Eric Mazur’s Incredible Transformation in Teaching College Physics


In Our Underachieving Colleges, Derek Bok relates the rather incredible story of how Eric Mazur, a Harvard physicist, discovered a serious but hidden problem with his teaching and, as a result, changed his entire approach (Princeton UP, 2006, pp. 132-34).

Eric Mazur

Eric Mazur
Image by Ruzame

Mazur developed a way of teaching, Peer Instruction (PI), that proved significantly more effective than traditional methods. In line with the flipped classroom movement, many other college teachers have since come to use his approach to engage students and promote deep learning.

While the specifics of  the method bear considering, what interests me most is the story of how Mazur went about changing his practice, a story we can celebrate and emulate.

Bok tells the story well:

For several years, Mazur taught his quantitatively oriented introductory physics course in the manner common to most beginning science classes. He delivered lectures, distributed lecture notes, and left the students to clear up remaining ambiguities by reading from the prescribed textbook. His student evaluations were strong and everything seemed to be going well until he came across the article by Halloun and Hestenes describing how a simple test had shown that undergraduates in a similar physics course relied on memory to solve the problems assigned without truly understanding the underlying scientific principles.

Mazur’s immediate reaction was to doubt the results, or at least to question whether they were applicable to his students. Still, something led him to give the same test to his physics class. To his surprise, the results were very disappointing, so much so that he decided to alter his way of teaching fundamentally.

The strategy he developed departed radically from his previous method. Instead of allowing students to read the text after the lecture, he required them all to submit a short paper a day or two prior to each lecture answering two problems based on the text assignment and identifying any portions of the readings that they found particularly hard to understand. In this way, Mazur not only made certain that students completed the readings and thought about them in advance, he also discovered points he needed to emphasize in class to ensure that everyone understood the material.

In the classes themselves, Mazur no longer lectured for 60 minutes. Instead, he would talk for 10 to 15 minutes and then give students a multiple-choice question on the meaning of the underlying physics concepts. After a brief period, he invited the students to record their answers electronically. At this point, he would ask students to discuss their answers in small groups so that those with different answers could try to persuade one another why their solution was correct. After several minutes of animated discussion, students would again record their answers. If a large percentage reached the correct response, Mazur would explain the result briefly and move on. If a substantial number still had the wrong answer, he would spend more time trying to explain the underlying principle. During the course of an hour, students might have to respond in this way to three different questions. Weekly sections taught by teaching assistants were devoted to further discussion and small-group problem-solving.

What were the results of these sweeping changes? Did they work?

Compared to students “who had been taught the same material in the traditional way,” Bok reports that the students who learned with “the new method” not only “substantially outperform[ed] their classmates” in solving traditional introductory physics problems but also “made twice as much progress in grasping the underlying physics.”

But some may say, “That’s all fine and good for a tenured professor, with teaching assistants, at Harvard! But I can’t do that where I teach.”

While Mazur does have more resources, of various sorts, than most college teachers, the most important aspects of the story have very little to do with that. The most important aspects of the story apply to all of us. We can all fool ourselves. We can all read the scholarship on teaching and learning. We can all improve.

So, finally, I want to suggest several points for teachers everywhere to take away from this story.

  1. We can easily fool ourselves into thinking our students are learning.
  2. Just because students “pass the test” doesn’t mean they “understand the concepts.”
  3. Reading the scholarship on teaching and learning can catalyze major improvement.
  4. It is possible to make dramatic and dramatically effective changes in one’s teaching.
  5. Well-implemented active learning strategies are demonstrably and empirically superior to the traditional lecture-textbook-test approach.
  6. We must have enough courage to face facts and care enough to make changes.

One response to “Eric Mazur’s Incredible Transformation in Teaching College Physics

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