Voltage, Current, Resistance

Lesson Details

• Unit: Circuit Connections Unveiled (Lesson 2 of 4)
• Duration: 50 minutes
• Class Size: 30 students
• Year Group: 10
• Subject: Science (Physics - Electricity)
• National Curriculum Reference:
  • KS4 Science Programme of Study (Physics)
  • Electrical circuits: apply understanding of current, voltage, resistance and power relationships; link to Ohm’s Law (NC ref: Physics, GCSE, Electricity - Electrical circuits, parameters and calculations).
  • Working scientifically: use quantitative measurements, including volts and amps.

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Learning Objectives (WALT)

• We Are Learning To (WALT):
  • Define and explain voltage, current, and resistance in electrical circuits.
  • Understand and apply Ohm’s Law (V = I × R) to calculate voltage, current, or resistance in simple circuits.
  • Interpret and construct simple circuit diagrams including measurement components (ammeter and voltmeter).

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Success Criteria

• I can clearly define voltage, current, and resistance using everyday analogies and scientific terms.
• I can accurately calculate voltage, current, or resistance when given two of the values using Ohm’s Law.
• I can draw simple circuit diagrams including ammeters and voltmeters, showing correct placement.
• I can explain the relationship between voltage, current, and resistance in a circuit.

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Resources Needed

• Whiteboard & markers
• PowerPoint/slideshow with definitions, diagrams, and examples
• Circuit simulation software or online app (e.g., PhET Circuit Construction Kit) – classroom tablet or PC access
• Simple circuit kits (batteries, wires, resistors, ammeters, voltmeters) – ideally 5 sets for group work
• Worksheet with definitions, calculation practice, and blanks for circuit diagrams
• Dyslexia-friendly printed worksheets (with clear font, spacing, and colour coding for terms)
• Calculator (scientific or basic)

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Lesson Structure

1. Starter (5 minutes)

Objective: Activate prior knowledge & introduce topic with a relatable analogy.

• Begin with an everyday analogy for electricity: Water flow in pipes.
  • Voltage = pressure pushing water through pipe
  • Current = flow of water
  • Resistance = size/thickness of pipe restricting flow
• Quick Think-Pair-Share: Students discuss in pairs what they already know about voltage, current, and resistance.
• Share class ideas and write key terms on whiteboard.

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2. Introduction & Explanation (10 minutes)

Objective: Define terms and introduce Ohm’s Law.

• Present clear definitions using a slide:

  • Voltage (V): The electrical potential difference that pushes current through a circuit (measured in volts, V).
  • Current (I): The flow of electric charge (measured in amperes, A).
  • Resistance (R): The opposition to current flow (measured in ohms, Ω).

• Explain Ohm’s Law: V = I × R

  • Show formula triangle for easy calculation rearrangement.
  • Give simple numeric examples showing substitution.

• Highlight where ammeters and voltmeters are placed in circuits and why.

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3. Guided Group Activity (15 minutes)

Objective: Practical understanding and application of concepts.

• Divide class into groups of 5. Each group given circuit kits + worksheet.
• Task: build simple circuits and use ammeters/voltmeters to measure current and voltage.
• Use measurements and Ohm’s Law to calculate resistance.
• Circulate to support students, addressing difficulties and questioning groups on their reasoning.
• Use circuit simulator for groups who finish early or for those needing alternative format (computer use).

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4. Class Discussion & Consolidation (10 minutes)

Objective: Deepen understanding and clear misconceptions.

• Groups share findings - what did they measure and calculate?
• Discuss how changing resistance affects current and voltage.
• Clarify any misunderstandings, reinforce key concepts.
• Use a quick quiz: flashcards or verbal questions with hands-up responses.

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5. Independent Practice and Differentiated Worksheet (7 minutes)

Objective: Reinforce calculations and definitions.

• Students complete differentiated worksheets:

  • Standard: calculating one unknown using Ohm’s Law with guided help.
  • Support: matching terms to definitions, simple circuit labelling.
  • Extension: word problems involving multi-step calculations, reasoning with complex scenarios (e.g. two resistors in series).

• Dyslexia-friendly materials provided in all groups.

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6. Plenary (3 minutes)

Objective: Reflect on learning and confirm success criteria.

• Ask students to write a brief answer to:
  “How does resistance affect the current in a circuit if the voltage stays the same?”
• Share some responses aloud.
• Recap learning objectives and success criteria verbally.

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Differentiation

• Visual learners: use diagrams, circuit simulations, colour-coded worksheets.
• Kinesthetic learners: hands-on circuit building and measuring.
• Dyslexic learners: dyslexia-friendly reading options; simplified fonts; oral instructions; peer support.
• Advanced learners: additional extension problems and explanations relating to resistors in series and parallel as a preview for the next lesson.

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Assessment for Learning

• Observations during group work and questioning.
• Worksheet completion and accuracy.
• Plenary short-answer responses to assess conceptual understanding.

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Extension Activities for Higher Attainers

• Investigate how Ohm’s Law changes for non-ohmic components (e.g. filament bulb, diode).
• Explore series and parallel resistor calculations with given voltages and currents.
• Design a circuit to achieve a specific resistance and current with given voltage source.

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Homework / Further Study Suggestion

• Research real-life applications of current, voltage, and resistance — e.g., how electrical engineers use these concepts to design household wiring.
• Complete additional online Ohm’s Law quizzes or interactive simulations (offline for classrooms without internet).

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This detailed, inclusive plan follows the national curriculum requirements for KS4 Physics, ensuring students gain foundational knowledge and skills required for understanding electrical circuits and Ohmic behaviour. It uses mixed teaching approaches for engagement, practical learning, and provides scaffolded support to maximise progress for all learners.