| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Define the Hubble constant H_0 as the ratio of the speed at which the galaxy is moving away from the Earth to its distance from the Earth; recall and use the equation H_0 = v / d |
Learning Objective/s:
- Define the Hubble constant, state its units, and express it as H₀ = v / d.
- Explain how red‑shift relates to recession velocity and how this leads to Hubble’s law.
- Calculate H₀ from given velocity and distance values and solve related practice problems.
- Interpret typical observed values of H₀ and discuss common sources of error and misconceptions.
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Materials Needed:
- Projector and screen for slides/animation
- Whiteboard and markers
- Printed worksheet with practice questions
- Calculators or spreadsheet software
- Graph paper or digital graphing tool for Hubble diagram
- Laptop with internet access (optional video)
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Introduction:
Begin with a short animation showing galaxies moving apart and ask students what might cause this motion. Recall prior learning about Doppler shift and speed‑distance relationships. Explain that today they will learn how astronomers quantify the expansion using the Hubble constant and will be able to calculate distances of far‑away galaxies. Success will be demonstrated by correctly computing H₀ in practice problems.
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Lesson Structure:
- Do‑now (5'): Students answer a quick question on red‑shift using mini‑whiteboards.
- Mini‑lecture (10'): Define H₀, present the equation, units, and show a Hubble diagram.
- Guided derivation (10'): Walk through calculating v = cz and then H₀ = v/d with a worked example.
- Collaborative practice (15'): Groups complete worksheet problems (calculations and a conceptual question).
- Class discussion (10'): Review answers, address the listed misconceptions, and clarify any errors.
- Exit ticket (5'): Each student writes a concise definition of H₀ and one real‑world implication.
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Conclusion:
Recap that H₀ links recession speed to distance, providing a measure of the Universe’s expansion rate. Students demonstrated how to compute H₀ and interpret its typical value. The exit ticket confirmed understanding, and homework is to complete three additional practice questions from the textbook.
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