Mighty Morphin’ Milk

Who knew that ‘moo juice’ could be so much fun? In this investigation we mix milk and vinegar together to create our own plastic, ready to be moulded into any shape you want!

Adults you need to do the first part but the children can explore the stuff once it’s made.

You Will Need

- 125 mls of milk

- 1 teaspoon of vinegar

- a small pan

- a small clean jar

Instructions

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.

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.

What’s Happening?

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.

Have Fun!

Thanks to, and adapted from discovery.com