Lesson Plan

• Describe osmosis and its role in moving water into plant cells.
• Explain how turgor pressure is generated and how it supports plant structure.
• Identify the main factors that affect the rate of osmosis.
• Predict the effects of plasmolysis on plant tissue.
• Apply knowledge of turgor pressure to interpret experimental observations.

• Projector or interactive whiteboard
• Slides/handout on osmosis and turgor pressure
• Elodea stems, distilled water, 0.5 M NaCl solution, test tubes, forceps
• Worksheet with observation table and questions
• Rulers for measuring stem rigidity (optional)

Begin with a quick demonstration of a limp versus a stiff plant stem to capture interest. Ask students what they think keeps non‑woody plants upright, linking to prior knowledge of cell structure. Outline that by the end of the lesson they will be able to state how water pressure inside cells supports plants and how to explain experimental results.

1. Do‑now (5'): Students answer a short question on the difference between diffusion and osmosis on a worksheet.
2. Mini‑lecture (10'): Define osmosis, turgor pressure, and plasmolysis with projected diagrams.
3. Guided discussion (5'): Explore factors influencing the rate of osmosis using the provided table.
4. Practical demonstration (15'): Conduct the Elodea experiment; students record observations in pairs.
5. Data analysis (10'): Groups interpret results, linking water movement to turgor pressure.
6. Check for understanding (5'): Quick quiz (Kahoot/exit ticket) with three concept questions.
7. Summary & homework preview (5'): Recap key points and assign a worksheet on plant support.

Summarise that turgor pressure generated by osmosis provides structural support in plants and that changes in water availability lead to plasmolysis and wilting. Ask students to write one sentence on a sticky note describing how they would test the effect of temperature on osmosis. Assign a worksheet to calculate osmotic pressure using the van ’t Hoff equation for homework.