Physics COURSE CONTENT 330

Physics  COURSE CONTENT 330
OHIO’S NEW LEARNING STANDARDS I Science 330
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Physics
COURSE CONTENT
SYLLABUS AND MODEL CURRICULUM
The following information may be taught in any order; there is no ODErecommended sequence.
COURSE DESCRIPTION
Physics is a high school level course, which satisfies the Ohio Core science
graduation requirements of Ohio Revised Code Section 3313.603. This section of
Ohio law requires a three-unit course with inquiry-based laboratory experience that
engages students in asking valid scientific questions and gathering and analyzing
information.
Physics elaborates on the study of the key concepts of motion, forces and energy
as they relate to increasingly complex systems and applications that will provide a
foundation for further study in science and scientific literacy.
Students engage in investigations to understand and explain motion, forces and
energy in a variety of inquiry and design scenarios that incorporate scientific
reasoning, analysis, communication skills and real-world applications.
SCIENCE INQUIRY AND APPLICATION
During the years of grades 9 through 12, all students must use the following
scientific processes with appropriate laboratory safety techniques to construct
their knowledge and understanding in all science content areas:
• Identify questions and concepts that guide scientific investigations;
• Design and conduct scientific investigations;
• Use technology and mathematics to improve investigations and communications;
• Formulate and revise explanations and models using logic and evidence (critical
thinking);
• Recognize and analyze explanations and models; and
• Communicate and support a scientific argument.
MOTION
• Graph interpretations
• Position vs. time
• Velocity vs. time
• Acceleration vs. time
• Problem solving
• Using graphs (average velocity, instantaneous velocity, acceleration,
displacement, change in velocity)
• Uniform acceleration including free fall (initial velocity, final velocity, time,
displacement, acceleration, average velocity)
• Projectiles
• Independence of horizontal and vertical motion
• Problem-solving involving horizontally launched projectiles
FORCES, MOMENTUM AND MOTION
• Newton’s laws applied to complex problems
• Gravitational force and fields
• Elastic forces
• Friction force (static and kinetic)
• Air resistance and drag
• Forces in two dimensions
• Adding vector forces
• Motion down inclines
• Centripetal forces and circular motion
• Momentum, impulse and conservation of momentum
ENERGY
• Gravitational potential energy
• Energy in springs
• Nuclear energy
• Work and power
• Conservation of energy
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WAVES
• Wave properties
• Conservation of energy
• Reflection
• Refraction
• Interference
• Diffraction
• Light phenomena
• Ray diagrams (propagation of light)
• Law of reflection (equal angles)
• Snell’s law
• Diffraction patterns
• Wave – particle duality of light
• Visible spectrum and color
ELECTRICITY AND MAGNETISM
• Charging objects (friction, contact and induction)
• Coulomb’s law
• Electric fields and electric potential energy
• DC circuits
• Ohm’s law
• Series circuits
• Parallel circuits
• Mixed circuits
• Applying conservation of charge and energy (junction and loop rules)
• Magnetic fields and energy
• Electromagnetic interactions
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CONTENT ELABORATION: MOTION
Motion
In physical science, the concepts of position, displacement, velocity and acceleration
were introduced and straight-line motion involving either uniform velocity or uniform
acceleration was investigated and represented in position vs. time graphs, velocity
vs. time graphs, motion diagrams and data tables.
In this course, acceleration vs. time graphs are introduced and more complex
graphs are considered that have both positive and negative displacement values and
involve motion that occurs in stages (e.g., an object accelerates then moves with
constant velocity). Symbols representing acceleration are added to motion diagrams
and mathematical analysis of motion becomes increasingly more complex. Motion
must be explored through investigation and experimentation. Motion detectors and
computer graphing applications can be used to collect and organize data. Computer
simulations and video analysis can be used to analyze motion with greater precision.
• Motion Graphs
Instantaneous velocity for an accelerating object can be determined by calculating
the slope of the tangent line for some specific instant on a position vs. time
graph. Instantaneous velocity will be the same as average velocity for conditions
of constant velocity, but this is rarely the case for accelerating objects. The
position vs. time graph for objects increasing in speed will become steeper as
they progress and the position vs. time graph for objects decreasing in speed will
become less steep.
On a velocity vs. time graph, objects increasing in speed will slope away from the
x-axis and objects decreasing in speed will slope toward the x-axis. The slope of
a velocity vs. time graph indicates the acceleration so the graph will be a straight
line (not necessarily horizontal) when the acceleration is constant. Acceleration is
positive for objects speeding up in a positive direction or objects slowing down
in a negative direction. Acceleration is negative for objects slowing down in a
positive direction or speeding up in a negative direction. These are not concepts
that should be memorized, but can be developed from analyzing the definition of
acceleration and the conditions under which acceleration would have these signs.
The word “deceleration” should not be used since it provides confusion between
slowing down and negative acceleration. The area under the curve for a velocity
vs. time graph gives the change in position (displacement) but the absolute
position cannot be determined from a velocity vs. time graph.
Objects moving with uniform acceleration will have a horizontal line on an
acceleration vs. time graph. This line will be at the x-axis for objects that are either
standing still or moving with constant velocity. The area under the curve of an
acceleration vs. time graph gives the change in velocity for the object, but the
displacement, position and the absolute velocity cannot be determined from an
acceleration vs. time graph. The details about motion graphs should not be taught
as rules to memorize, but rather as generalizations that can be developed from
interpreting the graphs.
• Problem Solving
Many problems can be solved from interpreting graphs and charts as detailed
in the motion graphs section. In addition, when acceleration is constant,
average velocity can be calculated by taking the average of the initial and final
instantaneous velocities (􀳦􀳦avg = (vf − vi )/2). This relationship does not hold true
when the acceleration changes. The equation can be used in conjunction with
other kinematics equations to solve increasingly complex problems, including
those involving free fall with negligible air resistance in which objects fall with
uniform acceleration. Near the surface of Earth, in the absence of other forces,
the acceleration of freely falling objects is 9.81 m/s2. Assessments of motion
problems, including projectile motion, will not include problems that require the
quadratic equation to solve.
• Projectile Motion
When an object has both horizontal and vertical components of motion, as in a
projectile, the components act independently of each other. For a projectile in the
absence of air resistance, this means that horizontally, the projectile will continue
to travel at constant speed just like it would if there were no vertical motion.
Likewise, vertically the object will accelerate just as it would without any horizontal
motion. Problem solving will be limited to solving for the range, time, initial height,
initial velocity or final velocity of horizontally launched projectiles with negligible air
resistance.
While it is not inappropriate to explore more complex projectile problems, it must
not be done at the expense of other parts of the curriculum.
