Is it Possible to Turn Milk into Plastic?

Can you believe that milk can be changed into plastic? Our Turn Milk into Plastic is a super easy experiment with everyday household items. This experiment teaches your kids the basic chemical polymer knowledge.

Age: 6+          Time: <30min

 Safety 

1. Adult supervision.

2. Be careful, when cooking the milk.

 Materials List 

• Milk 240ml
• White vinegar 60ml
• Pot
• Heater
• Beaker
• Gauze
• mold (optional)
• Glass rod

 Instruction 

Step 1/5 – Pour 240ml of milk into the pot and cook it until it boils.

Step 2/5 – Pour 60ml of white vinegar after boiling the milk. Stir it up. You can find that the cloud-like chunks appear.

Step3/5 – When there are no more cloud-like chunks appearing, stop heating. Filter the milk through the gauze.

Step 4/5 – Squeeze the liquid out of the chunks on the gauze. Shape the solid into any shape you like.

Step 5/5 – Let it dry for 1-2 days and the milk becomes a hard ‘plastic’ after the water completely evaporated.

 Troubleshooting 

What if there are so less cloud-like chunks on the gauze? 

— You need to add more vinegar when cooking the milk.

What if your plastic is kind of soft?

— Let it dry for a longer time. It is mostly because there still is some water left in the plastic.

 Scientific Description 

Plastics are all similar, containing molecules stick together into a long chain called polymers. Milk contains negative charges. The vinegar is kind of acidic and contains a lot of positive charges. When they meet, they will neutralize.  This causes the casein molecules which are rich in the milk, to unfold and clump together into long chains which is a kind of polymer, a collection of many single molecules. And，without any doubt，this polymers share the trait of plastic.

 Extensions 

You can make some small dolls to decorate your kids' bedroom.