Equipment;
Five test tubes - To hold the potato and each one of the five sugar solutions individually;
Test tube rack;
Knife and equipment to cut potato into 5 pieces of equal mass;
Measuring cylinder for measuring amount of water and finding the correct amount;
Scales for weighing sugar;
Thermometer to ensure the temperature of each solution is identical to the others;
Spatula for stirring sugar solutions;
Sugar and distilled water.
Diagram
Method: Using a scalpel, cut five potato pieces. They should be of an almost equal size and mass. To ensure this, weigh the pieces.
Prepare the sugar solutions. These should be: a 10% sugar solution, a 20% sugar solution, the same for 30%, 40% and 50%. The solutions should be based around 20Ml of pure water. For example, a 10% solution would need 2 grams of sugar; a 20% solution would need 4 grams of sugar and so on. Add the measured amounts of sugar to the test- tubes containing 20Ml of water and stir until fully dissolved. Record the weights of the potato pieces then place them in the sugar solutions and leave for 20 minutes. Record their final mass and compare to the original mass.
Fair Test Points:
- Ensure that all the potato pieces are of the same mass.
- Ensure that each solution is at the same temperature.
- Leave all the solutions for the same amount of time.
- Make sure that all the potato pieces come from the same potato.
Results
Conclusion: It is difficult to conclude a lot from the results I have obtained. There is no obvious pattern in the results. But if you don’t include the result for a 10% sugar solution then one can say that the change in mass decreases the when the sugar solution increases. It may be possible to say that when potato is in a sugar solution, it’s mass decreases or that the lower the solution is, the more the mass decreases. This could be due osmosis and the potato may have gone turgid.
EVALUATION
All the results we recorded appear to be anomalous. However one might say that the result for the 10% sugar solution is the most unexpected as it is the only result which does not conform to the decrease in mass pattern that seems to arise at the 20% solution result. The reason that we had such irregular results could have been due to a number of things. Firstly, the temperature of each solution may have differed which would have lead to irregular results. We did not monitor our thermometers regularly during the experiment so if the temperatures had varied then we would not have known about it.
To improve our experiment, we could have ensured that we used the exact right amounts of sugar and water and stirred them fully.
We could of left the solutions for longer as we may not have given long enough time for any changes to occur.
