Results:
Carrots
Raisins
Conclusion
By looking at the results we could say that the three carrots reacted approximately the same way as each other. The 0 M water, is less concentrated than the carrot, therefore it passes in a greater quantity by the semi-permeable membrane. The carrot mass decreased probably because of a measuring error, as it would be expected to increase. The same happened with 0.5 M, probably also due to a measuring error, although with 1 M it remained the same, as the membrane wasn’t permeable to NaCl.
As the raisin’s mass increased at 0 M and 0.5 M, it means that the experiment was accurate and the water passed in a greater quantity through the semi permeable membrane. With 1 M the membrane was semi permeable, allowing some of the concentrated solution through, although still very few.
The longer the carrot/raisin is in the solution, the more the mass will rise until all the solution is absorbed into it.
By comparing the carrots with the raisins, we can see that the raisin’s percentage change in mass was a lot higher than the carrot’s. We can say this is due to the fact that it wasn’t a very accurate experiment.
Evaluation
The experiment could be improved in these ways:
- Using safer/more rigid containers, so that water doesn’t spill and the experiment remains intact.
- Programming the balance to return to 0 whenever a measurement is taken.
- Cleaning efficiently the carrots/raisins before weighing, so that the excess water is not counted.
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Cutting the carrot slices equally into pieces, (the same with raisins-same sized) to make it a fair test.
- Leaving the experiment for a longer period, so that the mass rises considerably and more accurate results can be taken.
