In the early 1980s, two physicists at Arizona State University wanted to know whether a typical introductory physics course... changed the way the students thought about motion...I earned a B.A. in physics as an undergrad at UCSB. (I didn't earn a B.S. because I didn't take the physics labs; they were too time consuming and I wasn't intending to continue in physics.) I was fortunate enough to be in a specialized program (College of Creative Studies) where we had a very good teacher for our lower-division physics classes. He taught us in ways that forced us to think about how we thought about the subject by assigning very difficult problem sets. What was difficult about them? It wasn't only computationally difficult, but he asked us to interpret the meaning of the results. This forced us to reconcile our results with reality and expanded our ability to think physically.
Did the couse change student thinking? Not really... They had memorized formulae and learned to plug the right numbers inoto them, but they did not change their basic conceptions...
[The professors] wanted to probe this disturbing result a little further. They conducted individual interviews with some of the people who continued to reject Newton's perspectives to see if they could dissuade them from their misguided assumptions. During those interviews, they asked the students questions about some elementary motion problems, questions that required them to rely on their theories about motion to predict what would happen in a simple physics experiment. The students made their projections, and then the researchers performed the experiment in front of them so they could see whether they got it right. Obviously, those who relied on inadequate theories about motion had faulty predictions. At that point, the physicists asked the students to explain the discrepancy between their ideas and the experiment.
What they heard astonished them: many of the students still refused to give up their mistaken ideas about motion. Instead, they argued that the experiment they had just witnessed did not exactly apply to the law of motion in question; it was a special case, or it didn't quite fit the mistaken theory or law that they held as true. "As a rule," [the professors] wrote, "students held firm to mistaken beliefs even when confronted with phenomena that contradicted those beliefs." If the researchers pointed out a contradiction or the students recognized one, "they tended at first not to question their own beliefs, but to argue that the observed instance was governed by some other law or principle and the principle they were using applied to a slightly different case." The students performed all kinds of mental gymnastics to avoid confronting and revising the fundamental underlying principles that guided their understanding of the physical universe. Perhaps most disturbing, some of these students had received high grades in the class.
Here are a couple examples of things he would do:
- In multi-body problems, we would see what would happen to the results as one of the masses becomes infinitely big or small. Did our new results match the expectations? Why or why not?
- Some problems resulted in two solutions. Did they both have a physical interpretation?
The book continues to discuss the views of the successful teachers with respect to the development of knowledge. I'll give the bullet points here and have you buy/read the book for yourself if you want to find out more:
- Knowledge is constructed, not received
- Mental models change slowly
- Questions are crucial
- Caring is crucial
