Bouncy balls are made from natural rubber, polymers, plastics or sometimes treated leather. Bouncy balls can be made at home using borax, cornstarch, glue, warm water and food coloring.
To make a bouncy ball, dissolve a half teaspoon of borax in two tablespoons water. If a colored ball is desired, add food coloring. Place one tablespoon of glue in another cup. Use white glue for an opaque bouncy ball or clear glue for a translucent ball. Add an additional half teaspoon of borax solution and one tablespoon cornstarch to the glue. Allow the mixture to stand for 10 to 15 seconds, then stir to combine. When the mixture is difficult to stir, use your hands to mold the ball until it solidifies.