Make a Plastic Toy
Create your own plastic, and mold it into a tiny toy. Don't expect it to look store-bought!
- 4 oz. of milk (120 ml)
- 1 teaspoon of vinegar (5 ml)
- a small pan
- a small clean jar
What to do:
Heat the milk in the pan until it forms lumps (curdles). Slowly pour off the liquid. Put the lumps into the jar and add the vinegar. Let stand for an hour or so.
A rubbery blob forms. Again slowly pour off the liquid and shape the blob into a ball or a face. Leave it to harden for a few hours or longer in the open jar or on a paper towel. Color it with acrylic paints if you wish.
When the vinegar and milk interact, the milk separates into a liquid and a solid made of fat, minerals and protein casein (made up of very long molecules that bend like rubber until they harden). At first, plastics were made from milk and plants. Now they are made from petroleum, and this poses a problem, because they don't decompose.