Investigating Series Circuits: Student Activity Lesson Plan
Subject/Strand/Topic:
Science / Physics: Electricity
Key Concepts:
Grade(s) / Course(s):
9 / SNC1D
Ontario Expectations:
PH1.09, PH1.10
series circuits, current, voltage, resistance
Link: http://phet-web.colorado.edu/web-pages/simulations-base.html Click on “Circuit Construction Kit”.
Required Materials: † Pre-Assessment/Answer Key, † Student Activity Handout, † Student Activity Answer Key,
† Post-Assessment/Answer Key, † Data Projector (Optional),
† Circuit Construction Kits [Batteries, Wires, Light Bulbs, Voltmeter, Ammeter] (Optional)
Before Starting:
1. Students should be familiar with simple electric circuits, current, voltage and using ammeters and voltmeters.
2. This activity works best with students in pairs.
3. If doing the optional activity, ensure circuit construction kits are complete and in working order.
Introduction (~ 10 minutes including pre-assessment)
1. Go to computer lab, put students in pairs.
2. Distribute the pre-assessment to each student; collect when complete (5 min).
3. Introduce the learning object to the class:
a. Review current, voltage and what series circuits look like.
4. Think-Pair-Share: Q - What will happen to the current as more light bulbs are added to a series circuit? (current
slows down as number increases) Q – Do you think the voltage at the battery will change as more light bulbs
are added to a series circuit? (across battery no, across each load, yes)
Student Activity Handout Explanation (~ 5 minutes)
1. Distribute activity sheet to each student. Students use the learning object to complete the activity.
2. Go over the organization of the activity sheet. Ensure students know where to record their data.
Use of Learning Object with Student Activity Handout (~ 25-35 minutes)
1. Give students 2-3 minutes to explore the learning object in their pairs. See if students can make a simple circuit.
2. Stop students. Get students to explain aloud the purpose of the learning object, where the options panel is,
where to find instructions, help, how to build a circuit, etc.
3. If a data projector is available, demonstrate how to build a circuit and use the ammeter and voltmeter. Address
issues that came up when students were explaining what to do (1-2 minutes). If a data projector is not available,
explain verbally.
4. Give students 25-35 minutes to work through the activity in their pairs.
5. If students finish early, have students use the learning object to explore other aspects of series circuits, e.g.
conduct the experiment with different resistors, increase the voltage or remove all loads.
Optional activity
ƒ Give students actual circuit components to manipulate as they are working through the learning object.
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Investigating Series Circuits: Student Activity Lesson Plan
Tips and Tricks
ƒ Circulate to ensure students are progressing through the learning object and activity sheet.
ƒ Remind students to share control of the computer and switch roles half way through.
ƒ The non-contact ammeter was chosen because it is simpler and faster to use than the traditional one. If desired,
the traditional ammeter can be substituted.
ƒ Switching often between small, medium and large view can cause the voltmeter to get ‘lost’ off screen. Close and
reload the program if this happens.
ƒ Ensure students know how to switch between the “schematic” and “lifelike” view.
Consolidation (~ 10 minutes including post-assessment)
1. Once students are finished, distribute the Post-Assessment; collect (5 minutes).
2. Take up activity sheet and / or collect as a ticket-out-the-door.
3. Ask students follow up questions, e.g., Q In a series circuit, what happens to the current and brightness of light
bulbs as you add more? (Current decreases throughout entire circuit, lightbulbs dim as more are added). Q: Is
the current the same or different throughout the series circuit? (same). Q The voltage across the source is 9
volts, and there are 3 loads in the circuit? What is potential difference across the 3rd load? (3 volts.)
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Investigating Series Circuits
Student Activity Pre-Assessment
Name: ___________________________
Birthday: ____________________________
6
1. Fill in the blanks. [2 marks]
a. In a series circuit, the total current __________________________ as you add more resistors.
b. In a series circuit, for a fixed number of resistors, the current is ______________________ at
different points in the circuit.
2. What happens to the voltage at the source (battery) as you add more light bulbs to a circuit? Explain.
[2 marks]
3. For the following circuit, what is the voltage at light bulb 2? Show your work. [2 marks]
.
9 volts
V2 = ?
V1 = 4.5
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Teacher-Created Resources: Student Activity Pre-Assessment
Investigating Series Circuits
Student Activity Pre-Assessment
Name: ___________________________
Birthday: ____________________________
10
Answer Key
1. Fill in the blanks. [2 marks]
a. In a series circuit, the total current ____decreases_____________ as you add more resistors.
b. In a series circuit, for a fixed number of resistors, the current is ___the same_____________ at
different points in the circuit.
