Gadgets outdo lectures in the physics classroom Active approaches enhance learning

September 22, 1991|By Patricia Meisol | Patricia Meisol,Sun Staff Correspondent

COLLEGE PARK -- Edward F. Redish has given up half the equations he used to write on the chalkboard in his physics lecture for non-majors. Instead, he surrounds himself with electronic toys on a revolving stage and in last week's lesson, walked back and forth in front of a machine that detects movement.

He asks his class to guess what his motion and speed would look like on a graph. While the students tried to figure out this real-life example of velocity, a computer decoded and translated the professor's footsteps and projected the results onto a screen.

If the approach by Dr. Redish and a small but growing number of professors is an indication, the university lecture may be on its way out, the victim of research about the way we learn.

According to Dr. Redish, whose past experiments in the classroom at the University of Maryland College Park have proved successful, you can't teach anybody anything. You can only make it easier for them to learn. For ideas to stick, students "have to reconstruct the whole theory in their heads," he says.

Dr. Redish is part of a quiet reform that has hit at least a dozen university physics departments around the country and is about to influence a new generation of textbooks.

The theories behind it have already spilled over into mathematics and, in the decades to come, could influence the teaching of reading, writing and Shakespeare.

Results of initial experiments are dazzling:

Even a fine Harvard lecturer has a hard time besting what Malcolm Wells can elicit from high school seniors in Tempe, Ariz., using balls rolling down rails and airplanes hanging by string from the ceiling.

Remedial students using "learning kits" in Alan Van Heuvelen's class of 140 students at New Mexico State University do 15 percent to 20 percent better than students in a conventional lecture. The number of students who emerge from typical physics courses understanding the laws of motion is 23 percent. In Dr. Van Huevelen's classes, the number is 80 percent.

"I hardly talk anymore," Dr. Van Heuvelen says. Enrollment has doubled.

What is happening in the classroom today is not so much about style, though that surely has changed. It's about the science of learning. Behind Dr. Van Heuvelen's kits and Dr. Redish's gadgets are a list of medieval notions students have when they enter his classroom and a sophisticated plan to dispel them.

Until recently, many academics held the view of students as empty vessels passively collecting information.

But the development of the computer after World War II heightened curiosity about how the mind works. A host of scholars working in different fields -- linguistics, philosophy, psychology, physics, computer science and artificial intelligence -- have become more and more convinced that the mind is a complex system of internal networks that process and categorize information rather than simply store facts at random.

Such networks, for instance, help you maneuver in an unfamiliar Baltimore neighborhood by drawing on previously stored information about similar places.

The network that helps memorize an equation is probably different from the one that helps solve a word problem associated with that equation. That explains why some students can excel at equations but fail to understand the world around them. The task for the physics teacher, then, is to get students to develop the same internal network to solve word problems.

How research on the mind influenced the teaching of physics is a story that involves a host of scholars building on one another's work at such places as the University of Washington, the University of Massachusetts, Tufts, the University of Arizona, the Johns Hopkins University, College Park and elsewhere.

It begins roughly in 1980, when a psychologist studying the mind's processes at Hopkins questioned students about their ideas of physics.

What Michael McCloskey and his colleagues discovered took them by surprise: More than half of the students, including those who had taken physics, didn't know the basic laws of mechanics. What they believed about motion was similar to what people believed in the three centuries before Sir Isaac Newton.

In retrospect, it made sense, Dr. McCloskey says.

"We forget that these are things that required hundreds if not thousands, of years to clarify, and the reasons they were not clear [to scientists] are the same reasons they are not clear to students," he said.

Physicists remained skeptical until 1985, when David Hestenes, physics professor at Arizona State University, used the findings of Dr. McCloskey and others to develop a test to measure what students knew before and after a physics class. The professors who reviewed this test thought it was easy -- but their students failed.

"It was a kick in the teeth for physics teachers," said College Park's Dr. Redish. "It blew the cover off physics."

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