Diffusion through the
Membranes
Sita Damaraju (Fellow)
Professional Day at NJIT
16 February, 2011
Applications
Biology of all Levels
 Chemistry
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Diffusion
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A process that allows ions or molecules to move from a
region higher concentration to a region of lower
concentration until equilibrium is attained.
Vernier Experiment
◦ A conductivity probe will be used to monitor
ions in solution and monitor its concentration
over a period of time.
◦ AIM: Study the effect of concentration
gradients on the rate of diffusion. Determine
if the diffusion rate for a molecule is affected
by the presence of a second molecule.
Materials
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Computer
Vernier conductivity probe
Logger pro software
Graduated cylinders-3
1%, 5% and 10% salt solutions
400 mL beaker
Dialysis tubing
5% sucrose solution
Dental floss or clamp
Ring stand and utility clamp
DATA
Part I: When dialysis consisting of salt solution is placed in clean water.
(Concentration gradients)
Part II: When dialysis tubing consisting of salt solution is placed in
sucrose solution. (Effect of other molecules)
Table 1
Prediction
Part 1
Part 2
Conclusion
Part I: Data
Table 2
Salt Concentration (%)
Rate of Diffusion (mg/L/s)
1
5
10
Part II Data
Table 3
Solution
Water
Sugar water
Conductivity
Data Summary
Table 4: Summary of Data
Solution
5% Salt
5% Salt/ 5%sugar
Rate of diffusion (mg/L/s)
Solutions
Part I: Data
Table 2
Salt Concentration (%)
Rate of Diffusion (mg/L/s)
1
0.25
5
1.23
10
2.19
Part II Data
Table 3
Solution
Conductivity
Water
1.5
Sugar water
1.9
Data Summary
Table 4: Summary of Data
Solution
Rate of diffusion (mg/L/s)
5% Salt
1.23
5% Salt/ 5%sugar
1.21