Investigating Osmosis

Osmosis is defined as ¡§the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration¡¨.
In a high concentration of water the amount of solute (e.g. sugar) is low. This could be called a weak or dilute solution. In a low concentration of water the amount of solute (e.g. sucrose) is high. This could be called a strong or concentrated solution. When two such solutions are divided by a semi-permeable membrane the water will move from the area of high concentration to the area of low concentration, until both sides are equal (have reached equilibrium).
Knowing that osmosis will occur across a semi-permeable membrane whenever there is a difference between the water concentrations on the two sides of the membrane, and knowing that when this happens to cells they will either become turgid if water flows into them, or plasmolysed if water flows out of them, and thus change their volume, we want to test the hypothesis that:
If the concentration of a solution into which a cylinder of potato is placed is greater than a certain level the cylinder will contract, and if the concentration is less than that level it will expand. This can be seen in living cells.…