Do Your Students Understand the Material, or Just Memorize and Forget?

Have you ever heard of Eric Mazur? If you teach physics and are into that discipline’s pedagogical literature, in all likelihood you have. But Mazur, who teaches physics at Harvard, is someone all of us should know. The reference at the end of this post contains a succinct and compelling introduction to his work.

Eric Mazur is the Balkanski Professor of Physics and Applied Physics at Harvard University and Dean of Applied Physics.

Mazur started out teaching like most of us—he lectured, pretty much all the time, until he discovered a problem. His students had learned Newton’s third law of motion—or at least they could recite it (as all physics students can). He decided to test their understanding of it with a conceptual problem involving a collision between a heavy truck and a light car. To his surprise, his students couldn’t answer the problem or they struggled mightily, not only with this but virtually any conceptual problem he gave them.

It seems the students were memorizing the material but not understanding it, and so Mazur decided to change his instructional approach. He replaced teaching by telling with teaching by questioning. He now structures class time around short conceptual questions. He starts with the question which students must first answer individually, then they report their answers and discuss them with each other, explaining, defending and questioning their answers. Mazur (and teaching assistants) circle the classroom asking questions and otherwise guiding student discussions. He might offer a brief presentation but students are the ones solving the problems.

Interestingly, Mazur started using this method of teaching long before it was trendy. In fact, when people discuss the reform of science education, Mazur is frequently mentioned as one of the first who found a better way. And it is a better way, as documented by multiple studies conducted by Mazur and his colleagues and by other college faculty who use the approach or variations of it. Mazur writes, “Data obtained in my class and in classes of colleagues worldwide, in a wide range of academic settings and a wide range of disciplines, show that learning gains nearly triple with an approach that focuses on the student and interactive learning… Most important, students not only perform better on a variety of conceptual assessments, but also improve their traditional problem-solving skills.” (p. 51) His article includes references to this research.

Mazur  had devised a very simple test, couched in everyday language, to check students’ understanding of one of the most fundamental concepts of physics—force—and had administered it to thousands of undergraduates in the southwestern United States. Astonishingly, the test showed that their introductory courses had taught them “next to nothing,” says Mazur: “After a semester of physics, they still held the same misconceptions as they had at the beginning of the term.”

The students had improved at handling equations and formulas, he explains, but when it came to understanding “what the real meanings of these things are, they basically reverted to Aristotelian logic—thousands of years back.” For example, they could recite Newton’s Third Law and apply it to numerical problems, but when asked about a real-world event like a collision between a heavy truck and a light car, many firmly declared that the heavy truck exerts a larger force. (Actually, an object’s weight is irrelevant to the force exerted.)

Reference: Mazur, E. Farewell, Lecture? Science, 323 (2 January, 2009), 50-51