Download Sample Collaborative Unit: DC Circuits Gregory

CURRICULUM UNIT PLAN
DC CIRCUITS
BY LINDA LAGUNZAD AND GREGORY SURAN
Contents

NJ Standards

Time Frame

Previous Knowledge

Goals
o Conceptual
o Procedural
o Epistemological

Most Important Ideas

Student Difficulties

Relevance to Students

Equipment Needed

Sample Lesson

Lab

Traditional and Alternative Assessment
o Traditional
o Alternative
o Projects

Resources

Reflection
NJ Standards Addressed in this Unit
New Jersey Core Curriculum Content Standard(s) (NJCCCS)
5.1
Scientific Process - All students will develop problem solving, decision-making,
and enquiry skills, reflected by formulating useful questions and hypotheses,
planning experiments, conducting systematic observations, interpreting and
analyzing data, drawling conclusion, and communicating results.
5.1.A.1: When making decisions, evaluate conclusions, weigh evidence, and recognize
that arguments may not have equal merit.
5.1.A.1. Evaluate the strengths and weaknesses of data, claims, and arguments.
5.1.A.3: Engage in collaboration, peer review, and accurate reporting of findings.
5.1.B.1: Select and use appropriate instrumentation to design and conduct investigations.
5.1.B.1: Identify questions and make predications that can be addressed by conducting
investigations. (Related to GEPA Skill Statement C 1).
5.2
Science and Society - All students will develop an understanding of how people
of various cultures have contributed to the advancement of science and
technology, and how major discoveries and events have advanced science and
technology
5.2.B.1: Examine the lives and contributions of important scientists who effected major
breakthroughs in our understanding of the natural and designed world.
5.2.B.2: Discuss significant technological achievements in which science has played an
important part as well as technological advances that have contributed directly to
the advancement of scientific knowledge.
5.2.B.3: Describe the historical origin of important scientific developments such as
atomic theory, genetics, plate tectonics, etc., showing how scientific theories
develop, are tested, and can be replaced or modified in light of new information
and improved investigative techniques.
5.3
Mathematical Applications - All students will integrate mathematics as a tool
for the problem-solving in science, and as a means of expressing and/or modeling
scientific theories.
5.3.D.3 Construct and use a graph of experimental data to draw a line of best fit and
identify a linear relationship between variables. (Related to GEPA Skill Statement C-H).
5.3.C.1 Identify patterns when observing the natural and constructed world.
5.3.C.1. Express physical relationships in terms of mathematical equations derived from
collected data. (Related to GEPA Skill Statement E, F, G, & H).
5.3.C.4. Use computer spreadsheets, graphing and database applications to assist in
quantitative analysis of data. (Related to GEPA Skill Statement C-H).
5.4
Nature and Process of Technology - All students will understand the
interrelationships between science and technology and develop a conceptual
understanding of the nature and process of technology.
5.4.A.1: Know that scientific inquiry is driven by the desire to understand the natural
world and seeks to answer questions that may or may not directly influence
humans, while technology is driven by the need to meet human needs and solve
human problems.
5.7
Physical Science - All students will gain an understanding of natural laws as they
apply to motion, forces, and energy transformations
5.7.B.1: Design an electric circuit to investigate the behavior of a system.
5.7.B.2: Describe the nature of various forms of energy, including heat, light, sound,
chemical, mechanical, and electrical and trace energy transformations from one
form to another.
5.7.B.3: Describe how heat can be conducted through materials or transferred across
space by radiation and know that if the material is a fluid, convection currents
may aid the transfer of heat.
Time Line: about 3 weeks
Day
Topics covered
What is necessary to light a
light bulb?
What is current?
1
What are necessary conditions
for continuous flow of electric
charge
What is role of battery?
2
Analogy for current and
potential difference
NJCCCS
5.7
5.7
5.7
5.7
5.7
3
(Double
Period)
4
5
6
7
8
(Double
Period)
9
10
Lab - Ohm's Law
What is relationship between
potential difference, current,
and resistance?
Series and Parallel Circuits
Project Collaboration and
Progress Report
What do the brightness of light
bulbs depend on?
What is power?
5.1,
5.3, 5.4
5.3
5.7
5.2
5.7
5.3
Lab - Power Dissipation
5.1, 5.4
Kirchhoff's Loop Rule
Kirchhoff's Junction Rule
5.7
5.7
5.1,
5.3, 5.7
5.1,
5.3, 5.7
5.2
11
Review
12
Unit Test
13
Project Due
Previous knowledge
1. concepts of work, energy, power
2. energy transformation and conservation
3. electric charge, force, field
4. work done by electric field
5. potential energy
6. electric potential difference –voltage
7. conductors and insulators – microscopic explanation
8. Power = E/t
Goals for the unit
Conceptual:
1. concept of electric circuit, parallel and series connections
2. application of the law of conservation of energy to electric circuit
3. build the concept of power output for electric circuit
4. understand how energy transformation in electric circuits is used for practical
application
5. understand interrelationship between V,I,R in circuits with different
connections and power output
6. understand efficiency of electric devices
Quantitative:
7. Derive a mathematical expression for power P = IV, P = I2R, P = V2/R for
different connections
8. Calculate power output for different connections
9. Calculate efficiency of electric devices
Procedural:
10. Be able to represent an electric circuit in a circuit diagram.
11. Assemble electric circuits from the same elements but with different power
outlet.
Epistemological:
12. Set up appreciation of analyzing your own thinking
13. Demonstrate why we can think similarly about in different manifestations of
energy
14. Develop higher level ob abstraction on potential energy of spring, gravity and
electric field
Most Important Ideas
 What is necessary to light a light bulb? Day 1
o Two poles of a battery must be connected to the light bulb with
conducting wires.
o Continuous flow of electrons/charge
 What is current? Day 1
o Flow of electric charge
 What are necessary conditions for continuous flow of electric charge? Day 1-2
o Continuous potential difference
o Closed circuit
 What is the role of a battery? Day 2
o Provide continuous potential difference – provides the push
 Analogy for current and potential difference. Day 2-3
o Water system
o Running people
 Ohm’s law – relationship between potential difference and current under ideal
conditions Day 3 – double period
o How to measure voltage and current
o Proportionality vs linearity
o Determine a mathematical expression
o Test this idea – non-ideal conditions
 What is relationship between potential difference, current and resistance Day 4
o What is resistance?
o What does it depend on?
o Determine a mathematical expression.





