the dish soap. All it takes is a little bit of food colouring, a little bit of milk and a drop of washing-up liquid. You can add a little bit more, but if you add too much it takes away the effect.

Even a minute later it will still be moving and swirling.

Tags: science

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