This article describes a simple laboratory experiment that aims at pedagogic as well as aesthetic aspects of chemical reactions. In a 0.5- or 1-liter glass cylinder almost completely filled with water, a slow precipitation reaction involving two soluble salts is made to occur by adding a sample of one salt directly to the water and then placing some of the second salt in a filter inside a funnel that has been placed on top of the cylinder. Whereas setting up the experiment takes only a few minutes, the reaction may go on for an hour or more, displaying a slow but continuous formation process. The same set up can be used for a variety of redox, complex formation, and other reactions that produce a visible effect. Several concrete examples are given. Experiments of this type have a high educational potential as students have the opportunity to observe the actual formation of a precipitate instead of just being able to see the result. The experiment is also suitable for demonstrating some of the fascinating beauty of chemical reactions to the general public.
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