In his ninth-grade English class, Timothy Martin was supposed to be studying word prefixes by himself while the rest of his class worked on forming the plurals of nouns. Instead, Martin sat at a classroom table, book closed, and chatted with two friends about the Redskins and girls.

Timothy attends the Friendship Learning Center, an "open space" school in Southeast Washington. Instead of having enclosed classrooms, Friendship has several classes all on the same floor. There are no walls to serve as dividers.

So, while Timothy's teacher tries to explain how to form the plural of elf in one corner, just a few yards away a math teacher can be heard asking her class how many fours there are in 72, and the voice of the civics teacher giving a quiz can be heard, too.

One of the major educational innovations of the 1970s both here and across the United States, open space schools were supposed to stimulate youngsters' learning by taking them out of regimented, desks-in-a-row classrooms and placing them in a wall-less setting. There, the theory was, they could move about moe freely and learn at their own pace from a variety of audio-visual aids and games, in addition to the teacher's lectures and traditional textbooks.

In the Washington area alone, tens of thousands of young students have come and gone through open-space classrooms in the 1970s.

But a decade later, as the 1970s wind down to a close experts and their studies are in disagreement over whether the open space setting even affects students' achievement, let alone improves it.

Furthermore, a significant body of expert opinion holds that such traditional factors as a child's natural ability, family background and the quality of his teachers are more important to learning than the setting.

"What it comes down to is that the highly motivated kid with an IQ of 140 is going to learn to read, no matter what," said Jonathan King of the University of Michigan, who recently studied the effects of open space classrooms on the way students learn. "The student with a low IQ and less motivation is going to lag behind, no matter what," he said.

Although the academic debate is inconclusive, the open space experiment has proved costly for Washington area school systems.

The District of Columbia spent $163 million in the last decade to build 17 open space schools without first testing whether the concept would succeed here.

In the same decade, Arlington County spent $25 million to convert 13 traditional schools into open space facilities. Montgomery spent $32 million to construct 21 open space schools and Fairfax spent $48 million on 13 buildings that provided for a combination of open and structured space.

Prince George's County spent $9 million for the construction of predominantly open space schools.

Dissatisfaction with the open space concept has grown as area school systems have spent additional hundreds of thousands of dollars over the years to erect walls where open space classrooms once stood.

All of these schools were built in the 1970s to meet experts' predictions of population trends in the Washington area. But the population, particularly in the suburbs, never reached those predictions, and school officials in the suburbs now say they didn't need all those schools after all.

There have been no major studies of how open space affects the way students learn in the United States. Several small studies conducted in different parts of the country offer varying conclusions.

One study of sixth-graders in Nashville, conducted by faculty members at the George Peabody College there, showed no significant differences in the achievement of students in open space schools and those in traditonal settings.

Another study of 146 grade-school students in Texas showed that students who like to learn independently do better in an open space setting. Still another study of 186 second graders in Illinois showed boys achieving better than girls in open space schools.

And so, after a decade of multimillion-dollar expenditures, the debate among educators goes on. Promoters of the open space concept say that elementary-age students, particularly, need more space to move around. The concept works, they maintain, when teachers are dedicated to it and are willing to put in enough time so that each child is occupied every minute of the school day, while learning at his own special pace.

Its detractors -- mostly teachers -- say the noise level and distractions hinder teaching -- and learning -- and add to behavior problems. They also say the resourceful teacher still can provide an "open classroom," where students learn at their own pace from a variety of teaching methods in the traditional four-wall classroom.

Dr. Robert Shockley, an assistant superintendent for the Prince George's schools, said, "The bottom line is that students learn best when they have good teachers."

In the District of Columbia, many teacher and principals now say flatly it was a mistake for the city to jump on the open space bandwagon.

D.C. built most of its open space schools in the city's poorer neighborhoods, where children come to school with a host of learning problems from severely disadvantaged homes.

In the suburbs, officials are beginning to respond to criticism of open space. Fairfax County, for example, spent $48 million to build schools that combined open and closed space. But over the years, principals there have requested more and more enclosed space. The county recently agreed to spend $320,000 for additional wall panels in the open space schools.

Montgomery County spent about $32 million for open space schools or open space additions to its structured schools. Now that county is considering spending $200,000 to wall up some of the open classroom. "Education tends to run on a pendulum," said the University of Michigan's King. "The tendency [in the 1960s] was toward openness, change, a new curriculum and new activities. Now . . . we're in a conservative or reactionary period. People are somewhat disappointed [with the changes] and want to go back."

One of the biggest stumbling blocks in the open space schools has been getting teachers to adjust to working in the looser setting.

In many so-called open-space schools in the area, teachers have seperated their classes as much as possible from the ones next to them by putting up bookcases, closets, or billboards as dividers.

What you basically have, then, says King, is a four-walled classroom in an open-space setting, where pupils get few of the benefits of either system.

One of the objectives of open space was to permit teachers to work in teams. This would mean that, even on an elementary level students could be exposed to different teachers. The team system also would enable some teachers to work with the slower learners, while other worked with those learning at a faster rate.

Generally, teachers prefer running their own show to coordinating their teaching efforts with colleagues.

At the Amidon School in Southwest, principal Dorothy Zucker had trouble over the past four years finding teachers to work in the school's four open classrooms. This year, Zucker converted the area that was supposed to be open space classrooms into one big resource center, where teachers can bring groups of students for a special purpose.

Carol Tatum, who taught in the open space setting at Amidon a few years back, said she found it difficult to discipline students. "If one child was making a disturbance in one corner, it upset the whole room. You not only had war duty in one class but all the other classes," she said.

Since the students had no desks in the open space setting, they kept their school materials in little trays. Stealing was common.

However, open space seems to be succeeding in schools where the principal and teachers are dedicated to the concept. Brookland School, racially mixed in a middle-class neighborhood in Northeast, is a prime example.

As the "model" for the District of Columbia open space schools, Brookland's success may reflect the amount of money, effort and teacher training was willing to give that school.

There, the teachers do work as a team. For example, the math teacher will coordinate a lesson on Roman numerals with the social studies teacher's lesson on Roman history.

The other day, language arts teacher Jacqueline Wood was giving her sixth-grade class a spelling test on both English and French words since some of the students were having problems with the French and needed the extra practice.

Many District of Columbia teachers complain bitterly that the open space concept would work better if the school system were willing to provide the money for sufficient personnel and materials.

The model school for Howard County is Northfield Elementary, which opened 10 years ago. There, teams of four teachers are responsible for 120 students. But each team has a teacher aide and a secretary to keep track of the student's assignments.

The classroom teachers do not teach math. Math is taught by specialists so that the classroom teachers can have one period a day to plan and coordinate their lessons.

In addition, parent volunteers come into the classrooms four days a week to help watch over students and correct assignments.

Northfield principal Shirley Meigham says the program has been successful, ironically, because the student's day is very structured, despite the open atmosphere.

The classroom may seem unstructured.Some youngsters may be lying on the carpet trying to match up vowels printed on little pieces of paper, with words that contain their sound. Other students may be at desks writing in workbooks. Still others may be reading in a small group around the teacher -- but the day before, the teacher has planned it to be exactly this way.

It is doubtful, despite the debate, that school systems will do away with open space entirely in the future, school officials and other say. Many educators prefer a combination of both the traditional self-contained classroom and an open space area for their schools.

"In education," said Joan Holtin, assistant principal at Brookland, "nothing is cut and dry because you're dealing with human beings."