LeaPS, 7th Grade
Forces and Motion
LeaPS
7th grade activities
Force and Motion
(with Work)
2010-2011
1
LeaPS, 7th Grade
Forces and Motion
Outline of Topics:
1. Describing Motion: Graphing, Speed and Velocity
2. Describing Motion: Changing Velocity
3. Forces, Their Sizes and Direction
4. Force and Mass
5. Its a grave matter: gravity and inertia
6. Weight and Mass
7. All work and no play: Work and Energy
Appendices
1: 7th Grade Vocabulary Related to Force and Motion
2: Motion Detector Directions
3: Day 1 Graphs with Focus Question at the End
4: Day 1 Data Collection Sheet
5: Day 2 Student Problem Sheet
6: Day 2 Second Set of Problems
7: Day 2 Graphs for is the Velocity Changing
8: Day 3 Student Tables with Questions
9: Day 4 Frame for Science Notebook
10: Day 5 Skateboard Prediction and Actual Sheets
11: Day 6 Data Table
12: Day 7 Student Handout
13: Day 7 Force Arrows
14: Day 8 Data Analysis
15: Uncovering Student Ideas in Physical Science probes
16: National Enquirer advertisements
17: Excerpt from Joy Hakim’s The Story of Science: Newton at the Center, pages 172-183
18: Directions for converting You Tube videos to another media file
2
LeaPS, 7th Grade
Forces and Motion
First topic: Describing motion
A three-day exercise
Learning goals
Reviewed from 6th grade (day 1):
I can interpret a position versus time line graph to determine types of one-dimensional
motion of an object.
I can draw a position versus time line graph given appropriate data.
I can represent changes in motion in a variety of ways, including words, motion arrows,
graphs, and by acting out.
(Day 2) I can use the information in a position vs. time graph to determine the speed of an object.
New for 7th grade: I can define velocity.
(Day 3) I can distinguish between speed and velocity.
Topic Word Bank
Speed
Velocity
Position
Distance
Time
Rate of change
Slope
Sequence of Experiences
Day 1: Interpretation of a
Position/Time Graph
Day 1: Creation of a
Position/Time Graph
Day 1: Making Sense of
Multiple Representations
Day 2: Calculating Speed
Day 2: Differentiating Speed
and Velocity
Day 2: Exit Slip
Day 3 Intro
Day 3:Collecting Initial Data
Day 3:Interpreting Data Parts 1
and 2
Day 3: Student Challenge
Day 3: Class Discussion
Day 4: Intro
Day 4:Interpreting Data Parts
3, 4 and 5
Day 4: Processing Information
Motion
Direction
Graph
Vertical
Horizontal
Representation
Negative
Positive
Pairs and whole group
10 minutes
Lab groups and whole group
25 minutes
Whole Group
10 minutes
Pairs and whole group
Pairs and whole group
23 minutes
18 minutes
Individually
Whole class
In pairs
In pairs, then groups of 4
5 minutes
3 minutes
12 minutes
20 minutes
Whole class
7 minutes
Whole class
Individual and Paired
3
LeaPS, 7th Grade
Forces and Motion
Day 4: Class Discussion
Day 4: Exit Slip
Whole Class
Individually
3 minutes
4
LeaPS, 7th Grade
Forces and Motion
Day 1 Focus Question: What can be learned from different representations of motion?
Materials and Preparation:
For the class:
o
o
o
o
o
o
o
o
Copies of graphs (each group to have at least two graphs)
Guided Question Sheet (1-2 per group)
Data Collection Guided Sheet (1-2 per group)
Toy cars (1 per group, 6-7 cars needed)
Meter sticks (1 per group, 6-7 meter sticks needed)
Graph Paper
Masking Tape
Exit Slip (optional and one is a long exit slip and one is a short exit slip)
For the teacher:
o Computer
o White board/Chalk Board
o Overhead/Document Camera
o Projector
o File of Graphs – on CD under day 1 investigating motion
Day 2
For the class
o
o
o
Copy of data table and questions (1 per pair of students)
Calculators (1 per pair of students)
Copies of exit slip (1 per student)
For the teacher
o
o
o
Velocity Ticket
Velocity Police Hat (optional)
Projector/Document Camera to project questions
Day 3
For the class
o
o
o
o
For each group of 2 students:
Lab Quest (LQ)
Motion Detector (MD)
Clear view of a wall or a table for placing the MD/LQ (aim at waist level)
Investigating Motion 1
1. Interpretation of a Position/Time Graph
Divide the class into pairs. Give each pair two graphs and a set of questions to answer. Allow
students to work in groups to interpret the provided graphs and answer the guided questioning
5
LeaPS, 7th Grade
Forces and Motion
page. Next, open up the graphs file on your computer. Select one graph (possibly one that you
did not pass out to the students) and ask several leading questions.
Example Questions include:









What does the slope of the line suggest about the motion of the object?
What should the title of the graph be?
What information is provided on the graph for you to determine its speed?
How would you calculate the speed?
Does this object change direction? Why? Or Why not?
Does this object change its speed? Why? Or Why not?
What units are represented? Why is it important to record units?
How is the graph scaled? (or what does it mean to scale a graph?)
Does anyone have a graph representing no motion? How did you determine there was
no motion?
Now you will transition to the next activity which is to practice creating a position vs. time
graph by collecting data.
2. Creation of a Position Time Graph
Now, students will work in groups (3 to 4 students) to collect time and distance data to
graph. Before sending students to obtain materials, it is important to stress students
need to make a distance mark every 10 cm. They will record how long it takes for the
wind-up car to travel 25cm, 50cm, 75cm, and 100cm. Each group should pick-up one
meter stick, one wind-up toy car, the instruction sheet, and a timer. Discuss roles for
students to assume in the activity for example:
-Timer (they have the timer and are responsible for starting and stopping the
timer, they also announce the time required for car to travel the specified
distance)
- Measurer (they mark the points where 25cm, 50cm, 75cm and 100cm, they are
responsible for informing the timer when the car reaches the distance)
- Car Holder (this student starts the car each time)
- Recorder (this student is responsible for recording the times for each trial)
- Car Catcher (optional)
Safety Notice: Students will spread out around the room. Cars
should be tested on the floor, but no group should block the door.
As students are collecting data, the teacher should circulate around the room. Asking questions
such as: What is the purpose for taking multiple readings at each measurement?
When students have completed collecting data, they must return their meter sticks and cars to the
teacher. Groups will then create a graph from the data. Groups that finish early will begin
answering questions about the graph. Teacher will circulate around the room looking for good
examples of a position vs. time line graph.
Teacher Note: A discussion about graph starts when all
groups have finished graphing.
6
LeaPS, 7th Grade
Forces and Motion
When all groups have completed construction of the graph, it is time for a post graphing debrief.
Start by showing one example of the graph on the overhead or document camera.
Review the concept, what does this graph represent, by asking questions of the students. For
example:

What does the slope of the line represent? (It represents motion, the speed)

What does the space between the points, but included in the line, represent?

What would the graph look like if the car were slowing down?

What would the graph look like if the car were constantly increasing its
speed/rate?
3. Making Sense of Multiple Representations
Next, ask the students to write three sentences describing the motion of the car (using page 160
in Writing in Science on Data Analysis). The following is paraphrased from the text.
Start with a topic sentence – to say what the graph is about such as the title and what
is graphed on the axes
Summarize the data – focus on the trend and not on specific data points
End with a conclusion – what is the main inference from this graph
Ask for a few to share their descriptions. Then write down your description of the motion. Discuss
the differences between their descriptions and your description. Finally, have students make
corrections (not copy) to their description.
Now ask the students the following questions:

What are the advantages of creating a graph? What are some of the disadvantages of
creating a graph? (The amount of time required is not an acceptable answer.)

