| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Explain, in terms of the motion and arrangement of particles, the relative order of magnitudes of the expansion of solids, liquids and gases as their temperatures rise |
Learning Objective/s:
- Describe how particle motion changes with temperature in solids, liquids, and gases.
- Explain why thermal expansion follows the order gas > liquid > solid.
- Compare typical expansion coefficients for each state of matter.
- Apply the concept to real‑world examples such as bridges, thermometers, and hot‑air balloons.
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Materials Needed:
- Projector and screen for diagrams
- Whiteboard and markers
- Printed worksheet with comparative table
- Sample materials (metal rod, liquid thermometer, balloon) for demonstration
- Calculator for coefficient calculations
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Introduction:
Begin with a quick demonstration: heat a metal rod and observe its slight length change, then compare with a balloon inflating when heated. Ask students what they already know about particle motion in different states of matter. State that by the end of the lesson they will be able to articulate the relative expansion magnitudes and the particle‑level reasons behind them.
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Lesson Structure:
- Do‑now (5'): Students answer a short question on particle spacing in solids vs. gases; teacher checks responses.
- Mini‑lecture (10'): Explain particle arrangements and kinetic‑energy increase using slides and the comparative table.
- Guided inquiry (12'): Small groups analyse data on expansion coefficients and rank the states; teacher circulates to support reasoning.
- Demonstration (8'): Heat a metal rod, a liquid thermometer, and a balloon; students record observations and link them to particle explanations.
- Check for understanding (5'): Quick quiz (exit ticket) with two conceptual questions on magnitude order and particle behaviour.
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Conclusion:
Recap the key idea that gases expand the most, liquids moderately, and solids the least because of differences in particle freedom and inter‑particle forces. Collect the exit tickets to gauge understanding and assign a short homework: calculate the expected length change of a 1 m metal rod heated from 20 °C to 100 °C using the linear expansion coefficient.
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