To Teach With or Against the Textbook

This has been a trying semester.  Besides juggling a couple of research projects, I’m teaching our calculus-based, introductory physics course for the first time. The material isn’t too challenging, but writing all those lectures, picking homework assignments and then grading them, followed by exam writing and even more grading, has led to very little free time for things like blogging.

Although this new-prep class has been eating away at my time, I’m enjoying the course. For the first time I’m teaching to a reasonably large (34 students) population of future scientists that don’t have a fear of numbers. Moreover, they’re interested in the material. It’s great.

The one hiccup I have ran into with this class is the textbook. We’re using Randall Knight’s, Physics for Scientists and Engineers: A Strategic Approach. I’m not here to bash the book. It’s not perfect, but it’s not all that bad either. As a colleague puts it, all introductory texts have their warts. The problem that I do have with this text is that it presents some material in a way that I don’t agree with. So the question arises, do I toe the line and teach like the textbook presents the material, or do I move away from the text and present the material in my own manner?

Before I delve into the pros and cons of both sides of this argument, I want to mention that it’s not that either side of the argument presents the physics wrong. Using hindsight and years of experience, it’s a trivial manner to demonstrate how the multiple approaches to teaching the same material are one and the same.  But to a student encountering the material for the first time, this is anything but true. For this reason, sticking with one approach and rolling with it is so much more conducive to a successful learning environment than one in which multiple strategies are employed and comparisons between techniques are discussed.

Pros for Teaching With the Textbook

The most obvious pro to teaching with the textbook is that the book acts as a resource to the students outside the classroom. Ideally students are spending time outside of class reading the text, studying the examples presented therein, and doing a few practice problems on their own. In studying on their own, it’s important that the students understand the nomenclature and symbols used by the text. By diverging from the text in the classroom students are left with a competing approach to how the material is presented without a personal guide to set the record straight. Since students are encountering the material for the first time (in the case of an introductory course) alternative approaches can be confusing and lead to frustrations.

To strengthen this argument, for those instructors that do require reading outside of the class (such as for Just-In Time Teaching), it seems to me that they are obliged to follow the textbook style. It would be unfair for an instructor to require students to learn the material only to come to class to find out that that is not the way the material will be taught.

Another small pro for teaching with the text is that the more the text is used, the less students feel ripped off by purchasing a high cost book that is never used. I remember being a student and having professors require texts that were barely used. Why spend hundreds of dollars and only use the text a few times during the semester?

Cons for Teaching Against the Textbook

As I see it, there are a few justifiable reasons for teaching against the textbook. The first argument starts with the ultimate goal: to educate the students. To this end, we should use the best pedagogical practices available that we, as instructors, are comfortable using. If those pedagogical approaches differ from what and how the textbook presents the material, then I feel justified in breaking away from the text and teaching using my own style.

Along those same lines, a second reason for teaching against the textbook is that occasionally multiple texts are used in the classroom. In my particular case, we supplement the Knight textbook with the Tutorials In Introductory Physics by McDermott et al. These tutorials often present the physics in a slightly different manner, using different nomenclature and notation. I have made the conscious decision to use a teaching style that closer complements the Tutorials than Knight. My reasoning for this is that the Tutorials introduce a certain systematic approach to handling forces that it introduces a number of safety nets for the students to work with.

The last reason for teaching against the text is that occasionally there are certain topics that a text presents in an unusual manner that may seem not quite right. As an example from introductory physics, different authors define the weight force in different ways. To some the weight force is simply the gravitational force while to others it’s the reading a scale outputs when an object is placed on top of it. Neither approach is more right than the other. It’s just that feel that one approach (defining weight through an interaction with a scale) is more confusing than simply calling it the gravitational force.

In the end, I think it’s up to the instructor to decide for themselves if they will teach with or against the course textbook. The importance in going either way is to always put the students first. Choose the approach that gives the students the best chance at learning the material. I’ve made the personal decision to teach against the text because I want to incorporate the best pedagogical approaches that I’m aware of.