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Investigating isotonic point of a potato

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Investigating the Isotonic Point of a Potato Aim: Finding the isotonic point of potato cells by testing it in different concentrations of salt water. This diagram shows the movement of water through hypotonic, hypertonic and isotonic. But what are the arrangements of molecule for them? This is shown on this simple diagram. Hypothesis: I believe the isotonic point will be around 0.25 mol. This is because I feel that the 0.1 solution will be too hypotonic. Therefore I believe at around 0.25 there will be little or no change in the mass of the potato because I'm predicting that this will be the isotonic point. Fair Test: - Three potato slices were used for each solution so that more accurate results could have been obtained. - All potatoes slices were of the same mass, this was done by using the same cork borer therefore the diameter was always constant so the volume would remain the same - All potato slices were taken from one potato so the cells will be similar. - The temperature will remain the same for all beakers. Safe Test: - We will be using scalpel and cork borer therefore we made sure we handled them with care - We made sure we used the beakers appropriately, so that they did not brake and cause any damage. ...read more.


Mass (gm) Trail 1 Trail 2 Trails 3 Average Before After Before After Before After Before After 0.1 0.25 0.31 0.24 0.32 0.22 0.28 0.23 0.30 0.2 0.24 0.27 0.27 0.29 0.23 0.24 0.24 0.26 0.3 0.29 0.25 0.26 0.25 0.28 0.23 0.25 0.24 0.4 0.25 0.21 0.23 0.21 0.22 0.23 0.23 0.21 0.5 0.21 0.20 0.26 0.21 0.27 0.18 0.24 0.19 Table Showing The Change in Mass Through the Different Concentration From The Averages Concentration Change in mass (gm) 0.1 mol 0.07 0.2 mol 0.02 0.3 mol -0.01 0.4 mol -0.02 0.5 mol -0.05 Physical Observation (Before): * Potatoes were light yellow in colour. * The thickness of the chip was very thin and narrow. * The potato chips were quite soft. * Extremely turgid Physical Observation (After): * The colour remained the same, therefore still yellow in coulur. * The thickness was roughly the same. * Not as turgid as before. * The potato chips were softer than before. Analysis & Conclusion: Looking at our graph we can see that nearly all the point fit into the line of best fit. But there was just one point that was slightly off. ...read more.


Therefore not the same proportionate of water must have been removed from each chip. What may have happened is that I could have moved a lot of water from one chip but a lot less from the other. Then when taking the mass of the chip it would likely to be wrong as the weight may be more in some and less in other. Therefore this affects the initial mass of the chip. I feel that these may have been the small errors that had caused the anomaly. Also I feel that to improve the results I feel we should have taken a wider range of concentration this would have bettered our accuracy in the results. If I were to do this experiment again I would make sure that I have enough time to carry out the experiment so the procedure will not be rushed. Next time I will make sure to use a ruler while cutting the chips. So that it will be a fair test. I will also try to reduce as much of the surrounding activity that affects the weighing scale e.g. by turning off the fans. And lastly I shall dry all the potatoes properly. I feel that by following this it will lead to obtaining much better results. ?? ?? ?? ?? Bio Lab- 2 Amandip Toor IBD 1st Year 1 ...read more.

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