Plastic Milk

Can you turn milk into plastic? Milk is full of a protein called casein. When you add an acid like vinegar, it lowers the milk’s pH and causes the casein molecules to unfold and link together into long, repeating chains — a process called polymerization. Those chains clump into solid curds you can lift out, dry, and knead into a moldable, all-natural plastic called casein plastic. Believe it or not, this same material was once used to make buttons, beads, and jewelry over 100 years ago!

Visit science-u.org for instructions on how you can perform this experiment at home.