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Released Items from the ATLAST Force and Motion Teacher Assessment
Horizon Research, Inc. (HRI) developed the ATLAST Force and Motion Teacher Assessment as
part of a larger study. The project—Assessing Teacher Learning About Science Teaching
(ATLAST)—was funded by the National Science Foundation under Grant no. EHR-0335328.
Information about the ATLAST project is available at HRI’s ATLAST website:
http://www.horizon-research.com/atlast.
This document contains the force and motion teacher items that were developed during the
process of creating the ATLAST Force & Motion Teacher Assessment, but were not chosen to
be on the final assessment. The items were developed through a months-long iterative process
that included cognitive interviews with middle grades science teachers, review by a panel of
three content experts (individuals with a Ph.D. in physics), and field testing with a large sample
of science teachers. To learn more about the item development process, please see the ATLAST
Force & Motion Teacher Assessment User Manual, which can be found at the ATLAST website.
Content Assessed by the Items
All of the items measure understanding of the idea that “an unbalanced force acting on an object
changes the object’s speed, or direction of motion, or both” (American Association for the
Advancement of Science/Project 2061, 1993). In addition, the content domain was specified by
“unpacking” this idea into 10 “sub-ideas,” which are shown in Table 1. Each of the released
assessment items included addresses one or two specific sub-ideas.
Content Levels of Items
In addition to each item addressing specific sub-idea(s) in the domain of force and motion, each
item addresses the sub-idea(s) at one of three content levels:
1. knowledge of science content (Level 1 items);
2. using content knowledge to analyze/diagnose student thinking (Level 2 items); and
3. using content knowledge to make instructional decisions (Level 3 items).
All of the items assess knowledge of science content, but “Level 1” items are the most basic type
of question; they attempt to isolate disciplinary content knowledge from a teacher’s ability to
apply the knowledge in making instructional decisions.
“Level 2” items require teachers to apply their content knowledge in analyzing or diagnosing a
sample of student thinking. In these items, more than one of the answer choices includes a
correct physics statement. Therefore, a teacher must understand the science content in order to
answer Level 2 items correctly, but s/he must also determine which answer choice is relevant to
the thinking expressed by the student.
“Level 3” items ask teachers to apply their content knowledge in choosing among instructional
moves. Teachers must evaluate the physical scenario, the student’s thinking in relation to the
physical scenario, and then evaluate each instructional choice. As with Level 2 items, more than
one answer choice has a correct physics statement, but only one has a correct physics statement
and is relevant to the instructional context.
Table 1
Force and Motion Content Domain
Idea: An unbalanced force acting on an object changes its speed or direction of motion, or both.
Sub-ideas:
A. A force is a push or pull interaction between two objects, and has both magnitude and
direction.
B. All of the forces acting on an object combine through vector addition into a net force; they
either balance each other out (net force is zero), or act like an unbalanced force (net force is
not zero).
1. If the sum of forces exerted on an object in one direction is the same strength as the
sum of forces exerted on the object in the opposite direction, then the forces on the
object are balanced (i.e., the net force is zero).
2. If the sum of forces exerted on an object in one direction is greater than the sum of
forces exerted on the object in the opposite direction, then the forces on the object are
unbalanced (i.e., the net force is not zero).
C. A force diagram uses arrows to represent the forces acting on an object at a particular
moment. The length of the arrow represents the relative magnitude of the force. The
direction of the arrow represents the direction of the force acting on the object.*
D. If an object is moving faster and faster, then there is a net force acting on the object in the
same direction as the motion.
E. If an object is moving slower and slower, then there is a net force acting on the object in the
direction opposite to the object’s motion.
F. If an unbalanced force acts on a moving object in a direction that is neither in the direction of
the object’s motion, nor directly opposed to it, then the object’s direction (and possibly
speed) will change.**
G. If there is an unbalanced force acting on an object, the greater the strength of the unbalanced
force, the greater the change in the object’s velocity.
H. If there is an unbalanced force acting on an object, the more massive an object is, the smaller
the change in the object’s velocity.
I. If an object has constant speed in a straight line (or zero speed), then there is no net force
acting on the object. This can occur either when:
1. the forces on the object are balanced; or
2. there are no forces exerted on the object
J. The force of friction acts to oppose the relative motion of two objects in contact. Friction
acts on both objects along the surfaces in contact with each other. The magnitude of friction
depends upon the properties of the surfaces and how hard the objects are pushed together.
