4D10.10 Brownian Motion

PURPOSE: To show Brownian motion and the random walk.
DESCRIPTION: A small cell contains 1 micron size particles of latex spheres suspended in water at room temperature.  The particles are viewed through a 100x microscope.  The image is projected by a video camera to the class.
EQUIPMENT: Home made Brownian motion cell and microscope with video camera.
SETUP NOTES: Cell must be made by hand.  Takes about 1/2 hour to make it.  The focus is critical.

Making a slide:
1. Cut out a square of parafilm larger than the size of a cover slip and apply it to the slide by pressing it down on the slide. Place Parafilm and slide in front of the heat source for about a minute and press it more securely onto the slide. The parafilm adhesive is activated by both pressure and heat.
2. Cut out a square from the parafilm, large enough to hold a single drop of solution such that the drop should not touch the parafilm, if possible, and small enough to be covered by a cover slip.
3. Put a drop of solution at the center of the cutout. The drop should be small enough so that it will not touch the parafilm.
4. Place a cover slip on top of the solution and parafilm, pressing down on it hard enough to create a bond between it and the parafilm. Pressing too hard may cause the cover slip to break.
5. Place a drop of immersion oil over the sample on the cover slip.
6. Insert the slide into the slide mount and bring the objective up to the slide so the immersion oil adheres to both the cover slip and the objective.
 

Edited by JZ on 8/29/05