Figure 1: Initial and Final Mass of Potato tubes
Figure 2: Graph depicting the percentage change in mass of the potato tubes in increasing concentration of a sucrose solution with the red line representing the line of best fit.
Conclusion:
The difference between the potato in the complete sucrose solution compared to potato in the distilled water is extremely high. It can be observed in the results that the potato in the distilled water was considerably heavier than before the experiment whereas the potato in the sucrose solutions had decreased in mass when compared to its mass before the experiment. 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. In addition, 5 results cannot support much more than a linear line of best fit and a rule cannot be determined for the rate of osmosis in relation to the solute’s concentration. Random error also may have played a role, however, the singular test means that random error has not been substantially reduced. Finally, Human error played a significant role as the measurements may have been off and the inaccuracy of the cuts resulted in different massed and shaped potatoes. This difference in shape and mass may have lead to variation in surface area which would let more or less water in or out over an extended period of time. In addition, human error may occur in the measurement of the sucrose and distilled water solution. The ration may not have been exact leading to variation in the results.
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.