* This sub-idea was not assessed explicitly, but forces were represented in this way in the items.
** This sub-idea is included for completeness of unpacking, but it is not included in the assessment. Only motion
in one dimension is addressed.
Field Test Response Data
All of the items include the p-values (proportion answering correctly) and distribution of
responses from a field test of the items. A pool of 60 force and motion teacher items, including
all of the items in this document, was distributed over three forms for the field test, with 15 items
common to each form. Just over 500 science teachers across the nation responded to each form.
Each field test group included roughly one-fifth high school physics/physical science teachers to
ensure an adequate distribution of levels of teacher knowledge in the sample. The remaining
respondents were middle grades science teachers.
Item ID: FM-RE01
Key: D
P-value: 0.59
Percent Responding:
A
B
C
D
4%
25%
12%
59%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
J: The force of friction acts to oppose the relative motion of two objects in contact. Friction acts on both objects
along the surfaces in contact with each other. The magnitude of friction depends upon the properties of the
surfaces and how hard the objects are pushed together.
Content Level: 1 – Knowledge of science content
In putting together an end-of-chapter test on forces and motion, a teacher finds the following item
on the Internet:
Student Assessment Item
You are riding your bike on a straight, level street.
Why does the bike go slower and slower after you
stop pedaling?
I. The force you gave to the bike is used up.
II. The bike's inertia takes over.
III. There are no forces affecting the bike's
motion.
IV. The force of friction acts on the bike.
Which of the following statements about the item is correct?
A.
B.
C.
D.
None of the answer choices is correct.
Answer choices I and IV are both correct.
Answer choices II and IV are both correct.
Only answer choice IV is correct.
Item ID: FM-RE02
Key: C
P-value: 0.61
Percent Responding:
A
B
C
D
5%
14%
61%
20%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
J: The force of friction acts to oppose the relative motion of two objects in contact. Friction acts on both objects
along the surfaces in contact with each other. The magnitude of friction depends upon the properties of the
surfaces and how hard the objects are pushed together.
Content Level: 1 – Knowledge of science content
A miniature golf course invites a middle school science class to their annual event – “The Physics
of Golf.” One of the students hits a ball along a straight and level surface. The teacher tells the
class, "Identify one horizontal force acting on the ball after it leaves the the golf club and is rolling
toward the hole."
Which of the following student answers correctly identifies a horizontal force?
A.
B.
C.
D.
The force of the ball’s velocity as it moves toward the cup
The force due to the golf club that struck the ball
The force of friction between the surface and the ball
The force of the ball’s inertia as it moves toward the cup
Item ID: FM-RE03
Key: D
P-value: 0.30
Percent Responding:
A
B
C
D
48%
4%
18%
30%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
A teacher asks his students, “Imagine you give a block a quick shove so that it slides across a level
floor. The block goes slower and slower as it gets farther away from you. In which direction is the
net force acting on the block once it leaves your hand?”
Most students reply that the net force is acting in the forward direction but getting smaller because
of friction.
Which of the following is an accurate assessment of the students’ response?
A.
B.
C.
D.
The students are correctly combining all of the forces acting on the block.
The students incorrectly think that forces have strength as well as direction.
The students correctly think that friction uses up other forces.
The students incorrectly think that after the block has been pushed it has a force in it that
keeps it in motion.
Item ID: FM-RE04
Key: D
P-value: 0.42
Percent Responding:
A
B
C
D
48%
9%
1%
42%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
A teacher places a book on a level floor where all the students can see it and gives it a quick, hard
push. The book slides across the floor and eventually stops.
The teacher repeats this demonstration a couple more times and then asks the students to respond in
writing to the following question – “Once the book leaves my hand, what forces act on the book?”
Which of the following represents an INCORRECT student idea?
A.
B.
C.
D.
The force due to the teacher's push stops acting once the book leaves the teacher's hand.
The force of friction acts on the book until the book stops moving.
The force of gravity is always acting on the book.
The force in the book, which came from the teacher’s hand, acts until the book stops.
