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Osmosis In Potatoes.

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AT1- Osmosis In Potatoes Aim: Investigate the movement of osmosis through a selectively permeable membrane, in this case potato. Introduction: Osmosis is the movement of water through a semi permeable membrane, separating solutions of different concentrations. The water passes from a region of high concentration to a region of low concentration, until the two concentrations are equal in concentrations of water. Many cell membranes behave as semi permeable membranes, and osmosis is a vital mechanism in the transport of fluids in living organisms, for example, in the transport of water from the soil to the roots in plants. If a cell is in contact with a solution of lower water concentration than its own contents, then water leaves the cell by osmosis, through the cell membrane. Water is lost first from the cytoplasm, then the vacuole through the tonoplast. The living contents of the cell contracts and eventually pulls away from the cell wall and shrinks, this is known as Plasmolysis. If you put a plant cell in water, water enters by Osmosis, then swells up. However, the cell will not burst. This is due to the fact that the cell walls are made from cellulose, which is extremely strong. ...read more.


Weight (mm) Before After Before After Before After 0 molar 5mm 5 8mm 8 33mm 33 36mm 34 0.57g 0.48 0.67g 0.5 0.1 molar 5 5 8 7 33 33 35 34 0.72 0.86 0.91 0.90 0.15 molar 5 5 7 6 33 33 35 33 0.64 0.75 0.71 0.81 0.2 molar 5 5 6 7 33 33 32 33 0.73 0.75 0.81 0.77 0.25 molar 5 5 6 5 33 33 34 29 0.65 0.66 0.68 0.66 0.3 molar 5 5 5 5 33 33 33 25 0.68 0.73 0.85 0.57 1 molar 5 5 4 4 33 33 28 23 0.78 0.75 0.82 0.57 Concentration Average change in Width (mm) Average change in Length (mm) Average change in Weight (g) 0 molar 3 2 0.06 0.1 molar 2.5 1.5 0.11 0.15 molar 1.5 1 0.065 0.2 molar 1.5 -0.5 0.05 0.25 molar 0.5 -3 0.015 0.3 molar 0 -4 0 1 molar -1 -5 -0.14 Analysis Of Graphs: � Graph 1 'Average change in width' shows me that the higher the concentration, the more width the potato chip will lose. For example, the potato chip to gain most width was the one in pure water, or 0 molar concentration. ...read more.


However, in doing this we could have removed water that was not excess, and altered our results. Another inaccuracy was when we put the potato chips into the solutions, because it was impossible to not leave a small interval between each test tube. The first test would have been going for a few seconds longer than the last. I do not know how I would resolve this problem. I also found 2 anamalous results. The first, was on the graph which showed average change in width, the anamalous result was for the test for 0.2 molar solution. The second was on the graph that showed average change in weight, the anamalous result was for the test with 0.1 molar concentration. The main reason for this is inaccuracy. I used the mean when plotting my graphs. That way, the information is clear and can be understood quickly, however, the disadvantage of this, is the fact that if one of the two results is inaccurate, the mean will also be. I believe that this is the reason for the anamalous results. I could extend this AT1 by investigating osmosis with a different factor as opposed to concentration of water. I could investigate the effects of temperature on osmosis, or surface area. This would give me a very clear understanding and knowledge of osmosis in potatoes. ...read more.

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