Observing Osmosis in Potato Cells

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Observing Osmosis in Potato Cells

Planning
Purpose: To observe the effect of osmosis on plant cells.

Hypothesis: The higher the salt content of the water, the lower the mass of the potato.

Variables:Independent: the salt percentage of the solution
Dependent: the weight of the potato in grams
Controlled: the amount of water
the length of time between measurements
the method of measuring
the type of plant cells tested

Equipment: (as seen on 2A Human Biology task sheet)

Method: (as seen on 2A Human Biology task sheet)

Results
Solution| Mass before (g)| Mass after (g)| Change of mass (g)| % of mass lost| Distilled| 2.75| 3.60| + 0.85| + 30.9%|
1% salt| 2.76| 2.70| - 0.06| - 2.17%|
3% salt| 2.89| 1.99| - 0.90| - 32.6%|
5% salt| 2.79| 2.06| - 0.73| - 26.16%|
10% salt| 2.80| 2.29| - 0.51| - 18.21%|

(see graph as attached picture on email)

Evaluation
The results in our graph show that the more salt in the solution the more osmosis occurs, until it reaches ~5% where the rate declines.

Our hypothesis was partially correct, however we discovered there was a point at which more salt didn’t aid osmosis.

Osmosis is the name of the process of diffusion of water through a semi-permeable membrane, from an area of high to low concentration. For example, in this experiment osmosis occurred when water from within the potato sample moved out of the potato to the salty water in order to even out the level of water:salt within the solution.

The reliability of our experiment is uncertain, as there may have been interfering factors that we are unaware of. When carrying out our investigation we were careful to go through the same processes each time, however, so under these conditions our results are as accurate as we could ascertain.

We had few problems with the experiment, though there are other variables that could have affected our investigation. An example of this would be if the...
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