Earth Day is on the horizon! On April 22, people around the world will celebrate our planet by raising awareness for the environmental movement and encouraging the protection and preservation of Earth’s natural resources. A great way to get students involved and thinking about sustainability is by making “milk plastic” or casein plastic. Unlike traditional plastics, casein plastic is renewable and environmentally friendly, making it the perfect experiment to pair with Earth Day.
Using a few everyday household items, this simple chemical reaction will amaze students as they watch two liquids turn into a sculptable solid. This experiment combines chemistry and creativity, making it a perfect STEAM activity for the classroom.
Step 1: Gather Your Materials
What you'll need:
Step 2: Heat the Milk
Microwave the milk in a microwave-safe bowl for about 90 seconds, making sure the milk is hot but not boiling.
Step 3: Add Vinegar
Add vinegar, stirring slowly for about one minute. The mixture will start to separate as the milk curdles, forming solid chunks (curds) and liquid (whey).
Step 4: Dry the Dough
Pour the mixture into the strainer. Use a paper towel to press down on the clumps and absorb any remaining liquid.
Step 5: Shape the Dough
Knead the dough into whatever shape you’d like, or flatten it and use a cookie cutter for the desired shape.
Step 6: Dry and Decorate
Wait 48 hours for the plastic to dry and harden. Once dry, use sharpies or paint to color or decorate the plastic however you’d like!
Milk contains a protein called casein. When vinegar is added to hot milk, the acid breaks down the protein, causing the casein molecules to unfold and reform into long chains called polymers. This causes the curdling or “clumping” and helps bind the solids together. The malleable nature of these new compounds is what classifies them as plastic. Casein plastic is the plastic made from milk.
Milk was commonly used to make plastic in the early 20th century. In the 1920s and 1930s, casein plastic was used for crafting buttons, jewelry, fountain pens, combs, and more!
Mobile Ed helps schools celebrate our planet all year round with the Earth Dome! This unique assembly program offers students an immersive opportunity to learn about the world's continents, oceans, and geographical features using a giant inflatable dome. This larger-than-life presentation helps students better understand the scale of the planet by giving them an all-new perspective. Contact Mobile Ed today to bring engaging, memorable educational assemblies like the Earth Dome to your school!
Project inspired by: Little Bins for Little Hands and Scientific American