Part 1: Series Circuit with Two Resistors, Designed in Terms of Resistance
1. Design a circuit that has two resistors connected in series. Given that you have a 20 V battery, choose resistors that will produce a current of 0.2 A. Record the resistance in data table 1.
Using the flash animation available on the launch page of the lab activity, construct a series circuit according to the specifications. Represent your circuit on graph paper, labeling each element in the circuit. Calculate the current through and voltage drop across each resistor, and record in data table 1.
2. Using the ammeter and voltmeter, determine the current through and voltage drop across each resistor by touching leads to the wires before and after each individual resistor.
Part 2: Parallel Circuit with Two Resistors, Designed in Terms of Resistance
3. Design a circuit that has two resistors connected in parallel. Given that you have a 20 V battery, choose resistors that will produce a current of 1.5 A. Record the resistance in data table

2.Using the flash animation available on the launch page of the lab activity, construct a parallel circuit according to the specifications. Represent your circuit on graph paper, labeling each element in the circuit. Calculate the current through and voltage drop across each resistor, and record in data table 2.
4. Using the ammeter and voltmeter, determine the current through and voltage drop across each resistor.
Part 3: Series Circuit with One Resistor, Designed in Terms of Potential Difference (Voltage)
5. Design a circuit that has a single resistor connected in series. Given that you have a 100 Ω
resistor, calculate a power source voltage that will produce a current of 0.4 A.
Use the instructions provided in step 1 to build the circuit.
6. Calculate the current through and voltage drop across the resistor, and record the values in data table 3.

7. Using the ammeter and voltmeter, determine the current through and voltage drop across the resistor.
Part 4: Parallel Circuit with Two Resistors, Designed in Terms of Potential Difference (Voltage)
8. Design a circuit that has two resistors connected in parallel. Given that you have a 22.5 Ω
equivalent resistance, calculate a power source voltage that will produce a current of 0.8 A.
Record the resistance and voltage in data table 4.
Use the instructions provided in step 1 to build the circuit.
9. Calculate the current through and voltage drop across each resistor, and record the values in
data table 4.
10. Using the ammeter and voltmeter, determine the current through and voltage drop across
each resistor. Record the values in data table 4.
Data Table 4: Parallel Circuit with Two Resistors, Designed in Terms of Potential Difference
(Voltage)
Resistance (Ω) Calculated
voltage (V)
Experimental
voltage (V)
Calculated
current (A)
Experimental
current (A)
Part 5: Series Circuit with Two Resistors with Unknown Current
11. Design a circuit that has two resistors connected in series. Use one 60 Ω resistor, one 20 Ω
resistor. Connect these two resistors to a 20 V battery.

Use the instructions provided in step 1 to build the circuit.
12. Calculate the current through and voltage drop across each resistor, and record the values in
data table 5.
13. Using the ammeter and voltmeter, determine the current through and voltage drop across
each resistor. Record the values in data table 5.
Data Table 5: Series Circuit with Two Resistors, Effect of Individual Resistors
Resistance (Ω) Calculated
voltage (V)
Experimental
voltage (V)
Calculated
current (A)
Experimental
current (A)
R1 = 60
R2 = 20
Part 6: Parallel Circuit with Two Resistors with Unknown Current
14. Design a circuit that has two resistors connected in parallel. Use one 100 Ω resistor and one
30 Ω resistor. Connect these two resistors to a 20 V power source.
Use the instructions provided in step 1 to build the circuit.
15. Calculate the current through and voltage drop across each resistor, and record the values in
data table 6.
16. Using the ammeter and voltmeter, determine the current through and voltage drop across
each resistor. Record the values in data table 6.
Data Table 6: Parallel Circuit with Two Resistors, Effect of Individual Resistors
Resistance (Ω) Calculated
voltage (V)
Experimental
voltage (V)
Calculated
current (A)
Experimental
current (A)
R1 = 100
R2 = 30
Part 7: Series Circuit with One Resistor, Designed in Terms of Current Through Electric Circuit

