How Kinetic Energy, Height and Speed in Bouncing Balls
Relate
Theodore Sauyet
Partners: Andrew Forbes and Ben Cowen
Due 11-23-10
Period 1
Mrs. Spinelli
I. Problem – There are qualities that affect kinetic energy when balls bounce. People want to
know which one(s) conserve kinetic energy the best in tennis, super, ping-pong balls, or a
marble.
Background – Balls bounce, or at least they are supposed to. But what bounces higher? Marbles
can get into interesting places, such as in the cabinet above the sink, so they must bounce. Pingpong balls have to bounce, otherwise ping-pong balls could not be used to play ping-pong.
Super balls are designed to bounce, so they bounce. Tennis balls are similar to ping-pong balls,
in the fact that they need to bounce.
Hypothesis – If tennis, super, ping-pong balls, and a marble are dropped from a height of 1
meter, then the marble will bounce the highest because it makes the least sound and has the
appropriate density.
Variables – The independent variable is the ball type, the dependent is the height of the bounce.
Controlled variables are the height from which they are dropped from, the surface it landed on,
and wind.
II. Materials: -Tennis Ball
-Super Ball
-Ping-Pong Ball
-Marble
-Meter Stick
-Stop watch
III. Safety: Do not throw balls. Do not sword fight with meter sticks. Do not open stopwatch and
play with electronics.
IV. 1. Measure the height of six bounces-following the steps below.
2. Hold the meter stick upright with the zero mark on the black table.
3. Drop tennis ball from top of the meter stick so that the ball does not touch the meter stick on
the way down.
4. Record the height of the firrst bounce in centimeters.
5. Start at the top agai and let the ball bounce twice and recod the height of the ball for second
bounce.
6. Repeat steps 2-4 with the tennis ball and record for 1st, 2nd, 3rd, 4th, 5th, and 6th bounce.
7. Repeat procedure with super ball, ping-pong ball, and marble.
8. Create a line graph of all bouncing balls. At zero on the graph, the height is 100 cm.
Procedure Part 2:
1. Get with you lab group from the previous lab.
2. Collect all the materials you used from the first lab.
3. Preform lab again, except time it with a stop watch and see how long it takes for each ball to
hit the table for its first and second bounce. Record on table
4. Start 1st bounce at 1m
5. Start second bounce where first bounce ended.
6. Use triple beam balance and find mass of each ball. Convert to kilograms.
7. Use information to calculate speed and then kinetic energy.
8. Find difference between 1st and 2nd bounce for kinetic energy.
9. Fill in all data tables and show work.
V.
Height of Bouncing Balls After Each Bounce:
Type of
Ball
Height
after 1st
bounce
(cm)
2nd
3rd
4th
5th
6th
Difference
Tennis
70
44
28.5
20
12.5
9
91
Super
72
51
41
30
22
17.5
82.5
Ping-Pong 71.5
54
38.5
30.5
23.5
19
81
Marble
47.5
26
24
10
9.5
90.5
65
Speed of Bouncing Balls:
Measure Tennis 2nd
ment
Ball 1st
Super
Ball 1st
Super
PingPingMarble
nd
st
nd
Ball 2
Pong 1 Pong 2 1st
Marble
2nd
Distance 1
(m)
.70
1
.72
1
.715
1
.65
Time (s) .42
.33
.40
.34
.44
.33
.44
.28
Speed
(m/s)
2.12
2.5
2.12
2.27
2.16
2.27
2.32
2.38
Kinetic Energy of Bouncing Balls:
Measu Tennis 2nd
Differ Super Super Differ Pingremen Ball
ence Ball
Ball
ence Pong
st
st
nd
t
1
1
2
1st
Mass
(g)
58
PingPong
2nd
Differ Marbl Marbl Differ
ence e 1st
e 2nd ence
58
x
47
47
x
2.2
2.2
x
5.4
5.4
x
Speed 5.66
Squar
ed
(m/s^
2)
4.49
x
6.25
4.49
x
5.15
4.68
x
5.15
5.38
x
Kineti 0.16
c
energy
(J)
0.13
.003
.15
.11
.04
.005
.0052 .0047 .01
.01
0
To calculate difference between 1st bounce and last: 100-x x=height of last bounce. For example; 1009=91 for the difference.
To calculate speed: m/s m=meters traveled. s=seconds traveled. For example; 1/.42 = 2.38
To calculate kinetic energy, KE=1/2(mv^2). KE = Kinetic Energy, m=mass(kg), v = speed. For
example; 1/2(.058*2.38^2)=.16 J
VI:“If tennis, super, ping-pong balls, and a marble are dropped from a height of 1
meter,
then the marble will bounce the highest because it makes the least sound and has the appropriate
density.” This hypothesis was not supported by the data, because the marble actually bounced
the lowest. The ping-pong and super ball were tied for highest. However, its kinetic energy is
the median of the data. It is also the median in mass, and because speed is always pretty close,
the difference could be appointed to human error, then a conclusion is that when dropped from
the same height, a object that has more mass will have more kinetic energy. Also, when two
objects are held above the ground at the same height, then the object with more mass will have
more potential energy. Unfortunately, humans are not perfect and therefore neither is the data.
Humans can not catch the ball at the exact moment every time, nor always start a stopwatch at
the same time the ball is dropped. Therefore, cameras with playback ability should be used to
find the height of each bounce. Also, a chart on the wall with heights on it would make it easier
to identify the height and also take another human factor out of the equation. But this raise new
questions, how long does it take various objects to reach maximum speed? Does this vary in a
vacuum? Does weight affect maximum speed?
1) The ping-pong ball retained the greatest amount of kinetic energy after each bounce.
2) Plastic contains energy well, and glass does not. Rubber does well, as good as plastic or better.
3) The slope of the line changes for each ball in the way that the more energy conserved in a ball,
the quicker the line levels out.
4) The balls can not bounce back to the same height because some energy is lost to heat and some
t mechanical sound.
5) The evidence that the ball conserved energy each time it bounced was the sound that it made.
6) If the experiment was preformed on a carpet, it would depend on the type of carpet and what
surface the carped was on. A fluffy carpet on soft wood would lose more energy to heat and
mechanical sound than a non-fluffy carpet on cork.
7) The marble lost the least amount of energy between each bounce, but it had the least in the first
place.
8) The super ball lost the most amount of kinetic energy.
9) The data results do match the previous lab.
10) The results do not support my hypothesis.
11) The energy types present in this lab are kinetic, gravitational potential, elastic potential, heat,
and mechanical sound.
12) Energy is converted into forms that are not useful to us.
13) Bill's toy train had the most kinetic energy because it had more mass and both were traveling at
the same speed.
14) Gravitational potential energy is energy due to an objects position, whereas elastic potential
energy is energy due to an object being twisted or stretched.