Electrical Resistance

Lesson Overview

This 60-minute session introduces Year 10 pupils to the concepts of electrical resistance, resistors, and Ohm’s Law, fully aligned with the National Curriculum for England (KS4 Physics - 4.4.2). The lesson will incorporate interactive explanations, online simulations, and targeted questioning to promote deep understanding despite the remote setting.

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National Curriculum Links

• Physics Key Stage 4 (Years 10-11)
  • 4.4.2 Electric Circuits: Use the idea of electrical resistance to explain how the current, voltage and resistance in a circuit relate to one another
  • Working scientifically (KS4): planning and analysing practical work, interpreting data and using quantitative relationships
• Focus on:
  • Understanding that resistance causes energy transfer in electrical circuits.
  • Apply and rearrange Ohm’s Law (V = IR).
  • Practical skills via digital simulations replicating real-world experimental investigations.

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Learning Objectives

By the end of the lesson, the pupil will be able to:

1. Define electrical resistance and describe its role in an electrical circuit.
2. Explain the function of resistors and identify their symbols on circuit diagrams.
3. State and apply Ohm’s Law to calculate voltage, current, and resistance.
4. Analyse circuit behaviour using an online simulation to model how resistance affects current.
5. Evaluate how practical experiments can measure resistance and interpret data critically.

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Key Concepts

• Electrical Resistance: Opposition to the flow of electric current. Measured in ohms (Ω).
• Resistors: Components designed to provide a specific resistance. Purpose includes controlling current and protecting circuits.
• Ohm’s Law: The fundamental equation ( V = IR ), connecting voltage (V), current (I), and resistance (R).
• Energy Transfer: Relation to current flow and heating effects in resistors.

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Resources

• Online circuit simulation tool (e.g., PhET Circuit Construction Kit - ensure chosen platform doesn’t require accounts)
• Digital whiteboard or shared screen for diagrams
• Pre-drawn virtual circuit diagrams (PDF or image files)
• Calculator application
• Worksheet with Ohm’s Law calculation problems
• Padlet or shared Google Doc for collaborative answers and reflections

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Lesson Breakdown

1. Introduction (10 minutes)

• Starter question: "What do you think happens when electricity flows through a wire?" (Use chat or voice)
• Definition of electrical resistance in simple terms with analogy (e.g., water flow through pipes).
• Show symbols for resistors on virtual whiteboard. Discuss where resistors appear in everyday objects.
• Link to prior knowledge: remind about current and voltage concepts covered in Years 7-9.

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2. Explanation & Demonstration (15 minutes)

• Introduce Ohm’s Law: write ( V = IR ) on virtual board. Explain what each variable represents, including units.
• Manipulate the formula (calculate I and R).
• Show worked examples of calculations.
• Use an online simulation: build a circuit with a battery, resistor, and ammeter/voltmeter. Adjust resistance and observe current changes in real-time.
• Discuss observations: What happens to the current if resistance increases?

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3. Guided Practice (15 minutes)

• Share worksheet problems including:
  • Calculating resistance when voltage and current are given.
  • Predict the current for a modified circuit with changed resistance.
• Pupil works through problems with teacher providing hints via chat or voice.
• Use Padlet/Collaborative doc for pupil to type their answers and reasoning.
• Teacher gives instant formative feedback.

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4. Independent Application (10 minutes)

• Ask the pupil to use the online simulation independently to:
  • Build a circuit with at least two resistors.
  • Vary resistors and hypothesise the effect on total current.
  • Record voltage and current readings.
• Have the pupil explain their findings either by typing or verbally summarising (microphone).
• Encourage linking observations back to Ohm’s Law.

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5. Recap and Assessment (10 minutes)

• Recap key points with targeted questioning.
• Quick quiz (4 questions):
  1. Define resistance.
  2. What type of component is used to provide resistance?
  3. Calculate voltage when current is 3A and resistance is 4Ω.
  4. Explain what happens to current if resistance doubles while voltage stays the same.
• Formative assessment based on quiz results and pupil explanations.
• Discuss real-world applications briefly (e.g., how resistance is used in household heating).

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Summary

In this lesson, the pupil explored electrical resistance and resistors, applied Ohm’s Law to solve problems, and engaged in an interactive simulation reflecting real circuits. By relating theoretical concepts to practical digital experiments, the pupil developed core physics skills aligned fully with KS4 expectations in the national curriculum, preparing them for both academic and real-world understanding of electric circuits.

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Optional Extension Ideas for Homework or Future Lessons

• Research items in the home that use resistors and explain how.
• Design a simple series or parallel circuit and predict how total resistance changes.
• Investigate the factors affecting resistance (material, length, thickness) for next lesson.

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This plan ensures active engagement, formative feedback, and cross-links scientific knowledge with practical skills, tailored to single-pupil online teaching whilst adhering strictly to the national curriculum standards for Year 10 Science.