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The aim of this experiment is to see the affect of five different sugar solutions on potato cells, and how osmosis affects there weight.

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Introduction

Osmosis coursework This experiment is on osmosis. Osmosis is the movement of water through a semi permeable membrane to a higher concentration of solutes to make the amount of sugar in each cell equal. Osmosis helps keep cell walls turgid, osmosis is useful because the cells have semi-permeable membranes which only allow water through, and without osmosis they would not get enough sugar and salts. The aim of this experiment is to see the affect of five different sugar solutions on potato cells, and how osmosis affects there weight. The five different sugar solutions are as follows: 1 molar 0.75 molars 0.5 molars 0.25 molars Water The experiment is broken down into simple steps. Collecting Equipment The equipment needed is: One potato------ To collect a sample of cylinders from One cork Borer------ To cut the cylinders out of the potato 5 Test Tubes------- To place the five cylinders in One test tube Holder/ Rack------ To hold the test tubes Electronic Scales------ To weigh the potato cylinders A J-Cloth------ To help remove excess solution from the potato cylinders Select potato Select a potato and then, using the cork borer cut out five equal cylinders. Using electronic scales weigh each individual cylinder, record each individual weight of each cylinder in a table. ...read more.

Middle

tampering? if someone tampered with your experiment then your results will be unreliable. My results My first experiment Potato number Solution on potato (M) Weight before (grams) Weight after (grams) Change in mass (grams) 1 Water 1.40 1.48 +0.08 2 0.25 m 1.40 1.42 +0.02 3 0.5 m 1.45 1.36 -0.09 4 0.75 m 1.24 1.0 -0.15 5 1 m 1.43 1.25 -0.18 My second experiment Potato number Solution on potato(M) Weight before (grams) Weight after (grams) Change in mass (grams) 1 Water 1.30 1.40 -0.10 2 0.5 m 1.48 1.38 -0.10 3 1 m 1.34 1.09 -0.25 4 1 m 50 1.41 1.13 -0.28 5 2 m 50 1.47 1.11 -0.36 The reason that the solutions 2 m 50 and 1m 50 are underlined is because these were two solutions I was not intending to use. Therefore these do affect my results. My third experiment Potato number Solution on potato(M) Weight before (grams) Weight After (grams) Change in mass (grams) 1 water 2.3 2.4 +0.01 2 0.25 m 2.3 2.3 0 3 0.5 m 2.1 2.2 +0.01 4 0.75 m 2.1 2.2 +0.1 5 1 m 2.3 2.4 +0.1 On this experiment we only had electronic scales that worked to one decimal place so my results will not be as accurate. ...read more.

Conclusion

This was because the water molecules in the solution are diffusing through the cell membrane to balance out the sugar solutions. These results prove that the higher the concentration of sugar solution, the less the potato weighs. All three experiments prove this-even the ones with the wrong sugar solution. It appears that as the sugar solution increases the weight of the potato cylinder decreases. The only time this rule didn't work was when I used distilled water, this was because the water has no sugar so the water just diffuses through the cell membrane to balance out the water solution-therefore balancing the sugar concentration. Evaluation After reviewing my method and how I did my experiment I think it was completed quite successfully. The experiment was relatively simple and was easily done between two people. The results obtained from my experiments, however, were not as reliable as they should be. For example the sugar solutions in the second experiment were not the same, this means that the average of two of the sugar solutions will not be correct, compared to the other solution averages. Also on the third experiment the scales I used only weighed to one decimal point. This means these results are not as accurate as the others and could on the average be wrong. Even though the reliability of the experiments is questionable most of them show evidence supporting my prediction. This suggests that even in faulty test conditions osmosis is still present. ...read more.

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