Activity: Mighty Morphin Milk Print

mighty-morphin-milk-300Who knew that moo juice could be so much fun? Mix milk and vinegar together to create your own plastic, ready to be molded into any shape you want!

You’ll need:

- 4 ounces of milk
- 1 teaspoon of vinegar
- a small pan
- a small clean jar

What to do:

1. Heat the milk in a pan until it curdles, or forms lumps.

2. Slowly pour off the runny liquid.

3. Put the lumps in the jar and add vinegar. Let it stand for an hour or so.

What happens:

After an hour or so, you’ll find that a rubbery blob has formed in the jar! Slowly pour off any runny liquid inside. Then take the blob out and shape it into a ball or some other simple shape. Let it harden in the open jar or on a paper towel for a few hours or longer. Once it has dried, you may want to decorate it with acrylic paints.

Why this happens:

When the milk and vinegar (or any kind of acid) are mixed together, the milk separates into a liquid and a solid made of fat, minerals, and a protein called casein (KAY-seen). Casein is made up of very long molecules that bend like rubber until they harden.

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