Ohm’s Law
012-10782 r1.04
Ohm’s Law
Introduction
Journals and Snapshots
The Snapshot button is used to capture the
screen.
The Journal is where snapshots are stored
and viewed.
The Share button is used to export
or print your journal to turn in your
work.
Each page of this lab that
contains the symbol
should be inserted into your
journal. After completing a
lab page with the snapshot
symbol, tap
(in the upper
right corner) to insert the
page into your journal.
Note: You may want to take a
snapshot of the first page of
this lab as a cover page for
your journal.
Ohm’s Law
Lab Challenge
From modern electronics to raw power generation, there is a fundamental
relationship between the voltage applied to a circuit, the current flowing through a
circuit, and the resistance present in a circuit. What is that relationship?
Ohm’s Law
Background
George Simon Ohm (1787-1854) discovered that when
the voltage (potential difference) across a resistor
changes, the current through the resistor changes. We
will measure voltage and current through a circuit to
determine that relationship.
Ceramic core
Nickel cap
Lead
Carbon film
Protective lacquer
Ohm’s Law
Materials and Equipment
Collect all of these materials before beginning the lab.
• Voltage Current sensor
• Charge/Discharge Circuit (EM-8678)
• Batteries (2)
• Banana Patch Cords
Ohm’s Law
Sequencing Challenge
A. Charge
capacitor through
resistor and collect
data on voltage
and current.
B. Repeat using a
different resistor.
C. Discharge
capacitor for
several seconds.
D. Connect the
voltage current
sensor to you
SPARK Science
Learning System.
The steps to the left are part
of the procedure for this lab
activity. They are not in the
right order. Determine the
correct sequence of the
steps, then take a snapshot
of this page.
Ohm’s Law
Prediction
How will voltage change with
relation to current using a 10
Ω resistor?
Draw your prediction on the
graph then take a snapshot
of this page.
*To Draw a Prediction:
1. Tap
to open the tool
palette.
2. Tap
then use your finger
to draw your prediction.
3. Tap
when finished.
4. If you make a mistake, tap
to clear your prediction.
Ohm’s Law
Setup: 10 Ω resistor
1. Use the 10 Ω resistor, 2 batteries, 1 F
capacitor, and switch on the circuit
board to create a circuit in which the
capacitor charges through the resistor
when the switch is in the "charge"
position, and discharges when the
switch is in the "discharge" position.
2. Connect the voltage/current sensor to
the data collection system.
Ohm’s Law
Setup: 10 Ω resistor
Q1: What is the proper placement of the leads for the
voltmeter and ammeter respectively?
a) voltage is measured in series with the resistor,
and the ammeter in series.
b) voltage is measured with vigor, and the current
is measured with style.
c) voltage is measured in series with the resistor,
and the ammeter in parallel.
d) voltage is measured in parallel with the resistor,
and the ammeter in series.
Make your selection below
then take a snapshot of this
page.
Ohm’s Law
Setup: 10 Ω resistor
3. Close the switch to the "discharge"
position for at least 30 seconds to
discharge the capacitor. Then move the
switch to open (upright) position.
Ohm’s Law
Setup: 10 Ω resistor
Q2: What is the purpose of the capacitor in the
circuit?
a) The capacitor captures excess charge from the
batteries.
b) The capacitor provides extra stability to the
circuit.
c) The capacitor creates a variable voltage source
as it charges/discharges.
d) The capacitor provides 1.21 gigawatts to the
flux capacitor.
Make your selection below
then take a snapshot of this
page.
Ohm’s Law
Collect Data: 10 Ω
1. Tap
to begin data
collection.
2. Move the switch to the
"charge" position.
3. After the capacitor charges
(values stop changing),
tap
to end data
collection.
4. Move the switch to the
open (upright) position.
Ohm’s Law
Analysis: 10 Ω resistor
1. Describe the shape of the
voltage versus current
graph in the text box
below, then take a
snapshot of this page.
Ohm’s Law
Analysis: 10 Ω resistor
2. Apply a linear curve fit to
the graph, then take a
snapshot of this page.
*To Apply a Curve Fit:
1. Tap
to open the tool
palette.
2. Tap
to open the Curve
Fit screen.
3. Tap the name of the
curve fit required.
Ohm’s Law
Analysis: 10 Ω resistor
3. Does the slope of the
linear fit appear to be
related to any other part
of the circuit? Answer
below, then take a
snapshot of this
page.
Ohm’s Law
Analysis: 10 Ω resistor
4. Annotate the voltage
curve with the value of
the resistor, then take a
snapshot of this page.
* To Annotate a Data Point:
1. Tap
to open the tools
palette.
2. Tap
and then tap a point
on the data run.
3. Adjust using
buttons
and then tap
.
4. Tap
to add an annotation.