2. What happens to the voltage at the source (battery) as you add more light bulbs to a circuit? Explain.
[2 marks]
.
The voltage at the source stays the same. Only the voltage across each light bulb drops.
3. For the following circuit, what is the voltage at light bulb 2? Show your work. [2 marks]
.
9 volts
Vs = V1 + V2
9 = 4.5 + V2
V2 = 4.5 volts
V2 = ?
V1 = 4.5
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Teacher-Created Resources: Student Activity Pre-Assessment
Investigating Series Circuits
Student Activity Handout
Name: ___________________________
Date: ____________________________
43
INSTRUCTIONS:
ƒ Use the Circuit Construction Kit to complete the activity sheet.
ƒ Read “How to use the Circuit Construction Kit” before you begin.
HOW TO USE THE CIRCUIT CONSTRUCTION KIT
Action
How to do the action
Selecting and
moving a piece:
To MOVE any piece (wire, battery, etc.) CLICK it, and HOLD. When you release, the piece
will stay where you dropped it. Click and hold to move it again.
Removing a piece:
To remove an item, RIGHT CLICK, and select “REMOVE”
Resizing wire:
To RESIZE a wire, CLICK and HOLD one of the RED circles at the end of the wire.
Attaching pieces:
To ATTACH pieces together, OVERLAP RED circles.
Splitting pieces
apart:
To SPLIT pieces apart. RIGHT CLICK on the junction of the pieces (grey circle), and
select “SPLIT JUNCTION”
Options panel:
Right side of screen. Allows you to select different views (schematic or lifelike), sizes,
types of resistors, tools, etc. You will be told what options to select.
Using the ammeter:
In the OPTIONS panel, check the “NON-CONTACT AMMETER” box. The ammeter will
appear. Move the ammeter over the area you wish to know the current.
Using the voltmeter:
In the OPTIONS panel, check the “VOLTMETER” box. The voltmeter will appear. Move
the leads of the voltmeter over the area of the circuit you wish to know the potential drop
(voltage).
Help:
See bottom of OPTIONS panel. Click “HELP” for generalized instructions on the screen.
Click “MEGA HELP” for a detailed screen shot describing how to use the features.
Construction
area
Ammeter
(non-contact)
Options panel
Circuit
components
Voltmeter
Help
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Investigating Series Circuits
Student Activity Handout
Name: ___________________________
Date: ____________________________
MEASURING CURRENT AND VOLTAGE AS RESISTANCE CHANGES IN SERIES CIRCUITS
When building your circuit, in the OPTIONS panel on the RIGHT of the screen, in the VISUAL box, click
“SCHEMATIC”.
After your circuit is built, in the OPTIONS panel, click “LIFELIKE” to see what your circuit would actually look
like. Use this to view the brightness of the light bulbs.
Do not change the settings for other components.
PROCEDURE
1. Construct the circuit shown in Figure 1.
2. With the non-contact ammeter, measure the current before light bulb 1
(Total Current) and after light bulb 1.
3. In the “Visual” box of the “Options” panel, click “LIFELIKE. Observe the
brightness of the bulb.
R1
4. Record the results in Table 1.
5. With the voltmeter, measure the potential difference across the battery and
across light bulb 1.
Figure 1.
6. Record the results in Table 2.
7. Construct the circuit shown in Figure 2.
8. With the non-contact ammeter, measure the current before light bulb 1
(Total Current) and after light bulbs 1 and 2.
R1
9. In the “Visual” box of the “Options” panel, click “LIFELIKE. Observe the
brightness of the bulbs.
R2
10.Record the results in Table 1.
11.With the voltmeter, measure the potential difference across the battery
(Across Battery) and across EACH light bulbs 1 and 2.
Figure 2.
12.Record the results in Table 2.
13.Construct the circuit shown in Figure 3.
14.With the non-contact ammeter, measure the current before resistor 1 (Total
Current) and after light bulbs 1, 2 and 3.
R1
15. In the “Visual” box of the “Options” panel, click “LIFELIKE. Observe the
brightness of the bulbs.
R2
16.Record the results in Table 1.
R3
17.Measure the potential difference with the voltmeter across the battery
(Across Battery) and across EACH light bulbs 1, 2 and 3.
18.Record the results in Table 2.
Figure 3.
