Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Biology
Lesson Topic: describe gas exchange between air in the alveoli and blood in the capillaries
Learning Objective/s:
  • Describe the pathway of gas exchange between alveolar air and pulmonary capillary blood.
  • Explain how partial‑pressure gradients and Fick’s law determine the rate of O₂ and CO₂ diffusion.
  • Analyse how surface area, membrane thickness, and other factors affect diffusion efficiency.
  • Evaluate clinical conditions that impair gas exchange and predict their impact on diffusion.
Materials Needed:
  • Projector and slide deck with alveolus diagram
  • Printed worksheet on diffusion calculations
  • Whiteboard and markers
  • Lung model (optional)
  • Quiz cards for case‑study activity
  • Exit‑ticket slips
 Introduction:
Imagine taking a breath and instantly delivering oxygen to every cell of your body. Students should recall the basic structure of the respiratory system and the principle of diffusion. By the end of the lesson they will be able to label the respiratory membrane, explain the role of pressure gradients, and describe how disease can disrupt exchange.
Lesson Structure:
  1. Do‑now (5') – quick recall quiz on diffusion basics.
  2. Mini‑lecture with slides (10') – anatomy of the alveolus and introduction to Fick’s law.
  3. Guided analysis (12') – work through the partial‑pressure table and calculate gradients.
  4. Group case‑study activity (15') – analyse edema, emphysema, and high‑altitude scenarios; create concept maps of factors affecting diffusion.
  5. Whole‑class discussion (8') – compare how surface area, membrane thickness, and pressure differences influence gas exchange.
  6. Formative check (5') – exit‑ticket question: “What factor would most reduce O₂ diffusion in pulmonary fibrosis and why?”
Conclusion:
We will recap the key determinants of gas exchange and review the case‑study findings. Students will complete an exit ticket to demonstrate understanding, and for homework they will finish the worksheet on diffusion calculations and read the textbook section on respiratory disorders.