Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Biology
Lesson Topic: State and use the formula: magnification = image size ÷ actual size.
Learning Objective/s:
  • Describe what magnification represents in microscopy and imaging.
  • Explain the relationship between image size, actual size, and magnification.
  • Apply the formula magnification = image size ÷ actual size to calculate magnification for given specimens.
  • Convert between units and avoid common errors when using the formula.
  • Interpret magnification results to assess microscope settings and scale bars.
Materials Needed:
  • Projector or interactive whiteboard
  • Digital microscope images or camera screenshots of specimens
  • Ruler or calibrated slide for measuring image and actual sizes
  • Worksheet with practice questions and a worked example
  • Calculator
  • Whiteboard and markers
 Introduction:

Start with a quick demonstration of a leaf vein displayed on the screen and ask students how they could tell how much larger it appears. Recall that magnification is a ratio comparing the image size to the actual size of a specimen. Today they will state and use the formula magnification = image size ÷ actual size and apply it to a range of examples.
Lesson Structure:
  1. Do‑Now (5’) – Students measure the image size of a provided specimen on a printed slide and record the value.
  2. Mini‑lecture (10’) – Define image size, actual size, and magnification; present the formula and stress unit consistency.
  3. Guided practice (12’) – Work through the leaf‑vein example together, filling a table of steps and calculations.
  4. Independent practice (15’) – Students solve three practice questions on the worksheet while the teacher circulates for support.
  5. Check for understanding (5’) – Exit‑ticket: write the formula from memory and calculate magnification for one new specimen.
  6. Review common mistakes (3’) – Highlight unit‑mixing errors and the correct rearrangement of the formula.
Conclusion:

Recap that magnification equals image size divided by actual size and that consistent units are essential. Collect the exit‑tickets to gauge mastery, and assign a short homework task: measure an everyday object, determine its actual size, and calculate the magnification using a photo of the object.