Ohio’s State Tests
ITEM RELEASE
SPRING 2015
PHYSICAL
SCIENCE
PART 1:
PERFORMANCE-BASED
ASSESSMENT
Student Name
Table of Contents
Questions 1 – 2: Content Summary and Answer Key ..........................1
Question 1: Question and Scoring Guidelines ......................................3
Question 1: Sample Responses...............................................................7
Question 2: Question and Scoring Guidelines ....................................13
Question 2: Sample Responses.............................................................17
Physical Science PBA
Item Release
Content Summary and Answer Key
Question
No.
Item
Type
Topic
Subtopic
Answer
Key
Points
1
Graphic Study of
Response Matter
Periodic Trends of the Elements
---
2 points
2
Forces and
Short
Response Motion
Dynamics
---
2 points
1
Physical Science
PBA Item Release
Question 1
Question and Scoring Guidelines
3
Question 1
14431
Points Possible: 2
See Alignment for more detail.
4
Scoring Guidelines
For this item, a full-credit (2 point) response includes:
• “Element Q” in the Group 17 region and “Element X” in the Group 18 region
(1 point);
AND
• “+ Ionic Charge,” “Is Conductive” and “High Reactivity” are selected (1 point).
For this item, a partial-credit (1 point) response includes:
• “Element Q” in the Group 17 region and “Element X” in the Group 18 region
(1 point);
OR
• “+ Ionic Charge,” “Is Conductive” and “High Reactivity” are selected (1 point).
Alignment
Topic
Study of Matter
Subtopic
Periodic Trends of the Elements
Content Elaboration
When elements are listed in order of increasing atomic number, the same sequence
of properties appears over and over again; this is the periodic law. The periodic table
is arranged so that elements with similar chemical and physical properties are in the
same group or family. Metalloids are elements that have some properties of metals
and some properties of nonmetals. Metals, nonmetals, metalloids, periods and groups
or families (including the alkali metals, alkaline earth metals, halogens and noble
gases) can be identified by their position on the periodic table. Elements in Groups 1,
2 and 17 have characteristic ionic charges that will be used to predict the formulas
of compounds.
Cognitive Demand
Recalling Accurate Science (R)
Requires students to provide accurate statements about scientifically valid facts,
concepts and relationships. Recall only requires students to provide a rote response,
declarative knowledge or perform routine mathematical tasks. This cognitive
demand refers to students’ knowledge of science fact, information, concepts, tools,
procedures and basic principles.
5
Explanation of the Item
This two-point, machine-scored, constructed-response item requires the student to
determine the position in the periodic table of two elements, given various physical
and chemical properties, and then to determine the properties of a third element,
given its location on the periodic table. Elements in the same group or family have
similar chemical and physical properties that are different from the chemical and
physical properties of elements in other groups. Group 18 consists of the noble gases,
which are nonreactive gases that do not tend to conduct electricity or form ions.
Since these are the properties of Element X, it should be placed somewhere in the
vertical column of Group 18. Group 17 are the halogens, which are highly reactive
elements that form negative ions and do not conduct electricity. Since these are
the properties of Element Q, it should be placed somewhere in the vertical column
of Group 17. Group 1 consists of the alkali metals, which are highly reactive solids
that form positive ions and conduct an electric current. Since Element Z belongs in
Group 1, “+ Ionic Charge,” “Is Conductive” and “High Reactivity” are identified
as properties.
6
Physical Science
PBA Item Release
Question 1
Sample Responses
7
Sample Response: 2 points
Notes on Scoring
This response earns full credit (2 points). “Element Q”
is correctly placed in Group 17, “Element X” is
correctly placed in Group 18, and “+ Ionic Charge,”
“Is Conductive” and “High Reactivity” are identified
as properties of “Element Z.”
8
Sample Response: 1 point
Notes on Scoring
This response earns partial credit (1 point). While
“Element X” is correctly placed in Group 18, credit is
not awarded for Part A because “Element Q” is
incorrectly placed in Group 1 rather than Group 17.
