Do not leave for a shorter or longer time because then the results have more chance of being less accurate. Under half an hour is not long enough for osmosis to work completely and more than three hours starts to rot the potato.
Remove the potato cylinders
Remove each individual cylinder one at a time from its test tube. Pat it gently to remove any excess solution and then weigh each cylinder individual cylinder on the same electronic scales.
Record results
Make a results table and fill in the weight of the potato before and after the experiment, the sugar solution it was in, the number it was and the difference in mass between the weight before and after.
Afterwards clean up all equipment used and areas.
The variables
As in all tests there are some variables. In this case the variables would be
The potato cylinders → different cork borers will produce different size cylinders this makes the test unfair because if the cylinder is longer or wider there will be more potato for the sugar solution to be put with.
The solutions→ in this experiment on one of the occasions I had a different set of solutions this means that the test was not actually fair because some of the solutions had a higher average because there was more experiments with that solution.
The heating in the room →the heat would affect the experiment.
Where the experiment was left→ if the experiment was left on a radiator or in direct sunlight in one test then in a cold corner the results would vary, to make sure its fair all experiments should be left in the same place and conditions.
tampering→ if someone tampered with your experiment then your results will be unreliable.
My results
My first experiment
My second experiment
The reason that the solutions 2 m 50 and 1m 50 are underlined is because these were two solutions I was not intending to use. Therefore these do affect my results.
My third experiment
On this experiment we only had electronic scales that worked to one decimal place so my results will not be as accurate. This then questions the reliability of the results.
An average table of results
* there are no results here because I was not given the correct solution. The averages for both of these are done using the experiment results I had.
The change in mass is the first experiment weight in grams minus the third experiment weight in grams. This gives the change in mass.
My graph
My results graph is going to be wrong because my experiment went wrong.
For the first experiment the cylinders were left in there test tubes for just under half an hour this may have affected these results because both the other experiments were left in for half an hour to about 45 minutes.
In my second test the correct range of sugar solutions was not given to us so I could do not a fair experiment on all of the solutions.
In the third experiment we only had electronic scales that measured to one decimal place. This meant that our weights were not all accurate.
If I was to re-do my experiment I would do all three tests at the same time. This is because the conditions would all be the same and then I could control all three tests and make sure they were all done under the same rules and procedures.
Analysis
From the experiments, even though they weren’t all down under exact same conditions, they still show roughly the same results.
When the solution of the sugar concentration outside the potato cylinder is higher than the solution inside the potato cylinder, the weight of the potato cylinder will decrease.
This was proven in my results, in most cases(if the solution outside is higher than inside) the weight did decrease.
This was because the water molecules in the solution are diffusing through the cell membrane to balance out the sugar solutions.
These results prove that the higher the concentration of sugar solution, the less the potato weighs. All three experiments prove this-even the ones with the wrong sugar solution.
It appears that as the sugar solution increases the weight of the potato cylinder decreases.
The only time this rule didn’t work was when I used distilled water, this was because the water has no sugar so the water just diffuses through the cell membrane to balance out the water solution-therefore balancing the sugar concentration.
Evaluation
After reviewing my method and how I did my experiment I think it was completed quite successfully. The experiment was relatively simple and was easily done between two people. The results obtained from my experiments, however, were not as reliable as they should be. For example the sugar solutions in the second experiment were not the same, this means that the average of two of the sugar solutions will not be correct, compared to the other solution averages. Also on the third experiment the scales I used only weighed to one decimal point. This means these results are not as accurate as the others and could on the average be wrong.
Even though the reliability of the experiments is questionable most of them show evidence supporting my prediction. This suggests that even in faulty test conditions osmosis is still present.
