During the past three weeks, 17-year-old Derrick Gibbs and a small group of friends have knocked on doors throughout Prince George's County in subfreezing temperatures, bearing petitions and reminding their neighbors of a man who died when the teen-agers were only 5.

The petitions ask that the birthday of slain civil rights leader Martin Luther King Jr. be made a national holiday. When musical superstar Stevie Wonder delivers the expected tens of thousands of signatures to representatives of Congress on the steps of the Washington Momument today, the signatures of some 2,000 Prince Georgians collected by Gibbs and his friends will be included.

And while Congress so far has not seen fit to declare a national holiday, Prince George's School Superintendent Edward J. Feeny and the county school board are observing King's birthday by giving the state's second-largest school system the day off for the first time.

The emphasis of this observance will be on making King's memory come alive for the county's youth. Because King was killed before most children under 16 could read the words "civil rights," mush less understand them, many young persons have no personal memories of the civil rights leader.

"We don't know him like our parents knew him, but we know what he's done for black people," Gibbs said, "If it wasn't for him, we wouldn't be walking through these integrated neighborhoods and going to integrated schools. wWe know what he's done, it's on the record," said Gibbs, who has already made a start in the field of radio and television that would have made King proud.

The Central High School graduate was host on "Stuff," a local children's television program, last year. He now works in public relations for the Military Sealift Command in Washington and attends American University at night.

Gibbs also produces "Teentalk," an interview and discussion program that premieres today as a regular feature on radio station WPFW. The first program will focus on King's life, a subject Gibbs feels young people need to know more about.

"It's really weird, because when a lot of teen-agers think of Martin Luther King, they think of riots and that sort of thing. We've been ill-informed," he said.

"One kid didn't even know who Martin Luther King was, or what he stood for. He just didn't understand. A lot of parents have neglected to enforce the basic principles of black history," Gibbs said.

Teachers at Martin Luther King Jr. Junior High School in Beltsville agreed that some students aren't aware of the importance of King's work.

"These seventh graders don't know about Martin Luther King," said Carol Cunningham, a 35-year-old teacher who added that hearing King make his famous "I have a dream" speech on the steps of Lincoln Memorial was "one of the highlights of my life."

"One year one seventh grader asked me, "Why do we have to learn about this dead preacher?" she asked.

John Whitehead, a social studies teacher, said of his young students, "Their world is now, today. You have to give them a sense of the past."

The social studies teachers at the school have planned a special program of discussions, films and lessons for their seventh-grade classes at the predominantly white school for this week. For one group of students, King was only a shadowy memory. As they described his accomplishments and what he symbolized, most spoke in generalities.

"Civil rights leader," said Michelle Becraft, 15. "Speeches and marches," said Stephanie Ray, 13. "I have a dream," said Tony Stashick, 12, who had been brushing up on King's life before talking to the reporter.

"Free at last, free at last. Great God Almighty, free at last!" said the blonde Stashick.

One of King's major accomplishments was ensuring "that black people could sit anywhere they wanted on a bus," said Colleen Dolan, 12.

Although the students knew little about civil rights struggles that forged King's life, they were savvy enough to doubt that his birthday would be made a national holiday soon.

"Everything takes a little bit of time, Stashick said.

The Prince George's school system took a step in that direction when the board unanimously approved the school holiday last spring. But even that took several years to accomplish; resolutions for the holiday were introduced by board member Bonnie Johns in January 1978 and 1979. Both were rebuffed by other board members who felt if King were to be so honored, so should other "ethnic heroes" like Christopher Columbus.

Last January, "I decided not to subject him (King) to that kind of humiliation," Johns said. She introduced what she called "a symbolic resolution" about the school holiday in an effort to jog the consciousness of the board.

School Superintendent Feeney and board Chairman Jo Ann T. Bell signed the measure, but it was not put to vote. Feeney said he was impressed with Johns' determination.

"I said, 'You hold onto that (resolution), wait and see, it's going to happen soon,'" recalled Feeney.

Last spring the superintendent had Jan. 15 placed on the official school calendar as a holiday. After some discussion, the board unanimously approved the measure, much to Johns surprise. She credited the approval to the superintendent's support and steady pressure by several community groups.

"What he (King) did and the way he did it set an example for our children to follow," Feeney said recently. "It says to them that we are truly honoring a man who did so much for humanity. If our young people are to believe that you can do anything, what better model can they have than to use King as an example?"