Both elements must be placed correctly to earn credit
for Part A. One point is earned for Part B because the
properties of “Element Z” are correctly identified as
“+ Ionic Charge,” “Is Conductive” and “High Reactivity.”
9
Sample Response: 1 point
Notes on Scoring
This response earns partial credit (1 point). Credit is
awarded for Part A because “Element Q” is placed in
Group 17 and “Element X” is placed in Group 18. Credit
is not awarded for Part B. While the response correctly
identifies “Is Conductive” as a property of “Element Z,”
it incorrectly identifies additional properties as “No
Reactivity” and “Is Not Conductive.” In order to
earn credit for Part B, all three properties must be
correctly identified.
10
Sample Response: 0 points
Notes on Scoring
This response earns no credit (0 points). Credit is not
awarded for Part A because “Element Q” is incorrectly
placed in Group 18 rather than Group 17 and
“Element X” is incorrectly placed in Group 1 rather than
Group 18. Credit is also not awarded for Part B. While
the response correctly identifies “Is Conductive” as a
property of “Element Z,” it incorrectly identifies
additional properties as “No Reactivity” and “Is Not
Conductive.” In order to earn credit for Part B, all three
properties must be correctly identified.
11
Sample Response: 0 points
Notes on Scoring
This response earns no credit (0 points). While
“Element X” is correctly placed in Group 18, credit
is not awarded for Part A because “Element Q” is
incorrectly placed in Group 18 rather than Group 17.
Both elements must be placed correctly to earn credit
for Part A. While the response correctly identifies “Is
Conductive” and “+ Ionic Charge” as properties of
“Element Z,” it incorrectly identifies an additional
property as “No Ionic Charge.” In order to earn
credit for Part B, all three properties must be
correctly identified.
12
Physical Science
PBA Item Release
Question 2
Question and Scoring Guidelines
13
Question 2
18499
Points Possible: 2
See Alignment for more detail.
Scoring Guidelines
Score Point
Description
2 points
The response provides a complete interpretation and/or correct
solution. It demonstrates a thorough understanding of the
concept or task. It indicates logical reasoning and conclusions.
It is accurate, relevant and complete.
The response correctly:
• Explains why the forces acting on the objects are different;
AND
• Explains why the accelerations of the objects are the same.
14
1 point
The response provides evidence of a partial interpretation and/or
solution process. It demonstrates an incomplete understanding of
the concept or task. It contains minor flaws in reasoning. It neglects
to address some aspect of the concept or task.
The response correctly:
• Explains why the forces acting on the objects are different;
OR
• Explains why the accelerations of the objects are the same.
0 points
The response does not meet the criteria required to earn one point.
The response indicates inadequate or no understanding of the task.
Alignment
Topic
Forces and Motion
Subtopic
Dynamics
Content Elaboration
The field concept is developed in physical science. The stronger the field, the greater
the force exerted on objects placed in the field. The field of an object is always there,
even if the object is not interacting with anything else. The gravitational force (weight)
of an object is proportional to its mass. Weight, Fg, can be calculated from the
equation Fg = m g, where g is the gravitational field strength of an object, which is
equal to 9.8 N/kg (m/s2) on the surface of Earth.
An object does not accelerate (remains at rest or maintains a constant speed and
direction of motion) unless an unbalanced net force acts on it. The rate at which
an object changes its speed or direction (acceleration) is proportional to the
vector sum of the applied forces (net force, Fnet) and inversely proportional to the
mass (a = Fnet/m). When the vector sum of the forces (net force) acting on an object
is zero, the object does not accelerate. For an object that is moving, this means the
object will remain moving without changing its speed or direction. For an object
that is not moving, the object will continue to remain stationary. These laws will be
applied to systems that consist of a single object upon which multiple forces act.
