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