Happy and Sad Balls

This demonstration uses two balls that look very similar but have different elasticity. When the balls are dropped, one experiences an elastic collision and the other an inelastic collision. In the inelastic collision, the kinetic energy is converted to heat and the ball doesn't bounce much. In the elastic collision, little heat is produced so the ball bounces close to its' original height.

* Equipment seen in the video may vary from equipment used in ND Demonstrations. See information and images below for ND equipment and setup.

Setup:

Place the balls on the lab table. Make sure they can't roll off.

Drop the balls at the same time and observe as one bounces and one settles and does not bounce.

Notes:

None

Courses Used In:

  • PHY 10111

  • PHY 10310

  • PHY 10410

  • PHY 30210

Discussion and Polling Questions:

  • (Before demos) Which ball will bounce higher?

  • What causes one ball to bounce higher than the other?

  • Is momentum conserved in both situations? Is energy? If not, where does the energy go?

Equipment Needed:

  • Arbor Scientific Happy and Sad Balls