Twilight of the Lecture
http://harvardmagazine.com/2012/03/twilight-of-the-lectureHarvard Magazine
March-April 2012
IN 1990, after seven years of teaching at Harvard, Eric Mazur, now Balkanski professor of physics and applied physics, was delivering clear, polished lectures and demonstrations and getting high student evaluations for his introductory Physics 11 course, populated mainly by premed and engineering students who were successfully solving complicated problems. Then he discovered that his success as a teacher “was a complete illusion, a house of cards.”
The epiphany came via an article in the American Journal of Physics by Arizona State professor David Hestenes. He 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.)
Mazur tried the test on his own students. Right at the start, a warning flag went up when one student raised her hand and asked, “How should I answer these questions—according to what you taught me, or how I usually think about these things?” To Mazur’s consternation, the simple test of conceptual understanding showed that his students had not grasped the basic ideas of his physics course: two-thirds of them were modern Aristotelians. “The students did well on textbook-style problems,” he explains. “They had a bag of tricks, formulas to apply. But that was solving problems by rote. They floundered on the simple word problems, which demanded a real understanding of the concepts behind the formulas.”
It is fashionable to criticize lectures. Many teachers are taught that it is better to be a "guide on the side" rather than a "sage on the stage". I think there are students, especially introverts, who would rather listen to a teacher or professor explain something (or read a book) rather than discuss material with classmates. The popularity of Khan Academy and the Teaching Company indicates that there is demand for lectures, if the price is low and the student can choose when to watch.
