Science 10: Uniform Acceleration
Janice Cotcher
Introduction ............................................................................................... 3
Objectives .................................................................................................................... 3
Suitableness of Topic .................................................................................................. 3
Curriculum Fit/Objectives ............................................................................................. 3
Criteria for Success of Unit .......................................................................................... 3
Estimate of an Ideal Time ............................................................................................ 3
Engagement Activity ................................................................................ 3
Materials ...................................................................................................................... 3
Safety .......................................................................................................................... 4
Description ................................................................................................................... 4
Background Information ............................................................................................... 5
Questions to Assess Prior Knowledge ......................................................................... 5
Questions to Stimulate Thinking .................................................................................. 6
Goals/Objectives.......................................................................................................... 6
Sources ....................................................................................................................... 7
Exploration Activity I ................................................................................ 7
Materials ...................................................................................................................... 7
Safety .......................................................................................................................... 7
Description ................................................................................................................... 7
Background Information ............................................................................................... 8
Questions to Check for Understanding ........................................................................ 8
Questions to Stimulate Thinking .................................................................................. 8
Goals/Objectives.......................................................................................................... 8
Source ......................................................................................................................... 9
Exploration Activity II ............................................................................... 9
Materials ...................................................................................................................... 9
Safety .......................................................................................................................... 9
Description ................................................................................................................... 9
Background Information............................................................................................... 9
Questions to Check for Prior Knowledge ................................................................... 10
Questions to Check for Understanding ...................................................................... 10
Questions to Stimulate Thinking ................................................................................ 10
Goals/Objectives........................................................................................................ 10
Source ....................................................................................................................... 11
Explain Activity ....................................................................................... 11
Questions to Encourage What Was Observed in the Engagement and Exploration
Activities .................................................................................................................... 11
Questions to Encourage Explanations Based on These Observations ...................... 12
Questions to Encourage as Much Student Interaction as Possible ........................... 12
Questions to Encourage Linking These Activities to Other Science Concepts .......... 12
Student Input to Develop Necessary Definitions and Explanations ........................... 12
Background: Definitions and Principles I Want Students to Arrive At ........................ 13
Extend Activity ........................................................................................ 13
Materials .................................................................................................................... 13
Safety ........................................................................................................................ 13
Description ................................................................................................................. 13
Guiding Rules for the Simulation ............................................................................... 13
Background Information ............................................................................................. 13
Questions to Assess Prior Knowledge ....................................................................... 14
Questions to Stimulate Thinking ................................................................................ 14
Goals/Objectives........................................................................................................ 14
Source ....................................................................................................................... 14
Evaluation I ............................................................................................. 15
Aims for Assessment ................................................................................................. 15
Expected Responses ................................................................................................. 15
Rubric for Assessment............................................................................................... 20
Evaluation II ............................................................................................ 21
Aims for Assessment ................................................................................................. 21
Expected Responses ................................................................................................. 21
Rubric for Assessment............................................................................................... 24
Learning Cycle Comments ..................................................................... 24
Introduction
Objectives
1. What is acceleration?
2. How are speed, time, and acceleration related?
3. How can uniformly accelerated motion be represented graphically?
Suitableness of Topic
Students often have a hard time comprehending what acceleration means and how to
visualize it. Acceleration is the rate of change of an object's speed, which may be a
change in magnitude of the speed or a change of direction of the speed. (The former is
a topic of study in this unit; the latter is not.)
Curriculum Fit/Objectives
Science 10 Physical Science: Motion in Our World: Investigate the relationship among
speed, time, and acceleration for objects that undergo uniformly accelerated motion
Criteria for Success of Unit
-
Understand the difference between when an object is traveling at uniform speed
and when an object is undergoing uniform accelerated motion
Understand that the force of gravity can decelerate the upward motion of an
object and accelerate the downward motion of an object
Estimate of an Ideal Time
Approximately at the midway point of the semester; 7 hours long
Engagement Activity
Materials
2 – 11 meter long strings
14 metal washers
Metal garbage can
Computer with a microphone
Data Projector
Garageband (or similar software where you can visualize the wave form of sound and
compare tracks)
Tall ladder
Safety
1. Only an adult (preferably the teacher) should perform this experiment since the
materials are to be dropped from such a great height. Another adult should be
present to assist with the ladder and help supervise the class.
