Combining Teaching and Advanced Research
By Dorothy Wright
Bryn Mawr welcomed two new Keck postdoctoral fellows in 2004. One studies phenomena occurring over tens, thousands or millions of years, and the other over nanoseconds — and both are enthusiastic about teaching at a liberal arts college where women are encouraged to excel in science. Geologist Catherine Riihimaki and physicist Aaron Marks hold three-year Bryn Mawr College Keck Postdoctoral Research/Teaching Fellowships in Science/Mathematics, which enable recent Ph.D.s to gain experience in teaching while pursuing advanced research.
"I am strongly committed to the liberal-arts model of college education," says Riihimaki, who is working with Don Barber, assistant professor of geology. "I pursued a Keck fellowship to gain additional teaching experience. To be able to gain that experience at such a strong institution as Bryn Mawr is an opportunity that is hard to pass up."
Riihimaki, who earned her Ph.D. in earth sciences from the University of California, Santa Cruz, integrates fieldwork and numerical modeling to understand the role of rivers in shaping alpine landscapes. Currently she is studying short-term erosion in the subglacial environment of Glacier National Park, Mont., and the long-term evolution of the Rocky Mountains.
Riihimaki's studies of glaciers document the role of meltwater and precipitation runoff in the evolution of the glacial landscape. "We are trying to understand why glacial valleys have particular shapes and how the landscape responds to climate change," she says.
The glacier itself is an obstacle to direct observation. "The ice blocks the view of what is actually going on below, so we have to monitor measurable variables that are accessible, and then try to reconstruct what is happening under the glacier," Riihimaki explains.
Toward that end, Riihimaki uses a differential global positioning system, which employs two antennas — one in a fixed location and one on the glacier itself — to monitor the millimeter-by-millimeter movement of the glacier over hours, days and weeks, and ground-penetrating radar to measure its thickness. A student from Haverford College is involved in this project.
Using numerical modeling and analysis of aluminum and beryllium isotope concentrations in sediments, Riihimaki is studying the evolution of the Rocky Mountains over the last five million years. "The dramatic relief you see in the Rockies today is a young feature," she says. "Rivers have drained much of the sediment from the low basins that separate the mountains.
"What caused this? That's the big question," Riihimaki says. "There are two models: either the rivers are fixed in space and the mountain range is being uplifted, or the mountain range is fixed and the rivers are cutting down in response to a changing climate."
Reflecting on her teaching experience in an environmental studies seminar last fall, Riihimaki observes, "The students were enthusiastic and engaged." Next year she will teach a new course in computational methods, as well as the senior seminar in environmental studies.
Riihimaki says she strives not only to convey knowledge, but also to give her students the tools and enthusiasm to learn on their own. "I want to foster independent and creative, dynamic people," she says. "That's what is exciting."
Aaron Marks earned his Ph.D. in physics from Lehigh University, Bethlehem, Pa. An experimental physicist, he focuses on laser-matter interactions and laser spectroscopy of atoms and molecules. He is also interested in comparing and testing theoretical atomic-collision models. Working with Physics Department Chair Liz McCormack and graduate student Bob Ekey, Marks is using laser spectroscopy to study the structure and decay of highly excited states in molecular hydrogen. Their work is supported by the National Science Foundation.
Marks says this investigation may reveal a breakdown of the Born-Oppenheimer Approximation, a tenet of molecular physics that describes the relative motion of the nuclei and electrons in a molecule. "Discovering a breakdown of this principle would be like going outside on a clear, sunny day and observing that the sky is not blue," he says.
Marks says he pursued the postdoctoral fellowship because it was the only one he found that combined teaching and research. "The Keck fellowship is a unique opportunity to do both," he says.
Thus far, Marks has taught an electronics lab and run the peer-led instruction sessions in introductory physics for Bryn Mawr's Postbaccalaureate Premedical Program.
Describing physics as a "hands-on" activity, he looks forward to involving undergraduates in his research. "The beauty of experimental work is the ability to involve undergraduates," he says. "With the right guidance, they can do meaningful research. It's one of the reasons I like it so much."
As an undergraduate, Marks observed that female students were more likely than their male counterparts to drop out of physics. "There is a 'soft' form of discrimination, in which women are made to feel they are excluded from a 'men's club,'" he says. "We need to help women move ahead in physics. Bryn Mawr has a very good track record in helping women succeed in science, and I am happy to contribute to equalizing my field."
The Keck fellowship began in fall 2001. The first five years of the program are supported by a $750,000 grant from the W.M. Keck Foundation of Los Angeles, after which the College will provide continuing support.
Dorothy Wright contributes news and feature articles on science, technology, engineering and general-interest topics to a variety of publications, including Civil Engineering and Engineering News Record.