[NickHolt]

Hi, my 11th grade biology class just performed an experiment involving the solute potential of potatoes in a solution of water with varying sucrose concentrations. While we technically do not have to calculate the potential (only suggest a concentration where it is lowest), I would like to in order to receive those shiny extra points.
The lab was as follows:
We were given six sucrose solutions, one of 0.0M (distilled water), 0.1M, etc up to 0.5M. We then cut potatoes into .5cm X .5cm X 5cm "fries". We then put three of each into 40mL of one of the solutions (it was done for all six). The test tubes were then revisited 21 hours later, and the differences in weight and size were recorded.
Unfortunately, I do not take chemistry and don't even know where to begin in calculating the solute potential. It would be greatly appreciated if someone could show me how to do it, preferably by example of one of my solutions.
Here is the raw data of the sucrose solution of 0.5M in case you need more information:
Before submission in sucrose solution
Molarity:       0.50M      
Potato 1:      1.410      
Potato 2:      1.225      
Potato 3:      1.316      
Average:       1.317      



After 21 hours of submission in sucrose solution
Volume of potato slices (in cm3)
Molarity of solution: 0.50M      
Potato 1:               1.875      
Potato 2:               1.625      
Potato 3:               3.575      
Average:               2.358      

Weight of potato slices (in grams)
Molarity:                0.50M      
Potato 1:               1.4      
Potato 2:               1.7      
Potato 3:               1.8      
Average:                1.6   

Differences (of averages) before and after of the volume and weight for 0.5M
Difference of Weight Averages: 0.2
Difference of Volume Averages: 1.041      

Any help would be appreciated. Thanks!