Things You'll Need
Old plastic tablecloth
2 recyclable plastic cups
Food coloring in desired color
Craft sticks or coffee stirrers
Homemade bouncy balls offer double the delight, first in making the balls out of readily obtainable materials, then in putting them to the test by bouncing them. While homemade balls do not bounce quite as high as the manufactured rubber variety found in gumball machines, they still supply a surprising amount of bounce, considering one of the main ingredients is none other than school glue. A chemical reaction caused by mixing the ingredients turns the glue into a pliable polymer, which gives it stretchy, rubber-like properties that allow it to bounce and retain its basic shape.
Cover the work area with an old plastic tablecloth to keep it clean and free of glue. Set two recyclable plastic cups atop the tablecloth.
Measure and pour about 1 tablespoon of school glue into one of the plastic cups; the amount doesn't have to be exact. Squirt a few drops of food coloring into the glue, stirring with a craft stick or coffee stirrer until the colorant mixes into the glue.
Pour 4 tablespoons of water into the second cup and stir in 1/2 teaspoon borax with a craft stick until it dissolves.
Add 3 tablespoons cornstarch to the borax mixture and stir it briskly with the craft stick until the cornstarch dissolves.
Pour the watery mixture into the cup containing the glue, stirring with a craft stick until the mixture clumps together and becomes difficult to stir. When you're no longer able to stir it easily, fish the rubbery blob out with your fingers.
Roll the gooey material between your palms, shaping it into a sphere. It may feel sticky at first, but it eventually will lose the stickiness. Wipe your hands on a paper towel or damp paper towel occasionally as you roll the mass to make your hands less sticky. Continue rolling the substance until it doesn't feel sticky and is as round as you can make it. The ball is ready to bounce at this stage.
Store the bouncy ball in an airtight container. It will flatten out a bit when not in use, but it can be rolled back into its round shape with ease.
Experiment with different amounts of glue, cornstarch and borax to see how it affects the elasticity of the ball.
Wash your hands thoroughly before and after making or working with homemade bouncy balls. This keeps the ball and your hands clean.