EXPECTATIONS FOR LEARNING: COGNITIVE DEMANDS
This section provides definitions for Ohio’s science cognitive demands, which are
intrinsically related to current understandings and research about how people learn.
They provide a structure for teachers and assessment developers to reflect on plans
for teaching science, to monitor observable evidence of student learning and to
develop summative assessment of student learning of science.
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VISIONS INTO PRACTICE
COMMON MISCONCEPTIONS
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This section provides examples of tasks that students may perform; this includes
guidance for developing classroom performance tasks. It is not an all-inclusive
checklist of what should be done, but is a springboard for generating innovative
ideas.
• A buggy moving at constant velocity is released from the top of a ramp 1.0
second before a cart that starts from rest and accelerates down the ramp. At
what position on the ramp will the buggy and the cart collide? All data, graphs,
calculations and explanations must be clearly represented and annotated to
explain how the answer was determined. The cart and the buggy may be checked
out one at a time to collect data, but may not be used together until the prediction
is ready to be tested.
• Investigate the motion of a freely falling body using either a ticker timer or
a motion detector. Use mathematical analysis to determine a value for “g.”
Compare the experimental value to known values of “g.” Suggest sources of
error and possible improvements to the experiment.
Students often think that:
• Two objects side by side must have the same speed.
• Acceleration and velocity are always in the same direction.
• Velocity is a force.
• If velocity is zero, then acceleration must be zero, too.
• Heavier objects fall faster than light ones.
• Acceleration is the same as velocity.
• The acceleration of a falling object depends upon its mass.
• Freely falling bodies can only move downward.
• There is no gravity in a vacuum.
• Gravity only acts on things when they are falling.
• When the velocity is constant, so is the acceleration.
INSTRUCTIONAL STRATEGIES AND RESOURCES
This section provides additional support and information for educators. These are
strategies for actively engaging students with the topic and for providing hands-on,
minds-on observation and exploration of the topic, including authentic data resources
for scientific inquiry, experimentation and problem-based tasks that incorporate
technology and technological and engineering design. Resources selected are
printed or Web-based materials that directly relate to the particular Content
Statement. It is not intended to be a prescriptive list of lessons.
• “Moving man” is an interactive simulation from PhET that allows students to
set position, velocity and acceleration, watch the motion of the man and see the
position vs. time, velocity vs. time and acceleration vs. time graphs.
• “Motion in 2-D” is an interactive simulation from PhET that shows the
magnitude and direction of the velocity and accelerations for different types of
motion.
• “Motion Diagrams” is a tutorial from Western Kentucky University that shows
how to draw motion diagrams for a variety of motions. It includes an animated
physlet.
• “Projectile Motion” is a physlet from High Point University that illustrates the
independence of horizontal and vertical motion in projectile motion. The projectile
motion is shown in slow motion so the horizontal and vertical positions of the
ball can be clearly tracked and analyzed. While it shows a projectile launched
at an angle, it emphasizes the conceptual aspects of projectile motion that are
appropriate for physics students.
• Modeling workshops are available nationally that help teachers develop a
framework for incorporating guided inquiry in their instruction.
Students do not realize that the acceleration is zero. If the speed is constant, there is
no acceleration. A positive acceleration is always associated with speeding up and a
negative acceleration is always associated with slowing down.
DIVERSE LEARNERS
Strategies for meeting the needs of all learners including gifted students, English
Language Learners (ELL) and students with disabilities can be found at the Ohio
Department of Education site. Resources based on the Universal Design for
Learning principles are available at www.cast.org.
CLASSROOM PORTALS
“Teaching High School Science” is a series of videos-on-demand produced by
Annenberg that show classroom strategies for implementing inquiry into the high
school classroom. While not all of the content is aligned to physical science, the
strategies can be applied to any content.
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CONTENT ELABORATION: FORCES, MOMENTUM AND
MOTION
Forces, Momentum and Motion
In earlier grades, Newton’s laws of motion were introduced; gravitational forces
and fields were described conceptually; the gravitational force (weight) acting on
objects near Earth’s surface was calculated; friction forces and drag were addressed
conceptually and quantified from force diagrams; and forces required for circular
motion were introduced conceptually. In this course, Newton’s laws of motion
are applied to mathematically describe and predict the effects of forces on more
complex systems of objects and to analyze objects in free fall that experience
significant air resistance.
Gravitational forces are studied as a universal phenomenon and gravitational field
strength is quantified. Elastic forces and a more detailed look at friction are included.
At the atomic level, “contact” forces are actually due to the forces between the
charged particles of the objects that appear to be touching. These electric forces
are responsible for friction forces, normal forces and other “contact” forces. Air
resistance and drag are explained using the particle nature of matter. Projectile
motion is introduced and circular motion is quantified. The vector properties of
momentum and impulse are introduced and used to analyze elastic and inelastic
collisions between objects. Analysis of experimental data collected in laboratory
investigations must be used to study forces and momentum. This can include the
use of force probes and computer software to collect and analyze data.
• Newton’s laws
Newton’s laws of motion, especially the third law, can be used to solve complex
problems that involve systems of many objects that move together as one (e.g.,
an Atwood’s machine). The equation a = Fnet/m that was introduced in physical
science can be used to solve more complex problems involving systems of
objects and situations involving forces that must themselves be quantified (e.g.,
gravitational forces, elastic forces, friction forces).
• Gravitational Forces and Fields
Gravitational interactions are very weak compared to other interactions and are
difficult to observe unless one of the objects is extremely massive (e.g., the sun,
planets, moons). The force law for gravitational interaction states that the strength
of the gravitational force is proportional to the product of the two masses and
inversely proportional to the square of the distance between the centers of the
masses, Fg = (G·m1·m2)/r2). The proportionality constant, G, is called the universal
gravitational constant. Problem solving may involve calculating the net force for
an object between two massive objects (e.g., Earth-moon system, planet-sun
system) or calculating the position of such an object given the net force.
The strength of an object’s (i.e., the source’s) gravitational field at a certain
location, g, is given by the gravitational force per unit of mass experienced by
another object placed at that location, g = Fg / m. Comparing this equation to
Newton’s second law can be used to explain why all objects on Earth’s surface
accelerate at the same rate in the absence of air resistance. While the gravitational
force from another object can be used to determine the field strength at a
particular location, the field of the object is always there, even if the object is
not interacting with anything else. The field direction is toward the center of the
source. Given the gravitational field strength at a certain location, the gravitational
force between the source of that field and any object at that location can be
calculated. Greater gravitational field strengths result in larger gravitational forces
on masses placed in the field. Gravitational fields can be represented by field
diagrams obtained by plotting field arrows at a series of locations. Field line
diagrams are excluded from this course. Distinctions between gravitational and
inertial masses are excluded.