Item ID: FM-RE05
Key: C
P-value: 0.24
Percent Responding:
A
B
C
D
19%
38%
24%
20%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
A teacher takes a middle school science class to the bowling alley for a “hands-on” experience with
force and motion. The teacher asks Jill to take a turn. After she releases the ball and it is rolling
down the level alley, the teacher says to her,
“Describe the horizontal force(s) that are acting on the ball after you release it and it is rolling
down the alley.”
Jill describes two forces: (1) the forward force on the ball making it move, and (2) the force of
friction that makes the ball move slower and slower.
Which of the following is an accurate assessment of Jill’s thinking about the forces acting on the
ball after it has been released and is rolling down the alley?
A.
B.
C.
D.
Jill correctly identifies the only two horizontal forces acting on the ball.
Jill correctly identifies the force of friction, but should have called the force making the ball
move “the force of momentum.”
Jill correctly identifies the force of friction, but incorrectly describes the ball as having a force
on it that makes it move.
Jill correctly identifies the force of friction, but should have called the force making the ball
move “the force due to her hand.”
Item ID: FM-RE06
Key: B
P-value: 0.25
Percent Responding:
A
B
C
D
5%
25%
34%
37%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
Content Level: 3 – Using content knowledge to make instructional decisions
A teacher asks her students to imagine a soccer player kicking a ball upward. The teacher asks the
students to describe the forces acting on the ball once it has left the soccer player’s foot and is still
moving upward. The majority of students agree that one of the forces is the force in the ball
moving upward.
What should this teacher’s next step be to help students understand forces and motion?
A.
B.
C.
D.
Reinforce to the students that objects have a force in them that keeps them in motion.
Remind the class that a force is an interaction between two objects.
Explain that the force in the ball was transferred from the soccer player’s foot.
Introduce the concept of potential and kinetic energy and how it relates to the forces on the
ball.
Item ID: FM-RE07
Key: B
P-value: 0.36
Percent Responding:
A
B
C
D
27%
36%
15%
22%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
Content Level: 3 – Using content knowledge to make instructional decisions
A teacher places a book on a table and gives it a push. The book slides across the table and stops.
The teacher asks a student to describe the horizontal force(s) acting on the book after it was
pushed and is sliding across the table. The student describes two forces:
1) The force of the book moving across the table; and
2) The force of friction that makes the book move slower and slower.
Which of the following would be the best question to move this student forward in his
understanding of the horizontal forces acting on the book?
A.
B.
C.
D.
“If we could eliminate friction, what would happen to the book?”
“What do you mean by ‘the force of the book’?”
“What other forces, if any, act on the book in this scenario?”
“In which direction is the force of friction acting on the book?”
Item ID: FM-RE08
Key: B
P-value: 0.65
Percent Responding:
A
B
C
D
9%
65%
4%
23%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
Content Level: 3 – Using content knowledge to make instructional decisions
During a lesson in a unit on force and motion, students observe what happens when a car is
launched across the level floor with a rubber band, as shown in the diagram below.
The teacher asks the students to explain the forces acting on the car from the time that the rubber
band is released until the car comes to a stop. A student provides the following response:
“The force of the launcher makes the car go faster and faster. Once the force
of the launcher has run out, the force of friction takes over and will make the
car move slower and slower and eventually stop.”
What question should the teacher ask this student to determine what she understands and/or
misunderstands about forces and motion?
A.
B.
C.
D.
“What causes 'the force of friction'?”
“What do you mean by 'the force of the launcher has run out'?”
“What happens when the car reaches its maximum speed?”
“What would happen if there were no friction?”
Item ID: FM-RE09
Key: D
P-value: 0.32
Percent Responding:
A
B
C
D
23%
28%
18%
32%
Primary Sub-Idea(s) Assessed:
A: A force is a push or pull interaction between two objects, and has both magnitude and direction.
Content Level: 3 – Using content knowledge to make instructional decisions
Students in a middle school science class are working through a series of lessons that uses hockey
pucks and rubber band launchers to shoot the pucks across the level floor. During one of the
lessons, students are asked to observe what happens when the puck is placed in the launcher and
then released.
The activity then asks the students to draw a diagram showing the puck at three time points: 1) as
the puck is being launched (i.e., while the puck is moving but still in contact with the rubber band);
2) a few seconds after the puck leaves the launcher and is no longer in contact with the rubber
band; and 3) just before the puck comes to a stop.