What are the advantages of writing a description in words? What are some
disadvantages of writing a description in words?
Teacher note: Write the student answers on the board. If you have a student
that likes to write on the board, ask them to write and you can direct traffic.
Now, ask the class, “What are the advantages of having a graph (line graph) and a paragraph
description?”
(Optional) Exit Slip (a written formative assessment): An idea for an exit slip may be to give
them a position vs. time graph and they write a three sentence description of the motion. Or give
students a description of motion and create a graph from the description.
7
LeaPS, 7th Grade
Forces and Motion
Day 2 Focus Question: What is velocity?
Investigating Motion 2
1. Calculating Speed
Start the class with a graph of position versus time on the board. Ask the students what
information they need to calculate the speed of the object in the graph?
Student response - time and distance
So if we need time and distance, how do we use these values to calculate speed? Or what is the
formula?
Student response - speed equals distance traveled divided by time travel occurred.
Now begin distributing the speed table and questions. Explain that they are to determine the
speed of the four cars on the table. Then using information provided in the directions, they will
determine which cars will receive a speeding ticket. Remind pairs that they MUST show their
work. (Teacher should circulate around the room to answer questions and to focus students
upon work.)
Below is the table with the results of calculations with a speed limit of 25m/s (just over 55mph):
Car
Time (s)
Distance (m)
A
115
3452
B
104
2477
C
175
4117
D
542
15430
Path of the
Car
Turns left
after 2000m
Turns left
after 1500m
Does not turn
right; does
not turn left
Turns right
after 7,440m
Speed
Type of Ticket
3452m/115s =
30m/s
2477m/104s =
23.8m/s or
24m/s
4117m/175s =
23.5m/s or
24m/s
15430m/542s
= 28.4m/s or
28m/s
Speed
No ticket
Velocity
Speed
Ticket fine for car A is $10*100= $1000
Ticket fine for car D is $10*30 = $300
After students have calculated speed and determined which cars have speeding tickets, debrief
again by having student volunteers work at least two of the problems at the board. Emphasize
the importance of including your units while calculating speed. Next, the teacher will put on the
police hat and say: I have a new ticket to award one of the cars. This ticket is called a Velocity
Ticket. The car that has earned a velocity ticket is car C. [Pause and hold up the velocity ticket]
With your partner, look again at the data in the table and develop a reason for why Car C has a
velocity ticket. When you have decided upon the rule, write it on the back of the paper.
Wait a few minutes and then begin calling on students for their reason for a velocity ticket. In this
case, a velocity ticket has been given to the car that did not turn. So students should begin to
develop a connection between velocity and direction.
Now explain that velocity is a rate (distance traveled in a given time period) and it includes the
direction of travel. When one turns, but keeps speed the same, the velocity changes but not the
rate (speed). So cars A, B and D changed their velocity once, but did not necessarily change
8
LeaPS, 7th Grade
Forces and Motion
their rate. In this town, cars that do not turn at all have a velocity ticket (i.e. they did not change
direction).
Now put on the board the data for two additional cars, students must calculate the speed (show
your work) and then award the cars tickets earned based upon the data and the rules of the city.
Students will also need to explain their reasoning for the tickets awarded and not awarded per
car.
Teacher Note: have students work individually
Car
Time (s)
Distance (m)
E
295
7800
F
25
500
Path of the
Car
Does not turn
right; does
not turn left
Turns to the
right after
250m
Speed
Calculation
7800m/295s =
26.4m/s or
26m/s
500m/25s
=20m/s
Ticket
Speed and
velocity
No ticket
Review the results. Again, have students that have not already worked problems on the board do
so. Then show a graph of position versus time. The first graph will have the object moving at the
same rate, and in the same direction. Ask the students:
1. “Does the speed change?” No
2. “Explain how you know that?”
3. “Does the velocity change?” No
4. “Explain how you know that.”
Show the next graph which has the same slope for the speed, but it changes direction.
Ask the same four questions:
1. Does the speed change? No
2. Explain: the slope of the line is the same
3. Does the velocity change? Yes
4. Explain: the object is first moving away, but then it changes direction to come back.
Show the third graph, this time the graph shows an object not moving which then starts to move.
1. Does the speed change? Yes
2. Explain: the slope of the line changes from no motion to motion
3. Does the velocity change? Yes (this one will be difficult since they may have only
focused upon the direction factor for velocity)
4. Explain: the slope of the line changes indicating a change in rate, and velocity is a
measurement of rate and direction.
Teacher Note: Students will have difficulties at this point because
of an underlying misunderstanding of relative position and distance.
9
LeaPS, 7th Grade
Forces and Motion
Ask students to visualize a race track for NASCAR. While they visualize, you will draw an oval on
the board in a dark marker color. Make a start location for the cars. About halfway around the
track mark a point where a crash has taken place on the first lap of the race. Ask students to
describe the distance the car traveled before crashing. Now explain the relative position
compared to the start is described differently. Draw a straight line from the start to the crash
location.
Ask students to turn to a seat partner and explain the difference between distance and relative
position.
Personal Glossary Entry: Teachers need to pass out one page for the creation of a 7th grade
personal glossary for force and motion. In student’s personal glossary, have students define
speed, velocity, and rate of change using their own words and representations.
Now ask students to take out a piece of paper. Title it “Exit Slip Motion 2”
Indicate students are the answer the following questions:
1. What is the definition of speed?
2. What is the definition of velocity?
3. What is similar for speed and velocity?
4. What is different for speed and velocity?
10
LeaPS, 7th Grade
Forces and Motion
Day 3 Focus Question: What distinguishes velocity from speed?
Activities
Hook: Can motion be both positive and negative? What determines if a value is positive
or negative? How might this be represented on a graph?
Set up LabQuest and Motion Detector – see directions in appendix.
Collecting Motion Data:
1. Find an open area at least 4 m long in front of a wall. You will be measuring distances
from the wall using the MD which you will carry in your hand, or you can place the MD on
a table and move in front of it. Recall that carrying sound reflectors like pieces of
cardboard make this a better measurement. The spikes in position measurements that
come from poor reflection or other unintended conditions will cause very spikey velocity
measurements. So, it is crucial to make sure that your measurements do not include
these spurious measurements.
2. Make position AND velocity graphs of your motion when you walk away from the wall at a
constant speed. To do this, stand close to the wall, start moving , then start data
collection by pushing the start button in the center of the LQ (just above the circle of
buttons ). If you get a spike the LQ may Autoscale and carry it into the next
measurement; so check the limits before each measurement. It may take several
attempts to get good graphs.
3. Record in your notebook a sketch of position AND velocity graphs for moving away for
your best data, including axes labels and units and title the graph according to the type of
motion.
4. Make position AND velocity graphs of your motion when you walk toward the wall at a
constant speed. To do this, stand well away from the wall, start moving, then start data
collection by pushing the start button in the center of the LQ (just above the circle of
buttons ). Check the limits before each measurement.
5. In your notebook record a sketch of position AND velocity graphs for moving toward,
including axes labels and units and title the graph according to the type of motion.
Teacher Note: Cut up each section and handout separately to avoid overwhelming
students.
Interpreting Motion Data:
Working with your partner, use the motion graphs you generated and sketched in your
notebook to answer the following questions:
1.Making sense of the data
A. At anytime did you measure a
negative velocity? When?
B. At anytime did you measure a
negative position? When?
C. Is it possible to measure a
negative position using the Motion
Detector?
Yes, if object gets closer to MDLQ (origin)
Yes, if object gets further away from MDLQ (origin)
Position can only be positive, because object is a certain
distance away from the MDLQ (origin)
11
LeaPS, 7th Grade
Forces and Motion
D. What is the origin in this activity?
Motion Detector
E. Is it possible to measure a
negative position using a MD?
F. Is it theoretically possible to
measure behind the MD?
No, can’t get behind it; always positive
No, can’t get behind it. MD won’t measure behind it.
2. Position
A. What is the direction for
increasing position?
B. What is the direction for
decreasing position?
C. What does delta or Δ mean?
Away from origin
D. What is an example Δx i.e. what
is Δ (position)? Give example from
your graph.
X refers to position – away from or towards; Final position
– Initial position (Xf – Xi)
Back towards origin
Change
Students should provide specific examples from their
data.
E. Can Δx be positive? Give
example. Is x increasing or
decreasing?
F. Can Δx be negative? Give
example. Is x increasing or
decreasing?
Yes, +X, moving away from MD (origin); X is increasing.
Yes, -X, moving toward MD (origin); X is decreasing.
Exit Slip: Challenge students to try to get a negative position using the MD. Ask
students to describe the procedures they tried, what their results were, and how
they would account for their results.
Day 4 Focus Question: What distinguishes velocity from speed?
Activities
Hook: If you started at the origin (MD) and walked 5 paces away from the origin (MD),
then turned around and walked 4 paces towards the origin (MD), where would you be
with respect to the origin (MD)? What would your change in position or X be? Describe
motion that would provide a -X value.
Bridge: If position can be positive (+) or negative (-) with respect to the origin, can
distance be both + and - ? Can time?
3. Time and Distance
A. What time did movement start?
Zero (0) or ex. 1:00
B. Write down the start time on LQ.
Zero (0)
C. Write down the elapsed time on
LQ.
Will vary for each group
12
LeaPS, 7th Grade
Forces and Motion
D. What is Δt?
Change in time
E. What do we mean by change in
time?
F. Can Δt be positive? Give
example.
G. Can Δt be negative? Give
example.
Final time – Initial time; Tf - Ti
H. Is our position and distance the
same?
I. Can d, distance, take on negative
values or is it always positive?
No, distance is determined by adding the values
Yes, values on the horizontal or x-axis, + numbers
No, can’t go back in time. If we got a – value for time,
that would mean that we were going back in time.
Distance will always be positive, because distance
traveled is determined by adding the values together.
However, relative position is dependent upon the
relationship to the origin and could be negative.
4. Speed and Velocity
A. Can speed take on negative
values or is it always positive?
Speed is always positive (+), because distance, d, can
only be positive (+) and t can only be positive (+).
Therefore, speed, which is d/t, can only be positive (+).
B. How would you determine your
speed as you travel from home to
school? Write an equation
representing this relationship. Will
speed always be positive? Explain.
I would take the distance I travel from home to school in
miles and divide that by the time (in seconds, minutes, or
hours) it took me to get to school from home. d/t (time
interval for the trip)
Yes, because both distance and time are additive values
and therefore always positive.
C. The relationship for velocity is
Δx/Δt. Explain this relationship in
words.
Velocity is the relationship between the change in
position, xfinal – xinitial, of an object during a change in time,
time final – time initial.
D. How does the relationship get at a
sense of velocity? For example,
what would happen to the velocity
value if there was a large change in
position during a small change in
time? What would happen to the
velocity value if there was a small
change in position during a large
change in time?
E. Can Δx/Δt be positive? Give
example and interpret. Is x
increasing or decreasing for positive
Δx?
F. Can Δx/Δt be negative? Give
example and interpret. Is x
increasing or decreasing for negative
Δx ?
G. How is the velocity relationship
different from speed?
A large change in position during a small change in time
would result in a larger value for velocity. Conversely, a
small change in position over a larger change in time
would result in a smaller value for velocity. Velocity
indicates how rapidly something is changing position in a
given amount of time.
Yes, the value will be positive when an object is moving
away from the origin. X is increasing for a positive X
value.
Yes, the value will be negative when an object is moving
towards the origin. X is decreasing for a negative X
value.
Velocity measures the change in position, which can be
positive or negative, during a time change. Whereas,
speed measures the total distance traveled, which can
13
LeaPS, 7th Grade
Forces and Motion
only be positive, during a time change.
5. What have we learned?
A. What is the meaning of:
 position at zero?

velocity of zero?

time of zero?
B. What is the meaning of:
 negative velocity?

positive velocity?

negative position?

positive position?
Position at zero is at the origin.
A velocity of zero means that an object is not moving;
there has been no change in position for a given time
period.
A time of zero means the exact time the object began
moving.
Negative velocity means an object is moving towards the
origin during a time interval.
Positive velocity means an object is moving away from
the origin during a time interval.
There is no such thing as a negative position; this is not
possible.
A positive position is the distance with respect to the point
of origin.
Summarize: Provide the symbol or relationship and explain if the value can be positive or
negative. Write your summary in your notebook.

Position X, only +

Time t, only +

Distance d, only +

Speed d/t, only +

Velocity X/t, + or -
Pair-Share: Partner with another pair and compare answers to the questions you are not sure
about.
Individually: Compare speed and velocity by completing the comparison frame in your
notebook.
Speed and velocity are similar because they both ___________________________. In addition,
they _________________________________. (Add more as needed.)
Speed and velocity are different because speed _____________________________, but velocity
_______________________________________. Also, speed ___________________, whereas
velocity ______________________________________. (Add more as needed.)
14
LeaPS, 7th Grade
Forces and Motion
Class Discussion:
Randomly call on students to share his/her comparison statement; first similarities, then
differences. Chart the information as students share. (Randomly call on 3-5 students with the
‘rule’ that each student must share something different from what has previously been said. Stop
calling on students when no one has any additional ideas.) As students state their ideas, require
that they use evidence from their graphs for support.
Similarities: both happen over time, measure a change in position, are relative to a point of origin,
describe motion
Differences:


