Alternative Demonstrations of Slow Processes IV

It is well known that long-lasting (marathon) chemical experiments are not convenient for use as classical chemical demonstrations, simply due to their duration. Thus, the phenomena of chemical waves, diffusion, osmosis, etc, although very attractive and with high education value, are not suitable as lecture demonstrations. Some of them are often organized as corridor or exhibition demonstrations. In order to enable instructors to demonstrate these phenomena in real time, we offer the fast-motion technique, condensing an experiment that originally lasts several hours or even days into a half-minute movie. Examples are given for gas–gas and solid–liquid diffusion and are supported by video clips.