Series and Parallel Circuits Day 5
o Series -current through all elements connected in series the same but
potential difference is different; observe and explain with analogy
o Parallel – potential difference across all elements connected in parallel are
the same but current is different; observe and explain with analogy
What does the brightness of light bulbs depends on? Day 6
o Resistance of light bulb
o Source of potential difference and circuit connection (series or parallel)
determine power dissipated from the bulb
 Voltage across the light bulb
 Current through light bulb
What is power? Day 7
o Energy dissipated from the light bulb over time.
o Derive mathematical expression
o Connect electric circuits to the general concept of energy transformation,
which was previously discussed as only mechanical energy.
o What do light bulb markings mean?
o How are households wired?
o What does it mean to overload a circuit?
Testing Experiment – Power dissipation Day 8 – double period
Kirchhoff’s Rules Day 9 - 10
o Loop Rule
o Electric Circuits Process Problems
o Junction Rule
Student Difficulties
1. Mismatching terms current, voltage, power, thinking of them as electricity
2. Thinking that the current is consumed by circuit elements, and therefore its
intensity is diminished after passing through such elements
3. Believing that the battery is a source of constant current and that a change in a
circuit affects only the elements situated ‘‘after’’ the place where the change
happened
4. In understanding Loop rule as manifestation of energy conservation
5. In application of charge conservation to circuit – Junction rule
6. Misunderstanding when thinking about a battery as a vessel with charges that
can be used in short time interval – like water, just open valve and it will flow.
7. Understanding the concept of potential energy and PE difference
Real Life connections
1. What do the markings on light bulbs mean?
2. What does battery provide to electric circuit?
3. How to apply findings for power in parallel and series connections to efficient
connection of batteries?
4.
5.
6.
7.
8.
How household is wired?
What does it mean to overload the circuit?
How el. Breaker works?
Where does energy to household comes from?
Where does energy go (transferred to)?
Equipment needed
1. Wimshurst Generator Day 1
2. Insulator rod with insulator string and a ball of foil Day 1
3. Neon light bulb Day 1
4. Batteries, wires Day 1
5. Logger Pro Day 3
6. Voltage source Day 3,4,5,6,7,8
7. Connecting clips, circuit board, resistors. Day 3,4,5,6,7,8
8. Small light bulbs (two of identical and one different for each set) Day
1,3,5,6,7
9. Parallel circuit with two bulbs (at least one board) Day 5, 6
10. Series circuit with two bulbs (at least one board) Day 5, 6
11. Bulbs of different wattage markings Day 6
12. Circuit Puzzle (at least one board) Day 7
13. The Physics Active Learning Guide Day 1-10
14. Physics, the Human Adventure: From Copernicus to Einstein and Beyond Day
1-10
Sample Lesson – Power
Title: Unit: DC Circuits
Lesson: Power
NJ Standards Addressed in this Lesson
5.7.6 B. Energy Transformations
3. Design an electric circuit to investigate the behavior of a system.
5.7.8 B. Energy Transformations
2. Describe the nature of various forms of energy, including heat, light, sound,
chemical, mechanical, and electrical and trace energy transformations from
one form to another.
3. Describe how heat can be conducted through materials or transferred across
space by radiation and know that if the material is a fluid, convection
currents may aid the transfer of heat.
Previous knowledge
Potential Difference
Current – flow of charge (electrons)
Resistance – microscopic explanation of resistance
Ohm’s Law – Relationship between V,I, and R
Conductors and Insulators – microscopic explanation
Circuits – conditions for flow of electric charge
 Parallel and series circuits
Power = E/t
Goals of Lesson
Conceptual Goal (CG):
1. Build the concept of power
2. Understand how phenomena occurring in electric circuits are described
by the parameters of electric circuit elements and processes – voltage,
current and resistance the physical quantity electric power.
Quantitative Goal (QG):
1. Derive a mathematical expression for power P = IV, P = I2R, P = V2/R
Procedural Goal (PG):
1. Be able to represent an electric circuit in a circuit diagram.
Epistemological Goal (EG):
1. Connect electric circuits to the general concept of energy
transformation, which was previously discussed as only mechanical
energy.
2. Why can’t you put so many appliances together?
3. What energy transformations are common for all situations?
Real Life connections
 What do the markings on light bulbs mean?
Student Difficulties
8. Many students think that the current is consumed by circuit elements,
and therefore its intensity is diminished after passing through such
elements.
9. Many students believe that the battery is a source of constant current
and that a change in a circuit affects only the elements situated ‘‘after’’
the place where the change happened.
Equipment needed
Voltage source
Connecting clips and wires
Small light bulbs (two of identical and one different for each set)
Parallel circuit with two bulbs (at least one board)
Series circuit with two bulbs (at least one board)
Bulbs of different wattage markings
Circuit Puzzle (at least one board)
Lesson Description
1. Handout 1: This activity addresses SD 1, and SD2.
2. Observation Experiment: DC Parallel and Series Circuit with same light
bulb markings. This activity addresses CG2.
a. Observe and compare the brightness of the bulbs in parallel circuits
and series circuits.
b. Observe and compare the brightness of the bulbs.
c. Compare with voltage and current.
 Where is there more flow?
3.
4.
5.
6.
7.
 Where is there more push?
d. Why are the same light bulbs dimmer and brighter? What does
brightness depend on? Why?
e. How do you connect brightness with voltage and current
mathematically?
f. What else did you notice about the light bulbs when the switch was
on? (maybe switch here to the AC series and parallel circuits to
feel the warmth better)
Why is the bulb warm? Where does the energy come from?
a. Review Worksheets on Potential Energy. This activity addresses
