Gadgets outdo lectures in the physics classroom Active approaches enhance learning

THE BALTIMORE SUN

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."

With proof that what they were doing wasn't working, researchers such as Dr. Hestenes began to catalog students' misconceptions about how things work and design courses to )) debunk them.

At Marcos de Niza High School in Tempe, Ariz., one of Dr. Hestenes' proteges, Mr. Wells, began to experiment on his own. At year's end, 78 percent of his students correctly understood the laws of physics, compared with 75 percent of Harvard freshmen.

Now, in a three-year study funded by the National Science

Foundation, Mr. Wells is trying to teach his methods to 18 Arizona teachers. What happens to their 760 students by the end of this year will determine whether his ideas can work in classrooms across the country.

So far, whether the lecturer is brilliant or bumbling doesn't seem to matter in how much students in traditional classes learn, the study shows. Another finding is that the socio-economic background of the child doesn't make a difference in his or her success. "It is all technique," says Mr. Wells, 61.

Changing the way information is presented to students is an uphill battle.

But despite initial hesitancy among teachers, Dr. Van Huevelen's approach has attracted attention from 40 high schools and 12 universities, including Harvard. Now publishers are willing to consider alternatives to a third edition of his textbook. "I never dreamed it would go like this," he said.

His approach is simple: He developed "learning kits" for each student in the lecture hall that pose problems such as this: When a skydiver reaches constant velocity, how do the downward weight force and the resister force compare? (Almost everybody believes the weight is greater, but the two are equal).

The common ingredient in successful classes, he says, is that students become participants. In his classes, students argue with neighbors on either side about problems, then vote. The professor talks for 10 minutes of the 50-minute class.

In the past, physicists were expected to interest only a few graduate students, and it didn't matter that they did not reach 98 percent of the students in introductory classes, Dr. Redish wrote in a paper just submitted to the American Journal of Physics.

Now, when society needs a great number of people who understand science, he says, "We must treat the teaching of physics as a scientific problem."

Dr. Redish wants to see if he can develop such skills in a lecture hall of non-majors -- in this case, engineering students taking a required physics class. The outcome of his experiment won't be known until the end of the semester, but students said last week that his approach is making a difference.

"You get a physical idea of all the different laws," said Kristen Wagner, a sophomore engineering major.

"It's more show and tell. It's better," says Jarrett Dixon, an architecture and engineering major who dropped out of the same course taught by a different professor last semester.

Last week, in addition to measuring his movements, Dr. Redish gave a quiz, sent a glider down an air track, and began to get students to solve four case studies involving a drive to New York. Eventually, he wants them to write equations for what happens to speed and distance when you stop for lunch, hold a meeting at Newark Airport, get stuck on the George Washington Bridge, or make it all the way without stopping.

"To learn something, you have to be involved in it," Dr. Redish said.

Copyright © 2019, The Baltimore Sun, a Baltimore Sun Media Group publication | Place an Ad
39°