2. Use the one-to-four (1:4) ratio when using a ladder. To do this, place the ladder
so its base is one foot away from what it leans against for every four feet in
height to the point where the ladder rests.
3. Place a portable ladder so that both side rails have secure footing. Provide solid
footing on soft ground to prevent the ladder from sinking. Place the ladder’s feet
on a substantial and level base, not a moveable object.
4. Never lean a ladder against unsafe backing, such as loose boxes or barrels.
When you use a ladder for access to high places, securely lash or otherwise
fasten the ladder to prevent its slipping.
5. Be especially careful on windy days.
6. Extend the ladder’s side rails at least three feet above the top landing.
7. Take special care when ascending or descending a ladder. Hold on with both
hands when going up or down. Always face the ladder when ascending or
descending. Never slide down a ladder.
8. Be sure that your shoes are not greasy, muddy or slippery before you climb. Do
not climb higher than the third rung from the top on straight or extension ladders,
or the second tread from the top of stepladders.
Description
1. Prepare 2 – 11 meter long strings as follows:
String AB should be prepared by attaching 7 metal washers at even intervals of
about 183 cm. Clearly label side A and side B.
A-------------x--------------x--------------x--------------x--------------x-------------B
String CD should be prepared by attaching 7 metal washers at the following
points along the string: 0 cm, 31 cm, 123 cm, 276 cm, 490 cm, 766 cm, and 1100
cm. Clearly label side C and side D.
C-x---x-------x---------------x-----------------------x---------------------------------D
Do not let the students examine the strings ahead of time
2. Set up a computer with a microphone and use a program like Garageband to
record the sound of the metal washers falling into the metal garbage can for each
trial.
3. Holding the string CD by the D end, hold it at a height so the C end is just
touching the bottom of the metal wastebasket. As the weights hit the
wastebasket a series of sounds will be heard at evenly spaced time intervals.
4. From the same height, the second string (AB), identical in length and number of
weights, is dropped, but this time when the weights hit the wastebasket the
sounds are not evenly spaced.
5. When the strings are retrieved from the wastebaskets and laid on the floor,
students are asked to pick the string that made the evenly spaced sounds.
Common sense would dictate choosing string AB because the weights are
attached to the string at identical intervals. (This, however, is not the correct
choice!)
6. Repeat the drop for the class, string AB can be dropped from either the A or B
end and will result in sounds of hitting the wastebasket with unequal time
intervals. This time drop string CD from the opposite end (C) that it was dropped
from in the first time, once again unequal time intervals between the washers
hitting will result. Only when CD is dropped from the D end will there be equal
time intervals.
7. Display the tracks of all the trials on a data projector for the students so they can
see and hear the rate that the washers fell.
Background Information
If the string was falling with uniform velocity, the one with the equally spaced weights
would produce evenly spaced sounds, because each weight would be traveling the
same distance in the same time. Since each weight on string AB travels the same
distance before hitting the waste can (the weights are evenly spaced) and since each
arrives in a shorter time interval (the audio-recording proves that), each subsequent
weight must be traveling faster. In other words, the velocity of the string is increasing as
each weight falls through its 183 cm. This change in velocity per change in time is
acceleration. Each weight on the CD string is placed in such a way that washers hit the
bottom of the waste can at approximately equal time intervals.
Questions to Assess Prior Knowledge
1. What is position?
Expected answers: Where an object is; an object's location relative to a reference
point.
2. What is speed?
Expected answers: how fast an object is moving; the rate of change of distance
of an object.
3. How do position and time work together to give you speed?
Expected answer: Speed is how position of an object changes over a period of
time
4. What is uniform speed?
Expected answers: speed is constant; speed does not change over time
Questions to Stimulate Thinking
[After the strings are dropped the first time and the students have had time to explain
the strings]
Do you think either of the strings was falling with uniform speed? What evidence
do you have?
