Osmosis Required Practical

• What process is being investigated in this practical?

  Osmosis
• What is the aim of the practical investigation described?

  To investigate the effects of sugar concentration on plant tissue
• What type of solutions are used in the practical, besides the plant tissue?

  Sugar solutions
• What characteristic of the sugar solutions is varied in this practical?

  Concentration
• What are the steps of the method in this osmosis practical?

  • Use a borer to cut identical cylinders of potato tissue.
  • Blot dry then measure initial mass.
  • Place each cylinder in a different concentration of sugar solution for 24 hours.
  • Blot potato dry with a paper towel.
  • Measure the final mass of each cylinder.
  • Calculate the percentage change in mass.
  • Report and calculate a mean for each concentration.
  • Plot the % change in mass against concentration of sugar solution on a graph.
• How long should the potato cylinders be left in the sugar solutions?

  24 hours
• Why should the potato cylinders be blotted dry before measuring their mass?

  To remove excess surface water
• How is the percentage change in mass calculated?

  (Change in mass / starting mass) x 100
• On a graph, what is plotted against the concentration of sugar solution?

  Percentage change in mass
• What is the independent variable in this practical?

  Concentration of sugar solution
• What is the dependent variable in this practical?

  Change in mass of plant tissue
• What are the controlled variables in this osmosis practical?

  • Volume of solution
  • Temperature of solution
  • Time in solution
  • Variety of potato
  • Starting size/length/shape of potato