Vector addition will be limited to one dimension (positive and negative). While both
horizontal and vertical forces can be acting on an object simultaneously, one of the
dimensions must have a net force of zero.
15
Cognitive Demand
Interpreting and Communicating Science Concepts (C)
Requires students to use subject-specific conceptual knowledge to interpret and
explain events, phenomena, concepts and experiences using grade-appropriate
scientific terminology, technological knowledge and mathematical knowledge.
Communicate with clarity, focus and organization using rich, investigative scenarios,
real-world data and valid scientific information.
Explanation of the Item
This two-point, hand-scored, constructed-response item requires the student to explain
why two objects with different masses will have different gravitational forces but will
have the same acceleration on Earth. The student is given the option of answering in
words or using equations. These two approaches are explained below.
Mathematical Approach:
The gravitational force of an object can be calculated using the equation
Fg = m g, where g is the gravitational field strength of an object, which can
be assumed to be 10 N/kg (m/s2) on the surface of Earth (this is the value
given on the reference sheet). Therefore, the force of gravity acting on the
100 kg object will be Fg = (100 kg)(10 N/kg ) = 1000 N. The force of gravity
acting on the 10 kg object will be Fg = (10 kg)(10 N/kg ) = 100 N. This shows
that the force of gravity on the two objects is different.
The acceleration of an object, a, can be calculated using the equation
a = Fnet/m, where Fnet is the vector sum of the forces acting on the object
and m is the mass of the object. In the absence of air resistance, the net
force acting on the 100 kg and 10 kg objects will be the gravitational force
acting on them. The gravitational forces have already been calculated to be
1000 N and 100 N, respectively, in the previous paragraph. Using the equation
a = Fnet/m, the acceleration of the 100 kg object can be calculated as
a = (1000 N)/(100 kg) = 10 m/s2. The acceleration of the 10 kg object can be
calculated as a = (100 N)/(10 kg) = 10 m/s2. This shows the two objects have
the same acceleration.
Verbal Approach:
The force acting on each object is the force of gravity or weight. Since the
force of gravity acting on the object depends upon the mass and the
two objects have different masses, they must have different forces acting
on them.
The acceleration of an object is directly proportional to the net force acting
on it and inversely proportional to its mass. The 100 kg object has ten times
the mass and ten times the weight of the 10 kg object. Since it is directly
proportional to the force and inversely proportional to the mass, the tenfold
increase in both cancels out and the 100 kg object will have the same
acceleration as the 10 kg object.
16
Physical Science
PBA Item Release
Question 2
Sample Responses
17
Sample Response: 2 points
Notes on Scoring
This response earns full credit (2 points). The response
correctly explains why the forces are different (1 point):
• “. . . because gravity pulls down on an object by
its . . . mass, the more mass the more force that is
applied onto that object.”
The response also correctly explains why the
accelerations are the same (1 point):
• “The accelerations of the objects are the same
because there is no air resistance. Say there was a
feather and an elphent jumped off a building at the
same time with air resistance. The elphent would fall
faster because of its mass the air resistance would
have little affect on the elphent, the feather on the
other hand would fall much slowly because of its
light mass also because of the air resistances
oushing upward on it.”
18
Sample Response: 1 point
Notes on Scoring
This response earns partial credit (1 point). The response
correctly identifies why the objects have different
forces:
• “The law of gravity says that the gravity will be
greater on an object that has more mass.”
However, the response earns no credit for explaining
why the accelerations are the same. The student
states that:
• “The acceleration of an object is greater when the
object has less mass.”
While this may be true when the two objects being
compared have equal forces acting upon them,
these two objects do not. In addition, this suggests that
the accelerations for the two objects will be different
when the prompt asks for an explanation for why they
are the same.
19
Sample Response: 1 point
Notes on Scoring
This response earns partial credit (1 point). The response
weakly indicates why the objects experience different
forces and earns credit for:
• “The forces acting on the objects are different
because the two objects are both different masses.”