Ohm’s Law
Setup: 33 Ω resistor
1. Replace the 10 Ω resistor with a 33
Ω resistor.
2. Close the switch to the "discharge"
position for at least 30 seconds to
discharge the capacitor.
Ohm’s Law
Prediction
How will the curve change
relative to the 10 Ω resistor?
Draw your prediction on the
graph, then take a snapshot
of the page.
*To Draw a Prediction:
1. Tap
to open the tool
palette.
2. Tap
then use your finger
to draw your prediction.
3. Tap
when finished.
4. If you make a mistake, tap
to clear your prediction.
Ohm’s Law
Collect Data: 33 Ω
1. Tap
to begin data
collection.
2. Move the switch to the
"charge" position.
3. After the capacitor charges
(values stop changing), tap
to end data collection.
4. Move the switch to the
open (upright) position.
Ohm’s Law
Analysis: 33 Ω resistor
1. Describe the shape of the
voltage versus current
graph in the text box
below, then take a
snapshot of this page.
Ohm’s Law
Analysis: 33 Ω resistor
2. Apply a linear curve fit to
the graph, then take a
snapshot of this page.
*To Apply a Curve Fit:
1. Tap
to open the tool
palette.
2. Tap
to open the Curve
Fit screen.
3. Tap the name of the
curve fit required.
Ohm’s Law
Analysis : 33 Ω resistor
3. Does the slope of the
linear fit appear to be
related to any other part
of the circuit? Answer
below, then take a
snapshot of this page.
Ohm’s Law
Analysis: 33 Ω resistor
4. Annotate the voltage
curve with the value of
the resistor, then take a
snapshot of this page.
* To Annotate a Data Point:
1. Tap
to open the tools
palette.
2. Tap
and then tap a point
on the data run.
3. Adjust using
buttons
and then tap
.
4. Tap
to add an annotation.
Ohm’s Law
Setup: Light Bulb Resistor
1. Replace the 33 Ω resistor with a
light bulb resistor.
2. Close the switch to the "discharge"
position for at least 30 seconds to
discharge the capacitor.
Ohm’s Law
Collect Data: Bulb
1. Tap
to begin data
collection.
2. Move the switch to the
"charge" position.
3. After the capacitor charges
(values stop changing), tap
to end data collection.
4. Move the switch to the
open (upright) position.
Ohm’s Law
Analysis: Light Bulb
1. Describe the shape of the
voltage versus current
graph in the text box
below, then take a
snapshot of this page.
Ohm’s Law
Analysis: Light Bulb
2. How does the light bulb
curve compare to the
resistor curves?
Describe below, then take
a snapshot of this
page.
Ohm’s Law
Analysis: Light Bulb
3. How does the resistance in the light bulb differ
from the resistors you used previously in this DC
circuit?
a) As the light bulb gets brighter, its resistance
remains the same.
b) The resistance of light bulb is futile.
c) As the light bulb heats up, its resistance
changes, so it doesn't have a constant
resistance.
d) The resistance of the light bulb is a constant.
Make your selection below
then take a snapshot of this
page.
Ohm’s Law
Synthesis
1. What can you conclude about the mathematical relationship between current and
voltage for constant resistance?
Enter your answer in the text below, then take a snapshot of this page.
Ohm’s Law
Synthesis
2. Using a constant voltage, what can you conclude about the relationship between
current and resistance?
Enter your answer in the text below, then take a snapshot of this page.
Ohm’s Law
Synthesis
3. How do your results for voltage versus current compare to your prediction?
Enter your answer in the text below, then take a snapshot of this page.
Ohm’s Law
Multiple Choice Question
1. A voltage across a 580 Ω resistor is 120 V. How
much current is going through the resistor?
a) There isn't enough information to answer this
question.
b) 696 mA
c) 207 mA
d) 460 mA
Make your selection below
then take a snapshot of this
page.
Ohm’s Law
Multiple Choice Question
2. The current through a 100 Ω resistor is 0.150 A.
What voltage is being applied?
a) There isn't enough information to answer this
question.
b) 15 V
c) 1.5 V
d) 666 V
Make your selection below
then take a snapshot of this
page.
Ohm’s Law
Multiple Choice Question
3. A circuit with a 3 V battery pack and a resistor has
a current of 0.06 A. What is the value of the
resistor?
a) There isn't enough information to answer this
question.
b) 18 Ω
c) 2 Ω
d) 50 Ω
Make your selection below
then take a snapshot of this
page.
Ohm’s Law
Congratulations!
You have completed the lab.
Please remember to follow your teacher's instructions for cleaning-up and submitting
your lab.
Ohm’s Law
References
ALL IMAGES WERE TAKEN FROM PASCO DOCUMENTATION, PUBLIC DOMAIN CLIP ART, OR WIKIMEDIA
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