Speed
Always +
Distance traveled during a change in
time


Velocity
Can be + or –
Change in position during a change in
time
Have students revisit their personal glossary and make any revisions/additions to definitions of
speed and velocity.
Add rate of change to personal glossary, define, etc.
From day 2, redraw the NASCAR track. This time the focus is upon the concept differentiation
between speed and velocity. Ask the students to describe what quantities are used to determine
the speed (the line tracing the distance traveled and the time it takes to travel that distance). Now
ask the students what quantities are needed from the track to determine velocity (the position line
and the time it takes for the car to travel from the start to crash point).
X
X
d
Exit Slip:
Describe the motion of the toy car represented on the graphs below and explain why the two
graphs are different, even though they each represent the motion of the same car for the same
time period. What is the speed of the toy car? What is its velocity?
15
LeaPS, 7th Grade
Forces and Motion
16
LeaPS, 7th Grade
Forces and Motion
Topic 2 Describing Motion: Changing Velocity
A two-day exercise
Learning goals
I can predict changes in motion when the force acting on it changes.
I can distinguish between constant velocity and changing velocity, using graphs.
Topic Word Bank
Force
Constant Force
Instantaneous Force
Constant Velocity
Changing Velocity
Sequence of Experiences
Days 5: Intro
Prediction
Determine Measurement
Demonstration
Actual Experiment Sheet
Class Discussion
Vocabulary Practice
Exit Slip
Day 6: Intro
Collecting Data
Data Analysis
Class Discussion
Exit Slip
Whole class
Individually
In groups of 4
Whole class
Individually
Whole class
In groups
Individually
Whole class
In groups of 4
In groups of 4; individually
Whole class
Individually
17
2 minutes
5 minutes
10 minutes
10 minutes
5 minutes
5 minutes
7 minutes
2 minutes
2 minutes
25minutes
8 minutes
8 minutes
2 minutes
LeaPS, 7th Grade
Forces and Motion
Day 5 Focus Question: How is motion different when a continual push is applied compared to
when the pushing stops?
Materials
Skateboard Prediction Sheet
Skateboard Actual Experiment Sheet
Stopwatches
Meter Sticks
Skateboard (1 for demonstration purposes)
Bathroom Scale
Helmet
Toy Car for Exit Slip demonstration
Activities
Hook: Think for a minute about what you know about forces. What do you know about
the effect of different forces on motion? Today, we are going to begin exploring how
motion is affected when a constant force is applied to an object compared to motion
when an instantaneous force is applied.
Teacher Note: make sure there is plenty of room for pushing
students on skateboards in the hallway. Make other teachers
aware of hallway activity.
So, we are going to start by making some predictions about the motion of a person who
is given an instantaneous shove compared to that person’s motion when a continuous
push is applied.
1. Hand out Skateboard Prediction Sheet. Students will complete the Prediction sheet
individually. Do not permit students to leave sections blank. It is important for them to
know and write down what they think the motion will be like with two different
applications of force. Students will be making Position-Time graphs.
2. Form random groups of 4. Have each group determine what needs to be measured
and a how to make measurements needed to describe the motion of a continual push
vs. an instantaneous push of a person on a skateboard. Give the groups 3 minutes to
determine a method. The group with the most efficient and reasonable method will
get to set up and demo the motion for the whole class.
3. Have each group share their method. Select the “best” method. Hand out the
Skateboard Actual Experiment sheet. Each student watches and records any
necessary information on the Actual sheet, while the “winning” group demonstrates
the motion. Remind students that they are making Position-Time graphs.
4. Have students compare their predictions to the actual data. Record responses in their
science notebooks. Answer the focus question using data to support their answers.
18
LeaPS, 7th Grade
Forces and Motion
Description of the Motion
Graphical Representation
Continual push, constant force
Continual push, constant force
An object speeds up as a continual push/constant
force is applied.
After the pushing stops..
After the pushing stops..
Once the constant force has stopped being applied,
the object moves at a constant speed until it begins
to slow down and finally stops.
Class Discussion
1. On the count of 3, have students do a thumbs up if their prediction matched the actual
and a thumbs down if their prediction did not.
2. Pair-Share: With a partner, discuss any differences in their predictions and the actual.
What surprised them and why?
3. End the discussion by asking students to write their “rule” for describing the motion for
when a continual force is applied compared to when an instantaneous force is applied in
their notebooks.
With continual/constant force, the object will speed up. When an instantaneous force is
applied, the object will move with a constant speed.
Exit Slip:
Ask students to sketch a graph representing the motion they observe, during a 10 second
interval, as you tap a toy car and then as you apply a continual force to move the car across your
desk.
With Constant Force
With Instantaneous Force
19
LeaPS, 7th Grade
Forces and Motion
Day 6 Focus Question: How do motion graphs compare for constant and changing velocity?
Materials
For each group of 4 students:
Lab Quest (LQ)
Motion Detector (MD)
Clear view of a wall or a table for placing the MDLQ (aim at waist level)
Playground Ball
Meter sticks to form “tracks”
Masking tape
Fan Carts
Foam Board
Activities
Hook: Look back in your notebook to your velocity graphs. When an object is moving
with constant velocity what did the graph look like? Visualize an object moving that
would generate that graph. Today, we are going to continue to use representations of
motion to help us better understand, describe and make predictions about that motion.
Set up LabQuest and Motion Detector – see directions in appendix.
Collecting Motion Data:
1. Find an open area at least 4 m long in front of a wall. Place the motion detector (MD) on a
table. The MD uses sound reflection to measure distance. Carrying a sound reflector, like
pieces of cardboard, makes this a better measurement. The spikes in position measurements
come from poor reflection or other unintended conditions will cause very spikey velocity
measurements. So, it is crucial to make sure that your measurements do not include these
spurious measurements.
2. Make both a position and a velocity graph of your motion when you walk with constant
velocity. Stand close to the wall, approximately 4m away from MD holding a piece of
cardboard. Start moving, and start data collection by having another group member push the
start button in the center of the LQ (just above the circle of buttons). If you get a spike, the
LQ may Autoscale; so check the limits before each measurement. It may take several
attempts to get good graphs. When you are approximately 15cm from the MD, stop.
3. Record in your notebook a sketch of the position and velocity graph for ‘moving away’ using
your best data, including axes labels and units and title the graph according to the type of
motion.
4. Make both a position and velocity graph of your motion when you walk with increasing speed,
but no directional change. Stand well away from the wall, approximately 4m away from MD
holding a piece of cardboard. Start moving, and have another member push the start button in
the center of the LQ (just above the circle of buttons). Check the limits before each
measurement.
5. In your notebook, record a sketch of both the position and the velocity graph for increasing
speed, including axes labels and units and title the graph according to the type of motion.
6. Set up the MD so that you can capture the motion of a playground ball that has been tapped.
(Create a “track” using meter sticks to keep the path of the ball straight, so that the MD can
20
LeaPS, 7th Grade
Forces and Motion
capture it.) Make both a position and velocity graph of the motion of the ball.
7. In your notebook, record a sketch of both the position and the velocity graph of the ball,
including axes, labels, and units. Title the graph according to the type of motion.
8. Set up the MD so that you can capture the motion of a motorized fan cart. Make both a
position and velocity graph of the motion of the motorized fan cart.
9. In your notebook, record a sketch of both the position and the velocity graph of the fan cart,
including axes, labels, and units. Title the graph according to the type of motion.
Interpreting the Motion Data:
Motion/Object
Sketch Position Graph
Sketch Velocity
Graph
Verbal Description
(Use Key Vocabulary
Words)
1. Walk with
constant velocity
Constant speed
2. Walk with
increasing speed
Speeding up
3. Ball that was
tapped
Constant speed
4. Fan Car
Speeding up
Data Analysis:
In your notebook, compare the motion of #1 and #2, then #3 and #4. Summarize and draw
conclusions from the four motion graphs to answer the focus question. State your “rule” for
determining if a graph is showing constant velocity compared to changing velocity.
Constant velocity – flat, straight line; changing velocity – slanted, straight line
Class Discussion:
1. Randomly call on students (3-4) to share their rule and use their graphs to support.
2. Show the class several velocity graphs (see Appendix __) and have them identify the type of
motion represented. Some of these graphs will have different examples of motion, and they
should use words to describe what is taking place at each point.
3. Under what circumstances is the velocity constant? Compare this to situations when the
velocity is not constant. What is different in these two cases?
21
LeaPS, 7th Grade
Forces and Motion
Velocity is constant when the object is not speeding up or slowing down.
4. When a ball is sitting on the table and not moving, what can you say about its velocity? Is the
velocity constant or not constant? Are the forces acting on the ball balanced or unbalanced?
How do you know?
The velocity is constant. The forces acting on the ball are balanced, because the ball is not
moving.
5. In the next lesson, we will investigate conditions of changing velocity.
Personal Glossary Entry:
Students will add their definitions for constant velocity and changing velocity.
Exit Slip:
Describe the motion.
Describe
the velocity. Velocity Graphs?
How Can You Create
the Following
Graph 1.
V
(m/s)
0
V
(m/s)
Graph 2.
0
t (sec)
Graph 3.
Graph 4.
V
(m/s)
V
(m/s)
0
t (sec)
0
t (sec)
A. Speed Up, then Slow Down B. Turn Around
D. Stand Still
E. Walk Toward
t (sec)
C. Walk Away
Graph 1 represents the motion of an object that is moving away from the origin with constant
velocity (not speeding up or slowing down).
Graph 2 represents the motion of an object that is moving towards the origin with constant
velocity (not speeding up or slowing down).
Graph 3 represents the motion of an object that is moving away from the origin and speeding up
then slowing down. The object has a + velocity.
Graph 4 represents the motion of an object that is moving away from the origin and slowing down
then the object stops and moves back towards the origin and speeds up.
22
LeaPS, 7th Grade
Forces and Motion
Topic 3: Forces and their Sizes and Direction
Key idea: When an unbalanced force acts on an object, the change in speed or direction
depends on the size and direction of the force.
Learning Goals:
I can identify the force acting on an object.
I can use force arrows to predict change in the motion of an object.
I can explain the change in motion of an object when an unbalanced force acts on it.
What is the relationship between changing velocity and force?
Day 7 Focus Questions: How does the motion of an object suggest a net force is acting on it?
Under what circumstances is the velocity of an object changing or remaining constant? How can
forces be represented?
Topic Word Bank
Force Arrows
Balanced Force
Net Force
Gravity
Friction
Air Resistance
Materials
Copies of Probe entitled “Force and Motion Ideas” pg. 79 FnM Probe book; Appendix 15
Paper and colored pencils
Cut-outs of arrows with different lengths – there should be sets of arrows with 3 different
lengths (short, medium, and long) and 5 sets per group.
Activities
(10 min) Hook: Read the directions for the “Force and Motion Ideas” probe and have students
complete it.
Teacher Note: Students will need your insistence on summarizing their ideas about force and
motion. Model an example of how you would use the statements you have an X by to help you
summarize your thinking.
Collect the probes and analyze for trends and most prevalent ideas about force and motion.
(3 min) In your groups, discuss the following situations, and then do an open sort. In other words,
sort these into categories of the students’ choosing. You need to decide on what your categories
are and how many categories you will choose. You must use and identify evidence from your
own experiences to help you decide how to sort.
A.
B.
C.
D.
E.
The activity we did earlier with a student on a skateboard
A baseball player hitting a home-run
A ball is at the top of a hill and released
After a ball is kicked on a flat grassy field
A rock is just sitting on the ground
23
LeaPS, 7th Grade
Forces and Motion
(5 min) Then sort again by choosing categories (the teacher selects the categories or is it defined
by the entire class?) based on motion. Do two-category sorts (that is, if the idea is to sort based
on color, the categories might be blue and not blue).
Perform a second two-category sort based on constant velocity and changing velocity.
(10 min) In each of the above situations, there is a specific object involved. For example, in the
second situation, the object would be the baseball, even though it is not directly mentioned. For
each object, respond to the following questions in your groups:
Is its velocity changing?
Is its velocity increasing, decreasing, or remaining constant?
What caused the change in velocity?
How do you know? (provide evidence for each of your answers)
What forces are acting on the object in each case?
(10 min) In each case, draw a diagram of the situation. Do not draw a graph, but draw a
picture showing the situation as best as you can. For each, show the moving object (ball,
skateboard, rock, even though it is not moving) at a moment when forces are most active
on the object.
Position the provided arrows on your drawings, showing each of the forces at work, and
the direction for the arrow matching the direction of the force. Choose an arrow with an
appropriate length to get at the impact of the force.
 Check with the teacher about your diagrams and explain why you choose the arrows
and their positions as you did.
Situation
A.
Skateboard
(constant
force)
B. Baseball
player hitting a
home run
C. Ball
released from
top of hill
D. After a ball
is kicked on a
flat, grassy
field
E. Rock sitting
on the ground
What forces
are acting
on the
object in
each case?
Gravity
Constant
force
Friction
Gravity
Air
Resistance
Hit
Is velocity
changing?
If so,
describe the
change
What causes
the change
in velocity?
How do you
know?
Yes
Increasing
Unbalanced
forces
Changing
speed
Yes
Changing
direction
Unbalanced
forces
Changing
direction
Gravity
Friction
Yes
Increasing
Unbalanced
forces
Changing
speed
Gravity
Upward force
Friction
Yes
Decreasing
Unbalanced
forces
Changing
speed
Gravity
Ground
No
Balanced
forces
No change in
speed or
direction
24
LeaPS, 7th Grade
Forces and Motion
Class discussion (10 min)