Expected answer: The second string (CD) has uniform speed because we could
hear the washers fell into the can at equal time intervals
[After examining the strings after they were dropped the first time]
Which is the second string?
Expected Answer: String AB (the first string)
[After the strings are dropped the second time and the students know which strings
have dropped each time.]
1. Which string had washers that fell at equal time intervals?
Expected answer: The second string (CD) has uniform speed because we could
hear the washers fell into the can at equal time intervals
2. Why do think the string with the uneven spaced washers fell at equal time
intervals?
Expected answers: Do not know; washers are speeding up at different rates so
they fall at equal time intervals
Goals/Objectives
This activity is designed to facilitate the students' understanding of the differences
between velocity and acceleration.
Sources
“Ladders, Lifting and Falls”, Dawna L. Cyr, Steven B. Johnson, University of Maine
Cooperative Extension, National Ag Safety Database, Retrieved December 5, 2010,
http://nasdonline.org/document/1032/d000826/ladders-lifting-and-falls.html
“Acceleration (Free-Fall)”, Robert Hartshorn, Robert Casteel, Tanya Mullen, Chip
Lajeunesse, Betty Jackson. Physical Science Activity Manual (Summer 1995).
Retrieved December 3, 2010
http://www.utm.edu/departments/cece/cesme/psam/psam.shtml
Exploration Activity I
Materials
Computer with a microphone
Garageband (or similar software where you can visualize the wave form of sound and
compare tracks)
Meter sticks
Safety
No safety concerns
Description
1. Put students into groups of no more than 3 so they can analyze the data from the
CD string from the Engage activity on a computer.
2. Have each group analyze the audio recording and determine the time that each
washer fell into the metal garbage can.
3. Groups are to measure the distance between each of the metal washers on the
string. Since the bottom washer was already touching the garbage can, the total
distance from the bottom washer to each individual washer is the total distance
each fell. For each of the time points determined from the audio file, have
students determine how the total distance each washer has fallen. Have students
put data in tabular form.
4. For the last washer (#7) to fall into the garbage can (D end of string), students
are to determine the speed of the washer for each time interval and add it to their
table.
∆𝑑 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 2 − 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 1
𝑠𝑝𝑒𝑒𝑑 =
=
∆𝑡
𝑡𝑖𝑚𝑒 2 − 𝑡𝑖𝑚𝑒 1
5. Students are to put the results of the speed of the last washer in appropriate
graphical form (speed versus time).
6. Students are to hand in their group table of data, graph and responses to the
“Questions for Understanding” and “Questions to Stimulate Thinking” for
Evaluation I.
Background Information
Since the last washer has the farthest to travel, students will be able to collect the most
information on it. It should be apparent from the data that students collect that the
speed of the washer increases as it approaches the bottom of the metal garbage can.
The rate of change of speed is acceleration due to gravity (9.81m/s2).
Questions to Check for Understanding
1. Why did we think that the second string (CD) was falling at a uniform speed?
Expected answer: We thought the second string (CD) had uniform speed
because we could hear the washers fell into the can at equal time intervals
2. Was the speed of the last washer uniform?
Expected answer: No
Questions to Stimulate Thinking
1. Did the speed of the last washer increase or decrease over time?
Expected answer: Increase
2. By how much did the speed of the washer increase or decrease?
Expected answer: increase by~240cm/s
3. Remembering that speed is the rate of change in distance over change in time, at
what rate did the speed change over time?
Expected answer: 244 cm/s/0.25s = 976cm/s/s (976cm/s2)
4. What is the significance of the rate of change of speed? (Particularly the value of
the rate).
Expected answer: Unsure; Rate of change of speed is acceleration; This value
of acceleration is due to gravity
5. What could cause the last washer to speed up that much?
Expected answer: Gravity
Goals/Objectives
-
Collect data about everyday objects that undergo uniformly accelerated motion.
(NUM)
Construct and analyze speed-time graphs of objects that undergo uniform
acceleration. (NUM)
Source
“Acceleration (Free-Fall)”, Robert Hartshorn, Robert Casteel, Tanya Mullen, Chip
Lajeunesse, Betty Jackson. Physical Science Activity Manual (Summer 1995).
