Making gloop - The borax is acting as the crosslinking agent or "connector" for the glue (polyvinyl acetate) molecules. Once the glue molecules join together to form even larger molecules called polymers, you get a thickened gel very similar to slime.
Borax, PVA glue, water, bowls, food colouring, containers, newspaper.
1) In a small mixing bowl, combine 1/2 cup of glue and 1/2 cup of water.
2) Add a few drops of food coloring to tint the mixture to the desired shade.
3) In the second small mixing bowl, combine 1 teaspoon of Borax and and 1/2 cup of water. Mix thoroughly.
4) Pour the Borax mixture into the glue mixture. It will be very thick.
5) Knead slightly as the mixture starts to come together.
6) Spread play area with newspaper and/or wax paper to avoid staining surfaces.
7) Play Gloop!
Gloop is not edible, Borax is a laundry product, safe but toxic.