Are there always forces acting on objects?
List some forces that might be acting.
If an object is not moving, but has forces acting on it, what can you say about
these forces (to help you in your thinking about this, consider a tug-of-war in
which the two teams are perfectly balanced in their pulls)?
Suppose an object is changing its motion, what can you say about the forces
while its motion is changing?
How do the arrows help you predict how motion will be changing?
Arrows used to indicate the direction and strength of a force are called force
arrows.
When arrows cancel each other out, for example because they have the same
lengths and are pointing exactly away from each other, then the total force
represented is referred to as a balanced force, and there is no change in
motion. If they don’t cancel out, perhaps because one is longer than the other,
then there is a net force, and the motion continuously changes.
Revisit the “Force and Motion Ideas” probe. Have students individually review their initial
responses, change any as needed and revise their explanation. It is helpful if students use a
different color to make these changes. Have students refer to the chart they created and their
answers for the focus questions prior to revising their probe responses. Note: Students will
revisit their answers to this probe again after reading a selection about Newton. You will want to
wait to discuss their choices after the final revisit. Only D, G, and J are correct answers on this
probe. Many of the statements are examples of a belief that motion requires an unbalanced force
– only change in motion is a result of unbalanced forces. Many students think of force as a
property of an object rather than as an interaction between objects. Choosing statements K and
L may be indicators of this type of thinking. It will be helpful for you to note who seems to
understand the effect of unbalanced forces on an object and who does not. You will want
students to refer to their evidence and use their charts to help with their explanation.
Notebooking: Have students summarize their answers to the focus questions based on the
class discussion and probe discussion.
Exit Slip
Choose a specific playground game, sport, or activity, and write a brief paragraph
describing the motion that takes place over a period of one minute of play.
Then produce a diagram showing this one-minute of play in which you insert force
arrows. Explain how the force arrows allow you to understand better the change of
motion, or that motion is not changing.
25
LeaPS, 7th Grade
Forces and Motion
Topic 4: Force and Mass
A 3 day exercise
Learning Goals
I can predict changes in motion when an object’s mass or the force acting on it changes.
I can describe the relationship between mass and changing motion when a constant
force such as gravity is applied.
Unit Word Bank
Force
Velocity
Changing Velocity
Constant Velocity
Balanced Forces
Unbalanced Forces
Gravity
Summary of Events
Day 8: Force and mass
Day 9: Force and mass
Day 9: Force, mass and
changing velocity- skateboard
Day 9: Exit Slip
Day 10: Force, mass, and
changing velocity – vertical
Day 10: Force, mass and
changing velocity – horizontal
Newton
Air resistance
Horizontal
Vertical
Mass
Rate of Change
Groups of 3 to 4
Whole Group/Individual
Review: Whole Group
Whole Group
45 minutes
Individual
Groups
5 minutes
15 testing, 5 minutes
discussion
15 data collection, 10
discussion
Groups
5-10 minutes
20 minutes
Materials:
For the class
Day 8
--frictionless cart (1 per group) carts need to have a hole in the front and back
- one string
-ramp board (1 per group)
-pulley (1 per group)
-1.5N spring scale (1 per group)
-weights, each 300 g (4 per group)
-scissors if students cut string
-measuring tape (if students cut string themselves)
-calculators (optional)
-graph paper (1 per group)
-directions page
Day 8
Teacher Materials:
26
LeaPS, 7th Grade
Forces and Motion
-scissors if teacher cuts string
Day 9
Materials:
Skate board (possibly 2)
Large force scale (previously used on day 4)
Handout
Day 10
Activity 1
1 ring stand per group
1 ping pong ball per group
1 metal ball per group
1 cup of play dough per group
1 meter stick per group
Roll of masking tape (to keep the meter stick attached to the ring stand)
Timer (option for each group, need one for teacher)
Something to flatten the play dough
Balance for groups to use
Activity 2
Computer(s) with internet access
Optional projector and screen
Preparation for activity day 8/9:
1. Make sure you have enough room for all groups to have ramps out.
27
LeaPS, 7th Grade
Forces and Motion
Day 8
Focus Question: What is the relationship between force and mass?
1. Force and Mass
Begin class with a question such as: “what is force?” “What do you expect to happen to the force
when velocity is changing in a constant pattern but the mass is increased?” “What trend would
you predict between force and mass?”
Give an example of a force. (Teacher would create a list of identified forces) For each example,
the teacher should have a follow-up question such as and explain why you think this is a force or
what evidence do you have to support this is a force?
After reviewing force, the class should have a review of the concept of FAIR TEST.
-What does the word fair mean? How does it apply to scientific experiments?
Explain that today they will set-up and collect data. Show students the final set-up. To do this
students’ will be using a spring scale. Spring scales are difficult to use and to determine the
measurements because the increments are unfamiliar and change depending up the magnitude
of the scale. Pass out a spring scale to all groups and keep one for yourself. Have all students
look carefully at the spring scale. Students need to determine what the increments for each line
are. If you have a document camera, you may project a scale and have them record what the
force measurement is for several teacher “pulls”.
Today we will collect data and all participants must assume a role. Teacher should assign roles to
groups: some possible roles are recorder, puller, and materials handler.
Teacher note: give students a time limit for collecting data.
Write on the board the exact length of string needed, if students are to cut string. Teacher
circulates checking set-ups.
Now go over the data collection procedure by demonstrating how to pull. Place heavy emphasis
upon even pulling that does not pull upward or downward. The next point to make is that force
measurements should be taken after the initial pull. Pass out data instruction sheets. Make sure
all groups know to write data table and any answers to questions on a group member’s paper.
Nothing should be written on the instruction sheets.
Students will now begin to collect data using the guided instructions.
When groups complete five trials for 0, 300g, and 500g, they should begin disassembling the
apparatus and returning materials.
After disassembling the equipment, students should return to their groups for data analysis.
Groups may need access to calculators to determine the average force required for each
scenario tested.
When groups have calculated the average force for five trials, they will need graph paper to
create a graph of mass and force.
Next, ask one group to place their graph under the document camera.
-Begin reviewing with a check of the interpreting graphs.
28
LeaPS, 7th Grade
Forces and Motion
-What would you predict would happen if you had added 1500g to the cart?
-What is the amount of force needed for a 400g mass?
-What is the mass associated with a force of 1.8N?
-From the graph, what is the general rule that could be inferred?
Notebooking: Use the data analysis frame in Writing in Science to summarize the collected
data. Answer the Focus Question by having all students agree upon the rule and then write down
the agreed upon rule based on their observations and data analysis. The greater the mass, the
greater the force needed to move the object?
29
LeaPS, 7th Grade
Forces and Motion
Day 9
Review concept from the day before by asking students to share what the conclusion from the
day before was and the evidence they have for this conclusion. Ask students to discuss how this
is reflected in a graph of force and mass?
It may be helpful to review comparisons of speed and velocity prior to beginning this activity. You
may want students to review and revise their personal glossary definitions for speed and velocity
as a result of this review.
x
x
t
t
Speed -> steepness; always +
Velocity -> slope; x/t may be + or –
+ = going towards increasing values of x
- = going towards decreasing values of x
Focus Question: How does changing the mass relate to the observed velocity?
To begin the next activity, have all students move to an area where there is no carpeting, and the
area is long, and devoid of obstacles (i.e. the hallway, gym, or sidewalk).
Explain that the teacher will use the large scale which measures force in newtons to provide a
constant force to the back of the volunteer riding the skateboard. Ask for a set of volunteers and
select students that have different sizes.
Safety Note: have students line either side of the rolling area. If done in a
hallway, appoint door watchers. Door watchers will prevent anyone that exits a
door along the hallway from entering into the experiment (i.e. there will not be a
crash between the walker and the rider).
Explain to the other students, they need to make observations and record them after each run.
For example, students should describe qualitatively the rate of travel and if it stays constant.
Include any detail such as the skateboard rider went off course etc. Have the first student sit on
the skateboard holding their knees up. Student may be encouraged to wear a coat to protect
clothing, but the coat should not be hanging below the waist when standing.
Teacher note: select your largest volunteer to go first. The force you will use for your
push should be just large enough to achieve a slow acceleration. Record this force so
that in the subsequent trials you will use the same force.
Push the first student with a constant force.
30
LeaPS, 7th Grade
Forces and Motion
After waiting for students to record observations, then ask several students to describe in detail
what they observed. Also have the student riding the skateboard and pushing the skateboard
describe what they felt.
Repeat with a second volunteer of a different size. Wait for students to record observations. Ask
several different students to describe in detail what they observed. Also have the student riding
the skateboard and pushing the skateboard describe what they felt.
Ask for comparisons between run 1 and run 2.
Repeat with a third volunteer of yet another different size. Wait for students to record
observations. Ask several different students to describe in detail what they observed. Also have
the student riding the skateboard and pushing the skateboard describe what they felt.
Ask for comparisons between run 1, run 2, and run 3. You may repeat this as time allows.
Finally, have all students return to the classroom.
Notebooking: Ask, “Does anyone have any suggestions for an explanation of the different
results observed?” Address the Focus Question by having students answer in their notebooks
and share with class.
Record student explanations on the board. Explain: “tomorrow we shall explore this phenomenon
further.”
Day 10
Focus Question: Does the direction of force (vertical or horizontal) have any observed changes
upon the relationship between force and mass?
1. Force and mass with constant acceleration vertical
Ask each student to turn to the student next to them and state two things they observed the day
before. Next, ask each student to make one conclusion including the evidence that supports this
conclusion. Have students write down their conclusion and evidence.
Announce; “Today we will explore force and mass in the vertical and horizontal direction. Do you
predict they will be similar or different?” Students may simply write down yes or no and drop vote
in a beaker. Teachers may elect to tally these now, later during experimental time. Or have
students move to different corners for yes, no, or not sure. While students are in their like vote
corner, they should discuss their reasons and share out.
Have a discussion about variables and constants. Focus upon the idea of things the
experimenters intend to change, things the experimenters expect to change as a result of the
change, and that everything else that could change better not change. Then explain each group
is to test the force of two objects. In groups, they must first determine how they will test the force:
identifying the constants and controls. After class agrees upon a procedure, each group should
pick-up their materials and go to their assigned work area.
Safety Note:
Make sure students quickly pick-up dropped balls.
Notebooking: Go around the room to check on progress. As student groups complete testing,
they should be encouraged to write a conclusion statement in their science notebook. Use the
data analysis and conclusion frame in Writing in Science.
31
LeaPS, 7th Grade
Forces and Motion
Have students return to whole group. Ask if any group elected to test if the balls all take the
same amount of time to fall. If no group did this test, ask if this would be an important test.
(Simply conduct this test as a demo).
Have some groups share their conclusions. Make sure they provide evidence upon which the
conclusions are based.
2. Force and mass in the horizontal direction
Materials needed:
“Free Falling Objects” probe, pg 167 in Uncovering Student Ideas in Physical Science,
Appendix 15
Computers with internet access
Questions for students to answer
http://www.harcourtschool.com/activity/newton/
Teacher Note:
For this activity if the computer lab is available take the students
down so that they may use the Harcourt School demo individually.
.
Administer the “Free Falling Objects” probe and ensure that each student explains their
thinking by using the selected data table as support. You might have students go to 3
corners based on the table they selected and discuss their explanations. Have each group
come to a consensus and share their reasoning with the entire class.
Student task: test all of the force and mass combinations. Record your results in a data table.
Answer the following questions based upon the data collected:
1. Describe how the ball moves in a high mass, low force situation.
2. Describe how the ball moves in a low mass, high force situation.
3. Explain the relationship between mass and acceleration when force is kept constant?
4. Explain the relationship between force and acceleration when mass is kept constant?
When all students have answered the above questions, ask for several students to answer.
Notebooking: Now compare and contrast the horizontal experience with the vertical
experience by answering the Focus Question. Record comparison in science notebook.
Students should conclude that if a constant force is applied, then an object will accelerate.
Help them make the connection to gravity being a constant force.
32
LeaPS, 7th Grade
Forces and Motion
Topic 5: It is a grave matter…
An investigation of gravity and inertia
A four-day exercise
Learning goals
I can distinguish between visible and invisible forces.
I can identify several invisible forces and show differences among them.
I can recognize the role of mass in gravitational forces.
I can recognize the role inertia plays in the interaction between mass and a force.
Unit Word Bank
Gravity
Inertia
Magnetism
Electrostatic force
Charge
Visible force
Invisible force
Friction
Sequence of Experiences
Day 11: Intro
Activity A
Activity B
Class Discussion
Days 12, 13: Intro
Activity A
Activity B
Activity C
Class Discussion
Day 14: Intro
Activity A
Activity B
Class Discussion
Whole class
In groups
In groups
Whole class
Whole class
In groups
In groups
In groups
Whole class
Whole class
In groups
In groups
Whole class
5 minutes
10 minutes
20 minutes
10 minutes
10 minutes
30 minutes
15 minutes
15 minutes
15 minutes
5 minutes
10 minutes
10 minutes
15 min
33
LeaPS, 7th Grade
Forces and Motion
Day 11 Focus Question: Does a force require direct contact to affect an object’s motion?
Materials
Scotch Magic Tape
Ring stands with horizontal 18” wooden dowel attached,
At least 2 small bar magnets per group
Activities
A. Explore with the two magnets to answer the following questions:




Can one magnet cause the other one to move without touching it?
Can the magnets exert these effects when something such as paper or plastic is
between them?
Do the magnets cause the same response to each other in every orientation?
Does the magnetic effect occur as strongly at all distances between the
magnets?
Discuss in your groups, then write in your notebooks the following:
1. What evidence general tells us that a force is present or acting?
2. What evidence from this activity shows that the magnets exert a force on each
other?
B. Do other forces that don’t require contact behave in the same way as magnets?






Set up some plastic tape in the
Teacher’s note: this activity will work best
following manner: Take a piece
if the air is not hot and humid! Use an
of tape about 1 foot long and
air-conditioned room!
make small handles at each end
by folding a short segment of the
tape back onto itself. Press the sticky side of the tape firmly into a flat surface,
using your fingernail to be sure there is a strong contact between the surfaces.
Hold onto one of the handles and sharply pull the tape up and away from your
body and stick it from that end to the wooden dowel. Repeat this with a second
length of tape, and also hang it from the dowel, but not so closely to the first tape
that they get stuck to each other. At no point should you handle these tapes
except by their “handle” ends.
Prepare a third piece of tape the same way, but don’t hang it yet from the dowel.
Bring it close to but not touching the hanging tapes. What observations do you
make about their behaviors? Try not to get the tapes on yourself or the effects
will not be so clear!
Hang up this third tape alongside the others.
Now make two tapes in a different way: Press another foot-long length of tape
as before into the flat surface, but this time label it with the letter B (Bottom) on
one of the handles using a pen. Take another length of tape and press it directly
on top of B. Label this one T (Top). Grab hold of both tapes by their handles
and pull them together off the surface, and then pull them apart from one
another, and away from your body, so they do not stick to you.
Hold these tapes one at a time close to, but not touching, each of the tapes
hanging from the dowel and notice the responses. Do T tape and B tape show
the same effect?
Remove the original tapes, and hang the T and B tapes from the dowel, then
make another T and B pair. How do the T and T tapes respond to each other?
34
LeaPS, 7th Grade
Forces and Motion

How do the B and B tapes respond to each other? How do opposites (T and B or
B and T) respond to each other?
Thinking about the activity with the magnets, check the response of the tapes
after either flipping or turning the tapes around. Do they have a different
response in a different orientation?
 Check with your teacher that your results are coming out properly.

Check the tapes with one of the magnets. Then turn the magnet around and see
if the response changes.
Respond to the following questions, first by discussing with your partners, then writing in
your notebooks:




Do the tapes exert a force on each other without coming into direct contact?
Does this force remain as strong at a greater distance? Or maybe: As the
distance increase, what does the evidence suggest about the “amount” of force?
Is this force the same as the magnetic force?
What evidence can you provide for each of your answers?
Class discussion







What evidence is needed to show that a net force is present and acting on
something?
What evidence have you seen indicating direct contact is not necessary for a
force to act on an object?
When direct contact is not needed, the force is referred to as an invisible force.
One example of invisible forces you investigated is magnetism. The force
between the plastic tapes is called the electrostatic force, or sometimes
charge, and is also invisible.
Forces depending on direct contact, such as friction, pushes, pulls, hits and
similar things are called visible forces.
Do we have evidence that gravity is a force? Is it invisible or visible? How do
you know?
How does the strength of an invisible force depend on the distance between
objects? What evidence do you have for this? Do you expect this to also be true
for gravity? Why?
In the next session, we will look at gravity in another way.
Notebooking: Fill this in: ________forces such as ________ and _______ do not
require direct contact between objects, while _________forces such as _____________
and ______________ do require some sort of direct contact. I have observed the
following evidence to justify these answers:
35
LeaPS, 7th Grade
Forces and Motion
Days 12 and 13 Focus Question: How is gravity similar to and different from other forces?
Materials
Ramps
Motion detector/LabQuests
Stopwatches
Low-friction carts
2 weights per cart
Meter sticks
Spring scales
Activities
A. Focus Question #1: What is the effect of gravity on the motion of carts with different
masses?










Use the low-friction carts with the ramp at a shallow angle (with the high end
roughly 3-4 inches off the ground), with the motion detector/LabQuest positioned
at the top of the ramp, so that the cart will be moving away from the motion
detector, which should be aimed precisely at the cart. You may need to attach
the motion detector to the ring stand to achieve the best data collection.
You should use the following settings for your LabQuest:
o In the opening window after the motion detector is connected, use
Length = 3.0 seconds; the other settings are OK
o Click on the graph symbol at the top.
o Pull down the Graph menu.
o Under Graph Options, you should set Graph 1 to Position with Top=2
and Bottom = 0 (units are in meters)
o Graph 2 should be Velocity with Top=1.5 and Bottom = 0 (units are in
meters/second)
o Both graphs should have “Point Protectors” and “Connect Points”
checked
Experiment with the set-up so that you can reproducibly catch the motion of the
cart as it moves down the ramp. Have your teacher check () your ability. What
will be important in this activity will be the velocity vs. time graph (graph 2) for the
cart, and you will use the final velocity as the cart just reaches the bottom of the
ramp.
Set up your notebooks to record the final velocities of the cart for each of at least
6 trials, two for each mass level.
Determine and record in your notebooks the velocity of the unloaded cart as it
reaches the bottom of the ramp. Do this again to be sure the values are in close
agreement.
Repeat this measurement after loading one mass unit onto the cart (the added
mass unit should be close to the mass of the cart).
Repeat again with two mass units.
Each of your measurements should be repeated at least once.
Look at your data and use it to discuss with your group the following question: In
what way does changing the mass of the cart change its motion under the
influence of gravity?
Write your summary statement in your notebook.
B. Focus Question #2: How does changing mass affect the motion of a cart responding
to an instanteous force?
36
LeaPS, 7th Grade
Forces and Motion











For this activity, you will measure the velocity of the cart as it rolls across the
floor, but instead of using the motion detector, you will measure the velocity using
a stopwatch and meter stick.
To measure velocity, use masking tape on the floor to indicate the following
positions:
o One meter from the front end of the cart when its back is against a wall
or other solid support.
o Two meters from that same position.
You will use stopwatches to measure the time the cart takes to move from the
starting position to the 2 meter line. You will need to recall how to use time and
position data to calculate the cart’s velocity.
For the force, you will use the built-in spring in the cart, if it has one. Otherwise
you can use an external spring or you can make a “spring” with a ruler, being
sure to be consistent in its use.
Start timing the moment the cart is released and note the time it takes for the
front-end of the cart to cross the 2-meter mark, and record this time.
Repeat this measurement enough times that you are confident of the accuracy of
your measurement. Record your values in your notebooks.
Repeat this measurement using one weight added to the cart.
Repeat again with two weights in the cart.
Calculate the velocities for each run and enter them in your notebooks.
Discuss with your group: How does the motion of these carts with different
masses compare with the motion of different masses under the influence of
gravity?
Write your summary statement in your notebook.
C. Focus Question #3: How does changing mass affect the motion of a cart responding
to a continuous force?









