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Home Experiments

PLASTICS

Turn Milk into Plastic

Safety Rules:
Parent supervision
Take care with fire or heat. Always watch the milk while it is heating.
 
Materials you need are:
a stove
a saucepan
a wooden spoon
a teaspoon
a strainer
a container
full cream milk
vinegar
paper towel

Warm some milk in a saucepan. When it is just simmering, slowly add a few teaspoons of vinegar. Keep stirring until the mixture curdles (that is, has lumps in it). Allow it to cool and then drain off the runny part and keep the 'rubbery' lumps. Let them dry on some paper towel for a few hours. You have made plastic.

There is a protein called milk casein that reacts with the vinegar to make a form of plastic.

Shrinking Plastic

Safety Rules:
Parent supervision
Take care with fire or heat
 
Materials you need are:
various recyclable plastics (e.g. Try softdrink bottles, chip or sweets packets)
a pair of tongs
an electric jug to boil the water
a large container or a sink of boiling water

You will need various recyclable plastics (e.g. empty softdrink bottles, chips or sweets packets), a pair of tongs and a sink of boiling water.

Immerse the plastics in the boiling hot water and see if any of them shrink.

Some recyclable plastics shrink their long chain molecules on heating.