| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: state that light intensity, carbon dioxide concentration and temperature are examples of limiting factors of photosynthesis |
Learning Objective/s:
- Describe how light intensity, CO₂ concentration, and temperature influence the rate of photosynthesis.
- Explain the concept of a limiting factor and identify which factor is limiting under specific experimental conditions.
- Analyse experimental data to determine saturation points for each factor.
- Design a simple investigation that varies one factor while keeping the others constant.
- Evaluate the impact of environmental changes on plant productivity.
|
Materials Needed:
- Projector or interactive whiteboard
- PowerPoint/slide deck with graphs
- Elodea specimens or leaf discs
- Gas‑collection apparatus (inverted graduated cylinder)
- Adjustable light source with neutral‑density filters
- CO₂ delivery system (bubbler or gas cylinder)
- Water bath or thermostatically controlled chamber
- Student worksheet with data tables and analysis prompts
|
Introduction:
Begin with a striking image of a sun‑lit forest canopy and ask students what factors might limit plant growth. Recall that photosynthesis depends on light, carbon dioxide, and temperature, which they have previously studied. Explain that today they will identify these variables as limiting factors and learn how to investigate their effects. Success will be shown by correctly interpreting experimental graphs.
|
Lesson Structure:
- Do‑now (5'): Quick quiz on basic photosynthesis components.
- Mini‑lecture (10'): Define limiting factor, present key concepts and characteristic graphs.
- Demonstration (10'): Show Elodea setup; vary light intensity while measuring O₂ evolution.
- Guided practice (15'): In pairs, design a variation for CO₂ concentration and complete worksheet.
- Data analysis (10'): Plot sample data, identify plateaus, discuss which factor is limiting.
- Check for understanding (5'): Exit ticket – state one limiting factor and its optimum condition.
|
Conclusion:
Summarise that light intensity, CO₂ concentration, and temperature each have optimal ranges beyond which they become limiting. Students complete an exit ticket describing the factor they think most restricts photosynthesis in a warm, cloudy environment. For homework, they research how agricultural practices manipulate these factors to maximise crop yield.
|