Kid Science: Silly Putty

Today is a holiday and what better way to spend it than doing science with the kids.   The fun science today is homemade silly putty.  It is easy and quick to make, but will provide entertainment for the kids and you while showing off some chemistry in the process.

Here is what you need:

1.  1 bottle of 118 mL Elmer's Glue-All (not the school glue)
2.  118 mL of water
3.  1/2 teaspoon of Borax
4.  1/4 cup of hot tap water
5.  Food coloring
6.  Bowl to mix everything up
7.  Zip-lock bags for storage

Now the fun part.  To make the silly putty just follow these steps.

1.  Pour the 118 mL of water into the mixing bowl along with the entire bottle of Glue-All.  Stir the mixture until you have a glue soup.

2.  Add some food coloring of your choice so your silly putty has some color.

3.  In a separate measuring cup, measure out 1/4 cup of hot tap water and add the 1/2 teaspoon of Borax.  Stir well until the Borax is mostly dissolved.

4.  Now pour the Borax solution into the Glue soup.

5.  Take a spoon (or your hands for some messy fun)  and mix everything up.

As you mix everything up, you will get a big blob of silly putty to play with.  Once your done playing with it, just store the putty in a zip-lock bag.

Step 1:  Mix the glue and water

Step 2:  Add the food coloring

Step 3:  Dissolve Borax into hot tap water

Step 4:  Pour the Borax solution into Glue soup

Step 5:  Mix everything up

Silly Putty!!

Store in a zip - lock bag

So what is the science behind this experiment.  The Borax is the key.  It hooks the glue molecules together to form the putty.  Glue is already a liquid polymer and with the borax we have made a more solid like polymer.  A polymer is just a long molecule that is mostly made up of repeating units.

For the chemists, the glue is made up of polyvinyl acetate.  Since it is a polymer each repeating unit contains an acetate group.  Borax is mode up of sodium tetraborate and reacts with the acetate molecules of the glue.  One molecule of borax bonds between to acetate molecules and as more and more of these bonds are formed the glue becomes more solid like.