PEAZIT Aha card
Go straight to resources ↓Osmosis: water crosses the membrane
At equal pressure, water crosses a membrane permeable to water but not the specified solute toward the higher solute concentration. A developing pressure difference can balance this movement.
| Observation | What it means |
|---|---|
| Less sugar on the left | greater water availability |
| More sugar on the right | net water entry from the left |
One worked example
- Water can cross; sugar cannotFirst identify permeability.
- More sugar per volume on the rightAt equal initial pressure water enters there.
- The right-hand level may riseIncreased pressure can stop net flow.
Watch out: Membrane permeability and water potential, including pressure, matter; the word salt or sugar alone is insufficient.
Goal, prerequisites and card origin
What you will learn: Predict net water movement.
What you need first: Diffusion and solutes.
An original PEAZIT working card. Independent expert review and effectiveness testing have not yet taken place. · v1
Reference for the underlying principle ↗Show connections
At equal pressure, water crosses a membrane permeable to water but not the specified solute toward the higher solute concentration. A developing pressure difference can balance this movement.