Elements
17. Design a circuit that has a single resistor connected in series. Choose a resistor that will
provide 20 W of power from a 40 V power source.
Use the instructions provided in step 1 to build the circuit.
18. Calculate the current through and voltage drop across each resistor, and record the values in
data table 7.
19. Using the ammeter and voltmeter, determine the current through and voltage drop across
each resistor. Record the values in data table 7.
Data Table 7: Series Circuit with One Resistor, Designed in Terms of Current Through Electric
Circuit Elements
Resistance (Ω) Calculated
voltage (V)
Experimental
voltage (V)
Calculated
current (A)
Experimental
current (A)
40 0.5
Part 8: Parallel Circuit with Two Resistors, Designed in Terms of Current Through Electric
Circuit Elements
20. Design a circuit that has two resistors connected in parallel. Choose resistors that will each
provide 5 W of power from a 20 V power source.
Use the instructions provided in step 1 to build the circuit.
21. Calculate the expected current through and voltage drop across each resistor, and record the
values in data table 8.
22. Using the ammeter and voltmeter, determine the current through and voltage drop across
each resistor. Record the values in data table 8.
Data Table 8: Parallel Circuit with Two Resistors, Designed in Terms of Current Through
Electric Circuit Elements
Resistance (Ω) Calculated
voltage (V)
Experimental
voltage (V)
Calculated
current (A)
Experimental
current (A)

Part 9: Open Circuit Investigation
23. Construct a simple series circuit with one resistor. Use the circuit building interactive
linked on the Dry Lab page of this activity to answer question 24.
24. Use the voltmeter and ammeter to determine the voltage and current of the circuit. Open
the switch, and again measure the voltage and current of the circuit.
What happened to the voltage and current after the switch was opened?
Part 10: Use of Power by Lightbulbs Investigation
25. Design a simple circuit using one lightbulb and the instructions from step 1. Set the
power source at 20 V. Use the ammeter to determine the total current in the circuit as an
indication of its use of power.
What happens to the bulbs’ use of power if you add a second bulb with the same resistance
in series with the first?
Remove the second lightbulb, and then design a parallel circuit using two lightbulbs that
have the same resistance. How does the use of power in the parallel circuit compare to the
use of power in the simple circuit with one bulb?
26. Suppose you have a circuit with two lightbulbs that have the same resistance connected
in series and you have another circuit with two lightbulbs with the same resistance
connected in parallel. What would happen if you disconnected one bulb in each circuit?
Using a fixed 20 V from the power source and three lightbulbs that have the same

resistance, how would you design a circuit that would allow at least one bulb to use
maximum power (have maximum brightness)?
27. Test your idea by constructing the circuit. Record your observations of the power usage
along different parts of the circuit below.
Analyze
1. What happens to the current provided by a power source as more resistors are connected
in series?
2. What happens to the current provided by a power source as more resistors are connected
in parallel?
Draw Conclusions
1. What must be true about the sum of the voltage lost across each resistor connected in
series?
2. What happens to the power dissipated by a resistor as the current through the resistor
increases?

3. Three lightbulbs are connected in a series. A switch is placed between the first lightbulb
and the second lightbulb. If that switch is opened, what happens to each of the three
lightbulbs?
Explore Further
Materials:
Part 1:
Simple plug-in night-light
Part 2:
Electrostatics kit (plastic rod and electroscope)
Small piece of wool
Part 3:
Horseshoe magnet
Cathode ray tube
Part 4:
Bar magnet
Container of iron filings
White craft paper
Magnetic compass
Part 1: Household Circuit Field Investigation
In this field investigation, you will explore household circuits in which the circuit breaker
switches are labeled with the circuits’ location. Flip the switch for one location, then
determine what is not working in that area as a result. Test the outlets in that area by
plugging in a night-light. Which outlets work? Which do not? Which light switches turn on?
Which do not? Which electrical devices may have turned off as a result of the switch being
flipped? What do your observations indicate about the circuit design of the household?
CAUTION: Observe proper field safety guidelines for this study:
1. Make sure a teacher or other responsible adult is aware of your plans and has approved

your intended studies.
2. Work with at least one other student.
3. Ensure that no equipment is operating in the household that would be damaged or would
cause an individual harm if it were briefly turned off.
Part 2: Electrostatics Investigation
Rub the plastic rod from the electrostatics kit with the piece of wool. Touch the rod to the
electroscope. What happens to the leaves on the electroscope? What does this tell you
about the charge on the rod?
Part 3: Cathode Ray Tube Investigation
Set up the cathode ray tube according to instructions for your device. Move the horseshoe
magnet around the cathode ray tube. What do you observe?
Part 4: Magnetism Investigation
Roll out a large piece of white craft paper. Lay a bar magnet in the middle of the craft paper.
Sprinkle some iron filings around the magnet and observe. Now try the experiment again
with a horseshoe magnet instead of a bar magnet. What do the iron filings show you? Now
move a magnetic compass to various positions around the magnet. What does the varying
position of the compass needle tell you?
Set up a simple series circuit and connect it to the power source. Plan a way in which to
observe the connection between electric charge and magnetic fields and forces. What piece
of equipment should you use? What do your observations illustrate about the relationship
between moving electric charges and magnetic fields/forces?