Join our 4-H teen as he steps into the world of chemical science.
What are we learning about today?
Did you know you can actually make plastic out of milk?! It might sound unbelievable, but back in the 1900s, people used to craft buttons, jewelry, combs, and elaborate items for royalty.
Milk contains a protein called casein. It's what makes milk white! When the casein comes into contact with an acid, like vinegar, it changes the milk's pH, making the casein molecules unfold and link together into long chains called polymers.
What do you need?
- 1 cup of milk
- 4 teaspoons of white vinegar
- 2 mugs or heat-safe cups
- Paper towels
- A spoon
- Microwave or stove
- Optional: cookie cutters, glitter, food coloring, or markers for decorating
Try it yourself:
- Mix the ingredients
- Pour 1 cup of milk into a microwave-safe container and heat it at half power for about 5 minutes. You want it warm (like hot cocoa warm), not boiling.
- Pour it.
- Pour the 4 teaspoons of vinegar into your mug.
- Slowly pour in the hot milk. Watch closely, something's about to happen.
- The milk should start forming little white clumps called curds.
- Scoop it.
- Stir the mix gently for a few seconds, then scoop out the curds with a spoon. Try to drain off the extra liquid as you go.
- Lay down a few paper towels and pile the curds on top. Then fold the paper towels over and press to soak up as much liquid as you can. You can swap in fresh towels if it's still damp.
- Mold it.
- Squish the curds together with your hands, kind of like dough. That's your milk plastic!
- While it's still soft, you can mold it into shapes with cookie cutters, sculpt it by hand, or add food coloring or glitter.
- Then leave it out to dry for about two days. Once it's hard, you've made your very own casein plastic creation.
Open and print the supply list for yourself!
Want to learn more?