Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Physics
Lesson Topic: understand the de Broglie wavelength as the wavelength associated with a moving particle
Learning Objective/s:
  • Describe the de Broglie hypothesis and its formula λ = h/p.
  • Calculate the de Broglie wavelength for electrons, neutrons, and macroscopic objects.
  • Explain why wave effects are observable for sub‑atomic particles but negligible for everyday objects.
  • Apply the concept to predict diffraction outcomes in simple experiments.
Materials Needed:
  • Projector or interactive whiteboard
  • Slides with de Broglie equations and example calculations
  • Worksheet with practice problems
  • Laser pointer for a wave‑particle analogy demonstration
  • Computer simulation of electron diffraction (e.g., PhET)
  • Printed diagram of the Davisson‑Germer experiment
 Introduction:
Begin with a quick demonstration: shine a laser through a narrow slit to show diffraction, prompting students to recall wave behaviour. Link this to prior learning on the photoelectric effect and the particle nature of light. State that today they will uncover how moving particles also possess a wavelength, and that success will be measured by correctly calculating λ and explaining its significance.
Lesson Structure:
  1. Do‑now (5'): Students answer a short question on wave‑particle duality from the previous lesson; teacher checks responses.
  2. Mini‑lecture (10'): Introduce the de Broglie hypothesis, derive λ = h/p, and show an electron example using slides.
  3. Guided practice (12'): Work through sample calculations for an electron and a neutron on the board while students complete worksheet steps.
  4. Simulation activity (10'): Students explore an online electron diffraction simulation, record observed patterns and relate them to the calculated λ.
  5. Concept check (8'): Quick quiz (Kahoot) with conceptual questions about why macroscopic objects have negligible λ.
  6. Summary discussion (5'): Review key points and address any misconceptions.
Conclusion:
Summarise that the de Broglie wavelength links a particle’s momentum to wave behaviour, enabling diffraction for tiny particles. Ask students to write a one‑sentence exit ticket explaining why a baseball’s λ is unobservable. Assign homework: calculate λ for a proton moving at 2 × 10⁶ m s⁻¹ and predict whether diffraction could be detected.