Next, the activity asks students to draw and label force arrows representing the horizontal forces
acting on the puck at each time point. Below are the responses of four students.
Which student’s drawing is correct?
Item ID: FM-RE10
Key: D
P-value: 0.89
Percent Responding:
A
B
C
D
2%
7%
3%
89%
Primary Sub-Idea(s) Assessed:
B: All of the forces acting on an object combine through vector addition into a net force; they either balance each
other out (net force is zero), or act like an unbalanced force (net force is not zero).
(1) If the sum of forces exerted on an object in one direction is the same strength as the sum of forces exerted
on the object in the opposite direction, then the forces on the object are balanced (i.e., the net force is zero).
(2) If the sum of forces exerted on an object in one direction is greater than the sum of forces exerted on the
object in the opposite direction, then the forces on the object are unbalanced (i.e., the net force is not zero).
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
To determine how much students understand forces, a teacher presents the question below on a pretest.
Student Assessment Item
Mary, Susan, and June are playing tug-of-war. The arrows below
the picture show the forces each girl is applying to the rope. Draw
a diagram showing the net force being applied to the rope.
Most of the students answer with the following diagram.
What mistake are these students making?
A.
B.
C.
D.
No mistake; the students answered correctly.
The students should have indicated that there is no net force, because forces in opposite
directions always result in a net force of zero.
The students should have drawn the force arrow to the left, because two forces always
overcome a single force.
The students should have drawn the force arrow to the left, because it is necessary to take the
directions and the magnitudes of the forces into account when combining them.
Item ID: FM-RE11
Key: B
P-value: 0.43
Percent Responding:
A
B
C
D
23%
43%
14%
20%
Primary Sub-Idea(s) Assessed:
B: All of the forces acting on an object combine through vector addition into a net force; they either balance each
other out (net force is zero), or act like an unbalanced force (net force is not zero).
(1) If the sum of forces exerted on an object in one direction is the same strength as the sum of forces exerted
on the object in the opposite direction, then the forces on the object are balanced (i.e., the net force is zero).
(2) If the sum of forces exerted on an object in one direction is greater than the sum of forces exerted on the
object in the opposite direction, then the forces on the object are unbalanced (i.e., the net force is not zero).
Content Level: 3 – Using content knowledge to make instructional decisions
A teacher asks her students to identify whether the forces acting on a car accelerating onto the
highway are balanced or unbalanced. The majority of students agree that the forces acting on the
car are unbalanced.
Which of the following questions would NOT help the teacher assess the students’ level of
understanding of balanced and unbalanced forces?
A.
B.
C.
D.
“Is the net force on the car greater than or equal to zero?”
“What role does mass play in the effect of force on acceleration?”
“What are the individual forces that are acting on the car?”
“If two forces are acting in opposite directions, is the net force always zero?”
Item ID: FM-RE12
Key: D
P-value: 0.62
Percent Responding:
A
B
C
D
8%
13%
16%
62%
Primary Sub-Idea(s) Assessed:
D: If an object is moving faster and faster, then there is a net force acting on the object in the same direction as
the motion.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
At the end of a forces and motion unit, a middle school science teacher is creating a multiple choice
test for his students.
One item includes the illustration below, showing a box sliding to the right across a floor with two
forces acting on the box, and a force diagram showing the horizontal forces acting on the box. He
writes the following question, “Which of the following statements is true about the motion of the
box?”
Which of the following could the teacher include as an INCORRECT option for this test item?
A.
B.
C.
D.
The motion of the box depends on the relative strength of the two forces.
The box will accelerate to the right.
The acceleration of the box depends on the mass of the box.
The box will move at a constant speed to the right.
Item ID: FM-RE13
Key: C
P-value: 0.33
Percent Responding:
A
B
C
D
16%
19%
33%
32%
Primary Sub-Idea(s) Assessed:
D: If an object is moving faster and faster, then there is a net force acting on the object in the same direction as
the motion.
Content Level: 3 – Using content knowledge to make instructional decisions
One of the lessons in the textbook is a demonstration that has the teacher pull a low-friction cart
with a constant force across a level surface.
Which of the following is a misconception that this activity would confront?
A.
B.
C.
D.
Only living things can exert a force.
A moving object contains a force that keeps it going.
An object moves faster and faster only when the force on it gets stronger and stronger.
If an object is moving, there is a force acting on it in the direction of motion.
