Unlike some of the other 109 teachers across the country who have a chance to join a space shuttle crew next year, David Zahren from the Prince George's County school system does not intend to use the occasion to test gravitational pull on goldfish or study the aurora borealis.

He has the novel notion, instead, of beamimg a televised classroom lesson from space to Earth, something between an orbiting "Mr. Wizard" and "Good Morning, America."

"This is not the time to do some esoteric experiment that not very many people would understand," said Zahren, who wants to have "America tune in every day for a 15-minute lesson."

Zahren, a teacher at G. Gardner Shugart Middle School, is one of two Maryland nominees to the NASA Teacher in Space Program. He and Kathleen Beres, a Baltimore County biology teacher, will compete in a field of national finalists, each of whom submitted a proposal for scientific activity in space.

One teacher will be chosen, after rigorous screening, for a space shuttle launch scheduled for next January.

If he is aboard that flight, Zahren, 35, said, he feels that he would best be put to use doing what he does every day: teaching.

He said that his daily programs would be informative, yet entertaining. They would include lessons on gravity, for example, and on continental drift or on the daily operations of the crew.

He would ask newspapers across the country to carry maps so the public could plot the course of the orbiting shuttle.

"I want these things to be entertaining," he said. "If Americans can participate, there may be more commitment, more investment in this shuttle program."

The Teacher in Space program was initiated when President Reagan announced last August that a teacher would be chosen as the first shuttle passenger to go along just for the ride.

Zahren, a resident of Laurel who has taught in the county for 11 years, was one of 10,690 applicants nationwide, and one of 215 from Maryland.

The Maryland field was narrowed to six semifinalists, including Montgomery County teacher Katherine Seward and Geraldine McCarthy, coordinator of the special education wing at Oxon Hill Elementary.

Under NASA requirements, the teacher who finally is selected must have a blood pressure reading of less than 160 over 100, vision that can be corrected to at least 20-40 and be able to hear a whispered voice from three feet, with the help of a hearing aid if necessary.

The nominees selected by states range in age from 27 to 53 and include a number who have, on their off-hours, pursued adventures ranging from ballooning to yachting.

Maryland's other nominee, Beres, for example, has climbed mountains, gone on a safari and crossed the Atlantic in a sailboat.

Zahren, like a number of other nominees, is a veteran of the Peace Corps, where he spent two years teaching in Kenya. He earned a bachelors degree in biology from the University of Pittsburgh and is working on his master's degree in school administration at George Washington University. For most of his years in the classroom, Zahren has taught life sciences. This year, however, he was selected as one of 20 "instructional support teachers," to work with other teachers.

At Shugart he has become known as the host of "AM Warmup," a daily program that is broadcast to every classroom in the school on closed-circuit television. In the 15-minute program, Zahren tries to relate current events and culture to the lives of his adolescent students.

He hopes to use much of the same format if he gets to move his program to space.

Zahren believes that his proposal would be a shot in the arm for both the shuttle program and the teaching profession.

For NASA, the program could mean renewed public interest and a medium to bring the technicalities of space travel to the general public, Zahren said. And it could raise the esteem of the teaching profession, he added.

"If youngsters can see a teacher who's competent, articulate, having fun and receiving attention, teaching might become an option," he said.

Zahren and the other nominees are to attend a workshop in June, after which 10 semi-finalists are to be chosen in July.

The semifinalists will go to the Johnson Space Center in Houston for further testing and, in September, the winning teacher and a backup candidate will be selected. Then these two will receive 120 hours of training before the launch.

If he is selected, Zahren said, he believes that his most important mission would be to "translate" the experiences of those aboard the shuttle to people on Earth.

"I don't want it to be intimidating," he explained, "and I think that's what it is right now."