The height a rubber band ball (or any other
ball) bounces has to do with the elasticity of
the collision between the ball and the
In an elastic collision, kinetic energy and
momentum are conserved. In an inelastic
collision, kinetic energy is not conserved.
Energy can be lost to friction, sound, and
When you drop a ball from a stationary
position, it starts with all potential energy.
As it falls, it gains speed and kinetic energy,
but it still has the same amount of total
energy. When it hits the floor in an inelastic
collision, it loses some of its kinetic energy.
As it bounces back upward, it exchanges its
kinetic energy for potential energy, but it does
not bounce as high as before because overall, it
has less energy.
energy picture, click here
A collision between the rubber band ball and
floor will never be perfectly elastic (ideal).
The closer a collision is to being perfectly
elastic, the higher the ball will bounce. So
what makes the rubber band ball more ideal? The
less energy that is during the collision, the
more kinetic energy will remain. The most
important factor is how tightly the rubber bands
are wound onto the ball. If they are too loose,
they will absorb more energy. Another factor
that matters is the type of rubber the rubber
band is made out of; different types of rubber
have different elasticity. You can test which
kind works best by conducting an experiment.
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