To a novice only listening to the words going along with her hand motions, the formula seems complicated - an intimidating jumble of mathematics and jargon.

But watching her hands glide in the fluency of American Sign Language, the concept comes into focus.

"It's easier to describe in sign language," said Cooke, a University of Massachusetts geology professor. "I could sweep my finger through space to draw an angle. That's a lot easier than describing the angle verbally."

So it makes sense to Cooke - who has been partially deaf since birth but using ASL for only about 10 years - that deaf students who use sign language might have an easier time grasping some geological concepts than their hearing peers who rely more on the spoken word than gestures.

Because ASL users are so used to interpreting visual cues, she says, they're poised to pick up on the three-dimensional aspects that go along with geology, like determining angles and having to make two-dimensional sketches out of the rocks and formations they observe in the field.

She put her theory to work in May, when she led a field trip of 20 deaf high school students on an exploration of fault lines in Utah.

The work Cooke did with the high school students was part of a $420,000 five-year federal grant she received to study the evolution of geologic fault systems, the networks of cracks in the earth's surface that can lead to earthquakes.

The students, Cooke said, quickly learned how to measure the angles of the cracks and map out what they were observing in sketch books.

Mary Ellsworth, a science teacher at the Model Secondary School for the Deaf at Gallaudet University in Washington, D.C., brought two of her students on the Utah field trip.

"When Michele would explain something, such as the directions for using a compass to measure the angles of faults in the rocks, she would show the students, and they would then pick up the instrument and copy her movements precisely," said Ellsworth. "I have worked enough with hearing people to know that they would pick up the instrument, look at it, try to remember the orientation, reverse it, then set it down, maybe in the correct position but often not."

Harry Lang, a deaf professor who teaches physics and math to deaf and hard-of-hearing students at the National Technical Institute for the Deaf at Rochester Institute of Technology, said his own research has shown no evidence that deaf people make better use of vision than hearing people.

However, he said ASL users have proven much better at performing tasks that involve mental imagery.

He said there is "support for some advantages ASL students may have in terms of spatial skills over non-signing deaf students, but unless Michele pursues some studies herself, we will not know for sure if such students will grasp geological concepts more easily than their hearing peers."

Cooke decided to involve deaf high school students in her research as a way to get them interested in geology.

Having dealt with several frustrations as a partially deaf student herself, it was an easy connection for Cooke to make.

Able to hear only low sound frequencies - meaning she can pick out the vowels in a spoken word but not the consonants - Cooke learned how to absorb lectures in hearing classrooms by lip reading.

But the combination of hearing only partial words and filling in the gaps by reading lips became exhausting.

Studying geology in graduate school at Stanford University in 1993, Cooke said she was "hit by the limits" of her hearing loss when realized how much of the course work revolved around discussion groups.

"I was at a tremendous disadvantage to hearing students," she said. "It was a real wake-up call for me and I wondered if I wanted to pursue science because it was so hard."

She began learning American Sign Language, and quickly picked up on the visual gestures.

"It was very natural for me," she said. "I've always been a visual learner. That's why structural geology has been a good fit for me - it's very spatial."

After briefly considering leaving geology to teach at Gallaudet, a college for deaf and hearing impaired students, Cooke decided to pursue her love of science and use it as a way to educate the hearing world about deaf culture.

"I thought if I stayed within hearing institutions, I could touch more people," she said.

And the work she's done at UMass involving deaf high school students has bridged a gap between the hearing and deaf worlds.

"It was very interesting to see how the deaf students learned geology," said Mario Del Castello, a post-doctoral student who is part of Cooke's research team. "It seemed easy for them to understand three-dimensional planes and angles and put them on a map where it becomes two-dimensional. A lot of students who can hear don't have that good perception of space."

By Adam Gorlick