Physics Behind the Sport of Bowling

Name: ___________________________________
Physics & the Sport of Bowling
Whether you have rolled a bowling ball or have never set foot in a local
bowling center you should be able to use the physical concepts we have been
exploring and observe with a careful scientific eye and describe the physics
going on during a game.
We have talked about motion, forces, energy, heat, and waves. Whether you
are aware of them or not all of these physical phenomena can be observed
during a simple throw of a bowling ball down the lane.
A bit about bowling etiquette:
Always wear bowling shoes on the lanes.
Please do not cross the black foul line. The lane is oiled and the lane is
very slippery.
Wait for bowlers on the lanes to your right or left.
Be certain you wait until the pinsetting machine has completed its cycle
and the sweep bar is raised before rolling the ball.
Do not stray from your lane after delivering the ball.
Keep food and drinks in designated areas.
Try to keep your fun and games to within your own group.
Please clean up your area when finished and return balls to the rack.
Bowling & Physics Observations
First let’s look at the motional part of bowling, specifically, the ball as it travels
down the lane. (We will worry about the pins later.) Throw a few balls down the
lane and/or watch others toss the ball down the lane. After you have witnessed
the motion of the ball, it is your job to try and answer the following questions.
1. Describe the shape(s) of the path of a ball down the lane. Is the motion
straight or curved?
Some people will have a straight path, others a hook or
curved path depending on how they throw the ball.
2. A bowling lane is 60 feet long, use a stopwatch, to determine the average
speed down the lane of a tossed bowling ball.
Average Speed=distance/time = 60 ft / 2.5 seconds = 24 ft/s.
( About 18 mph – answers will vary for each person)
Name: ___________________________________
3. Does everyone throw a ball at the same average speed?
No. Some throw the ball with a higher average speed, others
4. What is happening to the “speed” of the ball down the lane once it is
thrown? Any idea why?
The speed appears to be decreasing as the ball travels
down the lane. The force of friction will help to slow the ball
because it always opposes motion.
5. What is happening to the “velocity” of the ball down the lane once it is
thrown? Any idea why?
Ah! Many descriptions are possible. The ball’s speed is
decreasing therefore the velocity is also decreasing. In
addition, if the ball has a curved path down the lane the
direction the ball is traveling is also changing. So, the
direction and speed may both be changing!
6. Does the ball experience “acceleration” once the ball is thrown down the
lane? Why of why not?
Yes, any change in velocity is the definition of acceleration.
Motion Diagrams:
1. Let’s try and draw a vector diagram of the motion of a bowling ball down
the lane. Using the diagram, add your own observations of the ball at
various times down the lane. (For example, you can time the ball from the
moment it is thrown. Say, it takes 4 seconds for the ball to reach the pins –
you could draw an approximation of where you feel the ball is on the lane
at 0s, 1s, 2s, 3s, and 4s.) (I did the picture below for a straight throw)
2. To the diagram - add an indication (arrows) of the velocity of the ball at
those times. (Velocity vectors are solid arrows)
3. To the diagram - add an indication (arrows) of the acceleration you feel
the ball is experiencing down the lane. (Acceleration vectors are dashed)
Side View
Overhead View
Name: ___________________________________
Now we can begin to ask ourselves questions about why the bowling ball is
moving in the ways that we have observed. Let’s try and answer these questions
concerning the forces that are in action during the motion of the bowling ball and
its interaction with the bowling pins.
1. What “force(s)” are acting on the ball to get it in motion down the lane?
(There might be many possible answers for this.)
Many good answers are possible. Force of gravity (or weight
of the ball), forces applied by the muscles in the bowler’s
arm, forces applied by the fingers to impart spin in the ball,
muscles in the bowler’s legs to accelerate the ball (and
bowler) forward…etc……
2. Once the ball is rolling down the lane, is there still a force(s) acting on the
Sure, some are in balance with other forces ( for example
force of gravity downward into the ground toward the Earth’s
center and the upward force the lane surface provides –
normal force) and others are not. Friction is unbalanced by
any other force, therefore the ball experiences an
acceleration – “slowing down.” (Friction is the “net Force”
causing the ball to slow down)
3. What do these forces acting on the ball cause the ball to do in terms of
If there is a “net Force” (such as friction in this case) the ball
experiences an acceleration making the ball “slow down.”
4. Once the ball is rolling down the lane, what is the direction of the force(s)?
(Think carefully – conceptual pitfall)
Since the ball is “slowing down” and a “net Force causes
masses to accelerate” – then the acceleration (and therefore
frictional force) of the ball is in the opposite
direction as the velocity of the ball.
5. How does the “mass” of a ball change the action of the forces?
The larger the mass, the harder it is for the “forces” to cause
a change in the motion (larger mass – smaller acceleration
with a given force).
