Chemistry Experiment: Make Your Own Glue

Chemistry explains hundreds of thousands of substances that we use every day. If you're interested in doing your very own chemistry experiment that will turn out something useful, this one for homemade glue is perfect.

You'll need:

  • 1 cup skim milk
  • 1 tablespoon vinegar
  • 1/4-1/2 teaspoon baking soda

Mix the milk and vinegar together until the milk curdles. You may want to speed the process up by heating it slightly.

Next, pour the curdled mixture through a coffee filter to remove the liquid, which can be discarded. Dry the remaining milk solids as best you can before putting them into a bowl.

Start by stirring in 1/4 teaspoon of baking soda. The mixture should turn into a smooth, sticky paste that can be used in exactly the same manner as any other glue. If it doesn't, continue adding baking soda until it does. You can use this homemade glue to stick wood or paper together.

Why It Works

The protein found in cow's milk is called casein. There is not a lot of it in one cup of milk, so you need to separate it out by adding vinegar. The vinegar changes the acidity of the milk and causes the proteins to clump together to make larger structures than normal, the curds, in a process called precipitation.

By removing the liquid from the casein, you are essentially getting down to pure protein. Adding the baking soda changes the acidity once again and causes the casein to break up once more into the tiny particles that it naturally occurs in. This results in the curds turning into a paste, since the liquid has been removed. Since casein is naturally sticky, it can be used as an adhesive in this reduced form.

Chemistry is an amazing thing. This experiment shows some very basic principles at work and you will be able to use the end result.

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