| Lesson Plan |
| Grade: |
Date: 01/12/2025 |
| Subject: Physics |
| Lesson Topic: recall that the Boltzmann constant k is given by k = R / NA |
Learning Objective/s:
- Describe the relationship between the macroscopic ideal‑gas law (pV = nRT) and its microscopic form (pV = NkT).
- Derive the expression k = R / NA from the two forms of the ideal‑gas law.
- Apply the Boltzmann constant to calculate average kinetic energy and root‑mean‑square speed of gas molecules.
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Materials Needed:
- Projector and screen
- Whiteboard and markers
- Printed worksheet with derivation steps and practice problems
- Scientific calculators
- Handout of constants (R, NA, k)
- Interactive gas‑particle simulation (e.g., PhET)
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Introduction:
Begin with a quick question: “What does temperature tell us about the motion of individual molecules?” Students recall the ideal‑gas law and Avogadro’s number. Explain that today they will link these macroscopic ideas to a single‑particle constant and will be able to use it in calculations.
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Lesson Structure:
- Do‑now (5'): Quick revision checklist – students write pV = nRT and pV = NkT and list values of R, NA, k.
- Mini‑lecture (10'): Derive k = R / NA by substituting n = N/NA into the ideal‑gas law and comparing with pV = NkT.
- Guided example (10'): Calculate the average kinetic energy ⟨Ekin⟩ = 3/2 kT for a given temperature.
- Interactive simulation (10'): Students explore a gas‑particle model to see how temperature affects rms speed, then compute vrms = √(3kT/m).
- Formative check (5'): Exit‑ticket – write the derived formula for k and one real‑world application.
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Conclusion:
Summarise how the Boltzmann constant bridges macroscopic gas behaviour and microscopic particle energy. Collect exit‑tickets as a quick retrieval check. For homework, assign the worksheet’s additional problems on kinetic energy and rms speed calculations.
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