A scale indicates weight by measuring the normal force between the object
and the surface supporting it. The reading on the scale accurately measures the
weight if the system is not accelerating and the net force is zero. However, if
the scale is used in an accelerating system as in an elevator, the reading on the
scale does not equal the actual weight. The scale reading can be referred to as
the “apparent weight.” This apparent weight in accelerating elevators can be
explained and calculated using force diagrams and Newton’s laws.
• Elastic Forces
Elastic materials stretch or compress in proportion to the load they support. The
mathematical model for the force that a linearly elastic object exerts on another
object is Felastic = kΔx, where Δx is the displacement of the object from its relaxed
position. The direction of the elastic force is always toward the relaxed position of
the elastic object. The constant of proportionality, k, is the same for compression
and extension and depends on the “stiffness” of the elastic object.
• Friction Forces
The amount of kinetic friction between two objects depends on the electric forces
between the atoms of the two surfaces sliding past each other. It also depends
upon the magnitude of the normal force that pushes the two surfaces together.
This can be represented mathematically as Fk = μkFN, where μk is the coefficient
of kinetic friction that depends upon the materials of which the two surfaces are
made.
Sometimes friction forces can prevent objects from sliding past each other, even
when an external force is applied parallel to the two surfaces that are in contact.
This is called static friction, which is mathematically represented by Fs ≤ μsFN. The
maximum amount of static friction possible depends on the types of materials
that make up the two surfaces and the magnitude of the normal force pushing
the objects together, Fsmax = μsFN. As long as the external net force is less than or
equal to the maximum force of static friction, the objects will not move relative to
one another. In this case, the actual static friction force acting on the object will be
equal to the net external force acting on the object, but in the opposite direction.
If the external net force exceeds the maximum static friction force for the object,
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the objects will move relative to each other and the friction between them will no
longer be static friction, but will be kinetic friction.
• Air Resistance and Drag
Liquids have more drag than gases like air. When an object pushes on the
particles in a fluid, the fluid particles can push back on the object according to
Newton’s third law and cause a change in motion of the object. This is how
helicopters experience lift and how swimmers propel themselves forward. Forces
from fluids will only be quantified using Newton’s second law and force diagrams.
• Forces in Two Dimensions
Net forces will be calculated for force vectors with directions between 0° and
360° or a certain angle from a reference (e.g., 37° above the horizontal). Vector
addition can be done with trigonometry or by drawing scaled diagrams. Problems
can be solved for objects sliding down inclines. The net force, final velocity, time,
displacement and acceleration can be calculated. Inclines will either be frictionless
or the force of friction will already be quantified. Calculations of friction forces
down inclines from the coefficient of friction and the normal force will not be
addressed in this course.
An object moves at constant speed in a circular path when there is a constant net
force that is always directed at right angles to the direction in motion toward the
center of the circle. In this case, the net force causes an acceleration that shows
up as a change in direction. If the force is removed, the object will continue in a
straight-line path. The nearly circular orbits of planets and satellites result from the
force of gravity. Centripetal acceleration is directed toward the center of the circle
and can be calculated by the equation ac= v2/r, where v is the speed of the object
and r is the radius of the circle. This expression for acceleration can be substituted
into Newton’s second law to calculate the centripetal force. Since the centripetal
force is a net force, it can be equated to friction (unbanked curves), gravity, elastic
force, etc., to perform more complex calculations.
• Momentum, Impulse and Conservation of Momentum
Momentum, p, is a vector quantity that is directly proportional to the mass, m,
and the velocity, v, of the object. Momentum is in the same direction the object
is moving and can be mathematically represented by the equation p = mv. The
conservation of linear momentum states that the total (net) momentum before
an interaction in a closed system is equal to the total momentum after the
interaction. In a closed system, linear momentum is always conserved for elastic,
inelastic and totally inelastic collisions. While total energy is conserved for any
collision, in an elastic collision, the kinetic energy also is conserved. Given the
initial motions of two objects, qualitative predictions about the change in motion
of the objects due to a collision can be made. Problems can be solved for the
initial or final velocities of objects involved in inelastic and totally inelastic collisions.
For assessment purposes, momentum may be dealt with in two dimensions
conceptually, but calculations will only be done in one dimension. Coefficients of
restitution are beyond the scope of this course.
Impulse, Δp, is the total momentum transfer into or out of a system. Any
momentum transfer is the result of interactions with objects outside the system
and is directly proportional to both the average net external force acting on the
system, Favg, and the time interval of the interaction, Δt. It can mathematically be
represented by Δp = pf – pi = Favg Δt. This equation can be used to justify why
momentum changes due to the external force of friction can be ignored when the
time of interaction is extremely short. Average force, initial or final velocity, mass
or time interval can be calculated in multi-step word problems. For objects that
experience a given impulse (e.g., a truck coming to a stop), a variety of force/time
combinations are possible. The time could be small, which would require a large
force (e.g., the truck crashing into a brick wall to a sudden stop). Conversely, the
time could be extended which would result in a much smaller force (e.g., the truck
applying the breaks for a long period of time).
EXPECTATIONS FOR LEARNING: COGNITIVE DEMANDS
This section provides definitions for Ohio’s science cognitive demands, which are
intrinsically related to current understandings and research about how people learn.
They provide a structure for teachers and assessment developers to reflect on plans
for teaching science, to monitor observable evidence of student learning and to
develop summative assessment of student learning of science.
VISIONS INTO PRACTICE
This section provides examples of tasks that students may perform; this includes
guidance for developing classroom performance tasks. It is not an all-inclusive
checklist of what should be done, but is a springboard for generating innovative
ideas.
• Given two spring-loaded dynamic carts with different masses that are located on
a table between two wooden blocks, determine where the carts must be placed
so that they hit the blocks simultaneously. Measurements may be taken of the
model set up at the front of the room, but the carts may not be released prior to
determination. Clearly justify the answer and state any assumptions that were
made. Test your prediction with the model set up at the front of the room.
• Plan and conduct a scientific investigation to determine the relationship between
the force exerted on a spring and the amount it stretches. Represent the data
graphically. Analyze the data to determine patterns and trends and model the
relationship with a mathematical equation. Describe the relationship in words and
support the conclusion with experimental evidence.
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INSTRUCTIONAL STRATEGIES AND RESOURCES
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This section provides additional support and information for educators. These are
strategies for actively engaging students with the topic and for providing hands-on,
minds-on observation and exploration of the topic, including authentic data resources
for scientific inquiry, experimentation and problem-based tasks that incorporate
technology and technological and engineering design. Resources selected are
printed or Web-based materials that directly relate to the particular Content
Statement. It is not intended to be a prescriptive list of lessons.
