The aim of this experiment is to investigate the movement of water into and out of plant cells by osmosis. The cells chosen for study will be taken from potato tubers as they provide a ready supply of uniform material.

Any substance dissolved in water is called a solute; a solvent is a liquid that is able to dissolve another substance, called a solute, to form a solution.

The water content of plants varies depending on environmental conditions. In land plants it plays a vital role in structural support and mineral transport and thus a lack of water may lead to wilting or possibly death.

Water is mainly absorbed through the roots, which are covered in specially adapted root hair cells, with large surface areas and thin cell walls to aid absorption by osmosis. The evaporation of water through stomata on plant leaves causes a transpiration stream, causing the water to be drawn up through xylem vessels.

Osmosis is the flow of water molecules by diffusion through a partially pe

· Place 20cm3 of each solution into each of three separate boiling tubes. This will result in eight sets of three test tubes, with each of the eight sets containing different molar concentrations of sodium chloride ranging from 0.05molar to 0.40 molar.

Between 0.0 molar concentration and 0.10 molar concentration the changes in length appear to be consistent as a straight line, thereby suggesting that increases in solute potential will result in proportionally smaller increases in length. However between 0.0 molar concentration and 0.155 molar concentration the changes in mass appear to be inconsistent as the line is not straight but disjointed at 0.05 molar, thereby suggesting that increases in solute potential will not necessarily result in proportionally less increases in mass. This may have been the result of not allowing excess solution on the external surface of the cores from draining away before placing it onto the top pan balance. This superficial water would be measured as extra mass by the sensitive weighing scales but would not be clearly visible when re-measuring the length of the cores.

· Place all boiling tubes into boiling tube rack.

· The time that the potato cores are left in the solution. This has to be kept constant as different times of exposure to the sodium chloride solution will result in different amounts of osmosis taking place.

· Mix up correct molar quantities of sodium chloride solution as shown in the molarity table as below using a measuring cylinder, and place into beakers.

rmeable membrane from areas of high water potential (low solute concentrations) to regions of low water potential (high solute concentrations).

Some common words found in the essay are:
Analysis Evaluation, Litres Solution, Volume H20, Hypothesis Pure, Background Information, Fair Test, Sodium Chloride, Length Mass, potato cores, length mass, Stopwatch Method, Scenario Plants, mass potato, length mass potato, molar concentration, sodium chloride, water potential, changes length, mass potato cores, solute potential, water molecules, sodium chloride solution, chloride solution, top pan balance, increases length mass,
Approximate Word count = 2441
Approximate Pages = 10 (250 words per page double spaced)