People have been using balls as toys for a long time, but the bouncy ball is a more recent innovation. Bouncy balls were originally made of natural rubber, though now bouncy balls can be made of plastics and other polymers or even treated leather. You can use chemistry to make your own bouncy ball. Once you understand the basic technique, you can alter the recipe for the ball to see how the chemical composition affects the bounciness of the ball, as well as other characteristics.
The bouncy ball in this activity is made from a polymer. Polymers are molecules made up of repeating chemical units. Glue contains the polymer polyvinyl acetate (PVA), which cross-links to itself when reacted with borax.
What You Will Need:
- PVA glue
- Warm Water
- Food Colouring
- Measuring Spoons
- Spoon or craft stick to stir the mixture
- 2 small plastic cups or other containers for mixing
- Marking Pen
- zip-lock plastic bag
- Label one cup ‘Borax Solution’ and the other cup ‘Ball Mixture’.
- Pour 2 tablespoons warm water and 1/2 teaspoon borax powder into the cup labelled ‘Borax Solution’. Stir the mixture to dissolve the borax. Add food colouring.
- Pour 1 tablespoon of glue into the cup labelled ‘Ball Mixture’. Add 1/2 teaspoon of the borax solution you just made and 1 tablespoon of cornstarch.
- Allow the ingredients to interact on their own for 10-15 seconds and then stir them together to fully mix. Once the mixture becomes impossible to stir, take it out of the cup and start moulding the ball with your hands.
- The ball will start out sticky and messy, but will solidify as you knead it.
- Once the ball is less sticky, go ahead and bounce it.
- You can store your plastic ball in a sealed zip lock bag when you are finished playing with it.