• “Collision Lab” is an interactive simulation that allows students to Investigate
collisions on an air hockey table. Students can vary the number of discs, masses,
elasticity and initial conditions to see if momentum and kinetic energy are
conserved.
• “Forces and Motion” is an interactive simulation that allows students to explore
the forces present when a filing cabinet is pushed. Students can create an applied
force and see the resulting friction force and total force acting on the cabinet.
Graphs show forces vs. time, position vs. time, velocity vs. time, and acceleration
vs. time. A force diagram of all the forces (including gravitational and normal
forces) is shown.
COMMON MISCONCEPTIONS
Students often think that:
• Forces are required for motion with constant velocity.
• Inertia deals with the state of motion (at rest or in motion).
• All objects can be moved with equal ease in the absence of gravity.
• All objects eventually stop moving when the force is removed.
• Inertia is the force that keeps objects in motion.
• If two objects are both at rest, they have the same amount of inertia.
• Velocity is absolute and not dependent on the frame of reference.
• Action-reaction forces act on the same body.
• There is no connection between Newton’s laws and kinematics.
• The product of mass and acceleration, ma, is a force.
• Friction cannot act in the direction of motion.
• The normal force on an object is equal to the weight of the object by the third law.
• The normal force on an object always equals the weight of the object.
• Equilibrium means that all the forces on an object are equal.
• Equilibrium is a consequence of the third law.
• Only animate things (people, animals) exert forces; passive ones (tables, floors) do
not exert forces.
• Once an object is moving, heavier objects push more than lighter ones.
• Newton’s third law can be overcome by motion (e.g., by a jerking motion).
• A force applied by an object, like a hand, still acts on an object after the object
leaves the hand.
• The moon is not falling.
• The moon is not in free fall. The force that acts on an apple is not the same as the
force that acts on the moon.
• The gravitational force is the same on all falling bodies.
• There are no gravitational forces in space.
• The gravitational force acting on the Space Shuttle is nearly zero.
• The gravitational force acts on one mass at a time.
• The moon stays in orbit because the gravitational force on it is balanced by the
centrifugal force acting on it.
• Weightlessness means there is no gravity.
• The Earth’s spinning motion causes gravity.
• Momentum is not a vector.
• Conservation of momentum applies only to collisions.
• Momentum is the same as force.
• Moving masses in the absence of gravity do not have momentum.
• Momentum is not conserved in collisions with “immovable” objects.
• Momentum and kinetic energy are the same.
• Circular motion does not require a force.
• Centrifugal forces are real.
• An object moving in circle with constant speed has no acceleration.
• An object moving in a circle will continue in circular motion when released.
• An object in circular motion will fly out radially when released.
DIVERSE LEARNERS
Strategies for meeting the needs of all learners including gifted students, English
Language Learners (ELL) and students with disabilities can be found at the Ohio
Department of Education site. Resources based on the Universal Design for
Learning principles are available at www.cast.org.
CLASSROOM PORTALS
“Teaching High School Science” is a series of videos-on-demand produced by
Annenberg that show classroom strategies for implementing inquiry into the high
school classroom. While not all of the content is aligned to physical science, the
strategies can be applied to any content.
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CONTENT ELABORATION: ENERGY
Energy
In physical science, the role of strong nuclear forces in radioactive decay, half-lives,
fission and fusion, and mathematical problem solving involving kinetic energy,
gravitational potential energy, energy conservation and work (when the force and
displacement were in the same direction) were introduced. In this course, the
concept of gravitational potential energy is understood from the perspective of a
field, elastic potential energy is introduced and quantified, nuclear processes are
explored further, the concept of mass-energy equivalence is introduced, the concept
of work is expanded, power is introduced, and the principle of conservation of
energy is applied to increasingly complex situations. Energy must be explored by
analyzing data gathered in scientific investigations. Computers and probes can be
used to collect and analyze data.
• Gravitational Potential Energy
When two attracting masses interact, the kinetic energies of both objects change
but neither is acting as the energy source or the receiver. Instead, the energy is
transferred into or out of the gravitational field around the system as gravitational
potential energy. A single mass does not have gravitational potential energy.
Only the system of attracting masses can have gravitational potential energy.
When two masses are moved farther apart, energy is transferred into the field
as gravitational potential energy. When two masses are moved closer together,
gravitational potential energy is transferred out of the field.
• Energy in Springs
The approximation for the change in the potential elastic energy of an elastic
object (e.g., a spring) is ΔEelastic = ½ k Δx2where Δx is the distance the elastic
object is stretched or compressed from its relaxed length.
• Nuclear Energy
Alpha, beta, gamma and positron emission each have different properties and
result in different changes to the nucleus. The identity of new elements can be
predicted for radioisotopes that undergo alpha or beta decay. During nuclear
interactions, the transfer of energy out of a system is directly proportional to the
change in mass of the system as expressed by E = mc2, which is known as the
equation for mass-energy equivalence. A very small loss in mass is accompanied
by a release of a large amount of energy. In nuclear processes such as nuclear
decay, fission and fusion, the mass of the product is less than the mass of
the original nuclei. The missing mass appears as energy. This energy can be
calculated for fission and fusion when given the masses of the particle(s) formed
and the masses of the particle(s) that interacted to produce them.
• Work and Power
Work can be calculated for situations in which the force and the displacement are
at angles to one another using the equation W = FΔx(cosθ) where W is the work,
F is the force, Δx is the displacement, and θ is the angle between the force and
the displacement. This means when the force and the displacement are at right
angles, no work is done and no energy is transferred between the objects. Such is
the case for circular motion.
The rate of energy change or transfer is called power (P) and can be
mathematically represented by P = ΔE / Δt or P = W / Δt. Power is a scalar
property. The unit of power is the watt (W), which is equivalent to one Joule of
energy transferred in one second (J/s).
• Conservation of Energy
The total initial energy of the system and the energy entering the system
are equal to the total final energy of the system and the energy leaving the
system. Although the various forms of energy appear very different, each can
be measured in a way that makes it possible to keep track of how much of
one form is converted into another. Situations involving energy transformations
can be represented with verbal or written descriptions, energy diagrams
and mathematical equations. Translations can be made between these
representations.
The conservation of energy principle applies to any defined system and time
interval within a situation or event in which there are no nuclear changes that
involve mass-energy equivalency. The system and time interval may be defined to
focus on one particular aspect of the event. The defined system and time interval
may then be changed to obtain information about different aspects of the same
event.
EXPECTATIONS FOR LEARNING: COGNITIVE DEMANDS
This section provides definitions for Ohio’s science cognitive demands, which are
intrinsically related to current understandings and research about how people learn.
They provide a structure for teachers and assessment developers to reflect on plans
for teaching science, to monitor observable evidence of student learning and to
develop summative assessment of student learning of science.