For this activity, you will exert a pull on the cart using the spring scales.
Again, you will not use the motion detector for this activity, but instead make
simple observations of relative velocities.
Start with the cart attached to the spring scale, but using two mass loads on the
cart.
Gently pull the loaded cart until it just begins to move, and note the force value
on the scale. Keep pulling for a total distance of 1 meter.
Repeat using half as much added weight. However, this time pull the cart using
the same force value as the first run.
Repeat again with the cart without any added load, again pulling with the same
force setting.
Compare in general what you observed about the final speeds of the cart at the 1
meter point: which moved fastest and which slowest, or did all move with the
same rate?
Discuss the lead question with your group: How does changing mass affect the
motion of a cart responding to a continuous force?
Write your summary statement in your notebook.
Class discussion:


Describe how gravity is similar or different from either brief or continuous push or
pull when objects of different masses are compared.
Recall from other activities the following points;
o Any change in force results in a change in motion.
o Any change in motion means there was a change in force.
37
LeaPS, 7th Grade
Forces and Motion
o










It requires a greater force to result in the same change in motion if the
object has a greater mass.
How does your data from activities B and C correspond to these main ideas?
What can you infer about the force of gravity acting on different masses from
your observations in activity A (is the force of gravity greater, less, or the same
for the carts with different masses).
So how is gravity different from the brief or continuous pushes and pulls you
normally use to make objects move?
Describe the motion of planets in the solar system.
Is their motion changing in some way?
What is it about the motion of planets that tells us a force is acting on them?
What is the force acting on planets?
Does gravity only work at the surface of the Earth or other planets?
If a planet is smaller than Earth, what effect does this have on its gravitational
attraction to objects near it?
What evidence from these activities helps you answer the previous question?
Help students relate carts to the skateboard experience. Describe motion when apply an
instantaneous force to a cart with an increase in mass – increase mass, slower speed. Describe
motion when apply a constant force to a cart with an increase in mass – increase mass, slower
object sped up. Describe motion when cart was rolling down the ramp due to the continuous
force of gravity – speed at the bottom of the ramp was the same no matter what the mass of the
cart was.
Notebooking: Compare and contrast the force of gravity with other familiar forces with
respect to the type of interaction (visible or invisible) and the relationship between mass
and the applied force.
Personal Glossary Entry: Have students provide their definition for gravity on a
“personal glossary” page.
38
LeaPS, 7th Grade
Forces and Motion
Day 14: Focus question: What is inertia?
Materials
Low friction cart
Two weights per cart
Motion detector/LabQuest
Spring scale
Ramp
Video clip of space shuttle (Note: this is a You Tube video. If your district blocks access
to You Tube, you will want to download and save. See Appendix 18 for directions for
doing this.)
Set-up
All these activities will take place on an ample horizontal surface such as the floor or
hallway.
Activities
A. Focus Question #1: What factor, in the absence of friction, determines how much
force is required for a given amount of change of motion?
Determine the amount of force required to bring the cart from rest to a final speed of 0.2
meters/sec over a distance of 1 meter. Use the motion detector, pulling the cart away
from it using the spring scale.
To do this you will have to practice with the motion detector until you can do it
reproducibly. Have your teacher check () your ability.
Once you have mastered the art of speeding up, apply it to the cart in the following
cases:



No added weight
One added weight
Two added weights
Record the amount of force needed in each instance in your notebook.
Discuss your data with your group: In what way does it answer the focus question? If you
double the mass of something, how much additional force is required to increase its
velocity by the same amount? Record your answer in your notebook.
B. Focus Question #2: What is the influence of mass on the distance something travels
before finally coming to a stop, if it is given a constant initial speed?






This is purely a “thought” experiment, in which you discuss with your partners
what you feel to be the expected outcome of an experiment you could carry out if
you had the right materials. It is necessary to cite evidence you have
experienced!
Suppose you are comparing bowling balls and pool balls.
Which has more mass?
Let’s also suppose you are in a bowling alley with lanes much longer than usual.
Now suppose you push them, the bowling ball and the pool ball, down the lane
each with the same force.
Which ball do you suppose will travel the farthest before it stops (assuming there
are no obstacles such as bowling pins in the way)?
39
LeaPS, 7th Grade
Forces and Motion




What causes the balls to stop?
Is it a force acting on the balls, causing them to stop? How can you tell?
How are the results of this situation related to your observations in part A?
So what is it about the balls that causes one to roll further than the other?
 Check with the teacher your responses to these questions.
Class discussion:




Mass is a property that keeps an object in motion if it is already in motion, and
causes its motion to resist any changes. The greater the object’s mass, the more
force it takes to cause any change in motion. If it is not moving, then it takes
more force to speed it up, the heavier the object is.
This property of mass causing it to resist changes in motion is called its inertia.
All mass has inertia, whether on the earth or in deep space.
The video shows an example of inertia in the microgravity of space.
Watch the Mass and Weight Space Shuttle video:
http://www.youtube.com/watch?v=c363AaSpObQ



In what ways are the inertial properties of mass helpful in space and in what
ways do they create problems?
The term inertial mass is used to refer to how much resistance an object has to
changes in motion due to its mass. The reason we spent so much time
discussing the difference between weight and mass is because the property of
inertia is always true for mass, while weight depends on where an object is
located (on the earth or on the moon, for example).
A question for general discussion: Modern science has shown that there are
very slight differences at different locations on the earth in the strength of the
gravitational field. At these locations, is the inertial mass of an object the same
or different? Is the weight of the same object the same or different?
Personal Glossary Entry: Have students enter their own definition for inertia into their personal
glossary.
Class discussion:
Why do we have two terms – mass and inertia? Use mass in gravitational environment
Why do we need the term inertia? When talk about the effect of push or pull on mass
Compare mass and inertia.
Similarities:




related to the amount of matter in an object
more mass, the more inertia that is required to resist change
mass and inertia are not forces
can measure both
Differences:


mass – visible
inertia – see effects of
40
LeaPS, 7th Grade
Forces and Motion

inertia is not mass, but a property of mass (other property of mass – two objects interact
with each other through gravity)
Return to the “Free Falling Objects” probe and ask students to revisit their choice and explanation
based on their experiences. Discuss that although it seems counterintuitive, their data suggests
that acceleration of all objects in free fall is the same near the surface of the Earth, if we assume
air resistance is negligible. The reason this happens is that the gravitational force is proportional
to the mass of an object. However, the acceleration of an object is inversely proportional to its
mass. Therefore, the heavier objects experience a greater gravitational force (they weigh more).
However, because they weigh more they are difficult to accelerate, based on Newton’s second
law. The result is that they will fall at the same rate regardless of their mass. (from Uncovering
Student Ideas in Physical Science, pg. 168)
Exit Slip: If you are given a choice between driving a very heavy SUV and a very light Smart
Car, which would you choose? Suppose the following happens in answering your question: a
deer suddenly jumps out into the road directly ahead of you. Consider this situation from the
perspective of both the driver of the car and the deer.
41
LeaPS, 7th Grade
Forces and Motion
Topic 6: Weight and mass
4 day activities based on “Gravity” from Science Court
Days 15, 16, 17, and 18
Learning Goals
Day 15 - I can distinguish mass from weight.
Day 16 - I can explain why some objects have more gravitational attraction than others.
Day 17 - I can explain why an object’s weight changes with gravity, but its mass remains the
same.
Day 18 - I can explain the significance of Newton’s Laws of Motion to our understanding of how
the natural world works.
Topic Word Bank
Attract
Balance
Scale
Weight
Gram
Sequence of Experiences
Day 15: Intro
Activity A
Activity B
Questions
Days 16: Intro
Activity A
Questions
Activity B
Class Discussion
Day 17: Intro
Activity A
Activity B
Questions
Activity C
Wrap-up
Day 18: Intro
Activity A
Activity B
Activity C
Individually and Whole class
Whole class
In groups
In groups
Whole class
Whole class
In groups
In groups
Whole class
Whole class
Whole class
In groups
In groups
Whole class
Individually
Whole class
Individually
Individually, pairs, 2 pairs
Individually
10 minutes
8 minutes
15 minutes
12 minutes
3 minutes
5 minutes
12 minutes
10 minutes
15 minutes
3 minutes
3 minutes
12 minutes
12 minutes
8 minutes
10 minutes
3 minutes
25 minutes
12 minutes
5 minutes
Day 15: Focus Question: What is weight?
Materials
“Experiencing Gravity” probe, pg. 157 from Uncovering Student Ideas in Physical
Science, Appendix 15
Excerpt from National Enquirer, Appendix 16
Science Court CD-ROM
Computer
Projector
42
LeaPS, 7th Grade
Forces and Motion
Copies of student sheets – Part 1, Information Sheets A – D; Part 1, Hands-on activity,
“Weight from Gravity”
Spring scale
Modeling clay
Mesh produce bag or baggie
Set-up
You will need a computer, projector, and screen for the Science Court portion. Have
materials ready for the Hands-on Activity, which follows Part 1.
Activities
1. Administer the “Experiencing Gravity” probe on page 157 from Uncovering Student Ideas
in Physical Science. Make sure each student writes a rule for deciding if an object
experiences gravity.
2. Use a few examples from the National Enquirer to illustrate that people are willing to
purchase all types of products that claim to help them lose weight, so the scenario in
Science Court is not so far-fetched.
Activity A
Show the trial animation for Part 1. The animation begins automatically. Enlarge the application
window to take advantage of your whole screen. (8 mins.)
Click the forward arrow when the animation has finished playing.
Activity B
Do the Hands-on Activity: “Weight from Gravity.” Record findings in Science Notebook.
Address the Focus Question with findings as well.
Questions
Students should work in groups of 4. Each member of the group will receive a different
Information Sheet (A-D), which contain the same 6 questions. The group should work
cooperatively to exchange information found in the different quotes on the student sheets to
answer the 6 questions. Make sure each student can answer the questions.
Use the Student Picker to call on students in groups randomly to answer the 6 questions. Click
on See the Answer to display an answer, so that students can self-assess.
The class must get 4 of the 6 correct before continuing.
Poll the class using the Random Picker to get predictions for what happens next in the trial.
Use the Table of Contents to resume the program.
Personal Glossary Entry: Have students enter their own definition of weight in their personal
glossary.
43
LeaPS, 7th Grade
Forces and Motion
Day 16: Focus Question: Do pencils have gravitational attraction? Do all objects have
gravitational attraction?
Materials
Science Court CD-ROM
Computer
Projector
Copies of student sheets – Part 2, Information Sheets A – D; Part 2, Hands-on activity,
“Do Pencils Have Gravity (Gravitational Attraction)?”
Quiz 1 as Exit Slip
Calculator
Set-up
You will need a computer, projector, and screen for the Science Court portion. Have
calculators ready for the Hands-on Activity, which follows Part 2.
Activities
Review predictions from the previous day concerning does gravity cause weight. Push students
thinking by asking if this is true anywhere in the universe? If so, why? If not, why?
Activity A
Show the Trial Animation for Part 2. (5 mins.)
Questions
Students should work in groups of 4. Each member of the group will receive a different
Information Sheet (A-D), which contain the same 6 questions. The group should work
cooperatively to exchange information found in the different quotes on the student sheets to
answer the 6 questions. Make sure each student can answer the questions.
Use the Student Picker to call on students in groups randomly to answer the 6 questions. Click
on See the Answer to display an answer, so that students can self-assess.
The class must get 4 of the 6 correct before continuing.
Activity B
Do the Hands-on Activity: “Do Pencils Have Gravity?” Use the data analysis frame from Writing
in Science to analyze and summarize data in Science Notebook. Address the Focus Question
with findings as well. Have students discuss what the gravitational factor suggests about the
mass of each planet.
Poll the class using the Random Picker to get predictions for what happens next in the trial.
Use the Table of Contents to resume the program. Note: If time, start Part 3 of the Trial.
Exit Slip: Use Quiz 1 from Science Court to gauge student understanding at this point.
44
LeaPS, 7th Grade
Forces and Motion
Day 17: Focus Question: How can an object lose weight but not lose mass?
Materials
Science Court CD-ROM
Computer
Projector
Copies of student sheets – Part 3, Information Sheets A – D; Part 3, Hands-on activity,
“Lose Weight But No Mass?”
Quiz 2 as Exit Slip
Modeling Clay
Balance
Mass Set (at least 120 grams)
Mesh produce bag or baggie
Spring scale
Set-up
You will need a computer, projector, and screen for the Science Court portion. Have
materials ready for the Hands-on Activity, which follows Part 3.
Activities
Activity A
Show the Trial Animation for Part 3. (3 mins.)
Activity B
Do the Hands-on Activity: “Lose Weight But No Mass?” Summarize findings in Science
Notebook. Address the Focus Question with findings as well.
Questions
Students should work in groups of 4. Each member of the group will receive a different
Information Sheet (A-D), which contain the same 6 questions. The group should work
cooperatively to exchange information found in the different quotes on the student sheets to
answer the 6 questions. Make sure each student can answer the questions.
Use the Student Picker to call on students in groups randomly to answer the 6 questions. Click
on See the Answer to display an answer, so that students can self-assess.
The class must get 4 of the 6 correct before continuing.
Poll the class using the Random Picker to get predictions for what happens next in the trial.
Use the Table of Contents to resume the program.
Activity C
Show the Trial Animation for Part 4. (6 ½ mins.)
Poll the class to determine their verdict.
Play the Jury’s verdict to wrap up. (1 ½ mins.) U
Use the Random Picker to have students share key points about gravity, mass, and weight.
Exip Slip: Have students complete Quiz 2 with the Science Court materials, individually.
45
LeaPS, 7th Grade
Forces and Motion
Day 18: Focus Question: What is the significance of Newton’s Laws of Motion?
Materials
Excerpt from Joy Hakim’s The Story of Science: Newton at the Center, pages 172-183,
Appendix 17
Small post-it notes
Activities
Hook: Read quotes at the beginning of the excerpt aloud to introduce the reading. To activate
prior knowledge before reading, randomly call on students to share anything they might know
about Newton as a person, his Laws of Motion, and the significance of his discoveries. Clarify
what is meant by a law in science.
Activity A
Have students read the excerpt individually. To help them stay focused on significant
information, have students use a “sticky note” reading strategy. Summarize the key information
for each page on a small post-it note. (Some pages may need more than one sticky note, i.e.,
page 175) Model the strategy for students for pages 172-173.
Pg. 172 Force and motion are not something inside an object. An outside force is needed to
change an object’s motion.
Pg. 173 1st Law (Law of Inertia) An object will remain at rest or in motion in a straight line at a
constant velocity unless a force acts on it.
Activity B
Once students complete the reading, use a 4-2-1 activity to help them synthesize the information.
Individually, each student reviews their post-it notes and writes the 4 most important or main
ideas from the reading.
In pairs, students share their 4 main ideas and then reach consensus on what they both consider
the 2 most important ideas from the reading.
One pair joins another pair, consolidate their 2 main ideas and determine the most important idea
from the reading by determining what they consider to be the 1 main idea from the reading.
Have each group of 4 share their main idea with the rest of the class.
Help students with their summary statement by referring to the Learning Target and Newton’s big
idea in The System of the World on page 181, “nature has basic laws that are the same
everywhere in the universe.”
Share this quote from the Bill Bryson book, A Short History of Nearly Everything, with students as
a way to sum up the reading, “Newton’s laws explained so many things – the slosh and roll of
ocean tides, the motions of planets, why cannonballs trace a particular trajectory before thudding
back to Earth, why we aren’t flung into space as the planet spins beneath us at hundreds of miles
an hour – that it took a while for all their implications to seep in.” (pages 49-50)
Activity C
46
LeaPS, 7th Grade
Forces and Motion
Have students revisit the “Experiencing Gravity” probe and revise their choices and ‘rule’ based
on what they have learned about gravity from the Science Court experience and the reading. Use
as an Exit Slip to help you gauge where students are in their understanding, but not for a grade.
Note: you may want to revisit the “Force and Motion Ideas” probe again as a review.
47
LeaPS, 7th Grade
Forces and Motion
Topic 7: All work and no play…
An investigation of work and energy
A three-day exercise
Learning goals
I can identify the components of a moving object related to its kinetic energy.
I can distinguish between kinetic energy and potential energy.
I can show in a given situation conversion between kinetic energy and potential energy.
I can recognize when energy is being transferred.
I can identify contexts in which work is being accomplished.
I can measure the components of motion of an object related to work being performed on
the object.
I can calculate the amount of work being performed on an object using data I collected
myself.
Topic Word Bank
Kinetic Energy
Potential Energy
Work
Conversion
Gravity
Friction
Energy Transformation
Energy Transfer
Sequence of Experiences
Day 19: Intro
Activity A
Activity B
Activity C
Class Discussion
Day 20: Intro
Activity A
Activity B
Activity C
Class Discussion
Day 21: Intro
Activity A
Activity B
Class Discussion
Whole class
In groups
In groups
In groups
Whole class
Whole class
In groups
In groups
In groups
Whole class
Whole class
In groups
In groups
Whole class
5 minutes
10 minutes
10 minutes
10 minutes
10 minutes
5 minutes
5 minutes
10 minutes
5 minutes
20 minutes
5 minutes
10 minutes
10 minutes
15 min
48
LeaPS, 7th Grade
Forces and Motion
Day 19 Focus question: What is kinetic energy?
Materials
Low friction carts
Stopwatches
Meter sticks
Ramp with objects that can be used to change the ramp angle, such as books
Activities
A. Investigate the cart and ramp using the following questions. Record your
observations and answers in your Science Notebook:




