Diffusion of water through a selectively permeable membrane
Osmosis factors affecting rate
Factors affecting rate - surface area, water potential gradient, thickness of exchange surface
Osmosis practical
- Cut up a potato into identical cylinders
- Get some beakers with different sugar solutions in them, one should be pure water and another should be a very concentrated sugar solution and some in between.
- Measure the mass of the cylinders and leave each one in each beaker for a day
- Take them out, dry them and weigh them again
- If water has been drawn in by osmosis they will have increased in mass
- If water has be drawn out they will decrease in mass
