Plastic milk experiment

Plastic milk experiment

This fascinating and easy science experiment shows your kids just how cool science can be! Make this weird plastic milk together and teach the little ones about chemical reactions. Best of all they get to be creative with the end result.

What you need:

  • Cup of milk
  • 4 teaspoons of white vinegar
  • Bowl
  • Strainer
  • Microwave oven

Number of players:


Put the milk into a bowl and microwave for a minute or two depending on the strength of your microwave. Be careful not to let the milk boil. You want it hot, not boiling.

Stir the vinegar into the milk. Keep stirring for about a minute.

Take a strainer and, over a sink, pour the hot milk mixture through it. You want to keep the white lumps left in the strainer when the rest of the liquid has passed through.

Once the lumps are cool, press them together into one mass.

Press the material into a mold or create your own shape and set it aside. In a few days time it will harden into a plastic-like consistency.



  • The lumps left behind by the strained milk are called casein. This is a material that is produced when the protein in the milk reacts to the acid in the vinegar.
  • The casein separates away from the acid and forms the lumps you can collect and then mold.
  • While it is plastic-like, true plastics are made from polymers and not milk and vinegar.

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