Osmosis: Extended
Extended Tier Only
- Osmosis is the net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution), through a partially permeable membrane
- It can get a little confusing to talk about the 'concentration of water' when we also talk about solutions being ‘concentrated’ (having a lot of solute in them), so instead we can say that a dilute solution has a high water potential (the right-hand side of the diagram below) and a concentrated solution has a low water potential (the left-hand side of the diagram below)
How osmosis works
Exam Tip
The best explanations to do with osmosis will refer to water potential, so if you are aiming for a 7, 8 or 9 you will need to understand the concept and use it in your explanations.