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Osmosis in Potato Tissue.

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Osmosis in Potato Tissue Osmosis: (special case of Diffusion) Osmosis is the movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration Background: * In pure water the potato tubes swell because water enters their cells by osmosis and then the potato cell becomes turgid. * In rich sugar solution the potato tubes shrink because water leaves their cells due to osmosis then the potato cell becomes flaccid. Apparatus: Potatoes : to get the potato chips from. Blade : to cut 15 same sized chips Cutting mat: to cut the chips on in the same size Boiling tube: to put the 15 potato chips and the solution in. Sucrose solution 0.5 molar: to put in the tubes and investigate osmosis. Measuring cylinders: to measure the amount of water and sucrose solution which I put in each tube. Cork borer: to extract 15 potato chips from a potato. Test tube rack: to hold my 5 test tubes properly. Ruler: to control the measure of the potato chips to 4 cm. Labels: to have a fair test and get accurate results. Method: 1. I will take two average sized ground potatoes and check that they are both healthy and hard. 2. Using the cork borer and the ruler I will cut the potato into 15 same-sized chips. ...read more.


in the potato chip; therefore the chips in higher water concentrations will have a taller chip than in higher sugar concentrations. I used this method because this method will give me a vary varied set of results which will make a descent conclusion, a more accurate graph and which will then prove that my variables and non-variables were considered in the right way within the experiment, and will also prove that my results were accurate . Table of results: Concentration Moles Original Final Change in length 1 2 3 1 2 3 Average 0 m 4 cm 4.2 cm 4.2 cm 4 cm 0.2 cm 0.2 cm 0 cm 0.13 cm 0.12 m 4 cm 4 cm 4 cm 4 cm 0 cm 0 cm 0 cm 0 cm 0.25 m 4 cm 3.9 cm 4.1 cm 3.8 cm -0.1 cm 0.1 cm -0.2 cm -0.06 cm 0.37 m 4 cm 3.8 cm 3.9 cm 3.9 cm -0.2 cm -0.1 cm -0.1 cm -0.1 cm 0.5 m 4 cm 3.9 cm 3.8 cm 3.8 cm -0.1 cm -0.2 cm -0.2 cm -0.13 cm This graph above shows a clear indication that there was an overall decrease in length during the experiment. At the point 0.00 M the line for after the experiment is above the line for before the experiment unlike any of the others. ...read more.


The range of concentrations was adequate but I would possibly create more concentrations if I repeated the experiment so that I would have more varied results. The cutting of the potatoes was the most difficult part of the experiment as although I was recording my results by length, it could well have affected the surface area and so the overall rate of osmosis. If I were to repeat the experiment I would have possibly found a machine to cut the potato as it would ensure that all potatoes would be the same length. As well as the potato I could have found a more accurate way to measure out the solutions and to determine the molar concentrations. There were not any out of the ordinary results, but some were not as close to the line as others. This may have been caused by human. When the potato chips were removed from the test tubes and dried I may well have dried some potatoes more thoroughly than others and so some would have more excess water, which would add to the length. If the experiment was repeated I could find another way to dry the potatoes that would ensure that all were dried in the same way for the same time. However with all this said I think that the experiment was truly successful and I was very pleased with the complete comparison of my results with my initial prediction. ?? ?? ?? ?? Omar Shalaby ...read more.

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