Vicki Fischer

Silly Putty

Scientific Concept: Observing a chemical change from a liquid to a solid and making a polymer.

Materials:

• 2 Tablespoons of Elmer's glue
• 2 Tablespoons of water
• food coloring
• 2-3 Teaspoons of solid Sodium Borate * Might try Borax detergent
  or could use 5 mL of 4% borate solution.
• stirring rod
• medium size beaker
• 1 paper cup

Procedure:

• Mix the glue and water together in the paper cup using the stirring rod.
• Then add the food coloring to the mixture (use as many drops until you get the color you would like).
• Add the teaspoons (2-3) of sodium borate to the solution
• Stir the solution util it forms a solid
• Knead the putty in your hand until it gets hard

Introduction: "How many of you have ever wanted to make one of your favorite things to play with right at your house?" Well, I have finally discovered how to make one of my favorite things right here at home. All of these ingredients are found at your local grocery store. Look I made silly putty!!!

Explanation: Silly putty is a polymer. Polymers are all around us. You probably know them best as plastics. Single molecules are called monomers, while a lot of single monomers linked together form long chains of polymers (have children link arms to show that they are forming a monomer). The ingredient in Elmer's glue is called polyvinylacetate. The monomer molecule is vinylacetate. The glue has already been formed into a polymer containing very long chains of polyvinylacetate. When I added the sodium boraite, the chains linked together in a cross-link to make bigger polymers (have our group go between rows of children and cross-link with them). This reaction changes the ingredients to putty.

If vinylacetate = A, then the polymer = A - A - A - A - A - A -A etc.

The borate links two or more of the AAAA chains together.

Reference: Borislaw Bilash, A Demo a Day, Flinn Scientific, 1997, p.201