This adorable DIY bouncy ball is Kelley green and a super-fun way to learn how to make a bouncy ball!
This St. Patrick’s Day, we’re going all out for hands-on St. Patrick’s Day STEM activities. We’re focusing mainly on science, and STEM topics this year, and my kids loved their Valentine’s bouncy ball experiment so much, we decided to do a bouncy balls experiment variation for St. Patrick’s Day.
Find out how to make a bouncy ball and how to make it into a STEM lesson below!
Kids will have a blast with the bouncy ball experiment.

Check out this list of Rainbow science experiments!
Turn this Activity into a Bouncy Ball Experiment

Here’s how you can turn your DIY bouncy ball project into a science experiment.
Discuss why this ball isn’t quite as bouncy as rubber balls.
Why would the glue mixture not bounce as much?
What is the science behind the thick slime mixture?
Add variables to find the best and bounciest recipe for your bouncy ball.
The Bouncy Ball Science Experiment Explanation

The science of the DIY bouncy ball is as follows.
Chemicals in the borax mix with chemicals in the glue, which creates long, polymer chains. These chains are shortened when less liquid is used and more borax powder is added.
So, instead of long, stretchy slime like you get with some recipes, you get a firm ball of flexible polymer chains. When you drop this on the ground, the ball flexes and the force of the ball hitting the ground causes it to bounce back into the air.
Kids Bouncy Ball STEM Extensions

Making the ball is only the first part of what makes this DIY bouncy ball experiment so interesting. What makes this project educational is the math and science behind the activity. With this activity, kids are open to discussing physics, polymers, gravity, the laws of motion, and energy.
The reason these DIY bouncy balls don’t bounce as high as rubber balls is fairly complicated. Simply put, since the balls are made of a softer material, when they hit the ground, they absorb some of the reaction and bend, rather than bouncing.
The more energy you expend dropping or throwing the ball, the higher it will bounce. Experiment with changing the shape of the ball or comparing bounce height to a traditional bouncy ball.
How to Make a Bouncy Ball Experiment
This fun bouncy ball science experiment is perfect for St. Patrick’s Day thanks to its bright green color!

Disclaimer: This post contains affiliate links at no cost to you for your convenience.
Supplies for making bouncy balls:
How to Make a Bouncy Ball Directions

In one of the plastic cups, mix 2 tablespoons of glue, 1 tablespoon of cornstarch and a few drops of green food coloring.

In the second cup, mix 4 tablespoons of hot water and 1 teaspoon of borax powder. Mix until the borax is dissolved, or else your bouncy ball will be grainy.

Add the liquid mixture to the glue cup. Stir with a fork until you can’t anymore, then take it out and squish it between your hands. There might be pockets of glue, so be careful. Keep massaging the mixture until it starts to form a ball.
Once the mixture fully hardens, you can roll it into a ball.

Try out your new ball on any hard surface! Watch as it bounces to nearly waist height.

More St. Patrick’s Day STEM Activities
Try these fun STEM activities for St. Patrick’s Day!