This document outlines an experiment to compare light globes in series and parallel circuits. It describes connecting 1, 2, or 3 light globes to a power pack in series and parallel configurations and measuring the brightness and voltage of each globe. The aim is to see how brightness and voltage are affected by adding more globes to the circuits in series versus parallel designs. Risks are assessed and methods, results, and discussion are presented to analyze the differences between series and parallel circuits.

1. SERIES AND PARALLEL
YEAR 9 – ELECTRICITY

2. AIM & HYPOTHESIS
Aim: To compare the
brightness of light globes
in series and parallel
circuits.
Hypothesis: (Write your
hypothesis here)

3. EQUIPMENT
• 3 light globes
• power pack
• 10 wires
• switch
• voltmeter

4. RISK ASSESSMENT
Risk
Injury
Prevention
Fill out a risk assessment for your experiment

5. METHOD
1. Connect a circuit (as shown)
containing one globe and turn it
on at 6V. Observe the
brightness of the globe.
2. Use a voltmeter to measure the
amount of energy used by the
globe. Record the voltage.
3. Modify the circuit by inserting
a second globe in series. Note
the brightness of each globe.

6. METHOD
4.
Use a voltmeter to measure the
amount of energy used by each
globe. Record each voltage.
5.
Modify the circuit by inserting a
third globe in series. Note the
brightness of each globe.
6.
Use a voltmeter to measure the
amount of energy used by each
globe. Record each voltage.
7.
Remove one globe from the circuit
and observe what happens.
8.
Repeat steps 2-7 but in a parallel
arrangement.

7. RESULTS
• Series Circuit
Circuit
Description of brightness of each globe
Voltage (V)
One light globe
Two light globes
Three light globes
• Parallel Circuit
Circuit
One light globe
Two light globes
Three light globes
Description of brightness of each globe
Voltage (V)

8. DISCUSSION
1. Draw circuit diagrams to demonstrate the three series and
parallel circuits.
2. Compare the brightness of globes in series with that of
globes in parallel.
3. How does the energy used by each globe in a parallel circuit
differ from the energy used by each globe in a series circuit?
4. Would it be sensible to have all of the ceiling lights in your
home connected in series? Give a reason for your answer.
5. What do you think will happen if you added a fourth globe
in the series circuit? What about the parallel circuit?
6. List two advantages of a parallel circuit over a series circuit.
7. Give one advantage of a series circuit over a parallel circuit.

9. CONCLUSION
Write a conclusion for your experiment here.