How can you tell the speed of the cart at the bottom of the ramp using the tools
available to you? Could another student use your directions to accurately
measure the speed of the cart?
What is the impact of the ramp height on its final speed?
Does the speed of the cart remain constant while it is on the ramp?
Does the speed of the cart on a level surface remain constant?
 Check – have teacher check how you are determining the speed of your cart.
Identify forces present when the cart is moving down the ramp; identify forces
present when the cart is moving on a level surface. Write down your list of forces
in your notebook, and share them with your teacher. Draw a diagram showing
the cart moving down the ramp, and use arrows to indicate the direction each of
the forces is acting in your Science Notebook.
B. Focus Question #2: How does position of release relate to final speed of cart?

Measure the speed of the cart at the bottom of the ramp for the following
situations and record in your Science Notebook:
 Cart released from top of the ramp
 Cart released from middle of the ramp
 Cart released from bottom quarter of the ramp
How does the speed of the cart change in each of these situations?
Group should develop a list of reasons why the speeds of the cart vary as they
do. Record in Science Notebook.
C. Focus Question #3: How does ramp angle affect cart speed?



Set up the ramp so that the high end of the ramp is about 1/3rd the length of the
ramp (this is about a 15˚ angle). Measure the speed of the cart at the bottom of
the ramp when it is released from the top.
Change ramp height to a level of about half this and again measure the speed of
the cart at the bottom.
Again vary the ramp height so it is somewhat higher than the initial trial, and
measure the speed of the cart at the bottom.
How does the speed of the cart change in each of these situations?
49
LeaPS, 7th Grade
Forces and Motion
Again, groups should prepare a list of reasons why the speeds of the cart vary in
this manner. Record in Science Notebook.
 Check – have teacher check your results. Share with the teacher your explanations
for the changes in the cart speeds.
Class discussion based on the data collected today:



What has the greater influence on cart speeds: the height the cart was when it
was released or the distance along the ramp it traveled? What evidence do you
have to support this?
Identify the forces present at each stage of this activity. Are the forces balanced
at some points? Are there net forces present? What evidence leads you to this?
Suppose there had been a ball of clay at the bottom of the ramp for each of these
runs. Describe how the clay would be changed by the impact of the cart in each
situation.
The clay changed because there was a transfer of energy from the
moving cart to the clay. The clay itself became deformed, and if you had
a very sensitive thermometer, you would be able to record a slight
increase in its temperature.
Any object in motion possesses kinetic energy. Kinetic energy depends both on the
speed of an object and its mass. If the cart moving down the ramp had been more
massive, then the clay would have been deformed more and its temperature would
have risen more because more energy would have been transferred to it by the
moving cart.

Based on this discussion, is there kinetic energy present if the cart is not
moving? Are there forces acting on it when it is not moving?
Tomorrow we will investigate and measure the kinetic energy in moving objects going
up the ramp as well as down the ramp!
Exit Slip: Describe using words and pictures the set-up used in today’s
activities. Indicate the evidence you collected, and how this evidence can be
used to justify the statement that the higher the cart is, the greater the amount of
kinetic energy it has at the bottom of the ramp.
50
LeaPS, 7th Grade
Forces and Motion
Day 20 Focus Question: What is potential energy?
Materials
Low friction carts
Stopwatches
Meter stick
Ramp with an ability to easily adjust its steepness
Spring scale
Masses for the cart at least equal to the mass of the cart, or greater
Preparation
Be prepared to demonstrate a pendulum to the class, with a relatively heavy bob.
Activities
A. Focus Question #1: How does the force involved in moving against the force of
gravity depend on the steepness of the motion? Record observations and data in
Science Notebook.




Have the ramp with medium slope initially. Place the cart at the bottom of
the ramp with the spring scale, and notice the scale setting when the cart just
begins to move up the ramp. The teacher will demonstrate this if needed.
Record this scale setting.
Change the ramp so it has a steeper slope, and determine the scale setting
as before. Next change the ramp to a shallower slope, and determine the
scale setting as before. Record each of these scale settings.
Discuss with your group: suppose the ramp was perfectly vertical – what
aspect of the cart is measured by the scale?
How would this change if you were on the moon? If you were on Jupiter?
 Check – share your data with the teacher as well as your responses to the questions.
B. Focus Question #2: Is force the same as energy? Record observations and data in
Science Notebook.




Pull the cart up the ramp slowly using the spring scale. Notice the scale
setting as you do this. You should be able to keep the scale setting close to
the value you obtained in part A.
Repeat this for each of the ramp heights.
Recall from the previous day about the speeds and energies from the cart
released from different heights. Discuss in your group whether the same
amount of force is applied in getting the cart to these positions. What does
the data from the spring scale tell you about this?
So what is different in moving the cart from the bottom of the ramp to the
middle compared with moving it all the way to the top? Is the amount of
force the same?
C. Focus Question #3: What factors determine the amount of energy required to lift an
object? Record observations and data in Science Notebook.
 Repeat these activities with the cart with additional mass.
 Observe and record in your notebooks how this changes the results from before.
 Note whether it takes more force or the same amount of force to pull the cart up
the ramp, using each slope.
51
LeaPS, 7th Grade
Forces and Motion
 Check – Use your data analysis and conclusion frame from Writing in
Science. Share with the teacher your conclusions at this point.
Class discussion






Consider pushing a real car (a small one, such as a “Smart Car”) up a steep
hill. Be sure the brake is off. If you keep the speed constant (but pretty slow
as it is pretty heavy), is the force you apply everywhere the same? Imagine
this: half way up the hill, are you tired? Are you more tired all the way up?
Are you sweating yet?
If at any point on the hill, you released the car and let it roll back down the
hill, how much kinetic energy will it have? Does this change depending on
where it was released?
To some extent, the tiredness you feel was a consequence of how much
energy you had to put into the car to push it up the hill. This is the same as
the energy that was gained back by the car if it rolled back to the bottom.
The amount of energy you add to the car is a consequence of both the force
you apply to it and how much higher it has to be pushed. There is also some
friction with a real car, so things are not as neat as we would like, but the
principle is that the amount of energy added to the cart in moving it to a
higher position can be gotten back when it is allowed to roll back down.
Do the following class demonstration: set up a pendulum with a fairly heavy
bob and allow it to swing normally.
o With the pendulum, have students identify forces present at various
positions.
o Ask – where is the speed at a maximum and at a minimum?
o Is there a point where the bob is not speeding up or slowing down?
o Is there a point where the forces are balanced? When is the net
force the greatest?
o Also, based on the above discussion, they should be able to identify
where kinetic energy is at high and low points.
The ability of the cart to gain kinetic energy, and the ability of the pendulum
to gain kinetic energy, in both cases from the drop between the highest point
and the lowest point, is called their potential energy. The higher an object
can fall, the greater is its potential energy, just as the faster an object is
moving, the greater is its kinetic energy.
What we are examining here is actually gravitational potential energy. Other types of
potential energy are common. For example, an object attached to a stretched-out spring
will also have potential energy. A magnet may also display potential energy, and forces
holding the atom together contribute to potential energy. In all cases, potential energy is a
consequence of the arrangements of components providing forces acting on each other.
Energy may be transferred between potential and kinetic energy. Whenever two
types of energy are converted between each other, we call this change energy
transformation. Energy may also be transferred between two objects, such as
during a collision.
You may want to show a quick video clip of downhill and slalom skiing if students are
not familiar with these.
Exit Slip: Describe energy transformations that take place during skiing.
Consider getting to the top of the hill, and skiing down the hill, and any other
things that might apply to this situation. Some skiers do a downhill run,
which means skiing straight down a hill, taking the fastest possible route,
52
LeaPS, 7th Grade
Forces and Motion
while others like the slalom, which is a longer zig-zag pathway down the hill.
Apply your thinking to the difference between these skiing types.
Day 21 Focus question: What is work?
Materials
Low friction carts
Stopwatches
Meter stick attached vertically to a ring stand with 0 at the base
Ramp
Spring scale
2-3 objects with different weights, but within the reading ability of the spring scale, and
that can be attached to the scale
Activities
A. Focus Question #1: How can we calculate work?
Recall that the higher an object is, or the greater distance it can fall, the higher is its
potential energy, and the greater its kinetic energy will be at the bottom of its fall. Record
observations and data in Science Notebook.





