More plastic milk

Plastic milk was one of the first experiments I posted on Science Sparks, when the kids were quite little.  It was a lovely sensory experience for them at the time, but they obviously couldn’t understand what was happening, with that in mind we revisited the activity with the addition of some food colouring. You can find the full instructions for how to make plastic milk here.

I didn’t measure the ingredients at all this time.

What you need:

  • Semi skimmed milk
  • White vinegar
  • Food colouring
  • A sieve
  • Cookie cutter


  • Pour about a cupful of milk into a pan, add some food colouring if you want it coloured and heat until bubbles start to form. – Be Careful and get an adult to help.
  • Add a tablespoon of white vinegar and watch the solid and the liquid parts of the milk separate.
  • Filter carefully using the sieve.
  • Leave to cool and then mould as you wish

How to make plastic milk

Plastic milk

The Science bit

Here’s what happened to the milk. By adding the vinegar, you created a chemical reaction which caused the milk to separate into two parts, a solid (the curds) and a liquid (the whey).The protein in the curds is what makes it act like rubber. A really simple experiment that gives you something very touchy and feely to do. It also makes a great sensory tool for little ones to play with.

Have fun and let us know if you try to make plastic milk.


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There are 3 comments

  1. Deb

    You can make this edible (and more palatable) if you use lemon juice rather than vinegar. This is exactly how the Indian cheese paneer is made.

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