EG1, EG3
Deriving a Mathematical Expression ALG 16.3.8 This activity addresses
QG1.
Observation Experiment: Parallel and Series Circuit with different light
bulb markings. (quietly move to AC) This activity addresses EG2.
a. Demo DC: Observe and compare the brightness of the bulbs in
each circuit.
b. AC Observation Experiment: Compare the circuits. Which bulb is
brighter in each circuit?
c. What do the markings on the light bulbs mean?
 This activity addresses SD1 when the students recognize
that the equal brightness of the two bulbs connected in
parallel implies that current is not "used up."
d. Switch the position of the bulbs.
g. Observe and compare the brightness of the bulbs in each circuit.
 This activity addresses SD2 when the students determine
that neither the direction of the current nor the order of
the elements affects bulb brightness.
 Explain.
h. Connect power to resistance.
i. How are circuits connected in houses?
 Make predictions for each case and compare with
observations.
j. What do the light bulb markings mean?
k. Why can’t you put so many appliances together?s
Application Experiment - Circuit Puzzle 2 groups. This activity addresses
PG1.
l. Figure out how the puzzle box is connected.
End Lesson: How do you circuit breakers work? (Get metallic strips? If
put it on warm thing it bends) What did you learn? This activity addresses
CG1
Time Table
Clock
reading
during the
lesson
“Title of the
activity”
Students
doing
Me doing
(hr:min)
0:00 - 0:15
Handout #1
Handout +
Discussion
0:05 - 0:50
Activity 1
Observation
Experiment
0:50 - 0:60
Activity 2:
Why Light
Bulbs
Warm?
Handout 2
Deriving
ALG 16.3.8
DC Demo
What Do
Markings
Mean?
Discussing
Writing
Listening and
Discussing
Working in
groups
Observing
Observation
Experiment
Writing
Setting up Next
Experiment
Demo
Walking
around;
Listening
Discussing
Walking
Around
Listening
1:00 - 1:10
1:10-1:15
1:15-2:00
2:00 - 2:30
Circuit
Puzzle
2:30 - 2:45
What Did
We Learn?
Figuring out
circuitry
connection
of puzzle
box
Talking
Formative Assessment
QuickTime™ and a
TIFF (U ncompressed) decompressor
are needed to see this picture.
BRIGHT IDEAS!
ACTIVITY 1: HANDOUT 1
Listening &
Addressing
SD1 & 2
Setting up AC
circuit board
Listening
Discussing
Listening
Assume that all generators and turbines mounted at power plant on the picture
are identical.
1
2
What combination of electric power generators generates more power?
Why?
Where energy comes from?
What parameters of water defines generated power?
ACTIVITY 2: QUALITATIVE OBSERVATION EXPERIMENT
Available Equipment: DC voltage source, connecting clips, 2 identical light bulbs,
connecting wires, voltmeters
WARNING: Do not let the potential difference in the circuit exceed 6V since this will
burn them out.
1. Connect one light bulb in a circuit and observe its brightness.
2. Add an identical light bulb to the circuit so that they are connected in series and
observe the brightness of the two bulbs.
3. Now connect the second bulb to the circuit so that the two bulbs are connected in
parallel. Observe the brightness of the two bulbs.
4. Compare the potential difference across and the current through the light bulbs in
each circuit.
o Where is there more flow? Explain using an analogy and connect it to
physics language.
Analogy of water piping system:
If there is a clog in a pipe and there is only one path, then the whole system slows
down. The flow can only be as fast as the slowest part in the system and so the whole
system flows at the same rate. The more clogs there are in the system the more the
system slows down. This is like the series circuit because there is only one path, or
loop, in a series circuit. The charge flows slower in the series circuit the more light
bulbs you add. If there is more than one path for the water to flow, then the water can
flow without slowing down the entire system. This is like a parallel circuit because
there is more than one path for the charges to flow. The flow of charge does not slow
down in a parallel circuit. It looks like brightness depends on the amount of flow
because the light bulbs got dimmer in the series circuit and not in the parallel circuit.
o Where is there more push? Explain using an analogy then connect it back
to physics language.
Analogy of water piping system
In the analogy of the water piping system, potential difference corresponds to the
fluid pressure difference between two points. This difference is why there is a push.
The larger the difference, the more push there is. The battery corresponds to the
pump, which provides a pressure difference for the entire system. The pressure
difference provided by the pump is the same for both systems. So in a system with
parallel pipes and there is a clog at each pipe there will be the same pressure
difference where the clogs are located and it will be the same as the pressure
difference provided by the pump.
(a)
(b)
Figure 1: Circuit Analogy of Potential Difference (a) water system with a pump (in
purple) and pipes, each with a clog connected in parallel; the same colored ovals
indicate locations that have the same pressure. Notice there is the same pressure
difference at each clog and it is the same pressure difference provided by the pump
(b) electrical circuit connected in parallel; the same colored ovals indicate locations
that have the same electric potentials. Notice there is the same potential difference at
each clog and it is the same pressure difference provided by the battery.
In a circuit with one loop, and two light bulbs, the potential difference is different at
the bulbs and they must somehow add up to the total potential difference provided by
the battery. So the potential difference at each bulb in a series circuit with multiple
bulbs is less than the potential difference at each bulb in a parallel circuit.
5. Why are the same light bulbs dimmer and brighter? What does the brightness
depend on?
They light bulbs in the parallel circuit have more voltage across them and more
current going through them. The light bulbs in the parallel circuit were brighter. It
looks like brightness depends on voltage across them and the current going through
them.
6. How do you connect brightness with potential difference and current
