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Investigating the amount of sag in potato chips due to osmosis.

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Investigating the amount of sag in potato chips due to osmosis. Analysis A clear trend can be identified when looking at the graph that shows the class means, the higher the molarity of the solution, the more the potato chip which has been soaked in that solution sags. This trend is shown as a result of osmosis and the movement of water in and out of the potato cells. When the potato chip has been left in pure water its cells have become turgid, and as a result of this has a very small amount of sag is measured. The cells have become turgid because, due to osmosis, water has been transferred from the solution in to the potato cells. This transfer happened because the potato cells had a much lower water potential than the surrounding water, which, being pure, had a water potential of 0kpa. The potato cells have a lower ? due to molecules of solute inside the potato cells. This imbalance leads to movement of water from the solution into the potato cells in an effort to reach an equilibrium. This diagram below gives a basic visual representation of the process of osmosis when the potato chip is placed in pure water. 0kpa -ve kpa On the other hand, when the potato chip has been left in a solution of a high molarity the level of sag measured is very ...read more.


One possible explanation is incorrect timing of the experiment; obviously, if the potato chips were removed from their solution of sucrose before the correct time span of 40 minutes had passed then they would have had less chance to lose or gain water through osmosis, and they would be stiffer than other chips left in for the correct time, this may be the reason for this anomaly. The next anomalous result, marked in red pen, is far above the average for the 0.5 column, which is only 1.8, whereas this anomalous result has a value of 4.4. Once again there are a number of possible reasons for this unexpectedly high value. One serious possible cause being the measuring technique used, which was far from accurate. Trying to measure the sag using a ruler when the strip of potato was swinging around was very difficult and would have led to some inaccuracy. Since this is a table of class results this anomaly may be down to this individuals measuring technique, different measuring techniques may well be a source of much variation in the results. Sources of error There are many possible errors that could of occurred in this experiment due to a method that was far prom perfect. Below is a list of the possible errors that could have occurred and how they would affect the results. ...read more.


The technique used in this experiment was suitable for measuring the level of osmosis in potato chips and the results obtained back this statement up. However, several improvements could be made to this experiment. Firstly, a system to accurately cut chips of the same size and shape could be developed, a chip cutter of the type sold in cooking shops would be perfect for this job. This would eliminate errors due to different sized chips and improve the accuracy of the results. A different measuring technique would also help improve the results. Instead of measuring the sag of chips due to osmosis, the length change of potato chips due to osmosis could be measured. This would be much easier to measure and therefore would improve the accuracy of the results. One other improvement that could be made to the experiment would be to increase the number of repeats, this would improve the accuracy of the overall averages. Despite the high standard deviation values of the results I feel that they accurate enough to support a firm conclusion. The fairly high number of repeats should have helped to smooth out the anomalies found in the data. The trend shown is what I was expecting to see, and this helps to show that the results were fairly accurate. Despite the potential errors and anomalies I have outlined, the graph produced from the data is good enough to support my conclusion. ...read more.

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