1. What are series and parallel circuits?
29 April 2019
What are series and parallel circuits?
Key terms: series circuit, parallel circuit
Secure:
I can define the terms: series circuit and parallel circuits.
I can describe how the number of components affects the current and how switches can control different kinds of circuits.
Develop:
Exceed:
Starter: most common link made by students is to TV series and series that run parallel to each other (spin offs)
I can describe the differences in current and voltage in series and parallel circuits.
Starter: What do the terms series and parallel mean? Where have you seen them before?

2. A series circuit has all its components wired in the same loop.
A parallel circuit contains junctions and so there is more than one path for the current.
e.g. tree lights are wired in series.
e.g. car headlights are wired in parallel.

3. TASK: Applying learning
M – textbook
I – individually
N – silently
T – 10 mins A B
Bronze
Silver
Gold
Define the terms series circuit and parallel circuit.
Bronze plus…
Draw a circuit diagram for picture A. Label it series or parallel.
Silver plus…
Draw a circuit diagram for picture B. Label it series or parallel.
Draw the silver task onto the board and discuss what the switches do in circuit B.
EXTENSION: Describe how adding switches to both circuits would effect if the bulbs came on.

4. A: Series circuit
Draw some switches over the diagram and ask the students what might happen to the bulbs.

5. Draw some switches over the diagram and ask the students what might happen to the bulbs.
B: Parallel circuit

6. Compare the brightness of the bulbs in the two circuits.
TASK: Series circuits
M – electrics kit
I – as a table
N – quietly
T – 15 min
Construct the circuit diagrams shown on the white board using your components.
Bronze
Silver
Gold
Compare the brightness of the bulbs in the two circuits.
Explain in terms of voltage why the brightness of the bulbs in the two circuits is different.
Explain why the brightness of the bulbs in the two circuits is different. Describe what you think is happening to the current.
EXTENSION: Describe how the light bulbs effect the current, in terms of resistance.
Stretch and challenge: Explain why there will be a difference in current in both circuits.

7. Circuit 1
Circuit 2

9. Current in a series circuit
In a series circuit, the current flows through one continuous pathway.
This is because the electrons have to flow at the same rate through all the component in the circuit.
The current is the same in all parts of a series circuit.

10. Potential difference in a series circuit
6 V V V V
3 V
3 V
In a series circuit, the voltage supplied by the battery is shared by the components.
The sum of the potential difference across the components equals the battery voltage.
As more bulbs are added in series, each bulb has less potential difference and so the bulbs become dimmer.

11. What is a parallel circuit?
29 April 2019
What is a parallel circuit?
Key terms: series circuit, parallel circuit, current, voltage and resistance
I can define and identify series circuit and parallel circuits.
Secure:
I can construct a circuit from a given circuit diagram and how the current and voltage behave in a parallel circuit.
Develop:
Exceed:
I can explain the differences in current and voltage in series and parallel circuits.
Starter: Write down everything you remember about series circuits.

12. Compare the brightness of the bulbs in the two circuits.
TASK: Parallel circuits
M – electrics kit
I – as a table
N – quietly
T – 15 min
Construct the circuit diagrams shown on the white boards using your components.
Bronze
Silver
Gold
Compare the brightness of the bulbs in the two circuits.
Explain why in the parallel circuit the bulbs have equal brightness in terms of voltage.
Explain why in the parallel circuit the bulbs have equal brightness. Describe what you think is happening to the current in this circuit.
EXTENSION: Describe how you could prove this using an ammeter and voltmeter.
Stretch and challenge: Explain why the battery will run out quicker in a parallel circuit.

13. Circuit 1
Circuit 2

15. Current in a parallel circuit
In a parallel circuit, the current divides at the point where the circuit branches and then recombines to complete the circuit.
The current is not the same in all parts of a parallel circuit.

16. Voltage in parallel circuits
In a parallel circuit, the voltage across each bulb is the same as the potential difference across the battery.
6 V V
6 V V
All bulbs will have the same brightness. V
The amount of energy each electron is carrying is unchanged.
However, this also means that the battery will run down faster in a parallel circuit.
6 V

17. RECAP: Our models…
Levels 5-6

18. Linking this to our models…
Levels 5-6

19. Linking this to our models…
Levels 5-6

20. Write one difference between a series and parallel circuit.
TASK: Comparing circuits
M – class book
I – individually
N – quietly
T – 8 mins
Bronze
Silver
Gold
Write one difference between a series and parallel circuit.
Complete the table to describe the differences in series and parallel circuits.
Write an extended paragraph describing the differences in series and parallel circuits in term of voltage and current.
EXTENSION: Given your knowledge of series and parallel circuits – how do you think our school is wired? Give reasons for your answer.

21. Series circuit Parallel circuit
What happens to the current?
(people walking round)
What happens to the voltage?
(energy - paper you were holding)

22. Series circuit Parallel circuit
What happens to the current?
(people walking round)
Stays the same the whole way round.
It will become lower the more components that are added.
Splits between the loops of the circuit.
Will not be the same all the way round.
What happens to the voltage?
(energy - paper you were holding)
Splits between the bulbs (components)
Is the same at each bulb (component).

23. Secure: Develop: Exceed: Confidence Check Not confident In between
Super confident
Secure:
I can define the terms: series circuit and parallel circuits.
I can describe how the number of components affects the current and how switches can control different kinds of circuits.
Develop:
Assess pupils by asking them to express their confidence in their achievement from 1-5 for the lesson aims.
Exceed:
I can describe the differences in current and voltage in series and parallel circuits.

24. Worksheet 2 accompanies this slide.
The worksheet involves a simple role play to model a circuit.

25. Plenary:
Series
Parallel vs
Levels 5-6