mathematically?
When there was more flow of charge, the light bulbs were brighter. Where there was
more potential difference, the light bulbs were brighter also. It seems that brightness
is directly related to current and potential difference.
7. What else did you notice about the light bulbs when the switch was on?
ACTIVITY 2: DERIVING A MATHEMATICAL EXPRESSION
ALG 16.3.8
ACTIVITY 3: WHY ARE THE BULBS WARM? HANDOUT #2
1. Let’s consider “mass – spring” system on surface that is frictionless on the left side
from equilibrium point and rough on the right from equilibrium point. Assume that
initial mechanical energy is 0. Compress spring by your hand and release.
0
0
a. Define system of interests
b. What is a source of external
force?
c. Draw energy bars for process
friction is present in grey area
2. Let’s consider object in gravitational field of the Earth. Assume that initial energy
(position 1) is 0. Object is lifted to the board (position 2) and allowed to slide down
over rough surface (position 3)
1
2
3
in 3- object is sliding down over the rough surface
a. Define system of interests
b. What is a source of external force?
c. Draw energy bars for process
3. Consider circuit from resistor,
battery and switch. When switched
is closed potential difference is
applied to resistor.
a. Define system of interests (neutral
resistor)
b. What is a source of external force?
c. Draw energy bars for process
ACTIVITY 4: QUALITATIVE OBSERVATION EXPERIMENT
WHAT DO THE MARKINGS MEAN?
Available equipment: AC voltage source, a marked parallel and series circuit board, 2
pairs of light bulbs of different markings.
1. Switch the board to series and observe the brightness of the bulbs and record your
observations.
2. Now switch the board to parallel and observe the brightness of the bulbs and record
your observations.
3. Compare the two circuits. What did you notice?
4. Now switch the position of the bulbs in each circuit and observe the bulb brightness.
What did you notice? Do the positions of the bulbs in the circuit matter?
5. Can you connect the brightness of the bulbs to the resistance of the bulb?
In the series circuit, the bulb with the lower number marking was brighter. In the
parallel circuit the one with the higher number marking was brighter.
Using the relationship P = IV which we just derived, from Ohm’s law we can relate
power to resistance.
P = IV
I = V/R or V = IR
P = V2/R or P = I2R
From the previous activity we observed and reasoned that the voltage across the
resistors in a parallel circuit should be the same. So using the new expression for
power P = V2/R, the power, which we observe as the brightness and thermal energy
released, is inversely related to the resistance.
We also observed and reasoned from the previous activity and from the last lesson
that the current in a series circuit is the same everywhere. So using the new
expression for power P = I2R, the power output, which we observe as the brightness
and thermal energy, is directly related to the resistance.
6. How do you think circuits are connected in your house? Make a prediction for each
case and think about what actually does happen. Why can’t you put so many
appliances together?
If the circuits in my house were connected in series then the lights should get
dimmer or my plate of food in the microwave should take longer to get warmer.
When I turn on more than one appliance the lights do not get dimmer nor does it
take longer for me to warm my food in the microwave. The circuits in houses are
connected in parallel.
7. What do the markings on the light bulbs mean?
Since these bulbs are made for homes and circuits in houses are connected in parallel
the bulb markings really mean that there is a lower resistance for higher wattage
markings. (maybe the tungsten filament is shorter or thicker)
8. Why can’t you put so many appliances together?
As I turn on more and more appliances in the house I am the lowering the equivalent
resistance and so more current runs through the circuit. The purpose of fuses and
circuit breakers.is to keep it from overloading. As we saw in the PhET simulation,
when the flow of charge through the circuit is too much/too fast, the circuit overloads
and can cause a fire.
ACTIVITY 5: CIRCUIT PUZZLE
Use what you learned in today’s lesson to figure out how the puzzle is connected. Draw a
final circuit diagram below.
Modifications for different learners
 Compensatory activities for those students who lack prerequisite knowledge.
o Online simulations
 See Journal 3 in Blog for NetLogo Models Library Simulations
links and for discussion of the simulations
 PhET Colorado DC Circuit Construction Simulation
o ALG Activities
 ALG 16.1.1-16.1.6 Conditions to light up a bulb in a circuit –
potential difference source, complete loop connection, electron
charge flow (from high potential to low potential).
 ALG 16.2.1 Analogy between electrical circuits, parts of water
system, and race track
 ALG 16.1.8 Parallel and series circuit; Drawing circuit diagrams
(non-schematic);
 Describe alternative instructional strategies for diverse learners such as the use of
multi-sensory teaching approaches, use of instructional technologies, advance
organizers, and cooperative learning activities.
o Physical demo for microscopic model for conductors  Conductors allow
for flow of free electrons. PhET Simulation DC circuits
o Lab structure is based on constructivist principles of peer learning where
learners of different levels and background collaborate in tasks and
discussions to come to a shared understanding of a new concept.
 Describe modifications for bilingual students.
o More pictures and gestures.
o Seat student next to who can be helpful.
o Frequently visit students’ station to check for progress and to make
student feel more comfortable.
 List opportunities for students to speculate on stereotypes that exist within
physical sciences.
o Women in physical science.
Homework (make sure that it addresses goals: strengthens this lesson and prepares
students for the next lesson. Describe the guidance that you will provide to the students.)
Lab
This lab addresses the following NJ Standards:
1. All the previously listed progress indicators for standard 5.1
