Lesson Plan

• Describe the components of water potential and how they combine to determine overall water potential.
• Explain how osmosis drives water uptake in plant roots and water loss through transpiration.
• Compare water‑potential regulation in plant and animal cells.
• Predict the effect of changing solute concentration on the direction of water movement.
• Apply the concepts to answer exam‑style questions on drought effects.

• Projector or interactive whiteboard
• PowerPoint slides with water‑potential diagrams
• Handout of the comparative water‑potential table
• Potato slices, NaCl solutions (0 %, 5 %, 10 %) and a balance for the demonstration
• Worksheets with practice questions
• Markers and chart paper for group concept maps

Begin with a quick demonstration of a wilted plant and ask students why it looks dry. Recall previous learning on diffusion and solute concentration. Explain that today they will explore how water potential and osmosis control water movement in organisms, and they will know the success criteria: explain the concepts, interpret data, and predict outcomes.

1. Do‑now (5') – students answer a short question on diffusion vs. osmosis on mini‑whiteboards.
2. Mini‑lecture (10') – introduce water potential, the equation Ψ = Ψ_s + Ψ_p, and component concepts with slides.
3. Interactive activity (10') – groups analyse the comparative table and create a concept map of plant vs. animal water‑potential regulation.
4. Practical demonstration (15') – potato slice experiment in different NaCl solutions; students record mass changes.
5. Guided discussion (10') – link observations to root uptake, transpiration, and animal regulation; work through the sample exam question.
6. Formative check (5') – exit ticket: one sentence explaining how a drought alters the soil‑root water‑potential gradient.

Recap that water moves from higher to lower water potential and that organisms adjust solute and pressure potentials to maintain balance. Students complete the exit ticket and are assigned a short worksheet to calculate water‑potential values for homework.