Progress in Practice: The Synergy Derived From Knowing Pedagogy as Well as Chemistry

What is the value that comes from consciously and explicitly linking what we know about chemistry with what we do in the classroom? It is tempting to dismiss this question because we are uncomfortable with the implication that there are times when what we do in the classroom is not informed by our personal understanding of chemistry. Yet instructors of introductory chemistry courses often lack the personal understanding, especially the kind that comes from laboratory experience, for significant parts of the course. An experienced general chemistry instructor, for example, probably understands the practical expectations of teaching this subject better than anyone who has recently graduated with a Ph.D. in physical or inorganic chemistry. Although the merits of this situation are worth reflecting on at another time, a reasonable operational assumption is that a substantial portion of the introductory program is defined by its own existence rather than as an identifiable area of specialization. The general chemistry curriculum is flexible to the degree that it can accommodate a variety of backgrounds in its instructors, yet it is constrained by the historical inertia that has defined it. To a lesser yet still significant extent, beginning instructors of organic chemistry face the same problem when their understanding of more specialized topics (such as the synthesis of heterocyclic compounds, transition metal organometallics, carbohydrate and peptide chemistry) is limited by their inexperience in those areas. Organic chemists might have only studied these topics as a part of their own introductory or intermediate instruction, and the textbook in use could be their primary source of information. Consequently, introductory chemistry instruction is filled with its own “urban myths”, or perhaps they are parables [1] passed down from author to author, about chemical phenomena that may or may not stand up to the scrutiny of contemporary understanding. Sometimes this is by design; for instance, demonstrating some general features about macroscopic properties can be done by using simplifications like the ideal gas assumptions or with the use of concentration instead of activity. Intentional simplifications that use less sophisticated models to explain phenomena at an adequate level of complexity are commonplace (in fact, this is not a bad interpretation of Occam’s Razor as it applies to science in general). This may be analogous to the way our colleagues in physics begin college instruction with Newtonian mechanics, or the way chemists can successfully use valence bond models for molecular structure to do a prodigious amount of chemistry without ever invoking a Hamiltonian operator. Problems can arise, however, whenever an instructor’s depth of understanding of a subject is only marginally different than the simplified version of it. Agassi [2] offers a sobering view on the way some writers of introductory textbooks “mislead the innocent reader” (implying that unwary instructors will sometimes mislead learners). He laments that individuals who ultimately choose science do so in spite of their formal education and he refers to them as “those who survive the injury of the science textbook.”