2. 5.7B1
This lab addresses the following Unit Goals:
 Conceptual:
1. Understand interrelationship between V,I,R in circuits with different
connections and power output.
 Procedural:
2. Be able to represent an electric circuit in a circuit diagram.
3. Assemble electric circuits from the same elements but with different power
outlet.
 Quantitative:
4. Calculate power output for different connections.
 Epistemological:
5. Set up appreciation of analyzing your own thinking.
QUANTITATIVE TESTING EXPERIMENT: POWER DISSIPATION
Goal:
Test the following hypothesis: “In a circuit with two resistors, the one with the larger
resistance will dissipate the greater amount of power.” Design and perform an experiment
to accomplish the goal. Use the rubrics and the questions below to guide your
investigation.
Available equipment: Voltage source, circuit board, resistors, connecting wires,
multimeter.
RUBRIC C: Ability to design and conduct a testing experiment
4
7
Scientific
Abilities
Is able to
make a
reasonable
prediction
from the
hypothesis
Is able to
decide
whether the
prediction
and the
outcome
agree/disagree
Missing
Inadequate
No attempt to
make a
prediction is
made
A prediction is made
that is distinct from the
hypothesis but is not
based on it.
No mention of
whether the
prediction and
out come
agree/disagree
A decision about the
agreement/disagreement
is made but is not
consistent with the
outcome of the
experiment.
Needs Some
Improvement
A prediction is
made that follows
from the hypothesis
but does not
incorporate
assumptions
A judgment is made
and is consistent
with the outcome of
the experiment but
experimental
uncertainty is not
taken into account.
Adequate
A correct prediction is
made, is distinct from
the hypothesis, and
incorporates
assumptions.
A reasonable decision
about the
agreement/disagreement
is made and
experimental
uncertainty is taken into
account.
8
Is able to
make a
reasonable
judgment
about the
hypothesis
No judgment
is made about
the hypothesis
A judgment is made but
is not consistent with
the outcome of the
experiment
A judgment is made
and is consistent
with the outcome of
the experiment but
assumptions are not
taken into account.
A reasonable judgment
is made and
assumptions are taken
into account.
RUBRIC G: Ability to collect and analyze experimental data
Scientific
Abilities
Missing
Inadequate
Needs Some
Improvement
Adequate
2
Is able to
evaluate
specifically
how identified
experimental
uncertainties
may affect the
data
No attempt
is made to
evaluate
experimental
uncertainties.
An attempts is made to
evaluate experimental
uncertainties, but most are
missing, described vaguely,
or incorrect. Or only
absolute uncertainties are
mentioned. Or the final
result does not take the
uncertainty into account.
The final result
does take the
identified
uncertainties into
account but is not
correctly
evaluated.
The experimental
uncertainty of the final
result is correctly
evaluated.
5
Is able to
analyze data
appropriately
No attempt
is made to
analyze the
data.
An attempt is made to
analyze the data, but it is
either seriously flawed or
inappropriate.
The analysis is
appropriate but it
contains minor
errors or
omissions.
The analysis is
appropriate, complete,
and correct.
Include the following in your write up:
a) Devise a procedure for your investigation and briefly
describe
your
experimental
design.
Include
a
circuit
diagram.
b) What is the hypothesis being tested and what does it
predict will happen when you perform the experiment? This
is the first part of hypothetico-deductive reasoning “If
the hypothesis is correct, and I do such and such, then
such and such should happen.”
c) Describe any assumptions that you made in making your
prediction. How do the assumptions affect your prediction?
How might they hinder your ability to make a judgment about
the hypothesis?
c) Connect the circuit according to your diagram, and have
your instructor check the circuit. Only then turn on the
voltage source and perform your experiment. Describe the
outcome with words, math, and a picture.
d)
What
was
the
outcome
of
your
experiment?
Was
it
consistent or inconsistent with the prediction? Explain in
detail how you decided this.
e) Based on the prediction and the outcome, what is your
judgment of the hypothesis? This is the second part of
hypothetico-deductive reasoning: “but this did not happen,
therefore…” or “and this did happen, therefore…”
Why did We Do This Lab?
1) This
experiment
was
a
testing
experiment.
In
past
labs we have performed observation experiments. What
is
the
main
difference
between
observational
experiments and testing experiments?
2) In this lab we measured the power dissipated from a
resistor using a multimeter. In your home power is
dissipated from appliances. How would we know power is
dissipated without using a multimeter?
Traditional and Alternative Assessment
Final Traditional summative assessment
Summative assessment is intended to summarize student attainment at a particular time
when test is given. Epistemological goals can not be efficiently tested in traditional test
and not covered by test below.
9 problems of the test below have been selected to check understanding each of 9 goals
chosen as the unit goals. The number of problem corresponds to the number of the goal.
Grading scheme: when all questions have the same level of complexity grade will be
calculated as average.
Test:
1) When two or more resistors are connected in series to a battery
A) the equivalent resistance of the combination is equal to the sum of the
resistances of each resistor.
B) the total voltage across the combination is the algebraic sum of the voltages
across the individual resistors.
C) the same current flows through each resistor.
D) all of the given answers
2) Kirchhoff’s loop rule is an example of
A) conservation of energy.
B) conservation of momentum,
C) conservation of charge.
D) none of the given answers
3) As more resistors are added in series to a constant voltage source, the power supplied
by the source
A) decreases.
B) increases for a time and then starts to decrease.
C) increases.
D) does not change.
4) Fluorescent bulbs deliver the same amount of light using much less power. If one kWhr costs 7 cents. Calculate the amount of money you would save each month by replacing
