Glue goo

Follow these instructions to make your own glue goo and learn about plastics and polymers.

• 8 June 2006 | Updated 14 October 2011

• What you need 
• What to do
• What's happening
• Other polymers

Warning: This activity involves Borax which is harmful when swallowed. Please ask an adult to help you. Borax is a form of soap and is used to clean clothes. It can be found in the laundry section of your supermarket.

What you need

To do this activity you need to find:

• PVA glue
• food colouring
• water
• Borax
• two plastic cups or similar containers
• a sealable plastic bag
• some paper towels
• a pop stick for stirring
• at least two plastic spoons.

What to do

1. Measure three teaspoons of PVA glue into the plastic cup.
2. Add three teaspoons of water and stir.
3. Add a couple of drops of the food colouring of your choice (traditionally slime is green).
4. Place approximately one cup of water into the other plastic cup.
5. Stir in one heaped teaspoon of Borax powder. Once the mixture has been stirred thoroughly you have made a Borax solution.
6. Add one teaspoon of Borax solution to the glue paste and stir. As you stir the slime should start to form. You might need to add a little more Borax solution. Be careful when you are adding the Borax solution. If you add too much your slime will go hard.
7. If your slime feels very wet and slippery (but is not still runny), remove it from the container and knead it in your hands. In a few minutes, any extra Borax solution will evaporate or be absorbed.
8. Place the slime into a sealable plastic bag and it should keep for a while.

Remember to keep the paper towel close by to clean your hands. If you get the slime onto fabric or carpet it can be removed with a little vinegar followed by warm soapy water. Make sure you wash your hands before and after playing with the slime.

What’s happening

When you mix glue with a bit of water, you make a substance that is known as a polymer. Polymers are very large molecules, formed by repeated patterns of chemical units strung together. The Borax solution is a 'cross-linking' substance that binds the polymer chains together to make the glue solution thicker.

As the polymer chains get more 'cross-linked', it gets harder for them to move around, and your slime starts look like putty. Experiment with adding more Borax solution to see if this indeed makes the slime thicker.

The trick to this activity is knowing how much Borax to add. It you add too little, your slime will be too sticky due to the excess glue. If you add too much Borax there will be too much 'cross-linking' and it won't feel like slime.

Other polymers

Probably the most important polymers in your home is the money in your wallet. From 15 May 1996, all Australian banknotes were made of plastic (all plastics are polymers). Australia's plastic banknotes are made from biaxally-oriented polypropylene, meaning the plastic has been stretched in both directions (that's what the 'bi' is for). When the plastic banknotes become unfit for use, they are recycled into a range of products including plastic polypropylene compost bins!

CSIRO and Note Printing Australia worked together to make Australia the world leader in the production of plastic banknotes. As well as being made of plastic, the notes also include a number of unique properties that make them one of the world's most difficult notes to counterfeit.

The activity and others like it are featured in The Helix: a science magazine for ages 10+.