Topic: Movement into and out of Cells – Diffusion
Lesson 1: Understanding Diffusion
| Section | Details |
|---|---|
| Objective | – Describe diffusion as the net movement of particles from a region of higher concentration to a region of lower concentration.– Understand that diffusion occurs due to the kinetic energy of random molecular motion. |
| Activities | Starter (5 mins): Show a short animation of perfume spreading in a room or dye dispersing in water and ask students to describe what is happening.Main (25 mins): 1. Define diffusion and explain the concept of concentration gradient.2. Explain that diffusion is driven by the kinetic energy of molecules.3. Use everyday examples, such as the exchange of oxygen and carbon dioxide in the lungs, to relate diffusion to living organisms.Plenary (10 mins): Students summarize diffusion in one sentence and provide their own example of diffusion in real life. |
| Resources | Animation of diffusion, diagrams of diffusion across membranes, whiteboard for definitions. |
| Time | 40 minutes |
| Homework | Write a paragraph explaining how diffusion occurs when perfume is sprayed in a room. |
| Assessment | Students explain diffusion and provide examples during class discussions. |
| Past Paper Practice | IGCSE Biology 0610/21/M/J/20 Q3(a). |
Lesson 2: Diffusion and the Cell Membrane
| Section | Details |
|---|---|
| Objective | – State that some substances move into and out of cells by diffusion through the cell membrane.– Describe the importance of diffusion of gases and solutes in living organisms. |
| Activities | Starter (5 mins): Show an image of a cell and ask students how substances like oxygen or glucose might enter or leave the cell.Main (25 mins): 1. Discuss the role of the cell membrane in diffusion.2. Use examples like oxygen entering cells for respiration and carbon dioxide leaving cells as waste.3. Explain the importance of solute diffusion, such as glucose in the bloodstream moving into cells.Plenary (10 mins): Students label a diagram showing diffusion of oxygen and carbon dioxide through a cell membrane. |
| Resources | Diagram of diffusion across a cell membrane, worksheets for labeling. |
| Time | 40 minutes |
| Homework | Research and write about one example of diffusion in plants or animals. |
| Assessment | Students label diagrams and explain the role of diffusion in living organisms. |
| Past Paper Practice | IGCSE Biology 0610/22/O/N/19 Q2(b). |
Lesson 3: Factors Affecting Diffusion
| Section | Details |
|---|---|
| Objective | – Investigate the factors that influence diffusion, including surface area, temperature, concentration gradient, and distance. |
| Activities | Starter (5 mins): Show two beakers with dye, one stirred and one left undisturbed, and ask students to observe the difference in how the dye spreads.Main (25 mins): 1. Discuss each factor affecting diffusion: – Surface Area: Greater surface area increases diffusion rate. – Temperature: Higher temperature increases particle movement. – Concentration Gradient: Steeper gradients result in faster diffusion. – Distance: Shorter distances speed up diffusion.2. Demonstrate diffusion using a practical activity, such as observing the spread of dye in water at different temperatures.Plenary (10 mins): Students summarize how one factor influences diffusion and explain why. |
| Resources | Beakers, water, dye, hot and cold water, worksheets for recording observations. |
| Time | 40 minutes |
| Homework | Design a simple experiment to test the effect of surface area on diffusion rate. |
| Assessment | Students explain the effects of factors on diffusion during class discussions and practical activities. |
| Past Paper Practice | IGCSE Biology 0610/31/M/J/20 Q3(a). |
Key Notes for Teachers:
- Use visual aids and practical activities to reinforce concepts of diffusion.
- Relate the importance of diffusion to real-life biological processes, such as respiration and nutrient uptake.
- Emphasize the factors affecting diffusion through clear examples and experiments.
Key Notes for Students:
- Remember the definition of diffusion and the concept of the concentration gradient.
- Understand the role of the cell membrane in diffusion of gases and solutes.
- Be prepared to explain how factors like temperature and surface area affect diffusion rates.
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