An Analogic Model for Understanding the Preparation of Volumetric Solutions

A squares-and-points analogic model of concentration is presented, and its utility is discussed with respect to comprehension of both the concept of concentration and the procedure for preparing a solution via the dilution of another more concentrated one. The visual power of the model helps to confront many of the difficulties and alternative conceptions regarding solutions. A logical sequence for the presentation of this model in the classroom is also demonstrated, as is the need to promote metacognitive reflections on its use. This is considered an example of a strategy for overcoming the almost exclusively quantitative focus that is characteristic of many classroom approaches to solutions.