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Investigating Series Circuits
Student Activity Handout
Name: ___________________________
Date: ____________________________
RECORD YOUR RESULTS
[21 marks]
Table 1. Change in Current as the Number of Light Bulbs (Resistors) Increases [12 marks]
Current, I, (Amps)
Number of
Resistors
Brightness of Light
bulbs
Current AFTER each Light Bulb
Total Current
in Circuit
#1
1 Light bulb
#2
#3
N/a
N/a
2 Light bulbs
N/a
3 Light bulbs
Table 2. Change in Potential Difference as the Number of Light Bulbs (Resistors) Increases [9 marks]
Potential difference, V, (Volts)
Number of
Resistors
Across Battery
(Source)
1 Light bulb
Across each Light Bulb
#1
#2
#3
N/a
N/a
2 Light bulbs
N/a
3 Light bulbs
WHAT DOES IT ALL MEAN?
1. What did the moving blue dots in the circuit diagrams represent? [1 mark]
The following questions pertain to your CURRENT observations. Look at your results from Table 1.
2. What happened to the brightness of the light bulbs as more were added? [1 mark]
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Investigating Series Circuits
Student Activity Handout
Name: ___________________________
Date: ____________________________
3. What happened to the current of the total circuit as more light bulbs were added? Justify your answer by
making reference to your data. Hint: Look at the “Total Current in Circuit” column of Table 1. [2 marks]
4. In a series circuit, for a fixed number of resistors (light bulbs), is the current the same at all places in the
circuit? Justify your answer by making reference to your data. [2 marks]
5. Consider your answer to Question 4. Circle the correct equation. Explain your answer using your data.
[3 marks]
Where,
Is is current at the source (battery).
I1 is the current at resistor (light bulb) 1, I2 is the current at resistor (light bulb) 2, etc.
A.
Is = I1 + I2 + I3
B.
Is = I1 = I2 = I3
Explanation:
.
6. For the following circuit, what is the current at resistor 1? Show your work. [2 marks]
.
Is = 1.0
I2 = 1.0
I1 = ?
The following questions pertain to your POTENTIAL DIFFERENCE observations. Look at your results from Table 2.
7. What happened to the potential difference at the source (battery) as more light bulbs were added? Justify
your answer by making reference to your data. 1 [2 marks]
.
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Investigating Series Circuits
Student Activity Handout
Name: ___________________________
Date: ____________________________
8. What happened to the potential difference across each resistor as more light bulbs were added? Justify
your answer by making reference to your data. [2 marks]
.
9. For 3 light bulbs, add the potential difference you recorded across EACH light bulb. What does this
equal? Justify your answer by making reference to your data. [2 marks]
.
10. Consider your answers to Questions 7 - 9. Circle the correct equation. Explain your answer using your
data. [3 marks]
Where,
Vs is the potential differnce at the source.
V1 is the potential difference across resistor (light bulb) 1, V2 is the potential difference at resistor
(light bulb) 2, etc.
A.
Vs = V1 + V2 + V3
B.
Vs = V1 = V2 = V3
Explanation:
.
11. For the following circuit, what is the voltage at resistor 2? Show your work. [2 marks]
.
6 volts
V2 = ?
V1 = 3
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Investigating Series Circuits
Name: Answer Key for Teacher
Student Activity Handout Answer Key
RECORD YOUR RESULTS
43
[21 marks]
Table 1. Change in Current as the Number of Light Bulbs (Resistors) Increases [12 marks]
Current, I, (Amps)
Number of
Brightness of Light
Total Current
Current AFTER each Light Bulb
Resistors
bulbs
in Circuit
#1
#2
1 Light bulb
N/a
Very bright
0.89
0.888
2 Light bulbs
Both, less bright
0.45
0.45
0.45
3 Light bulbs
All, very dim
0.30
0.30
0.30
#3
N/a
N/a
0.30
Table 2. Change in Potential Difference as the Number of Light Bulbs (Resistors) Increases [9 marks]
Potential difference, V, (Volts)
Number of
Across Battery
Across each Light Bulb
Resistors
(Source)
#1
#2
#3
1 Light bulb
N/a
N/a
9.0
8.9
2 Light bulbs
N/a
9.0
4.5
4.5
3 Light bulbs
9.0
3.0
3.0
3.0
1. What did the moving blue dots in the circuit diagrams represent? [1 mark]
Electrons flowing (i.e. the current).
2. What happened to the brightness of the light bulbs as more were added? [1 mark]
As more bulbs were added they ALL got dimmer.
3. What happened to the current of the total circuit as more light bulbs were added? Justify your answer by
making reference to your data. Hint: Look at the “Total Current in Circuit” column of Table 1. [2 marks]
The total current in the circuit was reduced as more light bulbs were added. With one light bulb, the
current was 0.89 amps, when 2 were added the current was 0.45 and when 3 were added the current
was 0.33.
