This is Part 1 of a three-part series.
Science doesn’t have to be complicated! While some experiments might need expensive lab equipment and dangerous chemicals, there are many cool projects you can do with things at home. Try out these 3 simple and easy experiments that you can do at home. Make sure to always have a parent present to help you with your experiments to ensure nobody gets hurt!
Turning Milk Into Plastic
Turn Milk into Plastic! (2023b, October 4). How Wee Learn. https://www.howweelearn.com/turn-milk-into-plastic/
Introduction
This experiment may sound like something made up or impossible, but you would be surprised to learn that milk was used to make many different items from the early 1900s up until around 1945. These items included buttons, beads, decorative buckles, fancy combs, and brush sets. Milk plastic, also known as casein plastic, was even used to make jewelry for Queen Mary of England!
Plastic can be defined as a group of materials that can look or feel different, but can all be molded into many shapes. The similarities and differences between various plastics are due to the molecules they are made of. All plastics are similar because they are all made up of molecules that are repeated continuously in a chain, called a polymer. Polymers can be a chain of one type of molecule, or a chain of many different molecules linked together in a sequential pattern.
Materials & Equipment:
1 cup of milk
4 teaspoons of white vinegar
Measuring cups/spoons
Mug or other heat-resistant cup
Paper towels
Spoon
Optional: glitter, food coloring, markers, cookie cutters
Microwave or stove top oven & pan
Instructions:
Heat one cup of milk in a pan on the stovetop until it is steaming
Alternatively, you can microwave milk by warming it at 50% power for 5 minutes
Add 4 teaspoons of the white vinegar to a mug
Add the hot milk to the mug - You should be able to see the milk form white clumps (curds)
Mix slowly with a spoon for a few seconds
Stack a few layers of paper towels on a safe hard surface to get damp
Once the milk and vinegar have cooled a bit, use a spoon to scoop out the curds onto the paper towel - try to let the excess liquid drain off the spoon while getting the curds out
Fold the edges of the paper towel stack over the curds and press down on them to absorb any excess moisture from the curds
Knead all the curds together into a ball of dough - this is the casein plastic
You can make the plastic into anything you’d like!: You can color, shape, and mold it now
Mold the plastic within an hour of making the plastic dough
Leave it on the towels for at least 48 hours. Once it has dried, the casein plastic will be hard.
What happened?:
Milk contains molecules of a protein called casein. When you add the hot milk to the vinegar, small, white chunks should have become visible in the mixture. This is because adding an acid, such as vinegar, to the milk changes the pH of the milk and makes the casein molecules unfold and reorganize into a long chain, curdling the milk. Each casein molecule is a monomer and the chain of casein monomers is a polymer. The polymer can be scooped up and molded, which is why plastic made from milk is called casein plastic.
Clean up:
To avoid clogging the sink, discard any unused curds in the trash - DO NOT pour them down the drain.
About the Author
Laney is a sophomore at Northwood High School and is a member of their track and field team, mix up club, and unified club. She loves working with kids, being outside, and hanging out with friends and family.
Sources
Science Buddies. “Turn Milk into Plastic.” Science Buddies, Science Buddies, 31 May 2014,
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