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Contributed by: Kentucky Department of Education (KDE)
PERFORMANCE TASK STUDENT RESPONSE FORM
TASK: S2 - HALF-BALL
Grade 8
Student Name: _______________________________________________
School Name: _______________________________________________
School Code: _________
GENERAL INSTRUCTIONS:
Write your name, school name, and school code on the lines above.
Do not open this packet until the directions tell you to do so.
You will have a total of 45 minutes to complete this task. You may
use up to 20 minutes to complete the group work.
Your group should have the following materials:
- one half-ball
- two meter sticks
- one racquetball
- calculators and pencils for each student
GROUP ACTIVITY:
Physical science plays a role in the way many things move. Among
the principles of motion and energy are Newton's Laws of Motion
and the Law of Conservation of Energy.
Newton's Laws of Motion
- If an object is at rest, it tends to stay at rest; if
it is moving, it tends to keep moving at the same speed
and in the same direction unless acted upon by an external
force.
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- Acceleration of a body is directly proportional to the
net force acting on the body and inversely proportional
to its mass.
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- When one object exerts a force on a second object the
second object exerts an equal and opposite force upon the
first.
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Law of Conservation of Energy
| Energy is neither lost, destroyed, or created. The amount
of energy in a system is constant as it transforms from one
form to another. |
Your task is to examine how a ball and half-ball behave and to
relate as many of the laws described above to what happens to the
balls.
Examine the illustration below. Notice how the half-ball is turned
inside out with the curve pointing upward in the second picture.
- Turn the ball inside out as shown in the illustration. Drop
the ball, making sure that you drop it straight down, with the
curved side pointing up. You will notice that the ball bounces
back up to you. Practice this one or two times.
- Drop the half-ball three times from each of the following
three heights: 50 cm, 100 cm, 200 cm. Each time, record on the
table below how high the half-ball bounces.
HALF-BALL DATA 
- Now drop the racquetball three times from the same three heights.
Record the height of each bounce below.
RACQUETBALL DATA 
When you are finished with the work on this page, one member of
the group should tell the facilitator that your group has finished.
Then do the individual work. Remember that you must work alone on
those pages. You may not discuss the questions or share information.
INDIVIDUAL ACTIVITY
- Produce an appropriate graph or graphs of the data your group
collected.
- What conclusions can you draw concerning the half-ball?
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- What conclusion can you draw concerning the racquetball?
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- Refer to the data from your group's experiment. Describe what
happened to the half-ball in terms of the laws stated on page
1. Be sure to consider each stage of each drop and the resulting
bounces.
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- How did the bounces of the half-ball compare to the bounces
of the racquetball? Explain why you think the bounces were similar
or different.
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Kentucky Department of Education
Performance Events 1995-96
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