Lesson Plan

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Lesson Plan
Grade: Date: 25/02/2026
Subject: Physics
Lesson Topic: recall and use Wien’s displacement law λmax ∝ 1 / T to estimate the peak surface temperature of a star
Learning Objective/s:
  • Recall Wien’s displacement law and its constant.
  • Apply the law to calculate a star’s surface temperature from its peak wavelength.
  • Convert wavelength units correctly and interpret the resulting temperature in terms of stellar classification.
  • Identify common errors when using Wien’s law and propose corrective strategies.
Materials Needed:
  • Projector or interactive whiteboard
  • Slides with example spectra
  • Worksheet with wavelength‑to‑temperature problems
  • Scientific calculators or spreadsheet software
  • Printed spectral data handouts
  • Whiteboard and markers
 Introduction:
Begin with a striking image of a rainbow‑colored star spectrum and ask students what determines the colour of a star. Review that stars behave like black‑bodies and that temperature controls the peak wavelength. Explain that by the end of the lesson they will be able to use Wien’s law to estimate a star’s surface temperature and justify their answer with a brief calculation.
Lesson Structure:
  1. Do‑now (5') – students examine a printed spectrum, note the visible colour, and share observations.
  2. Mini‑lecture (10') – recap black‑body radiation, derive Wien’s law, and stress unit conversion.
  3. Guided practice (12') – work through the worked example (λmax = 500 nm) together using calculators.
  4. Independent activity (15') – worksheet with several λmax values; students convert units, apply Wien’s law, and classify the stars.
  5. Check for understanding (5') – quick quiz/exit ticket where each student writes the temperature for a given wavelength and notes one possible pitfall.
  6. Extension discussion (8') – brief link to the Stefan‑Boltzmann law and how temperature feeds into radius calculations.
Conclusion:
Summarise that Wien’s displacement law provides a rapid way to estimate stellar temperatures from spectral peaks, reinforcing the importance of correct unit conversion. Collect the exit tickets to gauge mastery and address any lingering misconceptions. Assign homework: students must select a real star, find its peak wavelength from an online catalogue, calculate its temperature, and compare it with the listed spectral type.