Lesson Plan

• State that water diffuses through partially permeable membranes by osmosis.
• Explain the factors that influence the rate of osmosis.
• Compare osmosis with diffusion, highlighting key differences.
• Describe real‑world examples of osmosis in plants and animals.
• Predict the effect of hypotonic, isotonic and hypertonic solutions on cell volume.

• Projector and screen
• Whiteboard and markers
• Diagram handout of osmosis
• Osmosis demonstration kit (dialysis tubing, sugar solutions, beakers)
• Student worksheets
• Exit‑ticket slips

Begin with a quick question: “How do plant roots pull water from dry soil?” Connect this to students’ prior knowledge of diffusion. Explain that today they will discover the specific process—osmosis—that moves water across membranes. Success criteria: students will be able to define osmosis, list influencing factors, compare it with diffusion, and give biological examples.

1. Do‑now (5') – short quiz on diffusion concepts to activate prior knowledge.
2. Mini‑lecture (10') – definition of osmosis, key features, and factors affecting its rate.
3. Demonstration (15') – dialysis tubing experiment showing water movement between solutions of different concentrations.
4. Guided analysis (10') – students complete a comparison table of diffusion vs. osmosis.
5. Group activity (10') – case studies on plant root uptake and intestinal water absorption; groups present findings.
6. Check for understanding (5') – exit‑ticket question: “State the definition of osmosis and one factor that speeds it up.”

Recap the definition of osmosis, the main factors influencing its rate, and the key differences from diffusion. Collect exit‑ticket responses to gauge understanding and assign a short homework: students sketch a diagram of water movement in a plant root and label the direction of osmosis.