topic
Osmosis
Osmosis is the net movement of water through a partially permeable membrane from a dilute solution to a more concentrated solution.
Let’s learn
Core knowledge: Osmosis is the net movement of water through a partially permeable membrane from a dilute solution to a more concentrated solution.
Predict and explain water movement and calculate percentage mass change.
See it
A potato cylinder changes from 5.0 g to 5.6 g. Percentage change = (0.6 ÷ 5.0) × 100 = 12% increase because water entered the cells.
Try it together
Draw particle diagrams on both sides of a membrane and add arrows showing net water movement.
Now you try
1. Predict a plant cell in pure water. 2. Calculate percentage change from 8.0 g to 7.2 g. 3. State two control variables in a potato investigation.
Check your answers
1. It becomes turgid. 2. −10% (10% decrease). 3. Examples: cylinder size, time, temperature, solution volume.
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