For this particular investigation I think that the lower the concentration of the sugar solution in the beaker the larger the mass of the potato will be. This is because the water will pass from a high concentration, (in the water itself) to a low concentration, (in the potato chip). Therefore, the chips in more water will have a larger mass than in higher sugar solution.
Method
- cut up equal sizes of potato and weigh them out and make them as equal weight as possible
- put the weight of the potato chip in a table (you’ll need them later)
- measure out 5 solutions 100% water / 0% sugar solution
75% water / 25% sugar solution
50% water / 50 % sugar solution
25% water / 75 % sugar solution
0% water / 100% sugar solution
- put the potato chips in at the same time and leave them in there for an hour
- take the potato chips out and weigh them again on the same scales
- put down the new weights on a table
Table of results
Table/graph
(What did I find out?)
My graph gives the line of best fit for the change in mass of the potato chips over the course of the experiment. There is a pattern on my graph and this is that as the amount of the solution increases, the change in mass decreases. The graph goes down on a steep gradient but I think that the line will eventually even out, I think this because the potato chip will eventually becoming as flaccid as it possibly can. The line of best fit that has been put in, you can see that all of my points were very close to creating a perfectly smooth curve. This shows that my results are fairly reliable apart from the second one, this might of happened because of one of the variables we have previously discussed might have happened. My graph fits in with my prediction which I made.
Evaluation
The experiment was very successful in my opinion. I got a large quantity of very accurate results from which I was able to create a good graph. I think I took 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. 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 for example 0.10m, 1.15m, 1.20m e.g. This way it would have allowed me to find out the isotonic point
The cutting of the potatoes was the most difficult part of the experiment because I was recording my results by mass; it could have affected the surface area and the overall rate of osmosis. If I were to repeat the experiment I would have possibly (if there is such a thing) found a machine to cut the potato as it would make sure that all the potatoes would be the same weight and size. As well as the potato I could have found a more accurate way to measure out the solutions, if I could do this it would make sure that I have an accurate amount of liquid in each beaker. I could also weigh each chip on a more accurate scale for example not to 0.00g but to 0.0000g if I had a better set of scales.
There was not any out of the ordinary results, but one was not as close to the line as the others. This may have been caused by myself or my partner. This may have been when the potato chips were removed from the beakers and dried I may well have dried some potatoes more than others this might make some 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 the potatoes were dried in the same way for the same time. However I think that the experiment was successful and I was pleased with my results and with my prediction. us
Conclusion
Because water molecules have kinetic energy, they are constantly moving around as a liquid. The greater the concentration of water molecules in a solution, the greater the total kinetic energy. This means that as the concentration of sugar is increased in a solution, the concentration of water decreases, loosing some of the solution’s water, and decreasing its ability to move between solutions by osmosis. Relating this to the potato chip, as the concentration of sugar in each solution was increased, the water in that solution can not move easily to the potato, causing water from the potato to move to the solution, decreasing its size and weight. This would explain why potato chips put into a solution of 0 molar seemed very stiff compared to the potato chip used for 1 molar which went all soft.
In conclusion I can say that the movement of water through semi permeable membrane of a potato is affected by concentration of sugar solution. The higher the concentration of glucose solution, the more the potato chip will lose its weight and size.