| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Physics |
| Lesson Topic: Know that the distance d of a far galaxy can be determined using the brightness of a supernova in that galaxy |
Learning Objective/s:
- Describe what a standard candle is and why Type Ia supernovae qualify.
- Explain the distance modulus relationship between apparent and absolute magnitude.
- Apply the distance modulus to calculate the distance to a galaxy using a measured supernova magnitude.
- Convert distances from parsecs to megaparsecs or light‑years as required.
- Identify common errors such as mixing apparent and absolute magnitudes.
|
Materials Needed:
- Projector or interactive whiteboard for slides.
- Printed worksheet with supernova data and calculation tasks.
- Scientific calculators (or calculator app).
- Graph paper or digital plotting tool for magnitude diagrams.
- Short animation/video of a Type Ia supernova explosion.
- Whiteboard and markers.
|
Introduction:
Begin with a striking image of a distant galaxy illuminated by a supernova and ask students how we can know its distance.
Recall that they have already used the inverse‑square law for light in previous lessons.
Today they will learn the specific steps for using a Type Ia supernova as a standard candle to determine galactic distances.
|
Lesson Structure:
- Do‑now (5'): Students answer a quick question on apparent vs absolute magnitude on the board.
- Mini‑lecture (10'): Review standard candles and introduce the distance modulus formula with a short animation.
- Guided practice (15'): Work through the example calculation (m = 22.0) together, filling in each step on a projected worksheet.
- Independent activity (15'): Students use a new set of apparent magnitudes to calculate distances, convert to Mpc, and record answers; teacher circulates for misconceptions.
- Check for understanding (5'): Exit ticket where each student writes the key equation and one common mistake to avoid.
|
Conclusion:
Summarise that a Type Ia supernova’s known absolute magnitude lets us turn a simple brightness measurement into a cosmic distance.
Ask a few students to share their calculated distances and highlight correct unit conversions.
Assign a homework problem requiring the distance to a galaxy with m = 24.5, reinforcing the steps learned.
|