VISIONS INTO PRACTICE
This section provides examples of tasks that students may perform; this includes
guidance for developing classroom performance tasks. It is not an all-inclusive
checklist of what should be done, but is a springboard for generating innovative
ideas.
• Design and build a mousetrap car that will travel across the floor. Test and calibrate
the vehicle so that the distance it travels can be controlled. After calibrating the
cars, each group will be given a different target distance for each of the cars to
reach. Designs will be compared and evaluated to determine the most effective
design factors.
• Release a cart from several different positions on a ramp and let it travel to the
bottom of the ramp and across the table until it slows to a stop. Investigate the
relationship between the height of release and the distance it travels before
stopping. From the data, determine the average friction force acting on the rolling
cart. Identify the assumptions used to determine the friction force.
OHIO’S NEW LEARNING STANDARDS I Science 338
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INSTRUCTIONAL STRATEGIES AND RESOURCES
DIVERSE LEARNERS
BACK TO PHYSICS OUTLINE
This section provides additional support and information for educators. These are
strategies for actively engaging students with the topic and for providing hands-on,
minds-on observation and exploration of the topic, including authentic data resources
for scientific inquiry, experimentation and problem-based tasks that incorporate
technology and technological and engineering design. Resources selected are
printed or Web-based materials that directly relate to the particular Content
Statement. It is not intended to be a prescriptive list of lessons.
• “Masses and Springs” is an interactive simulation from PhET that allows
students to hang masses from springs and adjust the spring stiffness and
damping, and transport the apparatus to different planets. The resulting motion
can be shown in slow motion. A chart shows the kinetic, potential and thermal
energy for each spring.
• This tutorial from The Physics Classroom demonstrates the strategy of using
energy bar graphs to solve conservation of energy problems.
• Constructing energy bar graphs is a way for students to conceptually organize the
energy changes involved in a problem. Once such a diagram is completed, the
appropriate equation for a specific problem can be written using an understanding
of conservation of matter. Some methods show work done on and by the
system as energy flowing into and out of the system. Other methods show
work done on and by the system as a part of the bar graph. The second reference
shows the equation first, then the diagram. However, students have an easier
time drawing the diagram, then writing the equation from the diagram.
• Energy flow diagrams picture energy transformations in an accurate, quantitative
and conceptually transparent manner. Energy Flow Diagrams for Teaching
Physics Concepts is a paper that was published in The Physics Teacher that
outlines how to use these tools in the classroom. It proceeds from simple
processes to complex socially significant processes such as global warming.
Strategies for meeting the needs of all learners including gifted students, English
Language Learners (ELL) and students with disabilities can be found at the Ohio
Department of Education site. Resources based on the Universal Design for
Learning principles are available at www.cast.org.
COMMON MISCONCEPTIONS
Students often think that:
• Energy gets used up or runs out.
• Something not moving cannot have any energy.
• Force acting on an object does work even if the object does not move.
• Energy is destroyed in transformations from one type to another.
• Energy can be recycled.
• Gravitational potential energy is the only type of potential energy.
• When an object is released to fall, the gravitational potential energy immediately
becomes all kinetic energy.
• Energy is not related to Newton’s laws.
• Energy is a force.
CLASSROOM PORTALS
“Teaching High School Science” is a series of videos-on-demand produced by
Annenberg that show classroom strategies for implementing inquiry into the high
school classroom. While not all of the content is aligned to physical science, the
strategies can be applied to any content.
OHIO’S NEW LEARNING STANDARDS I Science 339
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BACK TO PHYSICS OUTLINE
CONTENT ELABORATION: WAVES
Waves
In earlier grades, the electromagnetic spectrum and basic properties (wavelength,
frequency, amplitude) and behaviors of waves (absorption, reflection, transmission,
refraction, interference, diffraction) were introduced. In this course, conservation of
energy is applied to waves and the measurable properties of waves (wavelength,
frequency, amplitude) are used to mathematically describe the behavior of waves
(index of refraction, law of reflection, single- and double-slit diffraction). The wavelet
model of wave propagation and interactions is not addressed in this course. Waves
must be explored experimentally in the laboratory. This may include, but is not
limited to, water waves, waves in springs, the interaction of light with mirrors,
lenses, barriers with one or two slits, and diffraction gratings.
• Wave Properties
When a wave reaches a barrier or a new medium, a portion of its energy is
reflected at the boundary and a portion of the energy passes into the new
medium. Some of the energy that passes to the new medium may be absorbed
by the medium and transformed to other forms of energy, usually thermal energy,
and some continues as a wave in the new medium. Some of the energy also
may be dissipated, no longer part of the wave since it has been transformed
into thermal energy or transferred out of the system due to the interaction
of the system with surrounding objects. Usually all of these processes occur
simultaneously, but the total amount of energy must remain constant.
When waves bounce off barriers (reflection), the angle at which a wave
approaches the barrier (angle of incidence) equals the angle at which the wave
reflects off the barrier (angle of reflection). When a wave travels from a twodimensional (e.g., surface water, seismic waves) or three- dimensional (e.g.,
sound, electromagnetic waves) medium into another medium in which the wave
travels at a different speed, both the speed and the wavelength of the transferred
wave change. Depending on the angle between the wave and the boundary,
the direction of the wave also can change resulting in refraction. The amount
of bending of waves around barriers or small openings (diffraction) increases
with decreasing wavelength. When the wavelength is smaller than the obstacle
or opening, no noticeable diffraction occurs. Standing waves and interference
patterns between two sources are included in this topic. As waves pass through
a single or double slit, diffraction patterns are created with alternating lines of
constructive and destructive interference. The diffraction patterns demonstrate
predictable changes as the width of the slit(s), spacing between the slits and/or
the wavelength of waves passing through the slits changes.
• Light phenomena
The path of light waves can be represented with ray diagrams to show reflection
and refraction through converging lenses, diverging lenses and plane mirrors.
Since light is a wave, the law of reflection applies. Snell’s law, n1sinθ1 = n2sinθ2,
quantifies refraction in which n is the index of refraction of the medium and θ
is the angle the wave enters or leaves the medium, when measured from the
normal line. The index of refraction of a material can be calculated by the equation
n = c/v, where n is the index of refraction of a material, v is the speed of light
through the material, and c is the speed of light in a vacuum. Diffraction patterns
of light must be addressed, including patterns from diffraction gratings.
There are two models of how radiant energy travels through space at the speed
of light. One model is that the radiation travels in discrete packets of energy called
photons that are continuously emitted from an object in all directions. The energy
of these photons is directly proportional to the frequency of the electromagnetic
radiation. This particle-like model is called the photon model of light energy
transfer. A second model is that radiant energy travels like a wave that spreads out
in all directions from a source. This wave-like model is called the electromagnetic
wave model of light energy transfer. Strong scientific evidence supports both the
particle-like model and wave-like model. Depending on the problem scientists are
trying to solve, either the particle- like model or the wave-like model of radiant
energy transfer is used. Students are not required to know the details of the
evidence that supports either model at this level.
