BiologyGrade 9Cells

Osmosis Lab: Cell Membrane and Water Balance

Place a plant or animal cell in different solutions, change membrane permeability and temperature, then observe water movement, cell volume, and turgor.

SimulationsLab index
Textbook unitCellsGrade 9 Biology Unit 3
Keywordscell, membrane, osmosis, solute, waterMapped to available textbook headings
Practice modeManipulate, measure, explainUse the controls, then read the live evidence

Biology · Grade 10

Control the solution and observe water movement

Change the environment around a cell, then use cell volume, solute concentration, and turgor to explain osmosis.

StatusBalanced
1

Isotonic: set external solute near 4 mol/L (matches internal). Does cell volume stay stable? Record volume and water flow direction.

2

Hypotonic: reduce external solute to 1 mol/L. Which way does water flow? Observe volume change and turgor in the plant cell.

3

Hypertonic stress: raise external solute to 8 mol/L. What happens to plant vs animal cell? Record both and explain the difference.

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Volume history100%
Osmosis insight

Hypotonic: external < internal (gradient -2.00 mol/L). Water enters by osmosis — plant cell gains turgor pressure.

Solution typeHypotonic
Water movementWater enters cell
Internal solute4.0 %
Cell volume100%
Turgor pressure42%

Lab task

Create one hypotonic and one hypertonic setup. Record both, then explain why the water movement changed direction.

Observation rule

Water moves toward the side with higher effective solute concentration until the system approaches balance.

Mission

What to prove in this lab

  1. Distinguish hypotonic, isotonic, and hypertonic solutions using measured cell volume.
  2. Explain how solute concentration changes the direction of water movement.
  3. Compare how plant and animal cells respond to water gain or water loss.