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Chemicals:	Elmers White Glue or equivalent (polyvinyl acetate glue) Borax detergent Food coloring All chemicals can be bought at a grocery store.
Materials:	Two large plastic glasses (clear if possible) and a spoon to stir.
Notes:	Gack is also known as "Flubber".

Procedure:

1. Put about 4 oz. of water in one plastic glass.  Add Borax.  Stir with spoon.
2. Continue to add Borax and stir until no more will dissolve.
3. Put about 4 oz. of white glue in a second plastic glass.
4. Dilute the glue with 4 oz. of water.  If, at the end of the experiment, the resulting GACK is too thick, try it again adding more water.
5. Add a small amount of your favorite color of food coloring to the glue solution and mix well.
6. Pour a small amount of the Borax solution into the glass with the glue, being careful not to transfer any solid Borax into the glue.
7. Stir well.
8. If some of the glue solution doesn't thicken, add more Borax solution and stir again, repeating the process until the entire mixture has thickened.
9. The resulting GACK should be rubbery, and will slowly flow from a high spot to a low spot, such as if you try to pour it out of the glass.