December 2021 What are series and parallel circuits

December 2021 What are series and parallel circuits? Key terms: series circuit, parallel circuit Secure: I can define the terms: series circuit and parallel circuits. Develop: Exceed: I can describe how the number of components affects the current and how switches can control different kinds of circuits. I can describe the differences in current and voltage in series and parallel circuits.

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.

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

A: Series circuit

B: Parallel circuit

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

Circuit 2 Circuit 1

Current in a series circuit 1 A A A 1 A • In a series circuit, the current flows through one continuous pathway. • The current is the same in all parts of a series circuit.

Potential difference in a series circuit V V 3 V 6 V 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.

December 2021 What is a parallel circuit? Key terms: series circuit, parallel circuit, current, voltage and resistance Secure: I can define and identify series circuit and parallel circuits. Develop: Exceed: I can construct a circuit from a given circuit diagram and how the current and voltage behave in a parallel circuit. I can explain the differences in current and voltage in series and parallel circuits.

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

Circuit 2 Circuit 1

Current in a parallel circuit 2 A A A 2 A 1 A A A 1 A • 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.

Voltage in parallel circuits • In a parallel circuit, the voltage across each bulb is the same as the potential difference across the battery. V V 6 V 6 V • All bulbs will have the same brightness. • However, this also means that the battery will run down faster in a parallel circuit. V 6 V

RECAP: Our models…

Linking this to our models…

TASK: Comparing circuits Bronze Silver M – class book I – individually N – quietly T – 8 mins Gold Write one difference Complete the table to Write an extended between a series and describe the paragraph describing parallel circuit. differences in series the differences in and parallel circuits. 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.

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

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

Confidence Check Not confident Secure: In between Super confident I can define the terms: series circuit and parallel circuits. Develop: Exceed: I can describe how the number of components affects the current and how switches can control different kinds of circuits. I can describe the differences in current and voltage in series and parallel circuits.

Plenary: Series vs Parallel