Find More  Science Experiments
- Plastic Container With a Lid
- Measuring Cup
Pour 1/2 cup of milk into a bowl. Put the bowl in the microwave for 1 minute. Check the bowl – if the milk looks lumpy you are done. If the milk does not look lumpy yet microwave it again for 25 seconds. Check it again. Repeat until the milk has formed lumps. After the lumps appear add 1 teaspoon vinegar to the bowl and let the bowl sit for 1 hour. After 1 hour is up pour the liquid off the milk lumps. Smash the lumps of milk together like play dough. You can make it any shape you want. If you leave it alone it will turn hard. If you want to save it keep it in a sealed container.
When the milk and vinegar (an acid), mix together a chemical reaction takes place. A substance called Casein forms. Casein is a very long molecule that bends like plastic – that’s why your lump of milk is pliable and bendy until it dries out and turns hard. Casein is also found in cheese…which is made from milk. Does this give you a clue as to how cheese is made?
Science Project Idea:
Make 3 different bowls of milk play dough. Use the same amount of milk in each bowl but use different amounts of vinegar in each one. OR use the same amount of vinegar in each bowl AND the same amount of milk…but use three different kinds of milk: skim, 2% and whole. Guess which bowl will make the best milk play dough. Why do you think so?
Here are some websites and books that will help you understand the science behind milk play dough:
- Zoom: Plastic Milk 
- Science Bob: Make Plastic Milk 
- TryScience: Stick To It Glue 
- ZOOM Glue 
Science Experiments That Surprise and Delight – Lumpy Milk. (page 24-25)
Words to Know:
Chemical Reaction – When a substances or substances is changed into a new substance.
Acid – A chemical that is often sour tasting and corrosive. It dissolves some things.