Amount of Potato – the more potato you have in mass, the more potato particles there are to move during osmosis.
Prediction
I predict that the higher the concentration of the solute used (eg 50%) the more osmosis will occur. I also predict that it will be the potato pieces in the stronger solutes will increase in weight and that it will be the pieces of potato that are in the weaker solutes and the distilled water that will decrease in weight.
Method
For the test you will need:
A range of different strength solutes
Some Beakers
Some Potato’s
A Stop Watch
Some paper towels (for drying)
Some Weighing Scales
And a knife
First you must bore a cylinder of the potato out. You must then cut each of the cylinders of the potato to the same length then you must weigh each one. You must then put in the 200ml of the solute that you are going to use after this you must add the potato pieces to the solute and use the stop watch to time the 15 minutes. After the 15 minutes you must take the potato out from the solute and dry it in the paper towels. You must then weigh the potato after this to see if the weight has decreased or increased.
Results
Conclusion
My graphs above show the difference from each of the three experiments they show how the difference goes down on the first concentration and then up and then down and then up and then down again, Because the line is not in a straight line with each point parallel it shows that the gain strength of the solute and loss or gain in mass of the potato directly linked. However, there is a pattern on my graph, and this is that there is an increase in the concentration the potato decreases in weight until it reaches a saturation point 30% concentration the graph that shows this the best is the 3 difference graph that shows a drop of just under 0.3g. Although the only problem with this theory is that on the
Evaluation
The experiment was very successful in my opinion. I obtained a large quantity of very accurate results from which I was able to create informative graphs. I think I took easily enough results for the amount of concentrations that I was using, and the time that I used for the experiment to last was enough to allow sufficient osmosis to occur. However if I was to repeat the experiment I might well increase the time of the result to allow more osmosis to happen and to possibly find out the saturation point of the potato chips.
The range of concentrations was adequate but I would possibly create more concentrations if I repeated the experiment so that I would have more varied results, i.e. 5%, 15%, 25%, and so on.
The cutting of the potatoes was the most difficult part of the experiment as although I was recording my results by mass, it could well have affected the surface area and so the overall rate of osmosis. If I were to repeat the experiment I would have possibly found a machine to cut the potato as it would ensure that all potatoes would be the same weight and all the same dimensions. I also think that it would have been good if it was possible to get all of the weights and dimensions of all the potatoes as then it would be much easier to compare the results across the board. As well as the potato I could have found a more accurate way to measure out the solutions and to determine the molar concentrations. Perhaps I could have used a burette. This would ensure that I have an accurate amount of fluid in each test tube. I could also weigh each chip on a more accurate scale, e.g. not to 0.00g but to 0.0000g.
There were not any out of the ordinary results, but some were not as close to the line as others. This may have been caused by human error. When the potato chips were removed from the test tubes and dried I may well have dried some potatoes more thoroughly than others and so some would have more excess water, which would add to the mass. If the experiment was repeated I could find another way to dry the potatoes that would ensure that all were dried in the same way for the same time. However with all this said I think that the experiment was truly successful and I was very pleased with the complete comparison of my results with my initial prediction.