one 75 W incandescent bulbs in your house by 10 W fluorescent ones
5) You obtain a 100-W light bulb and a 50-W light bulb. Instead of connecting them in
the normal way, you devise a circuit that places them in series across normal household
voltage. Which statement is correct?
A) The 50-W bulb glows more brightly than the 100-W bulb.
B) The 100-W bulb glows brighter than the 50-W bulb.
C) Both bulbs glow at the same reduced brightness.
D) Both bulbs glow at the same increased brightness.
6) What is the maximum number of 100-W light bulbs you can connect in parallel in a
120-V circuit without tripping a 20—A circuit breaker?
A) 17
B) 24
C) 11
D) 27
7) A 3.0 Ohm resistor is connected in parallel with a 6.0 Ohm resistor. This combination
is connected in series with a 4,0-Q resistor. The resistors are connected to a 12-volt
battery. How much power is dissipated in the 3.0 Ohm resistor?
A) 12W
B) 6.0W
C)2.7W
D)5.3W
8) What Is the maximum number of 100 W light bulbs you can connect in parallel in a
120 V circuit without tripping a 20 A circuit breaker? Draw circuit diagram
A) 27
B) 24
C) 22
D) 17
9) Four car speakers need to he connected to amplifier to get maximum loudness. Draw
circuit diagram. How you will connect them?
A) in parallel
B) in series
C) doesn’t matter , maximum loudness will be the same
D) doesn’t matter one or two are connected maximum loudness will be the same
Alternative summative assessment
Alternative or formative assessment (also known in some literature as assessment for
learning, integrative, holistic, authentic assessment) in the case of summative assessment
is intended to assess the formation of the student thinking, abilities to reflect on the
reasoning process and construction of knowledge. It is intended not merely grade student
for performance at certain point of their development but to recognize current state and
trajectory of their development.123
Problems below4 require application of conceptual understanding and reflection based on
combination of previous knowledge ( in contrast to the traditional test that could be
successfully done in the way of matching a problem to a formula from formula sheet )
Grading system: formative assessment is emphasizing on scientific abilities and
conceptual understanding therefore grading is based on rubrics5
Problem 1
Attended unit goals:
o concept of electric circuit, parallel and series connections
o understand interrelationship between V,I,R in circuits with different connections
and power output
o Set up appreciation of analyzing your own thinking
Consider the two arrangements of batteries
and bulbs shown at the right.
All four bulbs are identical and have
resistance R. The two batteries are identical
and maintain a potential difference (EMF)
= E. Answer the following questions and
explain why you believe your answer.
(Most bulbs are brighter when there is more
current through them. Assume that is the
case for these bulbs.)
a. In system 1, which bulb is brighter?
b. In system 1, what is the current through each bulb, the voltage drop across each
bulb, and the power dissipated by each bulb?
c. In system 2, which bulb is brighter?
d. In system 2, what is the current through each bulb, the voltage drop across each
bulb, and the power dissipated by each bulb?
1
Etkina, EuginiaFormative and Summative Assessment in a Physics Class: Time to Change. Rutgers, the
State University of New Jersey, [email protected].
2
Crooks Terry
2001
The Validit of Formative Assesment. Electronic document. Paper Presented to the British
Educational Research Association Annual Conference, Universiry of Leeds.
3
Dufresne, Robert J., and Gerace, William J.
2004
454.
4
Assessing-to-Learn: Formative Assessment in Phisics Instructions. The Physics Teacher 42,:428-
Redish, Edward F.
2003
Teaching Physics with the Physics Suite. John Wiley and Sons, Inc.
5
Etkina, EuginiaFormative and Summative Assessment in a Physics Class: Time to Change. Rutgers, the
State University of New Jersey, [email protected].
e. Which bulbs are brighter, those in system 1 or those in system 2?
f. If one bulb in each system burns out, will the other go out as well? Why? If the
other bulb doesn't go out will it get brighter or stay the same when the first bulb in
the circuit burns out?
Note to the instructor: Students have well documented difficulties with simple battery
and bulb circuits. Many bring an undifferentiated concept of "electricity" to class, failing
to distinguish between voltage (pressure) and current (flow). This example, and other
related ones bring this out.
Problem 2
Attended unit goals:
o understand interrelationship between V,I,R in circuits with different connections
and power output
o Set up appreciation of analyzing your own thinking
o concept of electric circuit, parallel and series connections
All of the bulbs in the figure at the right have
the same resistance R. If bulb B is removed
from the circuit, what happens to the current
through bulb A, bulb D, and the battery?
Indicate whether it increases, decreases or
remains the same. For each case, explain your
reasoning. (Most bulbs are brighter when there
is more current through them. Assume that is
the case for these bulbs.)
Problem 3
Attended unit goals:
o Derive and apply a mathematical expression for power P = IV, P = I2R, P = V2/R
for different connections
o concept of electric circuit, parallel and series connections (for batteries)
Identical batteries are connected in different
arrangements to the same light bulb. Assume the
batteries have negligible internal resistances. The
positive terminal of each battery is marked with
a plus. Rank these arrangements on the basis of
bulb brightness from the highest to the lowest.
Please explain your reasoning. (Most bulbs are
brighter when there is more current through
them. Assume that is the case for these bulbs.)
Problem 4
Attended unit goals:
o Be able to use circuit diagram and different representations for electric circuit
parameters.
o Calculate electric circuit parameters and power output for different connections
The circuit shown in the diagram at the right
contains a battery and 3 resistors. The battery
has an EMF of 5 V, R1 = 2 , R2 = 3 , and
