Osmosis AT1

Essay by PaperNerd ContributorHigh School, 12th grade November 2001

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Conclusion: What I have found out is that the higher the concentration of sucrose the higher up was the potato chip in the test tube. The water inside the potato is moving from a area of high water concentration to an area of low concentration so in the sugar concentrated solutions the potato chip should decrease in mass my results showed the opposite of both my prediction and the source where I adapted information from. {CGP Books} said my prediction was correct thus proving something has gone wrong during the experiment maybe I did not leave it long enough for the osmosis to occur. In other words the water inside the potato is leaving it, as it is passing from a weak concentration to a strong concentration. Making it smaller and lighter. Where as with water as the solution, the potato piece stayed the same but theoretically it should have gained weight therefore became turgid.

In the potato chip there is the point at which the potato cell can reach its highest point of turgidity. The trends or patterns that I have found out are that with each of the experiment the line of the graph is up and down then straight. I think that the results of the experiment disagree with my prediction. I think that they disagree with my prediction as when the concentration of the sucrose solution gets higher the more limp the potato piece becomes, we know this is correct however my results didn't seem to show it. When it was 0.8% it should have the highest weight loss but my results show that it increased by 1gram. Also when the potato was put into the distilled water, we had found that it had taken on the least weight: completely defying with my prediction. The highest average mass gain was for the 0.6% sucrose solution. The highest average mass loss was for the distilled water and 0.4% sucrose solution. There was zero weight loss for the distilled water and the 0.4% sucrose solution, this means that no water moved into the cell to increase its mass or no water moved out of the cell to decrease its mass. Osmosis causes water to move in and out of the potato by diffusion. The following is a diagram to show how this happens: This process normally happens in nature when the root hairs of a root take in water by osmosis it happens when water goes into the soils the root hairs cover a large surface area and when the water goes on to the root hairs it diffuses into them and is taken up to the leaves via the xylem.

Evaluation: Originally the potato chip was 5cm long and I changed it to 4cm because it was difficult to fit the chip into the test tube. This alteration was done to all the potato chips. This change was relatively easy to make, and this could be easily performed. I think I took enough results for the amount of solutions that I was given, and the time restrictions that I had to follow, (30 mins). However given a greater time period, I could have investigated more concentration in terms of molarity. Also I could have repeated the experiment at least four times. This could have all been done at once; by this I mean that the four identical experiments running at the same time. This will allow me to obtain average results, which will be more representative than having results from another person in the class. Alternatively to make my experiment better I could have asked more students within my class for their result to come up with a more accurate average result. I could have also used a machine to cut the potato chips so that every chip would be identical and this eliminating human error.

If I were doing the experiment again I could make changes, some as mentioned above, I would use a top pan balance that would measure to 1/100 of a gram this could show even slight variations in mass. I would also use a digital measurer to get a more accurate result to ensure that I have a same amount of fluid in each test tube. Alternatively I could use a burette. There were some anomalous results for example when the distilled water and 0.4% sucrose solution didn't change in mass. Maybe this may have been caused by human error, or perhaps the potato chip was not cut accurately. My results did vary a lot with others for the same concentrations. My results were consistent, and there were no results that were poor. If I were to extend/improve my method I would eliminate the statement about human error by getting machines to do the cutting and the other aspects of the experiment that could have been caused by human error. I could extend my enquiry by testing the percentage change in mass with solutions using a different substance. By this I mean using a different vegetable, perhaps celery or cucumber. Then I could find out whether osmosis occurs with the same patterns and trends with any vegetable.