Humans can only perceive a very narrow portion of the electromagnetic spectrum.
Radiant energy from the sun or a light bulb filament is a mixture of all the colors
of light (visible light spectrum). The different colors correspond to different radiant
energies. When white light hits an object, the pigments in the object reflect one
or more colors in all directions and absorb the other colors.
EXPECTATIONS FOR LEARNING: COGNITIVE DEMANDS
This section provides definitions for Ohio’s science cognitive demands, which are
intrinsically related to current understandings and research about how people learn.
They provide a structure for teachers and assessment developers to reflect on plans
for teaching science, to monitor observable evidence of student learning and to
develop summative assessment of student learning of science.
OHIO’S NEW LEARNING STANDARDS I Science 340
BACK TO INDEX
VISIONS INTO PRACTICE
COMMON MISCONCEPTIONS
BACK TO PHYSICS OUTLINE
This section provides examples of tasks that students may perform; this includes
guidance for developing classroom performance tasks. It is not an all-inclusive
checklist of what should be done, but is a springboard for generating innovative
ideas.
• Design a system involving three refraction tanks and three different lenses so that
a beam of light entering the system at a given angle can pass through all three
tanks of liquid and leave the other side at a different angle.
• Investigate the refraction of light as it passes from air into a new liquid medium.
Draw incident and refracted rays for many different angles and measure the
angles of both. Present the material graphically to determine the index of
refraction for the liquid.
Students often think that:
• Waves transport matter.
• There must be a medium for a wave to travel through.
• Waves do not have energy.
• All waves travel the same way.
• Frequency is connected to loudness for all amplitudes.
• Big waves travel faster than small waves in the same medium.
• Different colors of light are different types of waves.
• Pitch is related to intensity.
• Light just is and has no origin.
• Light is a particle.
• Light is a mixture of particles and waves.
• Light waves and radio waves are not the same thing.
• In refraction, the characteristics of light change.
• The speed of light never changes.
• Rays and wave fronts are the same thing.
• There is no interaction between light and matter.
• The addition of all colors of light yields black.
• Double slit interference shows light wave crest and troughs.
• Light exits in the crest of a wave and dark in the trough.
• In refraction, the frequency (color) of light changes.
• Refraction is the bending of waves.
INSTRUCTIONAL STRATEGIES AND RESOURCES
This section provides additional support and information for educators. These are
strategies for actively engaging students with the topic and for providing hands-on,
minds-on observation and exploration of the topic, including authentic data resources
for scientific inquiry, experimentation and problem-based tasks that incorporate
technology and technological and engineering design. Resources selected are
printed or Web-based materials that directly relate to the particular Content
Statement. It is not intended to be a prescriptive list of lessons.
• “Radio waves and electromagnetic fields” is an interactive simulation from
PhET that allows students to explore how electromagnetic radiation is produced.
Students can wiggle the transmitter electron manually or have it oscillate
automatically and display the field as a curve or as vectors. There is a strip chart
that shows the electron positions at the transmitter and at the receiver.
• “Geometric Optics” is an interactive simulation from PhET that illustrates how
light rays are refracted by a lens. Students can adjust the focal length of the lens,
move the object, move the lens or move the screen and see how the image
changes.
Career Connection
Students will examine commonalities among careers within this field, such as
sonographer, air traffic controller, optician, photographer, cosmos, and physical
therapist. Then, they will research careers that use waves as a necessary aspect
of their typical duties, including career interviews, workplace visits, and navigating
company websites. Students will apply this information to their plan for education
and training through high school and beyond.
DIVERSE LEARNERS
Strategies for meeting the needs of all learners including gifted students, English
Language Learners (ELL) and students with disabilities can be found at the Ohio
Department of Education site. Resources based on the Universal Design for
Learning principles are available at www.cast.org.
CLASSROOM PORTALS
“Teaching High School Science” is a series of videos-on-demand produced by
Annenberg that show classroom strategies for implementing inquiry into the high
school classroom. While not all of the content is aligned to physical science, the
strategies can be applied to any content.
OHIO’S NEW LEARNING STANDARDS I Science 341
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BACK TO PHYSICS OUTLINE
CONTENT ELABORATION: ELECTRICITY AND
MAGNETISM
Electricity and Magnetism
In earlier grades, the following concepts were addressed: conceptual treatment of
electric and magnetic potential energy; the relative number of subatomic particles
present in charged and neutral objects; attraction and repulsion between electrical
charges and magnetic poles; the concept of fields to conceptually explain forces at
a distance; the concepts of current, potential difference (voltage) and resistance to
explain circuits conceptually; and connections between electricity and magnetism
as observed in electromagnets, motors and generators. In this course, the details of
electrical and magnetic forces and energy are further explored and can be used as
further examples of energy and forces affecting motion.
• Charging Objects (friction, contact and induction)
For all methods of charging neutral objects, one object/system ends up with a
surplus of positive charge and the other object/system ends up with the same
amount of surplus of negative charge. This supports the law of conservation
of charge that states that charges cannot be created or destroyed. Tracing the
movement of electrons for each step in different ways of charging objects
(rubbing together two neutral materials to charge by friction; charging by contact
and by induction) can explain the differences between them. When an electrical
conductor is charged, the charge “spreads out” over the surface. When an
electrical insulator is charged, the excess or deficit of electrons on the surface is
localized to a small area of the insulator.
There can be electrical interactions between charged and neutral objects. Metal
conductors have a lattice of fixed positively charged metal ions surrounded by
a “sea” of negatively charged electrons that flow freely within the lattice. If the
neutral object is a metal conductor, the free electrons in the metal are attracted
toward or repelled away from the charged object. As a result, one side of the
conductor has an excess of electrons and the opposite side has an electron
deficit. This separation of charges on the neutral conductor can result in a net
attractive force between the neutral conductor and the charged object. When a
charged object is near a neutral insulator, the electron cloud of each insulator atom
shifts position slightly so it is no longer centered on the nucleus. The separation
of charge is very small, much less than the diameter of the atom. Still, this small
separation of charges for billions of neutral insulator particles can result in a net
attractive force between the neutral insulator and the charged object.