R3 = 5 .
1. Below are shown 3 graphs tracking some
quantity around the circuit.
On the first, plot the voltage a test charge
would experience as it moved throughout the
circuit.
On the second, plot the electric field a test
charge would experience as it moved through
the circuit.
On the third, plot the current one would
measure crossing a plane perpendicular to the
wire of the circuit as one goes through the
circuit.
2. Calculate power dissipated by each resistor
Project
This project addresses the following NJ Standards:
1. All the previously listed progress indicators listed in 5.2
This project addressed the following Unit Goals:
 Epistemological:
1. Set up appreciation of analyzing your own thinking.
DEVELOPMENT OF IDEAS PROJECT – HISTORY OF ELECTRICITY
Instructions:
In groups of 4, write the history of electricity. Include
the following scientists: Michael Faraday, Luigi Galvani,
Alessandro Volta, and George Ohm. This project will contain
two parts.
Part I
You
will
describe
(observational,
the
experiments
or
application
testing,
they
performed
experiments)
and
how they contributed to the development of the ideas in
Electricity. Make sure to include the important elements of
each experiment. For example for a testing experiment, make
sure to include the assumptions made, the hypothesis, an
outline of the procedure, the prediction, the outcome, and
the conclusion. Use the rubric below to guide you. Its
important
for
us
to
understand
the
scientific
process
involved in experimentation and to understand how ideas are
developed, tested, and can replaced or modified in light to
of new information and improved investigative techniques.
Part II
Each of you will choose one of the scientists to write
about.
It
should
be
an
“interesting”
story
about
the
scientist’s life that
(1) spans from childhood to adulthood
(2) includes failures and successes
(3) includes triumphs and tragedies
(4) includes important people in his life
(5) includes important contributions to physics.
Don't let this be a boring story! Every person's life is
interesting. You would be surprised what you find out about
the lives of some physicists like Marie Curie's husband,
Pierre Curie, died from a gruesome accident with a horse
and carriage. You want to capture the attention of your
audience. The emphasis of this part of the project is for
us to see the humanity in physicists. We talk about laws,
equations,
and
many
other
things
that
are
named
after
scientists, but it is also important to know about the
person. You'll be able to see how the physics fits into the
biography of the scientist.
I suggest you begin by using the textbook, Physics, the
Human Adventure: From Copernicus to Einstein and Beyond by
Holton and Brush and what you gained from class as sources.
List all the sources you used.
Part I Rubric
0
No mention is made
of the phenomenon to
be investigated.
1
An attempt is made to
identify the
phenomenon to be
investigated but is
described in a
confusing manner.
2
The phenomenon to be
investigated is described
but there are minor
omissions or vague
details.
3
The phenomenon to be
investigated is clearly
stated.
Described what was
observed without
trying to explain
No description is
mentioned.
A description is
mentioned but it is
incomplete.
Clearly describes what
happens in the
experiments
Communicated the
details of an
experimental
procedure clearly
and completely
Diagrams are missing
and/or experimental
procedure is missing
or extremely vague.
Diagrams are present
but unclear and/or
experimental
procedure is present
but important details
are missing.
A description exists, but
it is mixed up with
explanations or other
elements of the
experiment.
Diagrams and/or
experimental procedure
are present but with
minor omissions or
vague details.
Described the data
that were recorded
The data are not
mentioned.
No attempt is made
to describe a
relationship that
represented a trend in
the data.
No attempt is made
to explain the
observed
relationship.
All important data are
present, but described
vaguely.
The relationship is
described but some
features of the
relationship are missing.
All important data are
described clearly.
Described a
mathematical
relationship that
represented a trend
in data
Explained an
observation or an
observed
relationship
Some important data
are absent or
incomprehensible.
An attempt is made,
but the description is
vague.
An explanation is
made but it is vague.
An explanation is made
and is based on
simplifying the
phenomenon but uses
flawed reasoning.
A reasonable
explanation is made and
is based on simplifying
the phenomenon.
Identified the
phenomenon that
was investigated
Diagrams and/or
experimental procedure
are clear and complete.
The description is
complete and represents
the trend accurately.
Identified the
assumptions made
in devising the
explanation
No attempt is made
to identify any
assumptions.
Made a reasonable
prediction based on
a relationship or
explanation
No attempt to make a
prediction is made.
The experiment is not
treated as at testing
experiment.
Identified the
assumptions made
in making the
prediction
No attempt is made
to identify any
assumptions.
Described a testing
experiment
Diagrams are missing
and/or experimental
procedure is missing
or extremely vague.
Results are not
communicated.
Decided whether or
not the prediction
was confirmed
based on the results
of the testing
experiment
No decision is made
to confirm or
disconfirm the
prediction.
Made a reasonable
judgment about the
relationship or
explanation and
suggested a new
explanation if
necessary
No judgment is made
about the relationship
or explanation, or is
not based on the
results.
Part II Rubric
An attempt is made to
identify assumptions,
but most are missing,
described vaguely, or
incorrect.
A prediction is made
but it doesn’t follow
from the relationship
or explanation being
tested, or it ignores or
contradicts some of the
assumptions inherent
in the relationship or
explanation.
Most assumptions are
correctly identified.
All assumptions are
correctly identified.
A prediction is made that
follows from the
relationship or
explanation but does not
incorporate the
assumptions, but it
contains minor errors,
inconsistencies, or
omissions.
