It makes your bones strong, but what else can it make? For this activity, we’re creating fun plastic shapes out of that stuff you pour in your cereal: milk!
What you need:
- Non-homogenized milk
- Microwave or stove top and pan
- White vinegar
- Food coloring
- Small bowls
- Small cookie cutters in assorted shapes
- Paper towel
What you do:
The first order of business is to heat up the milk either on the stove in a pan or in the microwave for two minutes. When the milk is hot, add four teaspoons of white vinegar and stir for one minute. You should start to see clumps forming!
Pour the clumpy milk through a strainer to get rid of the extra liquid. Separate the clumps, which is our plastic, into different bowls. Add food coloring to the bowls to color your plastic.
Take the bits and pat them into cookie cutters to form them into shapes. Press down on them with paper towel to remove excess liquid and make your plastic stronger!
Questions to consider:
- Why did we heat the milk?
- What made the milk clumpy?
- Why do we need to remove the liquid to make the plastic strong?
Why it works:
What we created in our experiment is called casein! It occurs when the protein in the milk meets the acid in the vinegar. Because the two don’t mix, it forms clumps. We can then remove those clumps from the mixture and compress it to form a plastic-like substance. Casein is found in all mammal’s milk and used in processed foods, adhesives, paints, and other industrial products.