• Coulomb’s law
Two charged objects, which are small compared to the distance between
them, can be modeled as point charges. The forces between point charges are
proportional to the product of the charges and inversely proportional to the square
of the distance between the point charges [Fe = ke q1 q2) / r2]. Problems may be
solved for the electric force, the amount of charge on one of the two objects or
the distance between the two objects. Problems also may be solved for three- or
four-point charges in a line if the vector sum of the forces is zero. This can be
explored experimentally through computer simulations. Electric forces acting
within and between atoms are vastly stronger than the gravitational forces acting
between the atoms. However, gravitational forces are only attractive and can
accumulate in massive objects to produce a large and noticeable effect whereas
electric forces are both attractive and repulsive and tend to cancel each other out.
• Electric Fields and Electric Potential Energy
The strength of the electrical field of a charged object at a certain location is given
by the electric force per unit charge experienced by another charged object placed
at that location, E = Fe / q. This equation can be used to calculate the electric
field strength, the electric force or the electric charge. However, the electric
field is always there, even if the object is not interacting with anything else. The
direction of the electric field at a certain location is parallel to the direction of
the electrical force on a positively charged object at that location. The electric
field caused by a collection of charges is equal to the vector sum of the electric
fields caused by the individual charges (superposition of charge). This topic can
be explored experimentally through computer simulations. Greater electric field
strengths result in larger electric forces on electrically charged objects placed in
the field. Electric fields can be represented by field diagrams obtained by plotting
field arrows at a series of locations. Electric field diagrams for a dipole, two-point
charges (both positive, both negative, one positive and one negative) and parallel
capacitor plates are included. Field line diagrams are excluded from this course.
The concept of electric potential energy can be understood from the perspective
of an electric field. When two attracting or repelling charges interact, the kinetic
energies of both objects change but neither is acting as the energy source or
the receiver. Instead, the energy is transferred into or out of the electric field
around the system as electric potential energy. A single charge does not have
electric potential energy. Only the system of attracting or repelling charges can
have electric potential energy. When the distance between the attracting or
repelling charges changes, there is a change in the electric potential energy of
the system. When two opposite charges are moved farther apart or two like
charges are moved close together, energy is transferred into the field as electric
potential energy. When two opposite charges are moved closer together or two
like charges are moved far apart, electric potential energy is transferred out of the
field. When a charge is transferred from one object to another, work is required to
separate the positive and negative charges. If there is no change in kinetic energy
and no energy is transferred out of the system, the work increases the electric
potential energy of the system.
• DC circuits
Once a circuit is switched on, the current and potential difference are experienced
almost instantaneously in all parts of the circuit even though the electrons are only
moving at speeds of a few centimeters per hour in a current-carrying wire. It is the
electric field that travels instantaneously through all parts of the circuit, moving the
OHIO’S NEW LEARNING STANDARDS I Science 342
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BACK TO PHYSICS OUTLINE
electrons that are already present in the wire. Since electrical charge is conserved,
in a closed system such as a circuit, the current flowing into a branch point
junction must equal the total current flowing out of the junction (junction rule).
Resistance is measured in ohms and has different cumulative effects when added
to series and parallel circuits. The potential difference, or voltage (ΔV), across
an energy source is the potential energy difference (ΔE) supplied by the energy
source per unit charge (q) (ΔV = ΔE/q). The electric potential difference across a
resistor is the product of the current and the resistance (ΔV = I R). In physics, only
ohmic resistors will be studied. When potential difference vs. current is plotted
for an ohmic resistor, the graph will be a straight line and the value of the slope
will be the resistance. Since energy is conserved for any closed loop, the energy
put into the system by the battery must equal the energy that is transformed by
the resistors (loop rule). For circuits with resistors in series, this means that ΔVbattery
= ΔV1 + ΔV2 + ΔV3 +…. The rate of energy transfer (power) across each resistor
is equal to the product of the current through and the voltage drop across each
resistor (P = ΔV I) and Pbattery = I ΔV1 + I ΔV2 + I ΔV3 +… = IΔVbattery. Equations
should be understood conceptually and used to calculate the current or potential
difference at different locations of a parallel, series or mixed circuit. However, the
names of the laws (e.g., Ohm’s law, Kirchoff’s loop law) will not be assessed.
Measuring and analyzing current, voltage and resistance in parallel, series and
mixed circuits must be provided. This can be done with traditional laboratory
equipment and through computer simulations.
• Magnetic Fields and Energy
The direction of the magnetic field at any point in space is the equilibrium
direction of the north end of a compass placed at that point. Magnetic fields can
be represented by field diagrams obtained by plotting field arrows at a series
of locations. Field line diagrams are excluded from this course. Calculations
for the magnetic field strength are not required at this grade level, but it is
important to note that greater magnetic fields result in larger magnetic forces on
magnetic objects or moving charges placed in the field. The concept of magnetic
potential energy can be understood from the perspective of a magnetic field.
When two attracting or repelling magnetic poles interact, the kinetic energies of
both objects change but neither is acting as the energy source or the receiver.
Instead, the energy is transferred into or out of the magnetic field around the
system as magnetic potential energy. A single magnetic pole does not have
magnetic potential energy. Only the system of attracting or repelling poles can
have magnetic potential energy. When the distance between the attracting or
repelling poles changes, there is a change in the magnetic potential energy of the
system. When two magnetically attracting objects are moved farther apart or two
magnetically repelling objects are moved close together, energy is transferred into
the field as magnetic potential energy. When two magnetically attracting objects
are moved closer together or two magnetically repelling objects are moved far
apart, magnetic potential energy is transferred out of the field. Work is required
to separate two magnetically attracting objects. If there is no change in kinetic
energy and no energy is transferred out of the system, the work done on the
system increases the magnetic potential energy of the system. In this course, the
concepts of magnetic fields and magnetic potential energy will not be addressed
mathematically.
• Electromagnetic Interactions
Magnetic forces are very closely related to electric forces. Even though they
appear to be distinct from each other, they are thought of as different aspects of
a single electromagnetic force. A flow of charged particles (including an electric
current) creates a magnetic field around the moving particles or the current
carrying wire. Motion in a nearby magnet is evidence of this field. Electric currents
in Earth’s interior give Earth an extensive magnetic field, which is detected from
the orientation of compass needles. The motion of electrically charged particles
in atoms produces magnetic fields. Usually these magnetic fields in an atom are
randomly oriented and therefore cancel each other out. In magnetic materials, the
subatomic magnetic fields are aligned, adding to give a macroscopic magnetic
field.
A moving charged particle interacts with a magnetic field. The magnetic force
that acts on a moving charged particle in a magnetic field is perpendicular to both
the magnetic field and to the direction of motion of the charged particle. The
magnitude of the magnetic force depends on the speed of the moving particle,
the magnitude of the charge of the particle, the strength of the magnetic field, and
the angle between the velocity and the magnetic field. There is no magnetic force
on a particle moving parallel to the magnetic field. Calculations of the magnetic
force acting on moving particles are not required at this grade level. Moving
charged particles in magnetic fields typically follow spiral trajectories since the
force is perpendicular to the motion.