A prediction is made
that follows from the
relationship or
explanation and
incorporates the
assumptions.
An attempt is made to
identify assumptions,
but most are missing,
described vaguely, or
incorrect.
Diagrams are present
but unclear and/or
experimental
procedure is present
but important details
are missing. Results
are communicated
vaguely.
A decision is made but
it is not strongly based
on the results of the
experiment.
Most assumptions are
correctly identified.
All assumptions are
correctly identified.
Diagrams and/or
experimental procedure
and results are present
but with minor
omissions or vague
details.
Diagrams and/or
experimental procedure
and the results are clear
and complete.
A decision is made based
on the results of the
experiment, but the
reasoning is flawed.
A correct decision is
made and is based on
the results of the
experiment.
A judgment is made
but it is based only on
the degree of
agreement between the
results and the
prediction. In case of
disagreement no new
explanation is
suggested.
A judgment is made
based on the reliability
of the experiment and
the degree of agreement
between the results and
the prediction, but the
reasoning is flawed. In
case of disagreement no
new explanation is
suggested.
A reasonable judgment
is made based on the
reliability of the
experiment and the
degree of agreement
between the results and
prediction. In case of
disagreement a new
explanation is
suggested.
CATEGORY 4
Amount of
All topics are
Information
addressed with at
least 2
paragraphs about
each. The story
is interesting and
personal.
Quality of
Information
Information
clearly relates to
the main topic. It
includes several
supporting
details and/or
examples.
Sources
All sources
(information and
graphics) are
accurately
documented in
the desired
format.
Organization
Information is
very organized
with wellconstructed
paragraphs and
subheadings.
3
Most topics
(4) are
addressed
with at least 2
paragraphs
about each.
2
Some topics (3)
are addressed
with at least 2
paragraphs about
each.
1
Inadequate
amount of
topics are
discussed
thoroughly.
Information
clearly relates
to the main
topic. It
provides 1-2
supporting
details and/or
examples.
All sources
(information
and graphics)
are accurately
documented,
but a few are
not in the
desired
format.
Information is
organized
with wellconstructed
paragraphs.
Information
clearly relates to
the main topic.
No details and/or
examples are
given.
Information
has little or
nothing to do
with the main
topic.
All sources
(information and
graphics) are
accurately
documented, but
many are not in
the desired
format.
Some sources
are not
accurately
documented.
Information is
organized, but
paragraphs are
not wellconstructed.
The
information
appears to be
disorganized.
Resources
Bransford, J. D., Brown Ann L. & Cocking Rodney R. (1999). How People Learn: Brain,
Mind, Experience, and School.
Cohen R., Eylon B. & Ganiel, U. (1982). Potential differences and current in simple
electric circuits: A study of student's concepts. American Journal of Physics, 51(5,
May).
Crooks Terry. (2001). The validity of formative assessment. Paper Presented to the
British Educational Research Association Annual Conference, University of
Leeds (13-15/ September).
Dufresne, R. J. &, G., William J. . (2004). Assessing-to-learn: Formative assessment in
phisics instructions. The Physics Teacher, 42, (October 2004), 428-454.
Engelhardt, P. V. & Beichner, R. J. (2003). Students’ understanding of direct current
resistive electrical circuits. American Journal of Physics, 72(10, 1/August), 98115.
Etkina, E. Formative and summative assessment in a physics class: Time to change.
Rutgers, the State University of New Jersey, [email protected].
Heuvelen, A. V. (1991). Learning to think like a physicist: A review of research-based
instructional strategies. American Journal of Physics, 59(10, 21/03/1991), 891897.
Heuvelen, A. V., Etkina, E. (2006). The Physics Active Learning Guide. San Francisco.
Pearson Education.
Knight, R. D. (2004). Five Easy Lessons. Pearson Education, Inc.
Redish, E. F. (2003). Teaching Physics with the Physics Suite. John Wiley and Sons, Inc.
Rosenthal, A. S. & Henderson, C. (2006). Teaching about circuits at the introductory
level: An emphasis on potential difference. American Journal of Physics, 74(4,
6/01), 324-328.
New Jersey Core Curriculum Content Standard(s) (NJCCCS)
PhET Colorado Simulations http://phet.colorado.edu/simulations/sims.php?sim=Circuit_Construction_Kit_DC_Only
Reflection
On Designing the Unit
Our approach to designing the unit was large to small scale. Beginning with NJ
standards and goals and then listing the most important ideas, brainstorming about lesson
plans and possible equipment needed, and then planning out the time frame. I think this
kept me from getting stuck on the little details and thus helped me plan a more cohesive
unit making sure that the activities are geared towards the goals. Plus by starting with the
goals and NJ standards, it allowed us to work on separate tasks and ensure that our work
coincided. I find that designing the unit this way is much like erecting a building, the
general skeleton is first built, and then the floors are put on, and so on until you have a
finished building. The ALG was very helpful in designing the unit. I used it every step of
the way.
-Linda
On Implementing the Unit
I’m not sure how well we planned out the timing of the unit. I plan to have a little
bit of a review after each topic covered through homework and quizzes and I didn’t
always take it into consideration when planning the time frame. Still as is, three weeks
sounds like a lot of time spent on DC circuits. I included the NJ standards in the time
frame so that I can have an idea when they will be addressed but it was not very detailed.
We should decide as much as we can before the unit begins which tasks we can omit or
shorten just in case we are pressed for time and still accomplish all the goals and address
all the NJ Standards. For example, I can probably omit the Power Dissipation Lab
because it mostly targets goals that will be covered by the Ohm’s Law. Instead we can
use it as an end of the year practical that would assess the students’ scientific abilities.
-Linda