Better Teaching Through Chemistry — Dylon McChesney

analogyBecause I do research in philosophy, it might be confusing to some people why I talk about the hard sciences so much in relation to teaching. The reason is simple: philosophy is very abstract, and abstract things are not so easy to understand, thus I look to outside disciplines for strategies to concretize ideas. It turns out, of course, that philosophy has no monopoly on abstraction. Dorothy Gale (1999) shows that even elementary chemistry, that is, the kind of material covered in grade school, is abstract and “inexplicable without the use of analogies or models.” It is easy to assume that because a subject has to do with the natural world (for example) that it is de facto concrete, but this assumption is harmful to pedagogy.

Chemistry—like so many other things—is taught through dividing the world into hierarchical levels of abstraction: we establish the relationship between macro level phenomena like a glass of water, and the sub-micro level (H20) of that same phenomena. Simple, right? Well, as Gale notes in the aforementioned article, there are numerous obstacles to strengthening the understanding of each level and how they are interrelated. One obstacle is language choice. Many technical terms have different meanings when used in everyday communication, which can lead to a situation where a “student will be thinking one thing, the instructor another” (ibid.). Surely this situation is a nearly universal academic experience, a kind of growing pain for students and (hopefully) a wakeup call for instructors. Philosophers could be more self-aware that the term “realism” refers to a class of ideas that probably seem anything but realistic, and what counts as a valid argument in formal logic can look like a completely invalid argument from a common sense perspective. So, one thing we can all learn from Chemistry is to anticipate a struggle to “override” intuitive, non-technical definitions and concepts. From the privileged perspective of hindsight bias, these struggles might seem trivial, but they are not.

Perhaps the problem of technical language use is obvious, but what is likely less obvious is how we do—and how we should—use analogies in teaching. If Chemistry (taken here to be paradigmatic) is “inexplicable without the use of analogies or models” then we need to be very aware of the strengths and weaknesses of analogies. A convenient example is the Bohr “solar system” model of the atom. Because atomic particles are unobservable, they are much more difficult to conceptualize than dogs, trees, or even the components of cells which can at least be viewed through microscopes. But since planets are observable, a solar system is relatively easy to conceptualize. Drawing an analogy between a solar system and an atom (where the “star” is the nucleus and “orbiting planets” are electrons) allows for some visualization and a sort of functional template of understanding. This is extremely powerful! Unfortunately, sometimes these templates can cause misunderstandings. The Bohr model of the atom, despite its elegant simplicity, is not the best model. In fact, we now know it is misleading; yet for many the cognitive damage is already done and the inherent virtue of learning through connections will consequently be difficult to reverse.  Thus we have a ubiquitous example of how analogies can help and hurt all at once; although we need them to teach and learn, we also need to learn how to teach with them carefully. While it is unlikely that many of us will be able to anticipate specific paradigm shifts, such as transition from classical mechanics to quantum mechanics, we need to at least anticipate that some paradigm shifts are likely on the horizon. Analogies and models are indispensable, but promoting a critical stance and stressing the limitations of our best knowledge-generating tools might be even more so.

Although the objects of analysis differ substantially from discipline to discipline, ultimately we all face the same difficulty: making the leap from unknown to known. For both the arts and sciences this leap is theoretical and requires special attention to methodology. Since our theoretic knowledge of, well, almost everything, is so dependent on analogy, we are impelled to reflect on how it factors into our teaching in order to use it to its full potential.


Gale, D. 1999. Improving Teaching and Learning through Chemistry Education Research: A Look to the Future. Journal of Chemical Education, 76(4).

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