A changing magnetic field creates an electric field. If a closed conducting path,
such as a wire, is in the vicinity of a changing magnetic field, a current may flow
through the wire. A changing magnetic field can be created in a closed loop of
wire if the magnet and the wire move relative to one another. This can cause a
current to be induced in the wire. The strength of the current depends upon the
strength of the magnetic field, the velocity of the relative motion and the number
of loops in the wire. Calculations for current induced in a wire or coil of wire is
not required at this level. A changing electric field creates a magnetic field and
a changing magnetic field creates an electric field. Thus, radiant energy travels
in electromagnetic waves produced by changing the motion of charges or by
changing magnetic fields. Therefore, electromagnetic radiation is a pattern of
changing electric and magnetic fields that travel at the speed of light.
The interplay of electric and magnetic forces is the basis for many modern
technologies that convert mechanical energy to electrical energy (generators) or
electrical energy to mechanical energy (electric motors) as well as devices that
produce or receive electromagnetic waves. Therefore, coils of wire and magnets
are found in many electronic devices including speakers, microphones, generators
OHIO’S NEW LEARNING STANDARDS I Science 343
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BACK TO PHYSICS OUTLINE
and electric motors. The interactions between electricity and magnetism must be
explored in the laboratory setting. Experiments with the inner workings of motors,
generators and electromagnets must be conducted. Current technologies using
these principles must be explored.
EXPECTATIONS FOR LEARNING: COGNITIVE DEMANDS
This section provides definitions for Ohio’s science cognitive demands, which are
intrinsically related to current understandings and research about how people learn.
They provide a structure for teachers and assessment developers to reflect on plans
for teaching science, to monitor observable evidence of student learning and to
develop summative assessment of student learning of science.
VISIONS INTO PRACTICE
This section provides examples of tasks that students may perform; this includes
guidance for developing classroom performance tasks. It is not an all-inclusive
checklist of what should be done, but is a springboard for generating innovative
ideas.
• Design and build a generator that will convert mechanical energy into electrical
energy. Draw a labeled design plan and write a paper explaining in detail and
in terms of electromagnetic induction how the details of the design allow the
generator to work. Test the generator in an electric circuit. If it cannot supply the
electrical energy to light three flashlight bulbs in a series, redesign the generator.
• Use a source of constant voltage to plan and conduct an experiment to determine
the relationship between the current and the resistor in a simple DC circuit.
Analyze the results mathematically and graphically. Form a claim about the
relationship between the current and resistance and support the claim with
evidence from the investigation.
INSTRUCTIONAL STRATEGIES AND RESOURCES
This section provides additional support and information for educators. These are
strategies for actively engaging students with the topic and for providing hands-on,
minds-on observation and exploration of the topic, including authentic data resources
for scientific inquiry, experimentation and problem-based tasks that incorporate
technology and technological and engineering design. Resources selected are
printed or Web-based materials that directly relate to the particular Content
Statement. It is not intended to be a prescriptive list of lessons.
• The equations for gravitational force and electrostatic force can be compared to
determine similarities and differences between them.
• “Circuit Construction Kit” is interactive simulation produced by PhET that allows
students to design and build circuits with resistors, light bulbs, batteries and
switches; take measurements with the realistic ammeter and voltmeter; and view
the circuit as a schematic diagram or a life- like view.
• “Battery-Resistor Circuit” is an interactive simulation produced by PhET that
allows students to look inside a resistor to see how it works. The battery voltage
can be increased to make more electrons flow though the resistor. The resistance
can be increased to inhibit the flow of electrons. The current and resistor
temperature change with changing voltage and resistance.
• “5 Types of Microphones” from Discovery Company’s How Things Work
describes how different kinds of microphones are built and how they convert
sound to electrical signals.
• “How Speakers Work” from Discovery Company’s How Things Work describes
how speakers are built and how they convert electrical signals to sound.
• “How Electric Motors Work” from Discovery Company’s How Things
Work describes how motors can use magnets to convert electrical energy to
mechanical energy.
• “Direct Current Electric Motor” by Walter Fendt is an animation that shows
the construction of a simple DC electric motor that can be shown to students to
explain how it works.
• “Generator“ by Walter Fendt is an animation that shows the construction of a
simple generator that can be shown to students to explain how it works.
OHIO’S NEW LEARNING STANDARDS I Science 344
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COMMON MISCONCEPTIONS
DIVERSE LEARNERS
BACK TO PHYSICS OUTLINE
Students often think that:
• A moving charge will always follow a field line as it accelerates.
• If a charge is not on a field line, it feels no force.
• Field lines are real.
• Coulomb’s law applies to charge systems consisting of something other than
point charges.
• A charged body has only one type of charge.
• The electric field and force are the same thing and in the same direction.
• Forces at a point exist without a charge there.
• Field lines are paths of a charges motion.
• The electric force is the same as the gravitational force.
• Charge is continuous and can occur in any amount.
• An electron is pure negative charge with no mass.
• Voltage flows through a circuit.
• There is no connection between voltage and electric field.
• Voltage is energy.
• High voltage by itself is dangerous.
• Charges move by themselves.
• Designations of (+) and (-) are absolute.
• Resistors consume charge.
• Electrons move quickly (near the speed of light) through a circuit.
• Charges slow down as they go through a resistor.
• Current is the same thing as voltage.
• There is no current between the terminals of a battery.
• The bigger the container, the larger the resistance.
• A circuit does not have form a closed loop for current to flow.
• Current gets “used up” as it flows through a circuit.
• A conductor has no resistance.
• The resistance of a parallel combination is larger than the largest resistance.
• Current is an excess charge.
• Charges that flow in circuit are from the battery.
• The bigger the battery, the more voltage.
• Power and energy are the same thing.
• Batteries create energy out of nothing.
• North and south magnetic poles are the same as positive and negative charges.
• Poles can be isolated.
• Magnetic fields are the same as electric fields.
• Charges at rest can experience magnetic forces.
• Magnetic fields from magnets are not caused by moving charges.
• Generating electricity requires no work.
• When generating electricity only the magnet can move.
• Voltage can only be induced in a closed circuit.
• Water in dams causes electricity.
Strategies for meeting the needs of all learners including gifted students, English
Language Learners (ELL) and students with disabilities can be found at the Ohio
Department of Education site. Resources based on the Universal Design for
Learning principles are available at www.cast.org.
CLASSROOM PORTALS
“Teaching High School Science” is a series of videos-on-demand produced by
Annenberg that show classroom strategies for implementing inquiry into the high
school classroom. While not all of the content is aligned to physical science, the
strategies can be applied to any content.
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