The ingredients needed to create these bouncy balls are not bouncy in and of themselves. As you collect the ingredients for your balls, look at the textures – glue is sticky and cornstarch is powdery. Neither one can bounce on its own. The molecules of the ingredients are small and generally incomplete. But when you add a catalyst to the glue, starch and water, it transforms the characteristic properties of these ingredients – creating a rubbery-textured polymer. To make this ball, your kids just linked and mixed the molecules together.
A quick word of caution: this recipe includes borax, which is not edible. Please don’t let children chew on the finished product or taste it during any steps along the way.
Materials:
- Makes two bouncy balls
- 4 tablespoons warm water
- 1 teaspoon borax
- 2 disposable cups
- Disposable spoon for stirring
- 2 tablespoons glue
- 2 tablespoons cornstarch
- Food colouring
- Measuring spoons
Method:
First, pour the water and borax into the first cup and stir the mixture until is dissolved.
Next, pour the glue, cornstarch, food colouring and ½ teaspoon of the mixture from the first cup into the second cup. After the cornstarch and glue are mixed together, pour the contents of cup 2 into cup 1.
Our ball recipe seems to work best if you mix the glue, cornstarch, and food colouring first, then pour it into the borax mixture. Let the ingredients in the second cup interact on their own for about 15 seconds, then stir. We found that a folding method was the most effective way to stir the ingredients.
Once the mixture becomes difficult to stir, scoop it out of the cup and roll it into a ball. There will be plenty of watery borax mixture left in the container. You will want to dispose of that liquid and throw away the container.
We stored it in a resealable plastic bag for several days and it stayed fresh until it simply picked up too much dirt and we had to throw it out!
Modifications for younger kids:
Younger children can have fun bouncing balls – see which one of them can bounce their ball the highest.
Modification for older kids:
Older kids can test different sizes to make modifications to elicit more bounce action. Encourage your kids to tweak the ingredients – how does the ball change if you add more or less of just one ingredient? They can also test out different shapes and how that affects how the ball bounces. We found that this is a forgiving recipe – almost all of our versions bounced to some degree.
TIP: The ingredients and instructions to make a homemade bouncy ball will make a great gift when packaged together in a small plastic bucket.
Source: 101 Kids Activities That are the Bestest, Funnest Ever! By Holly Homer & Rachel Miller.