Retrieved December 3, 2010
http://www.utm.edu/departments/cece/cesme/psam/psam.shtml
Exploration Activity II
Materials
Supplies for each group:
Ramp (approximately 170 cm long) with the ability to change the angle of the incline
from 5° to 10°
Stopwatch
Ball or marble
Masking tape
Safety
No safety concerns
Description
After completion of the following activity, the students as a group will complete the
Questions to Check Understanding and Questions to Stimulate Thinking. Each group
will then be broken up then students will join a new group with different students than
before. Each individual will share their results and then make any necessary
modifications to their list of questions from what the other groups learned.
1. Set up a ramp with the angle of the incline at about 10° to the table.
2. Measure the length of the ramp and place a piece of tape at the half-way point.
3. Practice releasing a ball so that it can be released uniformly throughout the rest
of the experiment. Using a stopwatch measure the time required for a ball to
travel from the release point at the elevated end to the end of the ramp. Repeat
this measurement two more times and determine the average time for this length.
4. Now determine the average time for the ball to roll from the same release point to
the half-way mark.
5. Repeat steps 3-5 with an angle of only 5° to the ramp
Background Information
To facilitate the measurement of a falling body where the speed is constantly
increasing, Galileo slowed down the motion by using an inclined plane. Because the
change in speed occurs more slowly it is easier to measure accurately. The velocity for
the first half of the trip is much less than for the last half of the trip. The ball is therefore
accelerating. The acceleration is decreased with the smaller angle.
Questions to Check for Prior Knowledge
We saw in the last activity that the speed of the metal washers was increasing over
time. If you think about when you are driving a car, what is another word for speeding
up?
Expected Answer: accelerating
Questions to Check for Understanding
1. What conclusion can be reached about the velocity of the ball through the first
half of the trip and its velocity through just the second half of the trip?
Expected answer: The velocity for the first half of the trip is much less than for
the last half of the trip
2. Is the ball accelerating as it rolls down the ramp? What evidence do you have?
Expected answer: The ball is accelerating because velocity is less for the first
half of the trip
3. What happens to the acceleration as the angle is changed?
Expected answer: The acceleration is decreased with the smaller angle.
Questions to Stimulate Thinking
1. If you wanted to increase acceleration, how would you change the angle of the
ramp?
Expected answer: Increase the angle of the ramp
2. How do you think you could maximize acceleration of the ball?
Expected answer: Drop the ball vertically
3. How do you think you could minimize acceleration of the ball?
Expected answer: Roll the ball with the ramp horizontal.
Goals/Objectives
-
Collect data about everyday objects that undergo uniformly accelerated motion.
(NUM)
Work collaboratively to plan and carry out investigations, as well as to generate
and evaluate ideas to practice the skills, knowledge, and attitudes needed to
work effectively with and for others. (PSD, CD 2.3)
Source
“Acceleration (Free-Fall)”, Robert Hartshorn, Robert Casteel, Tanya Mullen, Chip
Lajeunesse, Betty Jackson. Physical Science Activity Manual (Summer 1995).
Retrieved December 3, 2010
http://www.utm.edu/departments/cece/cesme/psam/psam.shtml
Explain Activity
Questions to Encourage What Was Observed in the Engagement and
Exploration Activities
Questions from Engagement Activity
[After the strings are dropped the first time and the students have had time to explain
the strings]
Do you think either of the strings was falling with uniform speed? What evidence
do you have?
[After examining the strings after they were dropped the first time]
Which is the second string?
Expected Answer: String AB (the first string)
[After the strings are dropped the second time and the students know which strings
have dropped each time.]
Which string had washers that fell at equal time intervals?
Questions from Explore Activity I
1.
2.
3.
4.
Was the speed of the last washer uniform?
Did the speed of the last washer increase or decrease over time?
By how much did the speed of the washer increase or decrease?
Remembering that speed is the rate of change in distance over change in time,
at what rate did the speed change over time?
