Experiment While Making A Bouncy Ball
Amy Huntley is a former science teacher and Mom that runs a great blog where she shares activities that she has done with her family. This exploration of polymers and bouncing balls caught our eye and we were happy that Amy would share it with us. We’ve adapted it just a bit. The fun part is experimenting, and it is easy to make several of these and change up the recipe and check results. Note that this will not make a bouncy ball like you get at the grocery store, but ours bounced over a foot high and the ball has quite a unique feel to it.
You will need:
- Borax (found in laundry section)
- warm water
- corn starch
- glue (clear glue makes a see transparent ball and white glue makes an opaque ball)
- 2 small mixing cups
- a stirring stick (plastic spoon)
- food coloring (optional)
- Label one cup ‘Borax Solution’ and the other cup ‘Ball Mixture’.
- Pour 4 ounces (120ml) of warm water into the cup labeled ‘Borax Solution’ and 1 teaspoon of the borax powder into the cup. Stir the mixture to dissolve the borax.
- Pour 1 tablespoon of glue into the cup labeled ‘Ball Mixture’. Add 3-4 drops of food coloring, if desired.
- Add 1/2 teaspoon of the borax solution you just made and 1 tablespoon of cornstarch to the glue. Do not stir.
- 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 molding 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, continue rolling between your hands until it is smooth and round!
“My boys loved making these “bouncy” balls. They are not super bouncy like the plastic super balls that became popular when I was a kid, but they are pretty bouncy and fun to play with. We discovered that on the carpet, they have a lot more bounce then they do on the kitchen floor. ”
These are also “temporary” bouncing balls and will lose their elasticity within a few days as they dry. Keeping your bouncy ball in a sealed bag will increase its bouncy lifespan.
The original “Super Balls” got their amazing bounce ability from compressed rubber under thousands of pounds of pressure.
How does it work?
This activity demonstrates an interesting chemical reaction, primarily between the borax and the glue. The borax acts as a “cross-linker” to the polymer molecules in the glue – basically it creates chains of molecules that stay together when you pick them up. The cornstarch helps to bind the molecules together so that they hold their shape better.
Make it an experiment
You can turn this activity into a true experiment by adjusting the amount of borax, glue, and cornstarch to get the highest bounce. You can also experiment to discover the best way to get the bouncy ball to keep its bounce over time. Have fun!