Year 7 - Science
Diffusion through a selectively-permeable membrane: practical
Diffusion
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores diffusion's role in material movement in and between cells and involves making predictions, observations and measurements with various methods.
Lesson Summary
You will learn to explain observations of diffusion through a selectively-permeable membrane.
Key Notes
- Particles of some substances are small enough to diffuse through holes in a selectively-permeable membrane.
- Particles of these substances move through the selectively-permeable membrane in both directions.
- Predict the direction of net movement of particles through a selectively-permeable membrane.
- Observe the direction of net movement of a substance through a selectively-permeable membrane (e.g. Visking tubing).
- Explain observations of the diffusion of a substance through a selectively-permeable membrane.
Vocabulary To Learn
- selectively-permeable membrane: A membrane is selectively-permeable if some substances can move through it but others cannot.
- particles: All substances are made up of particles that are too small for us to see.
- diffusion: Diffusion is the net movement of particles of a substance down a concentration gradient.
- concentration gradient: A concentration gradient is a difference in the concentration of particles from one area to another.
- net movement: Net movement is the overall movement of particles from one area to another.
Common Mistakes To Avoid
- Particles only move through a selectively-permeable membrane in one direction.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
Particles of some substances are small enough to diffuse through holes in a selectively-permeable membrane. Particles of these substances move through the selectively-permeable membrane in both directions.
2. Define this scientific word and use it in context. 'selectively-permeable membrane'
A membrane is selectively-permeable if some substances can move through it but others cannot. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Particles only move through a selectively-permeable membrane in one direction. Correction: The lesson explores the idea that particles move through a selectively-permeable membrane in both directions, but that net movement is down a concentration gradient.
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