FREE Osmosis/Difusion Lab

Cell membranes and the transport of materials across membranes is fundamental to a study of biology.  There are, fortunately, many good lab activities that can be carried out when covering this material.  My students just finished doing this lab today.  It is called "The Effect of Concentration on the Rate of Diffusion", and you can download my version of this lab for free.

The concept is very simple.  First, the students fill dialysis bags with varying concentrations of sugar solutions.  The bags are then massed.

Each dialysis bag is placed in a cup of distilled water. The cups are allowed to sit for some period of time.  I have the students wait for 30 minutes, pull the bags out of the cups, and determine the final mass of the bag.  We get very good results in just thirty minutes.  If necessary, you can leave them overnight and get the final mass the next day.

The results are dramatic.  Students will clearly see the relationship between solute concentration and the rate of diffusion across the membrane.

Results are graphed showing the direct relationship between solute concentration and rate of diffusion.

This is one of my favorite labs and is a free download.  I hope you doing this lab as much as I.

FREE DOWNLOAD

The Effect of Concentration on the Rate of Diffusion

Other products related to this topic include:

Determining the Osmolarity of Cells

Lab: The Effect of Solutions on Cells

Transport Across the Membrane Jeopardy Review Game