3 - Osmosis

• What is the method for this practical? (part 1)

  1. Use a cork borer to cut 5 potato cylinders.
  2. Trim the cylinders using a sharp knife and a ruler to the same length (about 3 cm).
  3. Accurately measure and record the length and mass of each cylinder.
  4. Measure 10 cm2 of the 1.0M sugar solution and transfer to the first boiling tube and label.
  5. Repeat step 4 for other concentrations of the solution and distilled water.
  6. Add one potato cylinder (of known mass and length) to each boiling tube.
• What is the method for this practical? (part 2)

  7. Prepare a table.

  8. Record the original mass and length.

  9. Leave the cylinders in the boiling tubes overnight in a test tube rack.

  10. Remove the cylinders from the boiling tubes and blot them dry with paper towels.

  11. Measure the length and mass of each cylinder then calculate the percentage changes for each cylinder.

  12. Plot a graph of change in mass (in g) against the concentration of sugar solution.

  13. Plot a graph of change in length (in mm) against the concentration of sugar solution.
• What safety precautions should be taken with this experiment?

  Handle the cork borer and scalpel with care.