Make Your Own Gloppy Polymer: 'ExploraGoo'

A science teacher came up with this recipe, which she sold to a toy company (no, it's not Play-Doh). The toy company added a preservative and fancy packaging. But the science teacher retained the right to share her invention with science museums across the country, so long as they did not breathe a word of its trademarked name.

This version is from San Francisco's Exploratorium. It's reprinted from 'The Science Explorer' (by Pat Murphy et al., Henry Holt and Co., 1996).

What you need:

newspaper

plastic wrap or waxed paper

a four-ounce bottle of white glue

two large plastic containers or glass bowls

measuring cup

water

food coloring (if you want)

measuring spoon (teaspoon)

Boraxo powdered hand soap or a box of borax (in the laundry aisle)

small plastic container with a lid (margarine tubs are perfect)

1. You'll need a grown-up's help. This is really, really messy stuff. Put some newspaper on your kitchen counter or table. Then cover the newspaper with plastic wrap. (ExploraGoo sticks to paper.)

2. Pour the bottle of glue into one bowl. Add 1/2 cup of water and some food coloring. (Our favorite color is 10 drops of yellow and five drops of green.) Mix everything together.

3. In the other bowl, put 2 teaspoons of Boraxo powdered soap (or 1 teaspoon of borax powder). Add 1/2 cup of water and stir until the borax is dissolved. (You may still see a few specks of the soap.)

4. Pour the colored glue-water mixture slowly into the borax-water mixture. A big glob of ExploraGoo will form!

5. Reach into the bowl with both hands and pick up the glob. It will be very, very, very slippery. Pick up as much as you can. (There will be a little water and some pieces of goo left in the bowl. That's OK.)

6. ExploraGoo will get less slippery the more you play with it. Let it slide back and forth from one hand to the other for a few minutes. If you put it down, make sure it is on the plastic wrap, not the paper.

Don't put it on carpet, furniture, or clothes, either. It's sticky stuff.

Don't put ExploraGoo in your mouth. It tastes yucky and it is not good to eat.

Do play with it, try to bounce it, cut it, roll it. Let it ooze through your fingers.

Store it in a plastic container with a lid. It will last for a month or so. When it starts to ooze water, it's time to throw out that batch and make some more.

What is it?

When you stir the glue and borax together, you start a chemical reaction. Glue molecules (polyvinyl acetate) and borax molecules (borate ions) react with each other and combine to form long, flexible, cross-linked chains called polymers. Nylon and plastic are polymers, too.