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.
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.
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.
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.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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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