Nabban Tahsin Haque
Squash ball Investigation
Aim
To investigate the way in which the temperature affects the bounce of squash balls.
Hypothesis
A squash ball is made of an elastic material. When a ball hits a wall, if it has perfect elasticity, it
should be stretched to its elastic limit parallel to the wall when the kinetic energy of the ball has
been transferred to elastic potential energy. If it has perfect elasticity, all kinetic energy will have
been transferred to elastic potential energy and the ball should rebound at the same velocity.
Because elasticity is not perfect in any ball, some energy is “lost”. By law of conservation of
energy, some of the kinetic energy is converted to head and increases the temperature of the ball.
Due to this some kinetic energy will have been lost and the ball should require more force to reach
its elastic limit on the next hit. Considering the ball is hit at a constant force, the ball should
bounce lower and will not bounce back to the height from which it is dropped.1 It will however
increase the height up to which it bounces as it is heated. As the ball will be heated before it is
bounced, the heat will increase the pressure within the ball as per the pressure law. This increased
pressure will cause the ball to bounce higher as it will give added force to the pushback of the
elastic potential energy.
Variables
Independent The temperature of the squash ball.
Dependent The bounce of the squash ball.
Controlled Height of release.
 Force with which it is released.
 Angle of release.
 Angle of Surface.
Apparatus and Materials
 6 Squash ball.
 Measuring tape.
 Thermometer.
 Water.
 Beaker.
 Bunsen burner.
 Match sticks
 Gauze
 Goggles
 Tripod
 Tongs
1
(Adrian Popa), http://www.madsci.org/posts/archives/aug98/901564971.Ph.r.html
Nabban Tahsin Haque
Method
1. Measure temperature of squash ball.
2. Drop squash ball from a height perpendicular to the surface of contact. The surface
should be flat.
3. Measure how high the ball rebounds.
4. Increase the heat of the squash ball and measure temperature.
5. Drop it from the same height.
6. Measure height once more.
7. Repeat until a number of results have been collected.
Results
Height of Drop=185cm
Temperature of Squash ball (C)
23
30
40
50
60
70
80
90
Data processing
Average Bounce=
Trial 1
28
32
38
48
57
61
68
82
Height of Bounce (cm)
Trial 2
Trial 3
Trial 4
27
29
30
31
33
34
37
40
49
47
50
50
58
58
58
62
63
63
69
69
70
83
85
84
Trial 5
28
32
38
47
56
65
68
82
Trial1  Trial2  Trail3  Trial4  Trial5
5
Height of Drop=185cm
Temperature of Squash ball
(C)
Height of Bounce (cm)
23
30
40
50
60
70
80
90
Trial 1
28
32
38
48
57
61
68
82
Trial 2
27
31
37
47
58
62
69
83
Trial 3
29
33
40
50
58
63
69
85
Trial 4
30
34
49
50
58
63
70
84
Trial 5
28
32
38
47
56
65
68
82
Average Height of Bounce (cm)
28.4
32.4
40.4
48.4
57.4
62.8
68.8
83.2
Data Analysis
The results show that as the temperature seems to increase, so does the bounce of the ball, looking
at averages only. Also, following the trend line of the graph, the bounce seems to increase at a
consistent rate with a sudden ‘jump’ at the last 5 results, those for 90˚C which reduce the accuracy
of the trend line.
Nabban Tahsin Haque
Conclusion
In Conclusion my hypothesis does seem to be correct. As the temperature of the squash ball was
increased the bounce also increased substantially, following a trend. The ball did not bounce back
to the height of the drop, showing the ‘losses’ of energy present. The results are reasonably
accurate as the trend line has an R2 value of R2 = 0.9896.
Evaluation
The experiment was not completely accurate. As we increased the temperature of the squash ball
by immersing it in heated water, we did not know the exact temperature of the ball. Also we did
not know how long we had to keep the ball in the water in order to make sure the ball reached the
temperature of the water. Further more, as we dropped the ball, we did not know if the ball was
dropped straight down without any external force, and due to the round shape of the ball and
revolutions on it as it fell, there was some deviation in the bounce, making it difficult to tell the
exact height of the rebound. Also, because we measured the height at the top of the bounce by eye
with a ruler behind it, human error is present. The trend, however, can be used to prove the
hypothesis for the test was performed multiple times and there was a substantial increase in the
bounce for each temperature. One way to improve the experiment may be to heat the squash ball
by leaving it for an obligatory amount of time in an environment constant at the required
temperature. It may also help if we dropped the squash ball from a device such as a retort stand
which is constantly at the height of the drop, removing the problems of human error in the force
and height of the drop. Dropping the ball down a tube which minimizes friction and is see through
with a height measure to the side would help minimize the problems of bounce deviation and the
reading of the height.