Most people buy glue at the store to use when they need to stick things together. Store bought glue is convenient, but for fun, you can make your own glue from 
milk. It’s fun and it’s easy.
Just follow these steps.
Materials
Skim milk (do not use whole or 2% milk)
Vinegar
Coffee Filter Paper (cone type works best)
Paper Towels
Baking Soda
Procedure
Mix 1 cup of milk and ¼ cup of vinegar. Let the mixture sit for 10-15 minutes. The milk will separate and small pieces of a white solid will form. This white solid is some of the proteins in milk (casein) and will end up becoming the glue.
Place the coffee filter paper over a tall glass. Pour the milk/vinegar mixture into the filter. Pour a little bit at a time so the mixture doesn’t overflow the filter. Make sure the bottom of the filter is above the level of liquid in draining into the glass. Let the filter sit for 10-15 minutes so most of the liquid is removed.
Pour the solids into a clean bowl or plastic container. Add two teaspoons of baking soda to the solids and mix. Listen carefully—you will be able to hear the baking soda react with the extra vinegar and you may even see the some bubbles. Add about one teaspoon of water and mix. You’ve made glue. Now try it out on some paper!
Why does it work?
Milk is a suspension—solids are suspended in the liquid (not dissolved like in salt water). When you add vinegar (an acid), some of these suspended solids (the protein, casein) change their shape and can no longer be suspended. The casein forms the gloppy solid that is filtered from the liquid. Baking soda (a base) is then added to neutralize the acid and change the protein back into a shape that is more fluid. This becomes the glue. Water can be added to give the glue whatever consistency you would like.
