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Osmosis Investigation

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Introduction

Osmosis Investigation Aim: To investigate the effect of varying concentration of a certain sugar solution on the amount of osmotic activity between the solution and a potato chip of a given size. Osmosis is defined as the net movement of water or any other solutions molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found reaches a state of equilibrium, meaning that the molecules are randomly distributed throughout an object, with no area having a higher or lower concentration than any other. Equipment list * Potato borer * Boiling tube rack * Boiling tubes * Paper towels * Weighing scales * Knife * Test tubes Prediction: For this particular investigation I think that the lower the concentration of the sugar solution in the test tube the larger the mass of the potato will be. This is because the water molecules pass from a high concentration, i.e. In the water itself, to a low concentration, i.e. ...read more.

Middle

I had to be very careful whilst cutting the potato as the borer is exceptionally sharp. I then had 10 which weigh roughly the same mass. * Taking a test tube rack I placed 5 test tubes and then labelled them 0 molar, 0.2 molar, 0.4 molar, 0.6, 0.8 molar and 1 molar. * I swiftly put 1 chip into each boiling tube. * Whilst waiting I set out some paper towels with which I was going to dry the paper and I drew up a basic table for my results. * After 24 hours I drained out the solutions in the sink and placed all the chips on the paper towel in the order I had put them in the test tubes as to not confuse myself as to which chip came from which solution. * I dried each chip with the paper towel and then placed each one on the scales so that I could weigh them. * Each potato was measured accurately on the electronic scales and then the weights were recorded. Analysis From my graph I can see that osmosis took place in the potato. I know this as there was an increase and decrease in mass. From the graph you can see that the isotonic point is between a sugar concentration of 0.2 and 0.4. ...read more.

Conclusion

There were one anomalie result, and some were not as close to the line as others. This could have been caused by human error. 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 mass. 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. To further this investigation I could try to find the exact isotonic point as from my graph it shows me that the exact point is somewhere between 0.4 and 0.6. To achieve this I would use a range of concentrations between 0.2 and 0.4 the concentrations I would use would be: 0.4., 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58 and 0.6. These concentrations of sugar are so precise I would then be able to find the exact isotonic point. I would create a graph which would look the same as my previous graph just zoomed in with increased concentration recordings, the recording exactly on the line would be the exact isotonic point. ?? ?? ?? ?? Lloyd Walton 11CF ...read more.

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