6. Before the ball “hits” the pins, what is the speed of the pins?
They are not moving – zero. (They may have been wobbling
a bit, but mostly not moving)
Name: ___________________________________
7. Does the ball “hitting” the pins cause the pins to experience a change in
Yes, they are moving with many different speeds in many
different directions after the ball hits them. So they were
mostly stationary before the ball hits and moving after.
8. Do the pins experience a force when the ball “hits” them? How do you
Yes. Each pin is a mass. Each pin experienced a change in
velocity which we call “acceleration.” When a mass
accelerates we say it has experienced a “net force!”
Energy is everywhere - we just have to identify the forms of energy and when
and how it transfers between energy types.
1. Does the rolling bowling ball have “energy?” If so, what kind of energy?
Yes, kinetic energy of motion.
2. Where did the energy the ball has moving down the lane come from?
What is this type of energy?
Bowlers “raise” the ball upward above the lane before
throwing it. This increases the ball’s gravitational potential
energy. The bowler then drops it into a swing and lowers it to
the lane surface converting the potential energy of position
to kinetic energy of motion. (Some bowlers will also add
some energy by using the muscles of the arm and legs as
well…… )
3. Does every throw of a bowling ball have the same energy? Why or why
No, a faster ball will have more kinetic energy than a slower
ball traveling down the lane.
4. Do the pins have any easily observable kinetic energy before the ball hits
them? Why or why not?
No, the pins are stationary. No motion – no kinetic energy.
(Why did I say “easily observable?” – Well, the pins do have
a temperature – the nanoscale particles that make up the
solid wood of the pins will be jiggling with some motion.)
5. After the ball hits the pins, do the pins have any kinetic energy? How do
you know?
Yes, clearly the pins are moving around after the bowling
ball hits them. Moving pins means they have kinetic energy
that is easy to see.
Name: ___________________________________
6. If we compared the total amount energy of the bowling ball before it hits
the pins to the total amount of energy of the pins and ball after it hits the
pins what would we find? Upon what principle do you base your
The total amount of energy before the ball hits the pins will
be equal to the total amount of energy after the collision. We
just need to be careful to identify all the energy amounts and
types before and after the collision. (….energy of the ball
before and after, energy types of the pins before and after,
energy in the “sound” waves the collision creates…etc…).
This is the Law of Conservation of Energy.
7. Can you identify any time during the motion of the bowling ball down the
lane and/or when it hits the pins where we might say the “heat and/or
temperature” of an object changed? (Hint: think friction and/or kinetic
Temperature is based on the “average kinetic energy” of all
the pieces (molecules, atoms, etc) in a substance. So, in a
sense, anytime there is a “change in the kinetic energy” of
something you are “changing the temperature.” The pins
have a “change in kinetic energy.” The pins are not moving
around much before the collision, but after they are moving
around a lot more. The pins as a collection of particles could
be said to have experienced a temperature change.
The periodic motion of waves is also going on during the game. In fact, it is
being sensed by a way we observe the game as it happens.
1. Do you hear anything during a throw of the ball down the lane? What?
“Thunk” of the ball hitting the alley. “Rumble” of the ball
rolling on the lane….…. “Hip-Hip-Hooray” of the bowler
celebrating a strike!
2. Do you hear anything during the collision between the ball and pins?
“KaaPow” of the ball hitting the pins. “Crash” of the pins
hitting each other.
I observe “sounds.”
Name: ___________________________________
3. Explain, how you can “hear” these events? Does it have anything to do
with waves?
Some of the energy during the bowling ball’s collision with
the pins is transferred to air molecules near the collision
causing them to vibrate. This disturbance in the air
molecules travels outward as a longitudinal sound wave to
the bowler’s ears so that she “hears” the sound of the
4. Does it take “energy” to hear these “sounds?” Why or why not?
Yes, vibrations, oscillations, waves, depend on something
moving – therefore kinetic energy of motion is involved in the
5. Where does this energy come from?
Somewhere else. (Not trying to be coy). Energy is neither
created nor destroyed, so any energy comes from
somewhere else by changing form or being transferred from
place to place and process to process. The energy in
question creating the sound came from the kinetic energy of
the ball which came from the potential energy the bowler
gave the ball by lifting it, but the bowler ate some food earlier
in the day to store energy to lift the ball, the food eaten got
the energy from………… this list goes forever……
Conceptual Summary
Simply, the concepts and physical phenomena that science (physics) tries to explain are
going on around us all the time. In a simple game of bowling, we can witness all types of
situations that deal with motion, speed, velocity, acceleration, vectors, forces, kinetic and
potential energy, conservation of energy, heat, and waves. I hope this little activity, can help
inspire in you a new way to look at every day life and “see” the physics behind the observations.
Science is going on all around us and we certainly use it pragmatically everyday (sometimes in a
formal mathematical way) just living our lives.