Osmosis

• What is osmosis? The movement of water from a higher water potential to a lower water potential through a partially permeable membrane
• Describe how you would carry out an investigation into osmosis using potato tissue ● Cut identical potato cylinders using a cork borer ● Measure and record the length and mass of cylinders using ruler and balance ● Add each cylinder to one of three solutions: 1M sugar solution, 0.5M sugar solution and distilled water ● Leave cylinders in tubes overnight ● Remove cylinders from tubes and blot them using paper towels ● Record length and mass of each cylinder ● Draw graph of change in mass in grams (y axis) against concentration of solution in mol dm-3 (x axis)
• Why is it necessary to blot the cylinders with paper after removing them? Each cylinder may have a different amount of water on its surface, so masses may vary. Blotting cylinders allows masses to be comparable
• What safety precautions should be taken with this experiment? Handle cork borer and scalpel with care
• Why is it necessary to use a cork borer to cut the cylinders? Results in equal sized samples so changes in length and mass can be compared easily
• What safety precautions should be taken with this experiment? Handle cork borer and scalpel with care
• Why is it necessary to blot the cylinders with paper after removing them? Each cylinder may have a different amount of water on its surface, so masses may vary. Blotting cylinders allows masses to be comparable