Item ID: FM-RE14
Key: C
P-value: 0.28
Percent Responding:
A
B
C
D
14%
29%
28%
29%
Primary Sub-Idea(s) Assessed:
D: If an object is moving faster and faster, then there is a net force acting on the object in the same direction as
the motion.
Content Level: 3 – Using content knowledge to make instructional decisions
The question below is administered to a group of middle school students.
Student Assessment Item
A fan is attached to a cart. The fan is turned on and
the cart begins to move along the track. Friction
and air resistance are small enough to be ignored.
What will happen to the cart after it starts moving?
If a majority of students predict that the cart will keep moving at a constant speed, which one of the
following would be a good next step in the development of these students’ understanding of the
effect of a constant non-zero net force on motion?
A.
B.
C.
D.
Reinforce the concept by asking a similar question but in a different context.
Have students experiment by adding different size masses to the cart.
Demonstrate for students what happens when a constant non-zero net force is applied.
Introduce students to the concept of how a changing force affects an object’s acceleration.
Item ID: FM-RE15
Key: B
P-value: 0.64
Percent Responding:
A
B
C
D
5%
64%
6%
26%
Primary Sub-Idea(s) Assessed:
E: If an object is moving slower and slower, then there is a net force acting on the object in the direction opposite
to the object’s motion.
Content Level: 1 – Knowledge of science content
Using low-friction carts like the one depicted below, students have been observing the effects of a
constant force on motion. When switched on, Fan A exerts a force on the cart to the right, and Fan
B exerts a force to the left.
In one demonstration, the students observed what happens when Fan A is on and Fan B is off. The
teacher then asks the students, “What would happen to the cart's motion if halfway down the
track I used a remote control device to turn off Fan A and at the same instant turn on Fan B?”
Which of the following student answers is correct?
A.
B.
C.
D.
The cart will move at a constant speed to the right.
The cart will continue to move to the right and will move slower and slower.
The cart will move to the left and move slower and slower.
The cart will move at a constant speed to the left.
Item ID: FM-RE16
Key: B
P-value: 0.49
Percent Responding:
A
B
C
D
12%
49%
6%
33%
Primary Sub-Idea(s) Assessed:
E: If an object is moving slower and slower, then there is a net force acting on the object in the direction opposite
to the object’s motion.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
Students in a middle school science class are working through a series of lessons that uses hockey
pucks and rubber band launchers to shoot the pucks across the level floor. During one of the
lessons, students are asked to observe what happens when the puck is placed in the launcher and
then released.
The activity then asks the students to draw a diagram showing the puck at three time points: 1) as
the puck is being launched (i.e., while the puck is moving but still in contact with the rubber band);
2) a few seconds after the puck leaves the launcher and is no longer in contact with the rubber band;
and 3) just before the puck comes to a stop.
The activity then asks students to indicate whether the puck is moving faster and faster, moving at a
constant speed, or moving slower and slower at each of the time points. Below is one student’s
response.
At which time point, if any, is the student's response INCORRECT?
A.
B.
C.
D.
Time 1
Time 2
Time 3
It is correct at all three times.
Item ID: FM-RE17
Key: C
P-value: 0.45
Percent Responding:
A
B
C
D
49%
2%
45%
4%
Primary Sub-Idea(s) Assessed:
E: If an object is moving slower and slower, then there is a net force acting on the object in the direction opposite
to the object’s motion.
J: The force of friction acts to oppose the relative motion of two objects in contact. Friction acts on both objects
along the surfaces in contact with each other. The magnitude of friction depends upon the properties of the
surfaces and how hard the objects are pushed together.
Content Level: 3 – Using content knowledge to make instructional decisions
As part of a demonstration in a middle school science class, a teacher gives a quick push to a book
so that it slides across the table, moves slower and slower, and stops. The teacher asks, “Why does
the book move slower and slower and then stop?” One student answers,
“Because you didn’t push it hard enough.”
Which one of the following would be most likely to move this student forward in his understanding
of what causes the book to move slower and slower?
A.
B.
C.
D.
Demonstrate pushing the book again, but pushing it harder.
Discuss why pushing the book harder would keep it from slowing and stopping.
Demonstrate pushing the book again with the same force, but across a rougher surface.
Discuss real-world examples of objects moving slower and slower.
