Osmosis Courswork

Analysis

The trend that my graph and results show is that when the potato was placed in a solution that had a higher concentration than the chip itself, the potato lost weight (0.4, 0.6, 0.8 and 1.0 molars). In the same way when the potato chip was placed in a solution that had a lower concentration than itself, the potato chip gained weight (0.0 and 0.2 molars).

For my results I calculated the percentage gain/loss in weight using the following formulae:

Average change in weight/weight at start times 100

The graph slopes downwards. This means that the percentage gain and loss in weight and concentration are not directly proportional because the line is not straight and does not pass through the origin. However, there is a pattern on my graph, and this is, as the concentration of the solution increases, the percentage change in weight decreases.

From the line of best fit that has been added in, it can be seen that all of my points are very close to the line if not touching the line. This shows that my results are fairly reliable.

My results show a sufficient trend for me to be able to say that my prediction was correct.

When the potato chips were placed in a solution that had a higher concentration than itself, the potato chips lost weight. As there was a higher concentration of water molecules inside the potato chip compared to the concentration of water molecules outside the potato chip.

It was stated in my prediction that osmosis is the diffusion of water molecules from a high to a low concentration, therefore water molecules from inside the potato chip moved out into the solution. Leading to the cytoplasm inside the cells to shrink and become flaccid. As the cells of the potato chip have lost water they now weigh less than they did before.

When the potato chips were placed in a solution that had a lower concentration than itself, the potato chips gained weight. This was because that there was a lower concentration of water molecules inside the potato chip compared to the water molecules in the surrounding solution so osmosis again occurred making the water molecules move from the solution to the potato.

I can find no anomalies from my results or graph. The graph seems to have a trend, which is supported by my theories so I can say within reasonable doubt that my results are conclusive.

The concentration of the cell sap where the % loss is 0% is slightly over 0.2M. The amount that it is over 0.2M is too small to take into consideration for this particular experiment.

Evaluation

I believe that the experiment worked well. I believe this for these reasons:

* I got results that followed a trend, which corresponded with my prediction, my former knowledge of osmosis, and it's effects and also with the new knowledge I learnt during the course of the experiment.

* The results I got were consistent over all my experiments and all followed the same trend.

I can find no anomalies from my results or graph. The graph seems to have a trend, which is supported by my theories so I can say within reasonable doubt that my results are conclusive.

Anomalies could of occurred for a number of reasons. The potato may not have been blotted sufficiently; the wrong amount or concentration of solution may have been added to potato, residue from previous experiments in test tubes may affect results.

If I did this experiment