Science Fun

Milk Sculptures

Materials:

  • Microwave safe bowl
  • Skim Milk (1 and ½ cups)
  • White vinegar (4 tspn)
  • Strainer
  • Plate (paper plate is fine)

Instructions:

Have you heard the nursery rhyme “Little Miss Muffet?” Remember how she sat on her tuffet eating her curds and whey? But, do you know what curds and whey are? Here’s a fun way to find out:

  1. Pour 1 ½ cups of skim milk into the bowl. You can use whole milk, but skim works best.
  2. Add 4 teaspoons of white vinegar and stir it for about 10 seconds.
  3. Microwave this mixture for about 2 minutes. If you’re not allowed to use a microwave, make sure you ask an adult to help you.
  4. Carefully remove it from the microwave. Be careful because it can be hot. The milk should have separated into two parts, a liquid and a solid. The curds are the solid part and the whey is the liquid part.
  5. Pour the curds and whey through a strainer.
  6. Once you are sure it is not too hot, take the curds out and squish it into a ball. It will feel like rubber. You can even form shapes with the curds then leave it out to harden. If you let it sit out for 1-2 days, it will harden just like plastic.

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How it Works:

Vinegar has a type of acid in it called acetic acid. The acid in the vinegar causes a protein (casein) in the milk to clump together when it is heated. Casein is very similar to plastic because of the tiny molecules it is made out of.

Extra Experiments:

What happens if I use lemon juice instead?
What happens if I don’t heat it, but just let it sit out?
Can you use this to make fossil imprints? Let them harden and then paint them!