Questions from Explore Activity II
1. Is the ball accelerating as it rolls down the ramp? What evidence do you have?
2. What happens to the acceleration as the angle is changed?
Questions to Encourage Explanations Based on These Observations
Questions from Engagement Activity
[After the strings are dropped the second time and the students know which strings
have dropped each time.]
1. Why do think the string with the uneven spaced washers fell at equal time
intervals?
Questions from Explore Activity I
1. Why did we think that the second string (CD) was falling at a uniform speed?
2. What is the significance of the rate of change of speed? (Particularly the value of
the rate).
3. What could cause the last washer to speed up that much?
Questions from Explore Activity II
1. What conclusion can be reached about the velocity of the ball through the first
half of the trip and its velocity through just the second half of the trip?
2. If you wanted to increase acceleration, how would you change the angle of the
ramp?
Questions to Encourage as Much Student Interaction as Possible
For Explore Activity II, students are brainstorm together as a group, then break off into
other groups to determine the answers to the following questions:
1. If you wanted to increase acceleration, how would you change the angle of the
ramp?
2. How do you think you could maximize acceleration of the ball?
3. How do you think you could minimize acceleration of the ball?
Questions to Encourage Linking These Activities to Other Science Concepts
Questions from Explore Activity I
1. Why did we think that the second string (CD) was falling at a uniform speed?
2. Was the speed of the last washer uniform?
Student Input to Develop Necessary Definitions and Explanations
Questions to be asked after Explore Activity I and before Explore Activity II to check for
the students' understanding of the term acceleration.
We saw in the last activity that the speed of the metal washers was increasing over
time. If you think about when you are driving a car, what is another word for speeding
up?
Questions are to be asked after Explore Activity II and before the Extend Activity to
check for the students’ understanding of the force of gravity.
1. What is a projectile?
2. What happens if you throw a ball straight up in the air?
3. It has been said “what goes up, must come down”. Why is that?
Background: Definitions and Principles I Want Students to Arrive At
Acceleration – the rate of change of speed of an object
Acceleration due to gravity - the acceleration caused by the gravitational attraction of a
very large object. On Earth, acceleration due to gravity is approximately 9.81m/s 2.
Extend Activity
Materials
Class set of computers with Internet access
Safety
No safety concerns
Description
Students will use PhET Simulation: Projectile Motion
http://phet.colorado.edu/sims/projectile-motion/projectile-motion_en.html to devise a
way to determine answer the Questions to Stimulate Thinking and then display on a
group poster (Evaluation II):
Guiding Rules for the Simulation

Remember to change only one variable at a time.

Use the tape measure to determine the height from the horizon.

The firing angle must be fixed at 90o.

Remember to record all values you used for each simulation.
Background Information
When a ball is thrown straight upward, the speed decreases. After it reaches the top
and begins its return downward, then the speed increases. At the maximum height of
the projectile, the speed is zero. It decreases at the same rate in an upward direction as
it increases in a downward direction. It decelerates at 10m/s2 upward and accelerates at
10 m/s2 downward.
Questions to Assess Prior Knowledge
1. What is a projectile?
2. What happens if you throw a ball straight up in the air?
3. It has been said “what goes up, must come down”. Why is that?
Questions to Stimulate Thinking
Expected Responses are found in the section Evaluation II
1. Using the projectile motion simulation, what variables can be tested that could
affect projectile motion?
2. Predict which of these do affect the projectile’s motion and provide reasoning for
why you think a particular variable might affect or not affect projectile motion.
Explain this for each variable.
3. When a projectile is fired vertically upwards (and air resistance is ignored), what
path does the projectile take?
4. For the entire length of the projectile’s trip when is velocity:
a. Increasing
b. Decreasing
c. Zero
5. Why did the projectile stop at the maximum height?
6. Determine the acceleration when the projectile is travelling upwards and then
when it is traveling downwards.
7. Graphically estimate what the velocity versus time graph would look like for your
projectile.
8. How did each variable you test change the path of the projectile?
Goals/Objectives
-
Collect data about everyday objects that undergo uniformly accelerated motion.