Item ID: FM-RE18
Key: B
P-value: 0.67
Percent Responding:
A
B
C
D
27%
67%
3%
3%
Primary Sub-Idea(s) Assessed:
G: If there is an unbalanced force acting on an object, the greater the strength of the unbalanced force, the greater
the change in the object’s velocity.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
A teacher sets up the following demonstration. A string is threaded through a pulley and attached
to a 100g mass the teacher holds in her hand. The other end of the string is attached to a cart resting
on a table. When the teacher lets go of the mass, the string pulls the cart across the table.
The teacher plans to do the demonstration twice, once releasing the cart with a 100g mass attached
to the string, and once with a 200g mass attached to the string. The teacher asks them to predict in
which trial the cart will accelerate at a greater rate and to explain their prediction.
Which of the following is a correct prediction and explanation?
A.
B.
C.
D.
The cart will accelerate at the same rate because the 100g and 200g masses accelerate toward
the ground at the same rate.
The cart will accelerate at a greater rate when the 200g mass is used because a greater force is
applied to the cart.
The cart will accelerate at the same rate in both trials because the mass of the cart does not
change.
The cart will accelerate at a greater rate when the 100g mass is used because the 100g mass is
easier to accelerate.
Item ID: FM-RE19
Key: B
P-value: 0.91
Percent Responding:
A
B
C
D
3%
91%
3%
2%
Primary Sub-Idea(s) Assessed:
H: If there is an unbalanced force acting on an object, the more massive an object is, the smaller the change in the
object’s velocity.
Content Level: 1 – Knowledge of science content
A teacher sets two cardboard boxes of equal size on a level floor. One box is empty and the other
box is full of textbooks. The teacher asks the students to predict which box will have a greater
acceleration if they are both pushed with the same size force and for the same amount of time.
One student says, “The empty box will accelerate at a greater rate than the box
full of textbooks.”
Based on what this student said, what relationship does she seem to understand?
A.
B.
C.
D.
Acceleration is greater when force is greater.
Acceleration is greater when mass is smaller.
Acceleration is greater when mass is greater.
Acceleration is greater when force is smaller.
Item ID: FM-RE20
Key: D
P-value: 0.81
Percent Responding:
A
B
C
D
6%
0%
13%
81%
Primary Sub-Idea(s) Assessed:
H: If there is an unbalanced force acting on an object, the more massive an object is, the smaller the change in the
object’s velocity.
Content Level: 1 – Knowledge of science content
A teacher is trying to help students understand the effects unbalanced forces and mass have on the
acceleration of an object. To introduce the topic, the teacher asks the students “Which would
accelerate at a greater rate on a level surface when using the same pushing force, an empty or a
full shopping cart?”
What relationship is the teacher trying to get the students to understand?
A.
B.
C.
D.
Acceleration is greater when force is greater.
Acceleration is greater when force is smaller.
Acceleration is greater when mass is greater.
Acceleration is greater when mass is smaller.
Item ID: FM-RE21
Key: C
P-value: 0.84
Percent Responding:
A
B
C
D
4%
11%
84%
1%
Primary Sub-Idea(s) Assessed:
H: If there is an unbalanced force acting on an object, the more massive an object is, the smaller the change in the
object’s velocity.
Content Level: 1 – Knowledge of science content
In a class discussion about forces and motion, students get into a debate about how the mass of an
object affects its acceleration. You listen to the debate to decide who has the best understanding.
Darius: I don't think mass is important. It's the strength of the force
that matters. A strong force will make an object accelerate at a
greater rate than a weak force, regardless of the object's mass.
Guadalupe: I agree with Darius. I think mass doesn't matter at all. If you
drop a bowling ball and a marble off the roof, they will hit the
ground at the same time. The Earth's gravity is the same for
both, and they both accelerate at the same rate, so mass obviously
doesn't make a difference.
Jermaine: I disagree. I think mass is always important. It's harder to
change the speed of an object with a larger mass than it is to
change the speed of an object with a small mass.
Patty: I kind of agree and kind of disagree. I think mass is important,
but only for really heavy objects like a car or truck.
Which student has the best understanding of this concept?
A.
B.
C.
D.
