Series vs Parallel

Overview

This 60-minute lesson enables Year 7 students to compare and contrast series and parallel electrical circuits through investigation and practical experiments. It aligns with the National Curriculum for England’s Key Stage 3 Science programme, focusing on recognising common components, understanding circuit behaviour, and interpreting how current works in different circuit configurations.

National Curriculum Links

Relevant Programme of Study:

Key Stage 3 Science – Electricity
- Pupil can:
  - Associate the brightness of a lamp or the volume of a buzzer with the number and voltage of cells used in a circuit.
  - Understand that current is the same at all points in a series circuit, but may split in a parallel circuit.
  - Recognise and use circuit symbols to draw circuits.
  - Plan and conduct investigations to explore ideas and answer questions about circuits.

Learning Objectives

By the end of this lesson, students will:

Describe and differentiate series and parallel circuits using correct terminology.
Explain how electric current behaves in series and parallel circuits (constant in series, splits at junctions in parallel).
Assemble simple series and parallel circuits using circuit components safely.
Collect and record data on current flow to identify differences between circuit types.
Interpret results to relate theory with evidence from their experiments.

Resources

Battery holders, 1.5V cells
Wires with crocodile clips
Small bulbs (with holders)
Ammeters (one per group)
Switches
Circuit component cards with symbols
Worksheets for recording observations and predictions
Whiteboard and markers
Prepared circuit diagrams on A3 paper

Lesson Structure

Starter (10 minutes)

Engage & Recap:

Quick recall quiz on components and symbols (e.g., bulbs, wires, switches).
Discuss: "What is an electrical circuit?" and recap previous lessons on series circuits basics.
Introduce today’s learning focus: series vs parallel circuits.
Show animations or diagrams contrasting simple series and parallel circuits.
Teacher asks: "How do you think the current behaves at junctions?" Collect ideas.

National Curriculum focus: Recall components and their functions; scientific enquiry through questioning.

Main Activities (40 minutes)

Activity 1: Construct and Observe Series Circuit (15 minutes)

Students work in groups of 3-4 to build a simple series circuit: 1 battery, 2 bulbs, 1 ammeter, and a switch.
Predict before switching on (e.g., will both bulbs be equally bright? Will current change?) and record in worksheet.
Measure current at different points in the circuit (before first bulb, between bulbs, after second bulb) to see if it remains constant.
Teacher circulates monitoring correct use of equipment and encourages scientific discussion.
Group discussion: "What does the current tell us about series circuits?"

Curriculum links: Plan and conduct investigations; interpret current measurements.

Activity 2: Construct and Observe Parallel Circuit (20 minutes)

Using the same groups, students then build a parallel circuit: 1 battery, 2 bulbs each on their own branch, 1 ammeter placed before the branches and optionally on each branch.
Predict current behaviour at junctions (where circuit splits) on worksheet.
Measure current before junction and along each branch to observe how current splits.
Compare bulb brightness to series circuit findings.
Class discussion prompted by teacher: "How does current differ here from the series circuit? What would happen if one bulb goes out?"
Summarise findings: current splits at parallel branches; bulbs may be brighter.

Curriculum links: Use evidence to support explanations; interpret current behaviour in circuits.

Plenary (10 minutes)

Groups share findings with the class in a short presentation (2 minutes each). Focus on explaining current flow and observations of bulb brightness.
Teacher uses whiteboard to create a comparison table: series vs parallel circuits on current flow, bulb brightness, and circuit behaviour.
Final question to class: “Why might we choose parallel circuits for household wiring?” (Emphasising practical applications)
Exit ticket: Write one key difference between series and parallel circuits.

Curriculum links: Communicate scientific ideas clearly; apply knowledge to real-world contexts.

Assessment

Formative: Observing group discussions, measuring accuracy in using ammeters, and completing worksheet predictions and results.
Summative: Exit ticket summarising key differences between circuits to check conceptual understanding.
Peer and teacher feedback during this lesson supports misconceptions correction.

Differentiation

Support: Provide labelled circuit diagrams and symbol cards with visual aids. Give step-by-step instructions for circuit building. Teacher or teaching assistant supports less confident practical learners.
Extension: Challenge advanced learners to add a third bulb or more branches and predict current changes. Ask students to explain how voltage might behave in these circuits.
Encourage use of correct scientific vocabulary with sentence stems (e.g., “In a series circuit…”, “Current splits because…”).

Safety Considerations

Emphasise safe handling of batteries and wires.
Ensure students switch off circuits before changing components.
Check equipment for damage prior to use.

This lesson ensures students not only understand the abstract concept of current behaviour in circuits but also engage practically with hands-on experiments that consolidate learning through direct observation, evidence interpretation, and scientific communication — fully in line with the National Curriculum’s intent for Key Stage 3 science.

Teaching Instructions