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OBJECTIVE
This
activity page will offer:
-
Insight into the storage of potential energy within a disfigured
rubber ball.
- A
hands-on experience in energy transformation.
- An
opportunity to manipulate variables and observe effects.
- An
exploration of the physics of rebounds.
MATERIALS
- Hollow ball*
- Solid ball *
- Measuring stick
- Adding machine paper
- Tape
*Composed of rubber or other elastic material.
PROCEDURE
Part
1- Obtaining a Baseline
- Work with a partner to tape a length of paper along a
wall so that it extends upwards from the floor to a height
of around 6 feet.
- Use a measuring stick to create a scale along the length
of the paper.
- One team member holds a solid ball at a height of 6 inches.
The other member marks this point as the release height.
- The team member holding the ball releases it. The other
team member observes and marks the rebound height on the
chart. The person observing the ball should note any change
in the ball's appearance as it hits the ground and rebounds.
- The ball is then released from a height of one foot. Again,
its release and rebound heights are recorded and marked
on the chart.
- Keep elevating the release point until you are dropping
the ball from the top of the chart.
- Repeat steps 1-6. This time substitute a hollow ball for
the solid one. The same person should continue to drop the
ball, and the same person should continue to observe and
record it.
QUESTIONS
- How did the release height affect the rebound height?
- Did you observe a difference in the ball's shape as it
struck the ground? If so, what happened?
- Was the relationship between release height and rebound
height constant? In other words, did the ball bounce highest
when released from the highest point?
- CRITICAL ANALYSIS: At a certain point, further increases
in height do not produce a higher rebound height. Explain.
Part
2- Cooling Off
ADDITIONAL
MATERIALS
PROCEDURE
- Determine the average rebound height for a golf ball
kept at room temperature and dropped from a height of about
3 feet.
- Refrigerate the golf ball for several hours.
- Again, determine the average rebound height from a 3-foot
drop.
- Repeat steps 1-4, substituting a baseball for the golf
ball.
QUESTIONS
- Did the rebound height change when the golf ball and
baseball were refrigerated?
- Which ball's rebound was affected most by the change in
temperature?
- How would you find the percentage of the bounce lost due
to refrigeration?
- What percentage of the bounce is lost when a baseball
is refrigerated?
- What percentage of the bounce is lost when a golf ball
is refrigerated?
- Why does the change in temperature affect the bounce?
EXTENSIONS
Transfer of Energy
Beginning
with the sun, identify all of the energy changes responsible
for a basketball's rebound. To simplify matters, assume that
the basketball is already manufactured.
Flipping
Fun
Have you ever made an animated flipbook? Here's your chance
to create one that shows the deformation of a ball as it bounces
against the ground. Using scraps of square or rectangular
paper and a large fastening clip, assemble a blank flipbook.
Draw a sequence of image frames that shows a bouncing ball
that deforms as it strikes the ground and rebounds. Don't
forget to show the ball's return to its spherical form and
the associated rebound.
Hot
Stuff
Suppose a golf ball was heated instead of chilled. How might
additional thermal energy affect the rebound height? Make
a prediction. Then, develop a method for inquiry that would
uncover this relationship. Share your experimental design
with your instructor. With his or her permission, perform
your experiment, gather the data, analyze your results, and
draw conclusions based on your data.
Web
Connection
Bouncing
Balls
A comprehensive reference on the physics of ball bouncing.
Rebound
Differences During Play
An article describing the effects of temperature on the
bounce of squash balls.
The
Energy of a Bouncing Ball
A
University of Virginia activity on investigating the energy
of a bouncing ball.
The
activities in this guide were contributed by Michael DiSpezio,
a Massachusetts-based science writer and author of "Critical
Thinking Puzzles" and "Awesome Experiments in Light & Sound"
(Sterling Publishing Co., NY).
Academic Advisors for this Guide:
Corrine Lowen, Science Department, Wayland Public Schools,
Wayland, MA
Suzanne Panico, Science Teacher Mentor, Cambridge Public Schools,
Cambridge, MA
Anne E. Jones, Science Department, Wayland Middle School,
Wayland, MA
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