Prediction:
I think that a sugar solution of 0, the potato cell will increase, between 0-1, the potato will stay the same and a concentration of 1 or above, the potato cell will decrease in size. I think this because in osmosis, water moves from a high concentration to a low concentration of water.
Apparatus:
6 test tubes to put the solutions in
Distilled water to put a potato chip in
A solution of 0.2Molar to put a potato chip in
A solution of 0.4Molar to put a potato chip in
A solution of 0.6Molar to put a potato chip in
A solution of 0.8Molar to put a potato chip in
A solution of 1Molar to put a potato chip in
A test tube rack to put the test tubes in
Labels to indicate what test tube contains what solution
A Potato borer to cut chips from a potato
A potato
A ruler to measure the length of the potato chips
A measuring cylinder to measure how much solution to put in each tube
Method:
Then I put 20 cm2 distilled water into one test tube, then I put 20cm of a sugar/water solution of 0.2 mole concentration of sugar in to another test tube, We did this for four more test tubes each with an increment of 0.2molar of sugar. We cut potato chips in to equal sizes and measured them, we put a potato chip in each tube and left them overnight, we then took the potato chips out of the solution and measured them. We then recorded the results. We done this experiment three times to ensure a fair set of results.
Diagram:
Variables:
The independent variable was the concentration of the sugar solution, the dependant variable was the length of the potato chips in each experiment. The controlled variables were the amount of solution in each test tube, if this was not controlled, then the results would not be fair and useless.
Results:
Graph :
Analysis:
From these experiments, I have found out that my predictions were correct. In lower concentrations of Glucose, Osmosis takes place and the potato chips become turgid. In higher concentrations of Glucose, Osmosis takes place but the potato chips become plasmolysed. From the graph, I think that the concentration of sugar in a potato cell sap is 0.55 molar. I think this because this is where the end size is the same as the start size, showing that this is the isotonic concentration.
Evaluation:
In my opinion the experiment was very successful. I obtained a large quantity of quite accurate results. I was able, from these results, to draw up a somewhat informative graph. I think I took enough results for the amounts of concentrations I was using. I also think that I gave the experiment enough time for Osmosis to occur. Maybe if I were to repeat the experiments again I would probably try using a wider range of concentrations as to find a wider range of more varied results. The most difficult part of this experiment, in my opinion, was the accurate cutting of the potatoes. It was very difficult to accurately cut the potatoes to the same length. In my opinion, there were not many of my results, which were out of the ordinary. Slight differences may have been the result of human error. However, I think that my experiment was successful and am quite pleased with my results.
