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In my experiment I plan to find out whether the concentration of sugar in water affects how much water will go into a potato chip. I will find this out by osmosis

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Introduction

Biology Coursework Introduction: In my experiment I plan to find out whether the concentration of sugar in water affects how much water will go into a potato chip. I will find this out by osmosis. Osmosis is the movement of water molecules across a partially permeable membrane from an area of high water concentration to an area of low water concentration. I have chosen potato chips for my experiment, due to it having similar cells to a plant. It has a partially permeable membrane and the cell wall within the potato controls the water intake. Hypothesis: For the investigation, I think that the lower the concentration of sugar in the test tube, the larger the mass of the potato chip will be. And the higher the concentration, the smaller the mass of the potato chip will be. I think this, because I know that osmosis is the movement of water molecules from an area of high water concentration (in the water itself), to a low concentration (in the potato chip). Therefore, the chips in higher water concentrations will have a larger mass, than in higher sugar solutions. I predict that if the potato is in 0.6 or 0.8 molar solution, then the increase in mass due to osmosis will be little, as there is more sugar that water in the solution. And the net movement will therefore be outwards. If it is in 0.4 molar solution, the mass should increase a little, although there would be a small option for a net change, due to the concentration being the same in and outside of the potato chip. ...read more.

Middle

1.30 1.24 1.31 1.28 -0.47 0.8 1.75 1.64 1.55 1.65 1.14 1.01 0.95 1.03 -0.62 Concentration of sucrose Percentage change Average percentage change 1 2 3 0 26.25 23.39 22.85 +24.16 0.2 4.58 5.19 3.55 +4.44 0.4 -6.74 -8.72 -8.39 -7.95 0.6 -26.55 -27.90 -25.14 -26.53 0.8 -34.86 -38.41 -38.71 -37.53 (Graph attached) Analysis: Looking at the graph you will notice that the graph shows a positive correlation. My results agree with my prediction in the sense that they are showing the same thing that I had predicted. Which was, that the potato chip would increase in mass when it was put into pure water and would decrease in mass when put into pure sucrose solution. The steepness of the graph refers to how quickly the potato lost and gained weight. From 0-0.2, there is hardly a curve showing that it lost weight quickly, although the rest of the graph shows more of a curve, showing us that the weight decreased a lot faster as the concentration of the sucrose became higher. The line on the graph crosses the x axis at 0.24, showing us that at this point of concentration; the concentration of solution is the same inside the potato chip as well as out. Splitting the graph in two from where the line hits the x axis, the mass gain differs. Before it hits the line, the mass gain decreases, whereas after it hits the line, the mass gain increases. ...read more.

Conclusion

1, 1/2, 1/4, 1/8, 1/16, 1/32) this would show better the relationship between sugar solution concentration and the amount of osmosis occurring. We weighed the potatoes accurately, resetting the scales to zero every time we had finished, and taking done results with 2 d.p. Measuring the amount of solution being put into the syringes, we used a measuring cylinder. If I were to do this experiment again I would consider using a syringe to measure the volume, to receive a more accurate measurement. The results shown in the table are varied i.e. not having recurring numbers or amounts more than 2g apart. The results are reliable due to this, as we have don't have any results that vary incredibly, but are close together. With this our mean can be more reliable. The points plotted on the graph are the percentage change, showing the difference from the initial and final mass. The formula for this is shown earlier on. If able to hypothesise what would happen in this experiment again, I wouldn't change anything, due to the obvious trend shown on the graph, supporting my hypothesis. Although, there is always the possibility to find out the affects of osmosis in related situations, not using a potato. We could do this with a variety of plant cells, due to their expandable cell wall, for example, celery. By putting food dye into the water they feed off of, we can see how it affects the leaves. Using Carnations as an example is also a god way of showing the affects of osmosis. ?? ?? ?? ?? Nadine Rowe 10e ...read more.

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