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This week's LabZone activity
Oct. 12, 2005
Goofy Putty
Investigate glue and borax to make a stringy, bouncy creation and explore molecules, polymers, solutions, and chemical reactions.
Description:
A borax and water solution is mixed with a glue and water solution to create a polymer.
You Will Need:
- white school glue
- borax (found on the laundry detergent aisle)
- water
- measuring spoons
- clear bowls, plastic cups, or small cups for mixing
Instructions:
During this activity, you will be measuring and mixing solutions. If the measurements are not exact, the experiment will not work correctly.
Put one teaspoon of water into your cup or bowl. Add one teaspoon of white glue and mix well.
In another container, create your borax solution. Mix one teaspoon of borax with four teaspoons of water. Stir well.
Add one teaspoon of the borax solution to your original cup of glue and water. Stir for 60 seconds.
Remove the Goofy putty and knead it with your hands for 1 to 2 minutes.
Content:
A molecule is two or more atoms bonded together by an exchange or sharing of electrons. At the beginning of the last century, chemists learned how to create special molecules made of long chains of atoms or groups of atoms. These long molecules were called polymers. Most common polymers are made of long chains of carbon atoms. It's relatively easy for chemists to manipulate the bonding of carbon atoms.
Vinyl molecules are one of the main ingredients of white glue. The vinyl molecules are themselves polymers. Mixing the glue with water allows the long vinyl molecules to untangle and spread out in the solution.
In the case of the glue polymer, the vinyl molecules are not hooked together in long chains. They are cross-linked, or bonded along the sides of the molecules. It is borate ions that are responsible for the cross-linking. Borate ions are provided by the borax (sodium borate).
As more and more bonds are formed the characteristics of the polymer changes. The glue polymer will eventually become brittle as additional cross-link bonds are formed.
Teacher's Notes
Activity excerpted by permission of the Chemical Educational Foundation (www.chemed.org) from You Be The Chemist. For additional information about these activities and lesson plans, see www.chemed.org/Kit.html.
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