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Investigating The Effect Of Osmosis On Plant Cells And Tissue

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Introduction

Investigating The Effect Of Osmosis On Plant Cells And Tissue Planning I am going to investigate the effect of varying concentration of external sugar solutions on the amount of osmotic activity between the solution and a potato core of a given size. To create a fair test certain aspects of the experiment will have to be kept the same, whilst one key variable is changed. If this experiment is not a fair test, I will be obtaining the wrong results which could lead me to the wrong conclusions. As I have written above, I have chosen to vary the concentration of the sugar solution. The first and most important thing to do is to get the measurements of the solutions and the mass of the potato cores as exact and as accurate as possible. This will be done to every single potato core. I will use a 'size 6' cork borer (for all the potato cores taken out to make it a fair test) to get the potato cores out of the original potato. The cork borer produces almost perfect cylinders which make it a lot more accurate to work with, rather than having potato cores which aren't the same width or aren't similar in shape. I will be evenly cutting the potato cores with a scalpel to make them as equal in length as possible to make it a fair test. I will explain how the length will effect the effect of osmosis below. I will also be measuring the length to the nearest millimetre. If any of the non-variables are not kept constant , it would mean it would not be fair test. If we take the potato core for instance. If the potato core was taken out with different cork borers, it would mean that the potato core would be a different width, or if one potato core was longer than another potato core, there would be an increase in surface area which would therefore mean that there is more ...read more.

Middle

unless there is insufficient time. Range and Numbers There will be six different molarity levels; 0M, 0.2M, 0.4M, 0.6M, 0.8M and 1.0M. I will have three potato cores for each molarity level and I will take the average to give me more accurate results and reduce the amount of anomalous results. Preliminary Work This will be done before the main experiment mainly to see how long I should leave the potato cores for osmosis to occur. I will do two separate experiments to conclude what will be the best durati 2nd Experiment Time left: 20hours 34mins CONCENTARTION INITIAL MASS(g) FINAL MASS(g) CHANGE OF SUGAR SOLUTION IN MASS 0M 3.41g 4.11g +.7g 0.5M 3.34g 2.95g -.39g 1M 3.41g 2.95g -1.22g Conclusions From the Preliminary Results n of time to leave the potato cores. Three test tubes will be filled with 20ml of different concentrations; 0M, 0.5M and 1.0M. The reason I will use these specific concentrations for the preliminary experiment is to find out what will happen to a potato core where it is put in a concentration of under 0.5 M and above 0.5M. The three test tubes will be labelled with their molarity level on the test tube so I know which test tube will have which concentration. The potato cores will be taken out from the original whole potato using a cork borer. They will be then cut to the same size (4cm) as accurate as possible. They will then be wiped with tissue paper before weighing them to get rid of any excess liquid which might come from after the potato core is taken out of the test tube which could add to the mass of the potato cores, which would give inaccurate results. A petri dish will be placed on to of the top-pan balance to weigh the mass of each potato core. The mass of each potato core will be recorded and then put in each of the three concentrations. ...read more.

Conclusion

I did not take into account the effect of fluctuations in the room temperature on my experiment, although I couldn't have controlled the temperature inside the laboratory, I could have covered each test tube with cling-film to prevent any solutions escaping through evaporation. I was forced to rely on imprecise tools to cut the potato cores such as rulers, scalpels and my own judgement. I was able to partially solve the problem of different size potato cores by calculating the percentage change in mass as opposed to the actual change. I calculated the percentage change in mass by dividing the change in mass by the original mass of the potato core and then multiplying it by one hundred. I got the final percentage change in mass by calculating the average of the three different percentage change in mass. Some potato cores were still in their test tubes while I dried and weighed the others. The way I could solve this is to empty all the potato cores out of the test tubes, then dry and weigh them. There are a number of different ways to expanding my experiment. I can could introduce other variables such as the temperature; would osmosis slow down or speed up or will osmosis even occur in a low temperature, such as in a fridge? The size of the potato cores can effect the rate of osmosis. Would the lower surface area to volume ratio of a smaller potato core affect the speed off osmosis and would a potato core cut in tow halves react differently compared to a regular potato core? I can also compare the results yielded by two potato cores in separate test tubes and two potato cores in the same test tube but in the same concentration of sugar solution. I could also t likely to be different. I could investigate whether or not different varieties of potatoes yield different results and trends. Similar vegetables can be used such as onions, celery and many more. 6 ...read more.

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