However, this response does not correctly indicate why
the accelerations are the same:
• “Gravitational pull” is a force that is not the
same for the two objects. The 9.8 value represents
acceleration, but it is not identified as such and is
shown to have units of “m/s” instead of “m/s2.”
20
Sample Response: 1 point
Notes on Scoring
This response earns partial credit (1 point). The response
weakly indicates why the objects experience different
forces and earns credit for:
• “the forces are different because the objects have
different masses”
However, this response does not correctly indicate why
the accelerations are the same:
• “. . . because of newtons 2nd law” is not specific
enough to earn credit.
21
Sample Response: 1 point
Notes on Scoring
This response earns partial credit (1 point). One point is
awarded for correctly explaining why the forces of the
two objects are different:
• “The gravitational force acting on the object
with the mass of 100 kg will be greater then the
gravitational force acting on the object with the
mass of 10 kg because it has a mass of 100 kg
which is much larger than a mass of 10 kg. Greater
mass= greater gravitational force acting upon it.”
However, no credit is awarded for explaining why the
accelerations are the same. While the student gives
an equation for acceleration, this equation does not
explain why the 100 kg and 10 kg objects will have the
same acceleration.
22
Sample Response: 1 point
Notes on Scoring
This response earns partial credit (1 point). The response
indicates why the objects experience different forces
and earns credit for:
• “100 kg will have a greater force of gravity because
it has more mass.”
However, this response does not correctly indicate
why the accelerations are the same. The statement
“They are both dropped from the same point.”
does not explain why the two objects have the
same acceleration.
23
Sample Response: 1 point
Notes on Scoring
This response earns partial credit (1 point). The response
weakly indicates why the objects experience different
forces and earns credit for:
• “The forces acting on the objects are differnt
because the objects have diffrent masses. The one
with the greater mass means its going to be pulled
on by a greater force.”
However, this response does not correctly indicate
why the accelerations are the same. It incorrectly
states that “every object falls at about 10m/s.”
This statement claims that all objects fall with the
same constant velocity of 10 m/s, which is not true.
The response also incorrectly states that “Both of the
objects have a terminal velocity.” Terminal velocity
only occurs when air resistance is acting on an
object. The prompt states “Assume that there is no
air resistance.”
24
Sample Response: 0 points
Notes on Scoring
This response earns no credit (0 points). It does not
attempt to answer why the objects have different
forces acting on them. Saying that “The objects would
fall at the same speed” does not address acceleration.
25
Sample Response: 0 points
Notes on Scoring
This item earns no credit (0 points). It does not explain
why the objects experience different forces, nor does
it explain why the objects have the same acceleration.
The statement “will hit the ground slower” does not
address acceleration. The statement “the object that
weighs 10 kg because the kg weights less than the
object that weights 100 kg” demonstrates a lack of
understanding about the differences between weight
and mass.
26
Sample Response: 0 points
Notes on Scoring
This response earns no credit (0 points). The statement
“The 100kg object would have more gravity pulling it
down” is true, but it doesn’t explain that it is due to the
greater mass. The response does not explain why the
acceleration would be the same. In fact, the response
states that “the acceleration would be quicker on
the 100kg.”
27
Sample Response: 0 points
Notes on Scoring
This response earns no credit (0 points). The statement
“the greater the mass the more the objects attract”
is not specific enough to earn credit for explaining
why there are different forces acting on the objects.
The statement “ALL objects fall at the rate of 9.8 m/s2
so they should have the same terminal velocity” is
inconsistent and demonstrates a lack of understanding
of what 9.8 m/s2 and terminal velocity represent. The
rate of 9.8 m/s2 is the acceleration of the two objects.
This means the objects continue to get faster as they
fall, increasing by 9.8 m/s every second. Terminal
velocity is the constant speed at which an object falls.
Terminal velocity only occurs when there is an opposing
force of air resistance. The prompt states “Assume that
there is no air resistance.”
28
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