| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Explain conduction in solids in terms of the movement of free (delocalised) electrons in metallic conductors |
Learning Objective/s:
- Describe the free‑electron model and why metals conduct electricity.
- Explain how an applied electric field creates drift velocity and relates to current density.
- Derive Ohm’s law from the electron model and identify the factors that affect resistivity.
- Compare conduction mechanisms in metals, insulators and semiconductors.
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Materials Needed:
- Projector or interactive whiteboard
- PowerPoint slides on the free‑electron model
- Diagram of a metal lattice with an electron sea (digital or printed)
- Handout of conductivity and resistivity values
- Simple circuit kit (wire, battery, ammeter)
- Worksheet with practice questions
- Calculators
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Introduction:
Begin with a quick demonstration: connect a battery to a piece of copper wire and ask students what they observe. Recall that electric current is the flow of charge and that metals feel warm when current passes. State that by the end of the lesson students will be able to explain metallic conduction using free electrons and link it to Ohm’s law.
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Lesson Structure:
- Do‑now (5') – Prompt: “Why do metals feel colder than wood when touched?” to activate prior ideas about electrons.
- Mini‑lecture (10') – Present the free‑electron model with the lattice diagram; highlight the sea of delocalised electrons.
- Guided derivation (12') – Work through drift velocity, current density (J = ne vₙ) and derive V = IR; intersperse concept questions.
- Interactive demonstration (8') – Use the circuit kit to show how changing length or cross‑section alters current; students record observations.
- Group activity (10') – Analyse the conductivity table; complete a chart linking n, τ, A, L to resistivity.
- Practice questions (10') – Solve the resistance calculation and explain the temperature effect; teacher circulates for feedback.
- Exit ticket (5') – One‑sentence summary of metallic conduction and one lingering question.
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Conclusion:
Summarise that metallic conduction arises from a sea of delocalised electrons whose drift under an electric field produces current and obeys Ohm’s law. Collect exit tickets, address any misconceptions, and assign homework: calculate the resistance of a specified aluminium wire and write a short paragraph comparing metal and semiconductor conduction.
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