Key learning points

1. Plotting and interpretation of a graph showing the effect of sugar concentration on the mass of potato tissue.
2. Increase in potato mass means water moved in by osmosis (because the sugar solution was more dilute outside).
3. Decrease in potato mass means water moved out by osmosis (because the sugar solution was more concentrated outside).
4. The concentration of sugar in the potato tissue can be determined from the point at which there was no change in mass.
5. At this point the sugar concentration was equal inside and out, so there was no net movement of water.

Common misconception

Keywords

• Osmosis - the net movement of water molecules through a selectively-permeable membrane from a dilute solution to a concentrated one

• Net movement - the overall movement of particles

• Random error - causes results to differ by different amounts due to a factor other than the independent variable (the factor we changed)

• Concentration gradient - a difference in the concentration of particles from one area to another