Motion of a Bowling Ball

John J. Miller Maine Township High School East
2601 Dempster
Park Ridge IL 60068
(847) 825-4484

Objectives:

The students will be able to make a distance vs. time graph of a bowling ball
and have practice reading distance vs. time graphs of various motions.

Materials:

A bowling ball, 5 - 10 stopwatches, a massive object to let the ball collide
into and not hurt anyone, white boards (this is a 8 foot by 4 foot sheet of
white paneling board that can be bought at most big hardware stores and is cut
into 1 foot x 1 foot boards), dry erase markers, and paper towels to clean off
the boards.

Strategies:

Phase 1:
This is a Socratic/phenomenological form of questioning to do a lab. One of the
"hidden" purposes to this lab is to get away from the standard, cookbook forms
of the lab manual, and have the students make the plan of attack with small
prompts from the teacher. I will repeat, you want to get away from the "now
we'll do this" and move toward the "What do we need to do in order to make a
distance vs. time graph of a bowling ball as it rolls?"

In your mind, you know you want to have the students line at equally spaced
distances (for example every five feet) in the hall way. You could be courteous
with your fellow teachers and warn them a day or two ahead of time. I think it
is worth the extra trouble because this is an excellent opportunity to do
science outside of the classroom - which is an entire other story. You would
like stopwatches in there little hands. You would like the students to all
start there stopwatches when you roll the bowling ball slowly. When the ball
passes them you would like them to stop their stop watches. You would like
someone to collect the data in a column form so that you can make another trial
rolling the ball faster. You would like them to go into the classroom and graph
the data (distance on the vertical axis and time on the horizontal axis). You
can them ask questions such as "What do you notice about the best fit lines of
the two trials?" Hopefully you will get the faster trial is steeper and the
slower trial is less steep.

Now is a good time to regroup and explain that if the line is horizontal it
means the object is stopped and the slope of the line (steepness) tells the
speed.

Phase 2
Hand out the white boards and dry erase markers and a paper towel to clean them
off. Explain to the students you are going to walk across the front of the
class room and you would like them to make a sketch of a distance vs time graph
(qualitative graph) of your motion. The following are some suggested motions to
walk in order to have the students build from simple to more complicated.

a) walk at a constant speed
b) walk at a constant speed, stop for a time and walk at the original speed
c) walk at a constant speed, stop for a time and walk at a speed faster
than the original speed
d) walk slow and then speed up
e) walk fast and then slow down
f) walk forward at a constant speed and then back toward the origin

Phase 3:
Have two students come up to the front of the class room. Have one student make
a distance vs. time graph but not show anyone except the other student in front.
He will try to walk like the sketch the first student made and the rest of the
students will make a sketch of how the walking student walked. Compare the
original sketch made by the first student

Performance Assessment:

Walk some method and have the students make a distance vs. time graph of your
motion.

Conclusions:

On a distance vs. time graph the slope (steepness) of the line tells you about
the speed of the object. The larger the slope (steeper the line) the faster the
object travels. The smaller the slope (the less steep the line), the slower the
object. A flat line means the object has stopped.

References:
Me: Give me a call.

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