Apparatus Competition
2006 AAPT Summer Meeting
Syracuse, NY
Follow The Bouncing Ball
Clifford Bettis
116
Brace Lab
Dept.
of Physics and Astronomy
University
of Nebraska-Lincoln
Lincoln,
NE 68588-0111
402-472-2789
cbettis
ÔatÕ uniserve ÔdotÕ uni ÔdotÕ edu
Abstract:
This
apparatus is an intriguing hallway demonstration. It obviously shows elastic
collisions but it also raises the question of what the secret is to the
stability of the bouncing ball. Most often the public guesses that it has
something to do with magnetism.
Construction of Apparatus:
The apparatus is constructed out of a 6Ó x 1Ó disk of A2 tool steel that is
machined with a computer controlled milling machine so that one surface has a
radius of curvature of 1 m. Threaded holes for leveling screws are added and
then the disk is surface hardened by heating and quenching. The ball is a
¼Ó hardened steel ball
bearing.
Use of Apparatus:
I use it as a hallway exhibit. Children and their
parents are particularly intrigued by it.