Three senior students from Fairfax County high schools were among the 40 young scientists selected as winners in the nationwide 36th Annual Science Talent Search conducted by the Science Service.

Lawrence Robert Weatherford and Nancy Ellen Zeleniak, both students at West Springfield High School, and Glenn Curtis Poole, a student at Annandale High school, were chosen from among thousands of outstanding high school science students. They were honored at the Mayflower Hotel this week as was Arjun Gaurang Yodh, 17, a senior at Springbrook High School, Silver Spring.

In her study of a species of marine worms called nematodes, Zeleniaks, 18, of Springfield, directed a team of volunteers from the Smithsonian Museum of Natural History at Cape Henlopen on the Delaware coast.

Zeleiak tested the theory nematodes migrate away from the surface of the sand at high tide, and toward the surface when the tide ebbs. "The study of marine nematodes is a relatively new area," she said. "But," she continued, "this basic research may help further developments within the scientific community."

Modest about her achievements, Zeleniak pointed to her exhibit of the distribution and migration patterns of nematode worms in sediment and she said that "asking a lot of questions and using logic to come up some answers helped, too."

First in his graduating class at West Springfield High School, Westherford, 17, of Springfield, started research on variables which might inhibit enzyme acitivity. By employing an enzyme which gives off a colored by-product when it acts, he said, he was able to measure visually the rate of enzymic activity.

Poole, 17, of Springfield, was interested in studying "artificial intelligence," a term designating the computer's claimed potential to mirror or simulate human thought.

"After thinking and reading more on the subject of artificial intelligence, I thought I had better scale down my project to a manageable size," he said. The result is a system of classifying words into possible categories of useage, and is an attempt to deal with the problems inherent in man-machine interactions, he said.

Following a morning of classes, Zeleniak spends the rest of her day conducting research on nematodes at the Smithsonian. "When I go home, I might like to get out of helping around the house, but my parents don't spoil me and I'm glad," she said. After graduation, she plans to attend William and Mary College and looks forward to a career in biological oceanography.

Weatherford is active in a Mormon youth group, and he said this involvement with the chruch led him to choose Brigham Young University over Princeton. As for his career plans, he is considering either scientific research or medicine.

Poole was first introduced to computers while in 8th grade. Since then he has written computer programs to compose music, built his own micro computer terminal, and most recently for his project, designed a program to identify the semantic information in a sentence written in English.

For Poole, working with computers is a sport. It is a challenge, since mistakes are due to your own errors, he says. It requires discipline, he said, forcing one to think things out logically and precisely. He plans a career in computer design.