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Stanford Report, May 6, 1998

Teaching is an experiment for Waymouth: 5/98

'Vertical' learning key in teaching science, chemist says


For chemist Robert Waymouth, simple classroom demonstrations can be very effective. Take, for example, the "water dance." To illustrate the concept of heat, Waymouth occasionally acts out the role of a water molecule as it is being heated. His body becomes the oxygen atom and his hands become hydrogen atoms. As the "molecule" is heated, Waymouth waves his arms back and forth to show how it absorbs heat by vibrating more rapidly. Then he begins pacing back and forth, faster and faster, to show how the molecule also gains energy. Only this motion causes an increase in temperature, he explains.

"I could do this with a computer simulation, but there is some pedagogical value in having the professor act like the village idiot," he notes wryly.

A willingness to experiment with a variety of approaches is key to successful teaching, Waymouth said April 23 in a talk on "Seeing the Forest Through the Trees: Vertical Learning and Teaching Science," part of the Center for Teaching and Learning's "Award-Winning Teachers on Teaching" series.

"You learn teaching best by doing it. There is only so much you can learn about it in the abstract. So it really is an ongoing experiment."

Anyone who has done experimental science knows that, nine times out of 10, experiments fail, Waymouth said. "So you have to be willing to experiment with certain methods and pay the emotional costs when those experiments go awry. If you have a commitment to doing it well, the students are exceedingly bright and they appreciate what is going on and they are willing to cut you a little room to maneuver."

The young chemist, one of the handful of faculty members who have received three campus teaching awards, said that one of the teacher's most important roles is to set an intellectual standard for students. From the very beginning, it is extremely important to be explicit about what students should expect from a course.

More than once, Waymouth said, a student has come up after the mid-term and said that he understood the lectures and the textbook, but didn't do very well on the test. "I tell the student that I expect them to be able to 'speak' chemistry, not just understand it. The students may not like that, but they understand it. So now I explain this early in the course."

Waymouth said he sees a lot of truth in Harvard biochemist Frank Westheimer's statement that learning in the humanities is horizontal and learning in the sciences is vertical. In the science curriculum, many courses are built on other courses, Waymouth said. "I tell students that the learning curve is exponential. You can negotiate the curve if you work on it day by day. But, if you get complacent, you will smash against it like a bug on a windshield."

Teaching large, introductory chemistry courses represents a special challenge that Waymouth approaches with two basic goals: to teach the students the basic grammar of chemistry, the intellectual tools they need if they are to go on in the field, and to give them a picture of the beauty and majesty of the subject.

"I think we do a pretty passable job at providing the intellectual building blocks of knowledge. I think we are less good at providing the overall picture of the subject," he said.

Maintaining an intellectual empathy with students is something that gets more difficult for professors as time goes on, Waymouth said. "In science, as we get further and further along in our careers we get more and more specialized. We begin to lose sight of what it was like to be studying freshman chemistry. This is a danger that is quite common. So really good teachers have an appreciation for the intellectual leaps that students have to make as they are negotiating these introductory courses and trying to establish these foundations."

In large courses, Waymouth frequently works with seven to 15 teaching assistants (TAs). "Success depends on how well all of us are doing," he said. Involving the TAs in writing the exams and homework problems works well, he said. "This stimulates my TAs, and engages them intellectually in the enterprise," he said. Another method he uses to keep the TAs focused is to have them prepare lesson plans for the discussion sessions that they lead and then discuss these plans as a group. "Basically, you have to teach the TAs how to teach [as the course proceeds]," he says.

"If the secret in real estate is location, location, location, in teaching it is preparation, preparation, preparation," Waymouth said.

Although he was not receptive to the idea at first, Waymouth has recently experienced the advantages of co-teaching and now recommends it highly. "It gives you an opportunity to talk to somebody else. [Co-teacher Dan Stack] and I often have discussions, not only about teaching but also about other subjects that I find very beneficial," he said.

In science courses, students do not really learn in the lectures, he said. They learn most by doing the problem sets. He will select a textbook with interesting and innovative problem sets in favor of a textbook that has the clearest explanations of the material.

The chemist hasn't found multimedia very useful for teaching per se, but it's helpful for disseminating class information, schedules and other administrative materials, he says.

On the other hand, Waymouth finds simple demonstrations like the water dance very effective. "They can illustrate a key concept in a visceral way so that students will really get it," he said.

Waymouth also touched on differences between teaching freshmen and mentoring graduate students. "The trick in mentoring is to mediate the transition from student to scholar." From the classroom world where every problem has an answer, the teacher must initiate graduate students into the world of real science where each project is a venture into the unknown, where one never knows if Shangri-la or the Abyss lurks around the next corner, he said.

This requires something of a gentle hand and a certain amount of patience and judgment. One of the most crucial areas is recognizing when to let students fail. A critical distinction between an outstanding scientist and just a good one is the ability to pick the most interesting problem that can be solved, he said. That inevitably means wandering down a number of blind alleys. This can be an unpleasant experience, particularly for assistant professors who are expected to produce something.

When teachers tell their students what to do, they tend to have a linear progression in understanding. When a teacher gives students a certain amount of intellectual freedom, then their learning is exponential, although they also have periods when they are not productive and are very frustrated, Waymouth said. "But at the point where they really get it, the point where they really catch fire and really begin to think for themselves. . . [it] is one of the most important learning skills that they can develop." SR