To investigate the effect of water concentration on the mass of potato tissue.

Evaluation:

I was pleased with the results that I obtained from my experiments; they proved to be accurate as my repeat readings were very close to each other, there were also, as far as I can tell, no anomalous results. I did not encounter any anomalous results (An anomalous result being a result that does not agree with the general trend of the other readings) and therefore did not have to remeasure points. There is however, always room for improvement. Firstly, I did not take into account the effect of fluctuations in the room temperature on my experiment, though I could not have controlled the temperature inside the laboratory, I could have covered the test tubes with cling-film to prevent any solution escaping through evaporation. Another problem was the fact that I was forced to rely on imprecise tools to cut the potato cylinders such as rulers, scalpels and my own judgement. I was able to partially remedy the problem of different sized cylinders by calculating the percentage change in mass as opposed to the actual change. Yet another complication is that there is no guarantee that the potato was the same density throughout, in fact it is highly unlikely. A final obstacle was that some of the cylinders remained in the solution while I dried and weighed the others, an partial answer to the problem would be to empty all of the cylinders out of the test tubes first, then dry them all, then weigh them. Even the paper towels that I used to dry the cylinders may have either absorbed some of the water from inside the potato tissue or left some of the excess solution on the cylinders my only suggestion to remedy this would be to use a hair dryer on a cold setting to remove the excess water.

In terms of expanding my investigation, there are several different routes that I could take. Firstly I could use the concentrations 0.0, 0.1, 0.2 etc…

instead of 0.0, 0.2, 0.4 etc… in an attempt to achieve more accurate results. I could introduce other variables such as temperature (Would osmosis slow down or even fail to occur in the low temperature of a refrigerator?) or the size of the cylinders (Would the lower surface area to volume ratio of a smaller cylinder affect the speed of osmosis and would a potato cylinder cut in two react differently when compared with a regular cylinder) or even comparing the results yielded by a) two cylinders in separate test tubes and b) two cylinders in the same solution, the possibilities are endless. There was always a chance that the potato that I used was abnormal so a good idea would be to test a series of potatoes. It would be interesting to investigate whether or not other varieties of potato yield different results and trends. And why stop at potatoes? Why not try other similar vegetables such as sweet potatoes, carrots, turnips and parsnips.