The eighth graders at the Prince George's County school where Christa McAuliffe used to teach didn't move as they watched the ascending space shuttle burst into flames. It took a moment for them to realize that McAuliffe, a close friend of their own teacher and a woman they felt they knew, was dead. There was no outburst, only horrified silence.

"They were as stunned as the rest of us," said teacher Tom Campion, who worked with McAuliffe at Thomas Johnson Middle School in Lanham a decade ago. "There wasn't a word spoken."

A few miles away at Arrowhead Elementary in Upper Marlboro, where for weeks sixth graders had been studying about the space shuttle and preparing to watch the launch, the normal classroom decorum crumbled at the news. "They were devastated," said teacher Phyllis Cubbage. "They cried as they sat in their chairs."

For children across the country whose classroom assignment yesterday was to watch the launch of the space shuttle Challenger, the deadly dangers of science were brought home with stunning impact. The television screen they have trusted to bring them Sesame Street and adventure series this time brought them down to reality -- down from the high expectations engendered by a concerted national campaign to focus attention on McAuliffe and the lessons she would beam back to earth.

"I just stood there kind of empty for a minute," said 17-year-old Buong Bui, a student at Northbrook High School in Houston who was born in Vietnam and said he hopes to become an astronaut despite yesterday's accident. "I'll look at it differently, with a little bit more caution," he said in a telephone interview. "But I don't think we should stop technology because of a miscalculation. We just can't."

For many youngsters, it was the first experience with a major technological accident or scientific failure.

"They really see so much of the Star Wars movies . . . there is a gray area as to what we can do and not do," said Helenmarie Hofman, a program director at the National Science Teachers Association, which worked with NASA to develop the lessons McAuliffe was scheduled to present from space.

"We have taken this for granted. shuttle flights always get off; we've watched the safety," she said, adding that students often ask why there are no astronauts on Mars. "You need to start seeing what is not real and what is. Here's a good place to start . . . . "

Jerry Noble, a 14-year-old student at Laurel High School, said he and his classmates were upset not only because of the deaths of the seven crew members, but also because of what the accident may mean to space exploration. "It really didn't take hold until after a couple of minutes -- how far it set the space program back," he said.

But Hofman and others said they didn't believe that the accident would dampen student enthusiasm for the space program.

"Students don't stop wanting to be president or wanting to be movie stars because they know a movie star has been killed," she said.

Eugene Wilkerson, a science teacher at Belmont High School in Los Angeles, said he asked his chemistry students whether the incident should affect future space launches. "They said, 'Keep on going. Keep the program going.' It was unanimous," he said.

McAuliffe, 37, is remembered by several teachers in the Washington area who worked with her during the 1970s.

"I keep thinking back to last summer, how excited she was," said Campion, who saw his former colleague when she returned to Prince George's County last summer to address a rally for school employes. He and his family joined her later that August day at a ceremony at Bowie State College, where McAuliffe had earned a master's degree in education in 1978. "That was the last time I saw her," he said.

Hofman said she hoped teachers would not abandon the lessons McAuliffe was set to deliver over the next several days and that they would use the accident to emphasize a fundamental lesson of science: that failure can teach as much as success.

Yesterday, many teachers said they were so overcome by the news that they suspended their normal routines and let children gather to watch television newscasts.

Michael Hoover, an English teacher at George Mason Junior-Senior High School in Falls Church, said he was too upset to discuss literature with his 10th grade students. Instead, he instructed them to write about the accident in their journals.

"Honestly, I've rarely seen something affect them so strongly," he said, comparing the student reaction to the response when John F. Kennedy and Martin Luther King Jr. were slain. "It just doesn't feel right for things to go on."

At Taylor Elementary School in Arlington, Principal Ralph Stone brought his 570 students together for a short assembly and moment of silence. Softly, they sang "God Bless America." Then, at a signal from Stone, safety patrol captain Nicole Kaas tugged on a rope until the flag snapped at half-staff.

And at Patterson Elementary School in Southwest Washington, moments before the explosion, students heard a presentation by Dianne Prinz, who is scheduled to be the fourth American woman in space. NASA officials called Prinz at the school to inform her of the accident, but she already had left.

Stacey Tyrone Gray, a third grader in Prinz's audience, said later that he no longer wanted to be an astronaut. "It's too dangerous," he said. "The space Challenger just blew up."

Marie Ishee, a science teacher at Northbrook High School in Houston, had been in Florida for the launch but returned to Houston Monday night after the flight was postponed.

"When that shuttle burst into flames you felt like a piece of yourself was burning," she said in a telephone interview. "In front of 32 kids you can't sit down and cry. But you want to."

But, she added quickly, she would still volunteer for a shuttle mission.

"I would be there with bells on," she said. "We owe it to Christa."