Using the meter stick as a guide, slowly lift one of the provided objects (a
lighter object – you will use a heavier one next) straight up from the ground,
and measure the total distance it moved, in cm. What was the force you
applied to it, as shown on the spring scale, during its motion? Is this lifting
force you applied in a direction exactly opposite the force due to gravity?
If the object has a greater mass, what happens to the force? Try this with a
heavier object.
The idea in physics of work consists of both the force exerted on an object
and the distance it moves in the direction away from a restraining force, such
as gravity. For example, in lifting something, you need to know both the
force you applied in lifting it, and the distance you lifted it. Multiplying these
together gives you the value of the work accomplished:
Work = force x distance
But you must keep in mind that “distance” is meaningful only when it is
distance opposite the pull of gravity.
Using this formula, determine the work involved in lifting a [x gram] object 1
meter. You will need to use the spring scale to measure the amount of force
needed to lift such an object.
Note that if an object requires 1 newton of force, then lifting it 1 meter requires work
equivalent to 1 joule of energy.



Use the spring scale and meter stick to determine the amount of work
involved in lifting several objects.
Does lifting heavier objects involve more or less work, as defined above?
Does lifting to a higher level involve more or less work?
Suppose you are comparing lifting a 1 kg object 2 meters high at the surface
of the earth with lifting the same 1 kg object 2 meters at the surface of the
moon. Will the amount of work involved be less or more or the same? How
do you know?
53
LeaPS, 7th Grade
Forces and Motion
 Check – Share with the teacher your responses to the above questions.
B. Focus Question #2: Do ramps reduce the amount of work performed? Record
observations and data in Science Notebook.
Set up the ramp with cart and spring scale as before. Measure the height the ramp
reaches. Pull the cart up the ramp with the spring scale using the minimum force
necessary. Compare this force with the force needed to lift the cart directly.




Is it easier to lift the cart directly or to move it up the ramp? Justify your
response.
Note that you cannot easily measure the work involved in moving the cart up
the ramp, because the direction of motion is at an angle relative to the force
of gravity. However, as it happens, the amount of work is exactly the same
as if you lifted the cart straight up. The amount of work in an action depends
only on where the object started out and how high it was lifted, and does not
depend on the pathway.
Suppose you got into a roller coaster at an amusement park. It took you up
to dizzying heights, then you rolled down, it took you through several loopthe-loops, then up to the top again and back down where you finish exactly
where you started out. Given the discussion above, how much work was
accomplished on your ride? Explain.
A ramp makes a task easier, because less force is required for moving an
object up the ramp, but the amount of work corresponds only to how high the
object went up, and not how steep the ramp is.
Class discussion






Discuss with the class the formal definition of work, and how to apply it in
specific instances.
List the pitfalls in thinking about work – for example, is moving in a horizontal
direction adding to work? If one goes up and then down, is work
accomplished? Does the amount of work depend on the pathway one takes?
What are the components of a work problem – what is needed to know and
how do you get this information?
Note that when the height of an object changes, and work is accomplished,
then the potential energy is changed by adding kinetic energy.
In other words, work takes place because of an increase in potential energy.
Discuss the following problem:
o A car with a mass of 5000 kg (including occupants and luggage)
drove from the seaside to the top of a 2000 meter mountain. During
the trip, the car covered a distance of 500 km.
o What information is needed to determine how much work was
accomplished? (Assume that friction plays a negligible role in this
problem.)
o Do the math to determine the amount of work accomplished.
Personal Glossary Entry: Have students write their scientific definition of work in their
personal glossary.
Exit Slip: Consider a mountain climber and compare her with a hiker. Assume
both have the same mass, and are going up the same mountain. The hiker
follows a trail to the top, while the climber scales the steepest rock escarpment,
going nearly straight up. Describe the feelings of both on their trips, paying
special attention to how tired each is likely to be, and show how much physical
work each accomplished. Which would you rather do, climb or hike, and why?
54
LeaPS, 7th Grade
Forces and Motion
55
LeaPS, 7th Grade
Forces and Motion
Appendix 1: 7th Grade Vocabulary Related to Forces and Motion
Speed
Velocity
Inertia
Changing speed
Changing velocity
Positive
Negative
Mass
Weight
Gravity
Motion
Force
Constant force
Instantaneous force
Constant velocity
Changing velocity
Direction
Distance
Time
Rate of change
Slope
Net force
Balanced forces
Unbalanced forces
Force arrows
Position
Work
Kinetic energy
Potential energy
Energy transformation
Energy transfer
Friction
Magnetism
Charge
Electrostatic force
Visible forces
Invisible forces
Graph
Vertical
Horizontal
Representation
Newton
Air resistance
56
LeaPS, 7th Grade
Forces and Motion
Building the Word Wall
Level: is the top to bottom reference location on the word wall
Color of words:
Red: Important words, words that are important for students to make meaning. These
words may have been addressed as essential words in an earlier grade level
Green: Essential Word, words that need multiple exposures for students within the grade
level.
Blue: Procedural Vocabulary or Generic Science Vocabulary
Day 1
Level
1
2
3
All at the
bottom of
Wall
Words Added
Motion
Position, Distance, Time
Speeding up, Slowing Down, Constant
Representation, Line Graph, Horizontal (x-axis), Vertical (y-axis), Slope
Day 2
Level
1
2
3
4
5
All at the
bottom of
Wall
Words Added
Motion
Position, Distance, Time
Speeding up, Slowing Down, Constant
Speed (d/t) Velocity Δx/ Δt, Direction, Changing Direction
Rate of Change
Representation, Line Graph, Horizontal (x-axis), Vertical (y-axis), Slope
Days 3 and 4
Level
1
2
3
4
5
6
All at the
bottom of
Wall
Words Added
Motion
Position, Distance, Time, Origin
Speeding up, Slowing Down, Constant
Speed (d/t) Velocity Δx/ Δt, Direction, Changing Direction
Rate of Change, Δ = Delta (change), Changing Position
Positive, Negative
Representation, Line Graph, Horizontal (x-axis), Vertical (y-axis), Slope
57
LeaPS, 7th Grade
Forces and Motion
Day 5
Level
1
2
3
4
Words Added
Motion
Position, Distance, Time, Origin
Speeding up, Slowing Down, Constant
Speed (d/t) Velocity Δx/ Δt, Direction,
Changing Direction
Rate of Change, Δ = Delta (change),
Changing Position
Positive, Negative
5
6
All at the
bottom of
Wall
Force
Constant, Instantaneous
Representation, Line Graph, Horizontal (xaxis), Vertical (y-axis), Slope
Day 6
Level
1
2
3
4
5
6
7
All at the
bottom of
Wall
Words Added
Motion
Position, Distance, Time, Origin
Speeding up, Slowing Down, Constant
Speed (d/t) Velocity Δx/ Δt, Direction,
Changing Direction
Rate of Change, Δ = Delta (change),
Changing Position
Positive, Negative
Constant Velocity, Changing Velocity
Force
Constant, Instantaneous
Representation, Line Graph, Horizontal (xaxis), Vertical (y-axis), Slope
Day 7
Level
1
2
3
4
5
6
7
All at the
bottom of
Wall
Words Added
Motion
Force
Position, Distance, Time, Origin
Constant, Instantaneous, Force
Arrows
Speeding up, Slowing Down, Constant
Balanced, Unbalanced
Speed (d/t) Velocity Δx/ Δt, Direction,
Net
Changing Direction
Rate of Change, Δ = Delta (change),
Visible, Invisible
Changing Position
Positive, Negative
Air Resistance, Friction, Gravity
Constant Velocity, Changing Velocity
Representation, Line Graph, Horizontal (xaxis), Vertical (y-axis), Slope
Day 8, 9 and 10
58
LeaPS, 7th Grade
Forces and Motion
Level
1
2
3
4
5
6
7
All at the
bottom of
Wall
Words Added
Motion
Force
Position, Distance, Time, Origin
Constant, Instantaneous, Force
Arrows
Speeding up, Slowing Down, Constant
Balanced, Unbalanced
Speed (d/t) Velocity Δx/ Δt, Direction,
Net
Changing Direction
Rate of Change, Δ = Delta (change),
Visible, Invisible
Changing Position
Positive, Negative
Air Resistance, Friction, Gravity
Constant Velocity, Changing Velocity
Mass
Representation, Line Graph, Horizontal (xaxis), Vertical (y-axis), Slope
Newton
Day 11
Level
1
2
3
4
5
6
7
All at the
bottom of
Wall
Words Added
Motion
Force
Position, Distance, Time, Origin
Constant, Instantaneous, Force
Arrows
Speeding up, Slowing Down, Constant
Balanced, Unbalanced
Speed (d/t) Velocity Δx/ Δt, Direction,
Net
Changing Direction
Rate of Change, Δ = Delta (change),
Visible, Invisible
Changing Position
Positive, Negative
Air Resistance, Friction, Gravity,
Magnetism, Electrostatic Force
(Charge)
Constant Velocity, Changing Velocity
Mass
Representation, Line Graph, Horizontal (xaxis), Vertical (y-axis), Slope
Newton
Day 12 and 13
Level
1
2
7
Words Added
Motion
Force
Position, Distance, Time, Origin
Constant, Instantaneous, Force
Arrows
Speeding up, Slowing Down, Constant
Balanced, Unbalanced
Speed (d/t) Velocity Δx/ Δt, Direction,
Net
Changing Direction
Rate of Change, Δ = Delta (change),
Visible, Invisible
Changing Position
Positive, Negative
Air Resistance, Friction, Gravity,
Magnetism, Electrostatic Force
(Charge)
Constant Velocity, Changing Velocity
Mass, Inertia
All at the
Representation, Line Graph, Horizontal (x-
3
4
5
6
59
Newton
LeaPS, 7th Grade
Forces and Motion
bottom of
Wall
axis), Vertical (y-axis), Slope
Days 15, 16 and 17
Level
1
2
3
4
5
6
7
All at the
bottom of
Wall
Words Added
Motion
Force
Position, Distance, Time, Origin
Constant, Instantaneous, Force
Arrows
Speeding up, Slowing Down, Constant
Balanced, Unbalanced
Speed (d/t) Velocity Δx/ Δt, Direction,
Net
Changing Direction
Rate of Change, Δ = Delta (change),
Visible, Invisible, Attract
Changing Position
Positive, Negative
Air Resistance, Friction, Gravity,
Magnetism, Electrostatic Force
(Charge)
Constant Velocity, Changing Velocity
Mass, Inertia, Weight
Representation, Line Graph, Horizontal (xaxis), Vertical (y-axis), Slope
Newton, Gram, Balance, Scale
Days 18 and 19
Level
1
2
Words Added
Motion
Force
Position, Distance, Time, Origin
Constant, Instantaneous,
Force Arrows
3
Speeding up, Slowing Down,
Constant
Balanced, Unbalanced
4
Speed (d/t) Velocity Δx/ Δt,
Direction, Changing Direction
Rate of Change, Δ = Delta
(change), Changing Position
Positive, Negative
Net
5
6
7
Constant Velocity, Changing
Velocity
All at
the
bottom
of Wall
Representation, Line Graph,
Horizontal (x-axis), Vertical (yaxis), Slope
Visible, Invisible, Attract
Air Resistance, Friction,
Gravity, Magnetism,
Electrostatic Force
(Charge)
Mass, Inertia, Weight
Newton, Gram, Balance,
Scale
Day 20
Level
Words Added
60
Work
Kinetic Energy (KE),
Conversion,
Potential Energy
(PE)
Energy Transfer,
and Energy
Transformation
LeaPS, 7th Grade
Forces and Motion
1
2
Motion
Position, Distance, Time, Origin
Force
Constant, Instantaneous,
Force Arrows
3
Speeding up, Slowing Down,
Constant
Balanced, Unbalanced
4
Speed (d/t) Velocity Δx/ Δt,
Direction, Changing Direction
Rate of Change, Δ = Delta
(change), Changing Position
Positive, Negative
Net
5
6
7
Constant Velocity, Changing
Velocity
All at
the
bottom
of Wall
Representation, Line Graph,
Horizontal (x-axis), Vertical (yaxis), Slope
Work
Kinetic Energy (KE),
Conversion,
Potential Energy
(PE)
Energy Transfer,
and Energy
Transformation
Visible, Invisible, Attract
Air Resistance, Friction,
Gravity, Magnetism,
Electrostatic Force
(Charge)
Mass, Inertia, Weight
Newton, Gram, Balance,
Scale
61
Joule
LeaPS, 7th Grade
Forces and Motion
Appendix 2: Motion Detector Directions
Link for Trouble Shooting LabQuests: http://www.vernier.com/til/1688.html
62
LeaPS, 7th Grade
Forces and Motion
Appendix 3: Graph Pairs for Day One
Position/Time Graph
5
5
4
4
3
2
Car
1
Position
(m)(m)
Distance
Position
(m)(m)
Distance
Position/Time Graph
0
3
2
Car
1
0
0
1
2
3
4
5
0
1
Time (sec)
4
5
Position/Time Graph
5
5
4
4
3
2
Car
1
Position
(m)(m)
Distance
Position
(m)(m)
Distance
3
Time (sec)
Position/Time Graph
3
2
Car
1
0
0
0
1
2
3
4
0
5
1
2
3
4
5
Time (sec)
Time (sec)
Position/Time Graph
Position/Time Graph
5
5
4
4
3
2
Car
1
0
Position
(m)(m)
Distance
Position
(m)(m)
Distance
2
3
2
Car
1
0
0
1
2
3
4
5
0
Time (sec)
1
2
3
Time (sec)
63
4
5
LeaPS, 7th Grade
Forces and Motion
Position/Time Graph
Position/Time Graph
5
5
Distance (m)
Position (m)
3
2
Car
1
Position
(m)(m)
Distance
4
4
3
2
Car
1
0
0
0
1
2
3
4
0
5
1
Position/Time Graph
4
5
Position/Time Graph
5
5
4
4
3
2
Car
1
Position
(m)(m)
Distance
Distance
Position
(m)(m)
3
Time (sec)
Time (sec)
0
3
2
Car
1
0
0
1
2
3
4
5
0
1
Time (sec)
2
3
4
5
Time (sec)
Position/Time Graph
Position/Time Graph
5
5
4
4
3
2
Car
1
0
Position
(m)(m)
Distance
Position
(m)
(m)
Distance
2
3
2
Car
1
0
0
1
2
3
4
5
0
Time (sec)
1
2
3
Time (sec)
64
4
5
LeaPS, 7th Grade
Forces and Motion
Position/Time Graph
5
5
4
4
3
2
Car
1
Position
(m)
(m)
Distance
Position
(m)(m)
Distance
Position/Time Graph
3
2
Car
1
0
0
0
1
2
3
4
0
5
1
4
5
Position/Time Graph
Position/Time Graph
5
5
4
4
3
2
Car
1
Position
(m)
(m)
Distance
Position
(m)
(m)
Distance
3
Time (sec)
Time (sec)
3
2
Car
1
0
0
0
1
2
3
4
0
5
1
2
3
4
5
Time (sec)
Time (sec)
Position/Time Graph
Position/Time Graph
5
5
4
4
3
2
Car
1
0
Position
(m)
(m)
Distance
Position
(m)
Distance(m)
2
3
2
Car
1
0
0
1
2
3
4
5
0
Time (sec)
1
2
3
Time (sec)
65
4
5
LeaPS, 7th Grade
Forces and Motion
Position/Time Graph
5
5
4
4
3
2
Car
1
Position
(m)
(m)
Distance
Position
(m)
(m)
Distance
Position/Time Graph
3
2
Car
1
0
0
0
1
2
3
4
0
5
1
2
3
Time (sec)
Time (sec)
Guiding Questions
1. Do both graphs include an object in motion? Explain your reasoning.
2. How is the motion in graph 1 different from the motion in graph 2?
66
4
5
LeaPS, 7th Grade
Forces and Motion
Appendix 4: Data Collection Sheet, Day 1
Does our car go faster?
Goal: to collect data and create a position versus average time graph
Materials Needed:
Wind-up toy car
Meter Stick
Masking Tape
Stop watch/Timer
Graph paper
Calculator
Steps:
1. Find a good floor location where you and your group members are not
blocking the doorway and you can place your meter stick so that it does
not run into any other group.
2. At the zero point of your meter stick, create a starting line with masking
tape. You need to discuss with your group members if the start will be on
one side of the tape, in the middle of the tape or at some other point.
Once this is determined, make a long pencil mark. Next, place masking
tape over the meter stick at the 0 and 100 cm marks to secure its location.
3. Remember each group member has a role.
4. On your own paper, copy the example data table found below.
Distance
Trial 1
Trial 2
Time
Trial 3
Average
25cm
50cm
75cm
100cm
5. Now you will begin collecting the time it takes for the wind-up car to travel
25cm. When the car passes 10cm. The person with the stop watch will
hit stop and share the time. This will be repeated for three trials at each
distance.
6. Now collect the time for the wind-up car to travel 50cm. (Record the time
for each trial in the data table).
7. Now collect the time for the wind-up car to travel 75cm. (Record the time
for each trial in the data table).
8. Finally, collect the time for the wind-up car to travel 100cm. (Record the
time for each trial in the data table).
67
LeaPS, 7th Grade
Forces and Motion
9. When all three trials for the four distances are collected, determine the
average for each distance.
10. Now your group needs to construct a graph of the distance traveled and
the average time. When your graph is complete, ask your teacher to
review the work.
68
LeaPS, 7th Grade
Forces and Motion
The following questions are intended for
early finishing groups to do. Remember
you meaning making conversation
should begin when the last group
completes graphing. Not when your last
group completes all the questions.
69
LeaPS, 7th Grade
Forces and Motion
Questions to answer from your Wind-up Toy Car Graph
and Experiment
Directions: answer each question completely. Use your graph and not another
groups graph when answering the questions.
1. Why was it important to discuss where the starting point should be before
collecting data?
2. What is the purpose of collecting three times for each distance?
3. What was graphed along the x-axis? (the horizontal axis)
4. What was graphed along the y-axis? (the vertical axis)
5. What was your unit for time?
6. What was your unit for distance?
7. If your wind-up car traveled 15cm, how long would it take? Explain.
8. If you wind-up car traveled for 50cm, how long would it take? Explain.
9. Did your wind-up car travel at the same rate for each trial? Explain.
10. Did your wind-up car travel at the same rate for each distance? Explain.
70
LeaPS, 7th Grade
Forces and Motion
Appendix 5: Day 2 Material
Who Has Earned a Ticket?
Group Names: _________________________________________________________
Directions: in the table below are the data collected by local police about four cars
that traveled along highway 60. Your task is to determine which cars have earned a
speeding ticket.
Car
Time (s)
A
115
Distance
(m)
3452
B
104
2477
C
175
4117
D
542
15430
Path of the
Car
Turns left
after 2000m
Turns left
after 1500m
Does not
turn right;
does not turn
left
Turns right
after 7,440m
1. Calculate the speed of each car. Show all your work in the space below.
71
LeaPS, 7th Grade
Forces and Motion
Appendix 6: Day 2 Second Set of Problems
Below are the next two problems to work. If you are going to project the problems use the first
page. If you are planning on copying, then print page two.
Car Time
(s)
E
295
Distance
(m)
7800
F
500
25
Path of the Car
Does not turn right;
does not turn left
Turns to the right after
250m
1. Determine what type or types of ticket each
car may receive. Show all your work on your
paper
2. Write a short explanation for the ticket or
tickets awarded to each car.
Example:
Car XX has been awarded _______
because ___________.
72
LeaPS, 7th Grade
Forces and Motion
Position (m)
Appendix 7: Day 2 graphs
73
Position (m)
LeaPS, 7th Grade
Forces and Motion
74
Position (m)
LeaPS, 7th Grade
Forces and Motion
75
LeaPS, 7th Grade
Forces and Motion
Appendix 8: Day 3 Student Tables with Questions
Interpreting Motion Data:
Working with your partner, use the motion graphs you generated and sketched in your
notebook to answer the following questions:
1.Making sense of the data
A. At anytime did you measure a
negative velocity? When?
B. At anytime did you measure a
negative position? When?
C. Is it possible to measure a
negative position using the Motion
Detector?
D. What is the origin in this activity?
E. Is it possible to measure a
negative position using a MD?
F. Is it theoretically possible to
measure behind the MD?
6. Position
A. What is the direction for
increasing position?
B. What is the direction for
decreasing position?
C. What does delta or Δ mean?
D. What is an example Δx i.e. what
is Δ (position)? Give example from
your graph.
E. Can Δx be positive? Give
example. Is x increasing or
decreasing?
F. Can Δx be negative? Give
example. Is x increasing or
decreasing?
7. Time and Distance
A. What time did movement started?
B. Write down the start time on LQ.
C. Write down the elapsed time on
LQ.
D. What is Δt?
E. What do we mean by change in
time?
76
LeaPS, 7th Grade
Forces and Motion
F. Can Δt be positive? Give
example.
G. Can Δt be negative? Give
example.
H. Is our position and distance the
same?
I. Can d, distance, take on negative
values or is it always positive?
8. Speed and Velocity
A. Can speed take on negative
values or is it always positive?
B. Is an equation for speed
something like d/(time interval for
trip)? Does that seem correct for a
trip to Louisville and back? Will it
always be positive?
C. Is an equation for velocity
something like Δx/Δt? Does it
measure how rapidly something is
changing position?
D. How is the velocity relationship
different from speed?
E. Can Δx/Δt be positive? Give
example and interpret. Is x
increasing or decreasing for positive
Δx?
F. Can Δx/Δt be negative? Give
example and interpret. Is x
increasing or decreasing for negative
Δx ?
G. Is motion associated with
changes in position? Explain.
9. What have we learned?
A. What is the meaning of:
 negative velocity?

