Silly Semi-Solids

In everyday life we expect solids to have certain reliable  characteristics and liquids to have some very different qualities. It can be delightful to  play with materials that seem to bridge our expectations of both of  these states of  matter. Welcome to the world of polymer chemistry!

Materials

• white glue (Elmer's works well)
• water
• borax (in the laundry section of a grocery store)
• margarine tub or small mixing bowl
• measuring spoons
• small Ziplock bag  

Directions

1. Measure 2 Tablespoons of water and pour into a small bowl.
2. Measure 2 Tablespoons of white glue and pour into the bowl of water. Stir until well  mixed.
3. Measure 2 teaspoons of borax and mix into the same bowl. This mixture will begin to  congeal immediately. A remarkable  film will form on the surface of the water/glue  solution.
4. Use your fingers to thoroughly mix ingredients. A large "lump" of a wet  semi-solid will begin to form between your fingers. Keep mixing  ingredients until the lump  feels like wet putty. A small amount of fluid will remain in the bowl. This is safe to  flush down the sink drain.
5. Knead the putty-like material in your hands until it is completely smooth  (this may  take 5-10 minutes.)
6. Begin to experiment with the unusual properties of this substance. For example:
• What happens when you slowly stretch it?
• What happens when you pull it abruptly apart?
• If you roll it into a ball, does it stay in that shape?
• Is this substance a solid, a fluid, or something in between?
• Can you imagine any useful applications for a material with these properties?
7. You can store your silly semi-solid stuff in a Ziplock bag..

Wash your hands after this activity.

Thanks to Allison Edner in Washington for providing this activity idea.

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