WHAT YOU NEED: 1 cup whole milk, small saucepan, measuring spoons, white vinegar, clean, empty glass jar, wax paper.
WHAT TO DO:
1. Pour the milk into the saucepan, add 2 teaspoons vinegar, and heat, stirring frequently.
2. The milk will boil, then form tiny lumps (curds) in a clear liquid (whey). Slowly pour off the liquid from the pot into the sink. Then spoon the curds into the jar.
3. Add 1 teaspoon vinegar to the curds, and let the mixture stand for one to two hours.
4. The curds will form a yellowish glob at the bottom of a clear liquid. The glob is actually fat, minerals, and the protein casein. Pour out the liquid, remove the rubbery yellow glob from the jar, wash the glob with water, and knead it until it attains the consistency of dough.
5. Mold the plastic into any shape you wish, then place it on the wax paper. Let dry overnight.
WHAT HAPPENS: The casein from the milk hardens into plastic that can be painted with acrylic paints.
WHY IT WORKS: The combination of heat and acetic acid precipitates the casein, an ingredient used to make plastic, from the milk.