positive velocity?

negative position?

positive position?
B. What is the meaning of :
 position at zero?

velocity of zero?

time of zero?
77
LeaPS, 7th Grade
Forces and Motion
Appendix 9: Day 4 Frame for Science Notebook
Individually: Compare speed and velocity by completing the comparison frame in your
notebook.
Speed and velocity are similar because they both ___________________________. In addition,
they _________________________________. (Add more as needed.)
Speed and velocity are different because speed _____________________________, but velocity
_______________________________________. Also, speed ___________________, whereas
velocity ______________________________________. (Add more as needed.)
78
LeaPS, 7th Grade
Forces and Motion
Appendix 10: Skateboard activity
Prediction
Diagram or Picture that represents the motion
Description of the Motion
Continual push, constant force
Continual push, constant force……
After the pushing stops..
After the pushing stops….
Graphical Representation
Continual push, constant force
Questions that I have:
Skateboard
Continual push, constant force
After the pushing stops
After the pushing stops
79
LeaPS, 7th Grade
Forces and Motion
Actual
Diagram or Picture that represents the motion
Description of the Motion
Continual push, constant force
Continual push, constant force……
After the pushing stops..
After the pushing stops….
Graphical Representation
Continual push, constant force
Questions that I have:
Skateboard
Continual push, constant force
After the pushing stops
After the pushing stops
80
LeaPS, 7th Grade
Forces and Motion
Appendix 11: Day 6
Motion/Object
Sketch Position Graph
Sketch Velocity
Graph
1. Walk with
constant velocity
2. Walk with
increasing speed
3. Ball that was
tapped
4. Fan Car
81
Verbal Description
(Use Key Vocabulary
Words)
LeaPS, 7th Grade
Forces and Motion
Appendix 12
Student Handout Day 7 Force and Mass
Pre-question
1.
What do you expect to happen to the force when velocity changing in a constant pattern but
the mass is increased? (What trend would you predict between force and mass?)
Materials
1 spring scale
1 frictionless cart
5, 100g masses
String
Scissors
Meter stick
Ramp (not inclined)
Possible Roles
Force recorder
Puller-must be good at pulling at an increasing, but constant rate
Observer/recorder of observations
Directions
1. Attach string to your cart and then to your spring scale. Tie the knot tightly. String should
be about 30cm long.
2. Attempt to obtain a constant rate of change for each trial.
3. With the cart empty, pull the cart. Have one group member record the force indicated by the
spring scale. Repeat this about 4 more times. Take an average.
4. A group member should describe the motion from start to finish.
5. Add 300g (three, 100g masses). Again pull the cart at a similar rate of change. Practice this
pull and then do this five times. Have a group member record the results.
6. A group member should describe the motion from start to finish.
7. Add the last two masses. Pull the cart at a similar rate of change for the 0g and 300g case.
Have a member of the group record the results.
8. A group member should describe the motion from start to finish.
9. Obtain a mean for each mass case.
10. Put away all your materials.
Questions
1.
Is the first trial really mass less or is it just no mass added? Explain your answer.
2.
From the results, what does it suggest about the relationship between mass and force when
rate of velocity change is held constant?
82
LeaPS, 7th Grade
Forces and Motion
Appendix 13: Arrows
83
LeaPS, 7th Grade
Forces and Motion
Arrows of a different color
84
LeaPS, 7th Grade
Forces and Motion
Use different colors for these as well!
85
LeaPS, 7th Grade
Forces and Motion
Appendix 14: Day 8 Data Analysis Sheet and Framework
From the data observations you made about mass and force
Describe Starting Conditions
Describe Motion
1.
1.
2.
2.
3.
3.
The relationship between mass and force is _______________________________________
_____________________________________________________________________________
My evidence for this conclusion is _______________________________________________
_____________________________________________________________________________
86
LeaPS, 7th Grade
Forces and Motion
Appendix 15: Uncovering Student Ideas in Physical Science Probes
87
LeaPS, 7th Grade
Forces and Motion
Appendix 18: Converting You Tube Videos
How to Save a YouTube Clip
1. Copy the URL of the clip you wish to save
2. Go to www.zamzar.com
3. Under step 1, select URL. Paste your URL here.
4. Under step 2, select how you would like for the file to convert.
a. For audio only – select wav.
b. For video/audio – select avi.
5. Under step 3, enter your email address and click convert.
a. For file to convert, it may take about a half hour.
6. The file will be sent to your email, and you can save the clip wherever you would like.
88