Find More  Science Experiments
What You Need:
- Baking Soda
- Coffee Filter or Paper Towel
- 2 Large Cups
Pour 1/2 cup of milk into a large cup. Add 2 teaspoons vinegar. Mix. Place a coffee filter or paper towel over a second large cup. The coffee filter should sag a little bit to make a little filter bowl. Put a rubber band around the top of the cup so it holds the coffee filter in place. Now pour the milk/vinegar mixture into the filter bowl you made.
Let the liquid part of the mixture drip through the filter. This might take awhile. When the liquid is done dripping use a spoon to scrape the milky lumps off the coffee filter and into a bowl. Add 1/4 teaspoon baking soda to the lumps and mix. Is this substance getting sticky? Try it out – can you use it to glue two pieces of paper together?
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 the lumps of milk are pliable and bendy. When you add baking soda (a base) to the milk lumps another chemical reaction happens turning the milk lumps into a sticky glue.
Science Experiment Idea: Make three batchs of milk glue, but make the variable (the thing you change) the amount of baking soda you add to the mixture. If you add 1/8 teaspoon baking soda to one batch, 1/4 teaspoon baking soda to one batch and 1/2 teaspoon baking soda to one batch, which one will be the most sticky? Why do you think so?
Here are some books and website that will help you make and understand glue made from milk:
- eHOW: How to Make Glue Out of Milk 
- American Chemical Society: G is for Glue 
- ZOOM Glue 
- TryScience: Stick to It 
- Learn Chemistry: Developing Glue 
- PBS: Cheesy Chemistry 
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.