I then left each test for 20 minutes, but found after that time a slight reaction had taken place – the potato chips only increased or decreased by a very short amount. I then predicted that now I would have to leave the tests for a longer amount of time and use longer potato chips to ensure that there is enough of a reaction to compare them on a graph. I also made some other mistakes which I have to correct, one of which being the fact that I used normal tap water for 0 molar – but then decided that it would be better to distilled water to ensure that it was a effective enough reaction – there might be some chemicals in the tap water which alter the effect it should have on the potato chip. One thing I thought about a lot was if the amount of solution had on my effect on the potato chip at all. I finally agreed to not waste time and just estimate the amount of solution in the test tubes and make them fairly accurate.
Hypothesis:
I predict, that as concentration increases, the weight and length of the potato chip will decrease. My reason behind this, is that the higher the concentration of Sucrose in a solution, the lower the concentration of water. When the potato chip is put into the solution, it will, by osmosis lose some of its water, and the water will diffuse into the solution of Sucrose, causing the potato chip to lose water, therefore decreasing in length.
However, if a potato chip is placed into a solution of 0 molar concentration, it should gain length. This is because the solution has more water potential (its molecules’ ability to move) than the potato chip, and so water moves from a region of high concentration (the solution) to a region of low concentration (the potato chip.)
Method:
After having done my preliminary work, I knew exactly which measurements I needed to use in order to obtain the correct results. I set up 18 test tubes, because in order to save time, we intended on doing repeats at the same time as the original experiments were going on.
For organization’s sake, I set up all of the test tubes at once, and labeled them separately to avoid confusion later on. Into each test tube, I poured just enough Sucrose solution to cover the potato chip, and added one of the potato chips each measuring 50mm in length. In order to make it as much of a fair test as possible, I added the potato chips very quickly, to make sure one chip didn’t have a longer amount of time in the solution than another. I then left each one for 25 minutes.
After 25 minutes, I emptied each test tube, leaving only the potato chips inside. I then measured the chips in mm because they are a more accurate measurement.
Data Presentation:
Data Analysis:
The Graph shows the average change length and how this change came too – by which concentration. As you can see there is a trend – the higher the concentration the more water is lost – it seems to curve towards the end signaling that most of the water has already left the potato chip and if we put a higher concentration then there would be no more change than about 15 % as a guess. As you can see on the graph above the 0 molar concentration was low compared to the potato chip therefore the chip increased in length – but it is very close to change at all in the 0.2 molar section – so this allows me to make the prediction that the potato chips have a concentration of 0.2 molars.
Conclusion:
To conclude my investigation I have proven that the movement of Osmosis is effected by the concentration of a solution, in this case the concentration of a Sucrose Solution. Also the higher the concentration the higher the loss of length or weight will be, until all the water is gone – the limit.
The membrane is only thick enough for water molecules too pass through, Sucrose Molecules will be too big. If there are two concentrations placed right next too each other with a semi permeable membrane in between, and there is a greater amount of sucrose molecules on one side. The side with the greater amount sucrose molecules will have a greater amount of energy than the other due too the larger amount of molecule on one side. Therefore since the glucose molecules cannot pass through to create a balance the water molecules must. This is the water gradient being balanced.
Evaluation:
I had a short amount of time to complete the experimenting for this investigation so a planned out my experiments over that time to get them all completed in a short time as possible. If I had the chance I would redo my experiment with more molar ranges, like a range from 0 to 5 as an idea and do each repeat separately as too insure I didn’t make the same mistake for all if I did make a mistake. By this I mean I do each repeat on a different day because if on one day 2 molar concentration seems to have been gone off and I did the experiment with out even realizing then all my repeats would give the same result making my results inaccurate and inconsistent. I, after my preliminary work, thought that the amount of solution used was not relevant because it would have no effect of the chips, the reason I did this was also due to the lack of time. If I had time I would go back and measure each solution equally to insure accuracy.