Darius
Guadalupe
Jermaine
Patty
Item ID: FM-RE22
Key: B
P-value: 0.91
Percent Responding:
A
B
C
D
2%
91%
3%
3%
Primary Sub-Idea(s) Assessed:
H: If there is an unbalanced force acting on an object, the more massive an object is, the smaller the change in the
object’s velocity.
Content Level: 1 – Knowledge of science content
Some students are conducting an experiment in which they build cars propelled by a fan and then
observe their motion. Keisha and Brian decide to race their cars by placing them on the level floor
and letting them go at the same time. Both cars accelerate, but Keisha's car crosses the finish line
first.
The students ask the teacher why Keisha's car seems to accelerate at a greater rate, even though
they both use 1 D-cell battery. The teacher examines the cars and notices the differences listed
below.
Which is the most likely to cause the difference in acceleration?
A.
B.
C.
D.
The fan on Brian's car is lower to the ground.
Brian's car has a greater mass.
Brian's car has a more pointed front end.
Brian's car is wider at the base.
Item ID: FM-RE23
Key: C
P-value: 0.33
Percent Responding:
A
B
C
D
2%
15%
33%
51%
Primary Sub-Idea(s) Assessed:
I: If an object has constant speed in a straight line (or zero speed), then there is no net force acting on the object.
This can occur either when the forces on the object are balanced, or there are no forces exerted on the object.
Content Level: 1 – Knowledge of science content
A teacher takes a middle school science class on a field trip to the Air Show, where the class
observes a group of skydivers jumping out of an airplane. The teacher asks the students to draw
pictures in their journals showing the vertical forces acting on one of the skydivers 30 seconds after
opening her parachute (while she is falling toward the ground at a constant speed).
Which of the following diagrams is correct? (The dot in each diagram represents the skydiver.)
Item ID: FM-RE24
Key: A
P-value: 0.66
Percent Responding:
A
B
C
D
66%
3%
4%
27%
Primary Sub-Idea(s) Assessed:
I: If an object has constant speed in a straight line (or zero speed), then there is no net force acting on the object.
This can occur either when the forces on the object are balanced, or there are no forces exerted on the object.
Content Level: 1 – Knowledge of science content
A class is engaged in a discussion about what the world would be like if there were no friction.
The teacher asks the students to describe how the motion of a book sliding across a frictionless
surface would be different.
Based on the following discussion, which student has the best understanding of forces?
Claire: If you gave a book a shove across the floor, it would never stop as long as
there were no obstacles.
Beth: I disagree. The book would have to stop, because the force that you gave
to the book would run out after a while.
Adam: I agree that the book could stop, but I think the book's motion depends
on the surface of the floor; for example, if it were a rug, the book would
stop.
Eli:
A.
B.
C.
D.
Gravity would still be pulling the book down, and that would eventually stop
the book even if there weren't any friction.
Claire
Beth
Adam
Eli
Item ID: FM-RE25
Key: D
P-value: 0.26
Percent Responding:
A
B
C
D
37%
33%
4%
26%
Primary Sub-Idea(s) Assessed:
I: If an object has constant speed in a straight line (or zero speed), then there is no net force acting on the object.
This can occur either when the forces on the object are balanced, or there are no forces exerted on the object.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
A teacher puts a drawing on the board like the one below showing an object and all the forces
acting on that object. The teacher asks the students to describe a motion the object could be
exhibiting.
Which of the following student answers is INCORRECT?
A.
B.
C.
D.
The object is traveling at a constant speed to the right.
The object is not moving at all.
The object is traveling upward but not accelerating.
The object is accelerating in a downward direction.
Item ID: FM-RE26
Key: A
P-value: 0.40
Percent Responding:
A
B
C
D
40%
5%
20%
35%
Primary Sub-Idea(s) Assessed:
I: If an object has constant speed in a straight line (or zero speed), then there is no net force acting on the object.
This can occur either when the forces on the object are balanced, or there are no forces exerted on the object.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
A teacher asks students to describe a situation on a roller coaster in which the forces on the roller
coaster are balanced (a net force of zero).
Student A says, “The forces on a roller coaster are balanced when it moves along a
straight section of track at a constant speed.”
Student B says, “The forces on a roller coaster are balanced when it is going
around a curve at a constant speed.”
Which of the following is true about the students’ statements?
A.
B.
C.
D.
Student A is correct and student B is incorrect.
Student B is correct and student A is incorrect.
Both students are correct.
