Lesson Plan

Resources → Subject Notes → Biology → Notes
Lesson Plan
Grade: 10 Date: 17/01/2026
Subject: Biology
Lesson Topic: Investigate osmosis using materials such as dialysis tubing.
Learning Objective/s:
  • Describe the process of osmosis and the role of a semi‑permeable membrane.
  • Explain how concentration gradient, temperature, surface area and pressure influence the rate of osmosis.
  • Conduct a dialysis‑tubing experiment, record mass changes and determine the direction of water movement.
  • Analyse experimental data to relate solute concentration to osmotic rate.
  • Identify sources of error and propose improvements to the procedure.
Materials Needed:
  • Dialysis tubing (5 cm lengths) with rubber bands
  • 250 mL beakers
  • Distilled water
  • Sucrose solutions (0.2 M, 0.5 M, 1.0 M)
  • Analytical balance (0.01 g)
  • Stopwatch
  • Thermometer
  • Paper towels and protective gloves/goggles
 Introduction:
Begin with a short video clip showing water movement in plant cells to spark curiosity. Ask students to recall the difference between diffusion and osmosis and record their ideas on a sticky note. Explain that today they will investigate osmosis quantitatively and will be assessed on their ability to predict and explain results.
Lesson Structure:
  1. Do‑now – 5 min: 3 rapid questions on diffusion vs. osmosis (quiz on board).
  2. Mini‑lecture – 10 min: Review semi‑permeable membranes and factors affecting osmotic rate.
  3. Demonstration – 5 min: Teacher sets up the first dialysis‑tubing trial.
  4. Group activity – 15 min: Students conduct a trial with a chosen sucrose concentration, record initial and final masses.
  5. Rotation – 10 min: Groups repeat the experiment with the remaining concentrations.
  6. Data collation – 10 min: Whole class builds a data table and plots mass change vs. concentration.
  7. Guided analysis – 10 min: Discuss how gradient, temperature and surface area are reflected in the graph.
  8. Exit ticket – 5 min: Write one sentence summarising how concentration gradient influences osmosis.
Conclusion:
Recap the key finding that a larger concentration difference produces a greater mass increase, confirming the relationship between gradient and osmotic rate. Students complete an exit ticket to retrieve the main concept and hand in their data sheets for marking. For homework, assign a short research task on how osmosis is exploited in medical treatments such as dialysis.