Diffusion through a selectively-permeable membrane: practical
I can explain observations of diffusion through a selectively-permeable membrane.
Diffusion through a selectively-permeable membrane: practical
I can explain observations of diffusion through a selectively-permeable membrane.
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning 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.
- 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.
Keywords
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 misconception
Particles only move through a selectively-permeable membrane in one direction.
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.
To help you plan your year 7 science lesson on: Diffusion through a selectively-permeable membrane: practical, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 7 science lesson on: Diffusion through a selectively-permeable membrane: practical, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 3 science lessons from the Diffusion unit, dive into the full secondary science curriculum, or learn more about lesson planning.
Equipment
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Starter quiz
6 Questions






Exit quiz
6 Questions









starch and iodine are both present
only iodine is present, no starch
iodine diffused into the tubing from the edges to the middle