Borax powder (you can get these in a supermarket or on an online store)
A cup of warm water (120ml)
Some corn starch powder
2 small mixing cups
A plastic spoon
Label one of the cups ‘Borax Solution’ and the other cup as ‘Ball Mixture’.
Pour the 120 ml of water into the borax solution cup and add a tablespoon of borax powder into it. Gently stir the solution with the plastic spoon to dissolve the borax.
Pour one table spoon of glue in the cup labelled ball mixture. You can also add a tablespoon of food colouring into the cup to change the colour of the ball.
Add ½ teaspoon of the mixture from the borax solution cup and 1 teaspoon of corn starch powder into the ball mixture cup. Do not stir.
Allow all the ingredients in the ball mixture cup to interact with each other for 10-15 seconds and then stir them together with the plastic spoon.
Once the mixture becomes a dough, pull it out of the cup and mould it in the shape of a ball using your hands. The dough will first be sticky and messy, but as you start rolling it, the ball will start to solidify.
How does this work?
This experiment is formed out of a chemical reaction between the borax and the glue. The borax acts as a ‘cross-linker’ with the molecules of the glue where it creates chains of molecules that stay together when you pick them up. The corn starch helps to bind the molecules together so that they can hold the shape.