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Introduction

Introduction: Osmosis is the transfer of a solute over a semi-permeable membrane in order to equalise the concentration of a solute over both sides. This practical aims to demonstrate the effect of osmosis on potatoes in sucrose solutions of varying concentrations. If the osmosis does occur, the potatoes in a high sucrose solution should lose weight as the water moves out of the potato into the solution to equalise the concentrations. In addition, the potatoes with little or no sucrose in their solution should gain weight as the water moves into the potato to dilute the concentration of sucrose in an attempt to equalise the solutes. Data Collection and Processing: Raw and processed data is shown below in a table including: the mass of each potato tube before and after the experiment and the percentage change in mass. ...read more.

Middle

It can also be observed that the potatoes which had mixes of distilled water and sucrose solution had results inbetween the two extremes. The data supports the model for osmosis where water moves through a semi-permeable membrane in order to equalise the solute concentrations on either side of the membrane. It showed that water moved into the potato tubes when the solution had a low concentration of sucrose to balance the concentrations. It also showed the opposite of that. The experiment also showed that smaller imbalances in concentration resulted in less osmosis and a smaller change in mass evident in both Figure 1 and Figure 2. Evaluation: The lack of results create a situation where the data is not enough to make a defined statement as the evidence is not suffiecnt to do so. ...read more.

Conclusion

Improving the Investigation: The investigation may have been improved by firstly repeating experiment at least 3 times. The repetition of the investigation means that the effect random error has on the results is greatly reduced and makes results more accurate. Another step that could be taken is having more results per experiment. This would lead to a more accurate data pool and show more clearly the trend displayed in the experiment and would result in a more appropriate line of best fit. Finally, the elimination of human error would be ideal in improving the investigation. This could be done by mechanical means and would result in more concise results and less variation in factors such as surface area and weight. It would also mean that the results would be more evident if the initial weight of each potato was the same. ?? ?? ?? ?? Osmosis in Potato Tubes Michael Zhao 4/04/2012 ...read more.

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