Science, Tech, Math › Science Making Natural Plastic From Dairy Products Polymerize Casein in Milk to Make a Polymer Share Flipboard Email Print MiguelMalo / Getty Images Science Chemistry Projects & Experiments Basics Chemical Laws Molecules Periodic Table Scientific Method Biochemistry Physical Chemistry Medical Chemistry Chemistry In Everyday Life Famous Chemists Activities for Kids Abbreviations & Acronyms Biology Physics Geology Astronomy Weather & Climate By Anne Marie Helmenstine, Ph.D. Chemistry Expert Ph.D., Biomedical Sciences, University of Tennessee at Knoxville B.A., Physics and Mathematics, Hastings College Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. She has taught science courses at the high school, college, and graduate levels. our editorial process Facebook Facebook Twitter Twitter Anne Marie Helmenstine, Ph.D. Updated October 28, 2019 Plastics are generally produced from petroleum, but they can come from other sources as well! All that is really required is the ability to join molecules containing carbon and hydrogen together, which you do whenever you curdle milk. This takes about 30 minutes. What You Need 1/2 C milk or heavy creamvinegar or lemon juicesaucepan Instructions Pour 1/2 cup milk or heavy cream in a saucepan and heat to simmering over low to medium heat.Stir in a few spoonfuls of vinegar or lemon juice. Continue adding vinegar or lemon juice until the mixture starts to gel.Remove from heat and allow to cool.Rinse the rubbery curds with water. The curds are plastic! Play with your cool creation :-) Useful Tips Adult supervision please - hot stove!The plastic is formed as a result of a chemical reaction between the casein in the dairy product and the acid (acetic in the vinegar, citric and ascorbic in the lemon juice).