OVERVIEW

In this laboratory you will investigate the process of diffusion and osmosis in a model of a membrane system. You also will investigate the effect of solute concentration on water potential as it relates to living plant tissues.

OBJECTIVES

Section A: Before doing this laboratory you should understand:

• the mechanisms of diffusion and osmosis and their importance to cells
• the effects of solute size and concentration gradients on diffusion across selectively permeable membranes 
• the effects of a selectively permeable membrane on diffusion and osmosis between two solutions separated by the membrane 
• the concept of water potential
• the relationship between solute concentration and pressure and the water potential of a solution 

• the concept of molarity and its relationship to osmotic concentration 

Section B: In this experiment, you will:

• use a computer and conductivity probe to measure the conductivity of various solutions.
• study the effect of temperature on diffusion.
• study the effect of concentration gradients on the rate of diffusion.
• determine if the rate of diffusion for a molecule is affected by the presence of a second molecule.

LAB GUIDE

To download a printable copy of the lab guide, right click on the lab title below.  Then select save target as.  If you do not have Microsoft Word 97 or later, you will need to download Microsoft Word Viewer (it is free!).

Lab1-Diffusion.doc (65K)

RESULTS

Yes, we successfully completed another computer based lab, and this was this years first lab!  Check out the images here...

Click on the following to view the full size image...