Both students are incorrect.
Item ID: FM-RE27
Key: C
P-value: 0.87
Percent Responding:
A
B
C
D
3%
2%
87%
8%
Primary Sub-Idea(s) Assessed:
I: If an object has constant speed in a straight line (or zero speed), then there is no net force acting on the object.
This can occur either when the forces on the object are balanced, or there are no forces exerted on the object.
Content Level: 2 – Using science content knowledge to analyze/diagnose student thinking
A teacher gives her physical science class the following thought experiment:
“Standing at the edge of an ice rink, you give a hockey puck a gentle push toward the middle of the
rink. This is a special ice rink that has absolutely no friction. About how far do you think the puck
would go before it stops?”
Virtually all the students agree that the answer depends on how hard you push the puck with your
foot.
Which of the following best represents the students’ understanding of forces and motion?
A.
B.
C.
D.
They do not understand the idea that forces combine to create a single net force on an object.
They do not understand the idea that a force occurs only when two objects interact.
They do not understand the idea that an object’s motion will not change unless an unbalanced
force acts on it.
They correctly understand the motion of the puck.
Item ID: FM-RE28
Key: B
P-value: 0.83
Percent Responding:
A
B
C
D
3%
83%
7%
6%
Primary Sub-Idea(s) Assessed:
J: The force of friction acts to oppose the relative motion of two objects in contact. Friction acts on both objects
along the surfaces in contact with each other. The magnitude of friction depends upon the properties of the
surfaces and how hard the objects are pushed together.
Content Level: 1 – Knowledge of science content
A teacher gives her students the following question on an end-of-unit test.
Student Assessment Item
A boy slides a salt shaker along a table toward the right. As
the salt shaker slides, in which direction does the force of
friction act on the salt shaker?
What would be the correct answer?
A.
B.
C.
D.
To the right
To the left
Upward
Downward
Item ID: FM-RE29
Key: B
P-value: 0.80
Percent Responding:
A
B
C
D
3%
80%
7%
11%
Primary Sub-Idea(s) Assessed:
J: The force of friction acts to oppose the relative motion of two objects in contact. Friction acts on both objects
along the surfaces in contact with each other. The magnitude of friction depends upon the properties of the
surfaces and how hard the objects are pushed together.
Content Level: 3 – Using content knowledge to make instructional decisions
As part of a lesson on friction, a teacher asks a student to perform a demonstration in which he
gives a box a quick push so it slides across the floor. The teacher asks the student why the box
slowed to a stop after it left his hands. The student says,
"After you push it, the only force acting on the box is gravity, so gravity must
have made it go slower and slower."
Which one of the following would be the best next step in helping this student further his
understanding of friction?
A.
B.
C.
D.
Ask the student to give the box a stronger push.
Ask the student to push the box across different surfaces, each time with the same force.
Give the student objects of varying weights to slide across the floor.
Give the student a spring scale to measure the force on the box as it is dragged across the
floor.
Item ID: FM-RE30
Key: A
P-value: 0.44
Percent Responding:
A
B
C
D
44%
23%
16%
17%
Primary Sub-Idea(s) Assessed:
J: The force of friction acts to oppose the relative motion of two objects in contact. Friction acts on both objects
along the surfaces in contact with each other. The magnitude of friction depends upon the properties of the
surfaces and how hard the objects are pushed together.
Content Level: 3 – Using content knowledge to make instructional decisions
Students in a middle school science class are working through a series of lessons that uses hockey
pucks and rubber band launchers to shoot the pucks across the level floor. During one of the
lessons, students are asked to observe what happens when the puck is placed in the launcher and
then released.
The activity then asks the students to draw a diagram showing the puck at three different time
points: 1) as the puck is being launched (i.e., while the puck is moving but still in contact with the
rubber band); 2) a few seconds after the puck leaves the launcher and is no longer in contact with
the rubber band; and 3) just before the puck comes to a stop.
Next, the activity asks students to draw and label force arrows on the puck at each time point. The
response of a student appears below.
Which of the following is INCORRECT about this student's response?
A.
B.
C.
D.
The magnitude of the force of friction should not change.
The force due to the launcher should be greatest at time one, smaller at time 2, and even
smaller (almost zero) at time 3.
The force of friction should be perpendicular to the floor.
The magnitude of the force of friction should decrease with time.