(NUM)
Work collaboratively to plan and carry out investigations, as well as to generate
and evaluate ideas to practice the skills, knowledge, and attitudes needed to
work effectively with and for others. (PSD, CD 2.3)
Source
“Acceleration (Free-Fall)”, Robert Hartshorn, Robert Casteel, Tanya Mullen, Chip
Lajeunesse, Betty Jackson. Physical Science Activity Manual (Summer 1995).
Retrieved December 3, 2010
http://www.utm.edu/departments/cece/cesme/psam/psam.shtml
Projectile Investigation for Middle School, Jefferson County Middle School Workshop,
PhET Contribution, Retrieved Dec 5, 2010.
http://phet.colorado.edu/en/contributions/view/3193
Evaluation I
Evaluation of Explore Activity I
Aims for Assessment
-
Organization of data
Graphical analysis
Good measurement taking
Articulation of explanation
Expected Responses
Correct Sample Data
#2
#3
#4
#5
#6
#7
Distance Distance Distance Distance Distance Distance Speed
Time (s) (cm)
(cm)
(cm)
(cm)
(cm)
(cm)
(cm/s)
0.25
31
31
31
31
31
31
0.5
123
123
123
123
123
368
0.75
276
276
276
276
612
1
490
490
490
856
1.25
766
766
1104
1.5
1100
1336
Change
in
Speed
(cm/s)
244
244
248
232
Change
in
Speed /
change
in time
(cm/s/s)
976
976
992
928
Speed (cm/s) of the Last Metal Washer
1600
y = 971.2x - 116
R² = 0.9999
1400
S 1200
p
e 1000
d
(
c
m
/
s
800
Speed (cm/s)
Linear (Speed (cm/s))
600
)
400
200
0
0
0.2
0.4
0.6
0.8
Time (s)
1
1.2
1.4
1.6
Speed as Each Washer Falls into the Can(cm/s)
1600
1400
S 1200
p
e
1000
e
d
800
(
c
m
/
s
Speed (cm/s)
600
400
)
200
0
1
2
3
4
5
6
Washer
Incorrect Sample Data
#2
#3
#4
#5
#6
#7
Change in
Distance
Distance Distance Distance Distance Distance Speed
Speed
Time (s) (cm)
(cm)
(cm)
(cm)
(cm)
(cm)
(cm/s)
(cm/s)
0.25
31
31
31
31
31
31
0.5
92
92
92
92
92
244
0.75
153
153
153
153
244
0
1
214
214
214
244
0
1.25
276
276
248
4
1.5
334
232
-16
If students incorrectly deduce total distanced traveled by the metal washers, it may in
fact appear that they are traveling a constant speed.
Change
in
Speed /
change
in time
(cm/s/s)
0
0
16
-64
Speed (cm/s) of the Last Metal Washer
300
y = -8x + 250.4
250
S
p
e 200
e
d
150
(
Speed (cm/s)
c
m 100
/
s
Linear (Speed (cm/s))
)
50
0
0
0.2
0.4
0.6
0.8
Time (s)
1
1.2
1.4
1.6
Speed as Each Washer Falls into the Can(cm/s)
300
250
S
p
e 200
e
d
150
(
Speed (cm/s)
c
m 100
/
s
)
50
0
1
2
3
4
5
6
Washer
Questions to Check for Understanding
1. Why did we think that the second string (CD) was falling at a uniform speed?
Expected answer: We thought the second string (CD) had uniform speed
because we could hear the washers fell into the can at equal time intervals
2. Was the speed of the last washer uniform?
Expected answer: No
Questions to Stimulate Thinking
3. Did the speed of the last washer increase or decrease over time?
Expected answer: Increase
4. By how much did the speed of the washer increase or decrease?
Expected answer: increase by~240cm/s
5. Remembering that speed is the rate of change in distance over change in time,
at what rate did the speed change over time?
Expected answer: 244 cm/s/0.25s = 976cm/s/s (976cm/s2)
6. What is the significance of the rate of change of speed? (Particularly the value of
the rate).
