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Osmosis on potatoes

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Bryan Telfer Osmosis on potatoes Background Information Before actually planning the experiment, I will do some research to find out about osmosis, and matters related to it, so that I can make predictions. And figure out a way to make this investigation fair and safe. Planning ahead would help me find out how to do what, when, which should lead me to good results at the end of the experiment. Hypothesis Osmosis is the passage of water molecules from a weaker solution into a stronger solution, through a partially permeable membrane. In this case, the tiny holes in the membrane of the potatoes will allow the water molecules to pass through in and out of the solution and the potato, depending on the concentration gradient of the two substances. So in this case, when the water concentration is lower in the tissue, the water will go inside the tissue of the potato, and the potato will gain weight. And if there is very little different in the two water concentrations, there shouldn't be such a big change in weight. And if there is a higher concentration of water in the potato, the water will go out of the potato. ...read more.


Another important factor of a fair test is to start and stop the clock as quickly as possible. This meaning that we should start the clock as soon as the potato is put inside the petri dish, and stop the clock as soon as 20 minutes have passed. Stopping the clock, taking 'em out and measuring it all in less than a minute us quite impossible because we lack the number of balances. And there are obviously too many sets to go through at such a fast time. Therefore, we will try our best to weigh the potatoes as quickly and as safely as we can. Getting and experimenting with the exact measurements of molars and water is vital to this task. If the volume of one solution in a petri dish is higher or lower than another, will affect the pattern of results later on. We will also make sure that the potato is fully covered by the 6 different kinds of solutions. This is because, is the potato isn't covered up by the solutions, the effect of osmosis might not occur to the fullest. Small things such as a dirty petri dish, and a slightly cracked measuring cylinder could still affect the results, and therefore we will take these into account as well. ...read more.


-0.12 -2.53 AVERAGE 4.76 4.61 -0.15 -3.15 0.6 1 4.87 4.63 -0.24 -4.93 2 4.86 4.57 -0.29 -5.97 3 4.88 4.55 -0.33 -6.76 AVERAGE 4.87 4.58 -0.29 -5.89 0.8 1 4.81 4.49 -0.32 -6.65 2 4.62 4.22 -0.40 -8.66 3 4.86 4.53 -0.33 -6.79 AVERAGE 4.76 4.41 -0.35 -7.35 1 4.64 4.23 -0.41 -8.84 2 4.86 4.51 -0.35 -7.20 3 4.80 4.39 -0.41 -8.54 AVERAGE 4.77 4.38 -0.39 -8.18 Analysis On the graph shown below, I have made the 'different solutions' as my independent variable, since it won't be changing on any event. And I have made the 'percentage' as my dependent variable, because it doesn't change in any particular order or a pattern. I have decided to make it a bar graph, because the independent variables aren't exactly in the same category. For example, I would have used a line graph if the independent variable in my experiment were time, which is changed deliberately, but these are different subjects of matter. And also, the results were very different, as well as the columns and there wouldn't be any advantages of using a line graph to view the results. I have taken the average result of the 6 different solutions and put it on the graph to be more accurate. ...read more.

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