4. In a series circuit, for a fixed number of resistors (light bulbs), is the current the same at all places in the
circuit? Justify your answer by making reference to your data. [2 marks]
Yes, the current was the same at all places in the circuit. When 1 bulb was in the circuit, the current
was 0.89. When 2 bulbs were added the current was 0.45 at all points in the circuit. Likewise, when
3 bulbs were added the current was 0.33 at all points in the circuit.
5. Consider your answer to Question 4. Circle the correct equation. Explain your answer using your data.
[3 marks]
Where,
Is is the sum or total current in the circuit.
I1 is the current at resistor (light bulb) 1, I2 is the current at resistor (light bulb) 2, etc.
A.
Is = I1 + I2 + I3
B.
Is = I1 = I2 = I3
Explanation: The answer is B because the current is the SAME at all place in a series circuit. In the
experiment, for a given number of light bulbs, the total current was the same as the current at all
other points in the circuit. When there were 3 light bulbs, the total current of 0.33 was the same as
the current at resistor 1, 2 and 3.
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Investigating Series Circuits
Name: Answer Key for Teacher
Student Activity Handout Answer Key
6. For the following circuit, what is the current at resistor 1? Show your work. [2 marks]
.
Is = 1.0
Is = I1 = 12
1.0 = R1 + 1.0
R1 = 1.0 amps
I2 = 1.0
I1 = ?
7. What happened to the potential difference at the source (battery) as more light bulbs were added? Justify
your answer by making reference to your data. 1 [2 marks]
The potential difference at the source did not change as more light bulbs were added. The potential
difference was always 9.0 volts.
8. What happened to the potential difference across each resistor as more light bulbs were added? Justify
your answer by making reference to your data. [2 marks]
As more resistors were added, the potential difference across each resistor got lower. For example,
when there was 1 resistor, the potential difference across it was 9.0 volts, when there were 3
resistors, the potential difference across each was 3.0 volts.
9. For 3 light bulbs, add the potential difference you recorded across EACH light bulb. What does this
equal? Justify your answer by making reference to your data. [2 marks]
The potential difference at the source. For 3 light bulbs, the potential difference across each was 3
volts. 3 + 3 + 3 = 9. The potential difference across the source was 9.
10. Consider your answers to Questions 7 - 9. Circle the correct equation. Explain your answer using your
data. [3 marks]
Where,
Vs is the potential difference at the source.
V1 is the potential difference across resistor (light bulb) 1, V2 is the potential difference at resistor
(light bulb) 2, etc.
A.
Vs = V1 + V2 + V3
B.
Vs = V1 = V2 = V3
Explanation: The answer is A because the voltage across the resistors sums to the voltage across
the source. For example, when there are 3 resistors, the voltage across the source is 9 volts, and the
voltage across each resistor is 3 volts.
11. For the following circuit, what is the voltage at resistor 2? Show your work. [2 marks]
.
6 volts
Vs = V1 + V2
6 = 3 + V2
V2 = 3 volts
V2 = ?
V1 = 3
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Investigating Series Circuits
Student Activity Post-Assessment
Name: _____________________________
Birthday: ______________________________
6
1. What happens to the voltage at the source (battery) as you add more light bulbs to a circuit? Explain.
[2 marks]
2. Fill in the blanks. [2 marks]
a. In a series circuit, the total current __________________________ as you add more resistors.
b. In a series circuit, for a fixed number of resistors, the current is ______________________ at
different points in the circuit.
3. For the following circuit, what is the voltage at light bulb 2? Show your work. [2 marks]
.
12 volts
V2 = ?
V1 = 6
10
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Teacher-Created Resources: Student Activity Post-Assessment
Investigating Series Circuits
Student Activity Post-Assessment
Name: _____________________________
Birthday: ______________________________
Answer Key
1. Fill in the blanks. [2 marks]
a. In a series circuit, the total current ____decreases_____________ as you add more resistors.
b. In a series circuit, for a fixed number of resistors, the current is ___the same_____________ at
different points in the circuit.
2. What happens to the voltage at the source (battery) as you add more light bulbs to a circuit? Explain.
[2 marks]
.
The voltage at the source stays the same. Only the voltage across each light bulb drops.
3. For the following circuit, what is the voltage at light bulb 2? Show your work. [2 marks]
.
12 volts
Vs = V1 + V2
12 = 6.0 + V2
V2 = 6.0 volts
V2 = ?
V1 = 6.o
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Teacher-Created Resources: Student Activity Post-Assessment