Expected answer: Unsure; Rate of change of speed is acceleration; This value
of acceleration is due to gravity
7. What could cause the last washer to speed up that much?
Expected answer: Gravity
Rubric for Assessment
Level
Graphical
Analysis
Appropriate
graph type,
Graph has a
meaningful title,
axes are labeled,
neat
Organization of
Data
Quality of
Results
Measurements
are correct,
calculations are
correct
2
Appropriate
graph type,
Graph lacks a
meaningful title
or axes are not
labeled, neat
Data in a table,
neat, table
columns and
rows are labeled
Most
measurements
are correct, Most
calculations are
correct
1
Appropriate
graph type,
Graph lacks a
meaningful title
or axes are not
labeled or not
neat
Inappropriate
graph type
Data in a table,
neat, table
columns and
rows are not
labeled
Incorrect
measurements
but calculations
are correct
Data not in a
table
Incorrect
Measurements
and calculations
3
0
Quality of
Responses
questions
are
answered
fully and
clearly with
evidence
given
questions
are mostly
answered
fully and
clearly with
evidence
given
questions
are lacking
evidence
questions
are lacking
evidence
and are not
answered
fully
and/clearly
Evaluation II
Evaluation of the Extend Activity.
Aims for Assessment
-
Organization of data
Articulation of explanation
Expected Responses
1. Using the projectile motion simulation, what variables can be tested that could
affect projectile motion?
Expected Responses: object (mass), initial speed, diameter
2. Predict which of these do affect the projectile’s motion and provide reasoning for
why you think a particular variable might affect or not affect projectile motion.
Explain this for each variable.
Expected Responses: object (mass) – larger mass would decrease the maximum
height (incorrect), the maximum height is independent of mass
Initial speed – a higher initial speed would increase the maximum height
Diameter – diameter of the object would not change the maximum height of the
object if air resistance is ignored
3. When a projectile is fired vertically upwards (and air resistance is ignored), what
path does the projectile take?
Expected response: The projectile will travel straight up, stop at the maximum
height and then come straight back down towards the ground.
4. For the entire length of the projectile’s trip when is velocity:
a. Increasing Expected Response: When the projectile is traveling back
down
b. Decreasing Expected Response: When the projectile is traveling upwards
c. Zero Expected Response: When the projectile is at the maximum height
5. Why did the projectile stop at the maximum height?
Expected response: Speed is changing from decreasing to increasing
OR
The projectile slowed down so much it stopped before coming back down again.
6. Determine the acceleration when the projectile is travelling upwards and then
when it is traveling downwards.
Expected Response: ~10 m/s2
7. Graphically estimate what the speed of your projectile looks like over time for
your projectile.
Expected Appropriate Graphs:
8. How did each variable you test change the path of the projectile?
Expected Responses: Object (mass) – larger mass would decrease the
maximum height (incorrect), the maximum height is independent of mass
Initial speed – a higher initial speed would increase the maximum height
Diameter – diameter of the object would not change the maximum height of the
object if air resistance is ignored
Rubric for Assessment
Level
3
2
1
0
Diagram of
change of
Speed of
Projectile
Correct shape,
Appropriate
graph type,
Graph has a
meaningful title,
axes are labeled,
neat
Correct shape,
Appropriate
graph type,
Graph lacks a
meaningful title
or axes are not
labeled, neat
Appropriate
graph type,
Graph lacks a
meaningful title
or axes are not
labeled or not
neat
Inappropriate
graph type or
incorrect shape
Organization of
Data
Quality of
Results
Quality of
Responses
Measurements
are correct,
calculations are
correct
questions
are
answered
fully and
clearly with
evidence
given
questions
are mostly
answered
fully and
clearly with
evidence
given
questions
are lacking
evidence
Data in a table,
neat, table
columns and
rows are labeled
Most
measurements
are correct, Most
calculations are
correct
Data in a table,
neat, table
columns and
rows are not
labeled
Incorrect
measurements
but calculations
are correct
Data not in a
table
Incorrect
Measurements
and calculations
questions
are lacking
evidence
and are not
answered
fully
and/clearly
Learning Cycle Comments
Depending upon the class, the extend activity (finding the acceleration of an object
projected vertically) maybe also be performed by the students themselves with
something like a ping pong ball gun.