Turn milk into plastic!

Did you know that you can use milk to make plastic? Why not give this simple experiment a go and experiment with different, shapes, sizes and colours.


You will need:

  • Milk
  • White Vinegar
  • Food colouring
  • A sieve/strainer
  • Hotplate/hob
  • Spoon


  • Use the hob to heat around 1 cup milk until it is hot but not boiling. Remove the milk from the heat and pour into a heatproof bowl. Make sure it is not too hot!
  • Add around 4 teaspoons vinegar to the the milk and stir until mixed
  • Pour the mixture through the sieve/strainer and you should find a lot of blobs left behind in the sieve
  • Mould these blobs into a shape (you could use a cookie cutter to help you) and place them on a tray/plate to dry.
  • It may take a few days but keep an eye on your milk shapes and they should turn into a plastic substance!

The Science Bit:

Milk is full of protein, a molecule made up of things called amino acids. When the protein meets the acid in the vinegar it clumps together to make something called casein which is what you have made. Casein is not a true plastic but it is very similar! Try the experiment with different types of milk or try adding food colouring to make coloured plastic!