Chemistry class plays ball

Students in Chemistry instructor Alexis Grinde's CHEM 1250, Principles of Chemistry I, made their own bouncing polymer balls using borax, glue, cornstarch, water and a few other materials, to gain an understanding of how differing chemical compositions affect the bounciness of the polymer balls as well as other characteristics.

Balls have been toys practically forever, but the bouncing ball is a more recent innovation. Bouncing balls were originally made of natural rubber, though now bouncing balls can be made of plastics and other polymers or even treated leather.

The bouncing ball in Grinde's chemistry lab is made from a polymer. Polymers are molecules made up of repeating chemical units. Glue contains the polymer polyvinyl acetate (PVA), which cross-links to itself when reacted with borax.




Photos: Chemistry students make bouncing polymer balls in the lab.