Balls have been toys practically forever, but the bouncing ball is a more recent innovation. Bouncing balls were originally made of natural rubber, though now bouncing balls can be made of plastics and other polymers or even treated leather. You can use chemistry to make your own bouncing 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 bouncing 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.
Bouncing Polymer Ball Materials
Here's a list of materials you need to gather to make bouncing polymer balls:
- borax (found in the laundry section of the store)
- cornstarch (found in the baking section of the store)
- white glue (e.g., Elmer's glue - makes an opaque ball) or blue or clear school glue (makes a translucent ball)
- warm water
- food coloring (optional)
- measuring spoons
- spoon or craft stick to stir the mixture
- 2 small plastic cups or other containers for mixing
- marking pen
- watch with a second hand
- metric ruler
- zip-lock plastic baggie
Let's make bouncing polymers balls...