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Osmotic Rate of Size and Concentration
By:Cody Sloan
Trenten Fenster
Purpose
• To see the affect that size has on osmotic rates• To observe how concentrations of the solute
affect osmotic rate
Procedure
• Cut two different size cores from a potato, two of each
• Weight and measure to make each potato core the same weight and length
• Create two different solutions: Distilled water, and 2% salt solution
• Put one small core and one big core in the distilled water and leave for 15min
• Do the same with the other cores in the 2% solution
Hypothesis
• If the smaller piece has a faster osmotic rate it is because the molecules don’t have to move as much. If the bigger piece has a faster osmotic rate its because it has a larger surface area.
• If the higher concentrated solution has a faster osmotic rate then it is because there are more particles to go out of the cell.
DataBig 1 Small 1 Big 2 Small2
Before
Diameter 1.4 1.0 1.4 1.0
Length 3.5 3.5 3.5 3.5Concentration %
0 0 2 2
Weight 4.1 2.5 4 2.5
NaCl (grams) 0 0 1 1
After
Weight 4.3 2.5 4.4 2.7
Diameter 1.3 0.9 1.3 0.9
Length 3.4 3.5 3.4 3.4
Analysis Mass percent change:Big 1: 4.65%
Small 1: 0%
Big 2: 9.09%
Small 2: 7.41%
Initial Weight Final Weight0
0.51
1.52
2.53
3.54
4.55
Big 1Small 1
Initial Weight Final Weight0
0.51
1.52
2.53
3.54
4.55
Big 2Small 2
Conclusion• All samples gained weight except for Small 1
which didn’t gain or lose weight• This means that the salt ion concentration
inside of the cell is greater than 2%• Also, the bigger samples gained more weight
overall (proven by the % mass change)• This proves the fact that the larger sample
gains more water because there is a bigger surface area for the water to get into the cell through
Errors and Improvements
• An error that could have occurred is that we could have left the potato cores in for different amounts of time
• Another thing that could have happened is that the cores could have been slightly different shapes and weighs
• A final error that could have occurred is that we could have measured an incorrect amount of salt for the concentrated solution