APLEWOOD, N. J., April 1 - Columbia High School seems to have it all - great sports teams, great academics, famous alumni and an impressive campus with Gothic buildings. But no one boasts about one aspect of this blue-ribbon school, that its classrooms are largely segregated.

Though the school is majority black, white students make up the bulk of the advanced classes, while black students far outnumber whites in lower-level classes, statistics show.

"It's kind of sad," said UgochiOpara, a senior who is president of the student council. "You can tell right away, just by looking into a classroom, what level it is."

This is a reality at many high schools coast to coast and one of the side effects of aggressive leveling, the increasingly popular practice of dividing students into ability groups.

But at Columbia High, the students nearly revolted. Two weeks ago, a black organization on campus planned a walkout to protest the leveling system. Word soon spread to the principal, who pleaded with the students not to go. The student leaders decided to hold an assembly instead, in which they lashed out at the racial gap.

The student uproar is now forcing district officials to take a hard look at the leveling system and decide how to strike a balance between their two main goals - celebrating diversity and pushing academic achievement.

Educators say that leveling allows smarter students to be challenged while giving struggling ones the special instruction they need. But many students, especially those in the lower levels, which often carry a stigma, say such stratification makes the rocky adolescent years only harder. And at Columbia High, there is no dispute that it is precisely the leveling system that has led to racial segregation.

Anthony Paolini, a senior at Columbia, is one of the few white students in a lower level math class. The fact that most of his classmates are black does not bother him, he said. But the low expectations do.

"It makes you feel like you're in a hole," he said.

The school, about 15 minutes from downtown Newark, draws from the cosmopolitan towns of Maplewood and South Orange. Some students live in million-dollar homes. Others rely on government lunches. Of 2,024 students, 58 percent are black, 35 percent white, 4 percent Hispanic and 3 percent Asian. The public school sends more than 90 percent of graduates to college, has a dropout rate of less than half a percent and won a national Blue Ribbon award from the federal government for its academic excellence during the 1992-93 school year. Notable alumni include the actor Zach Braff and the singer Lauryn Hill, and the fact that the two stars, one white, one black, graduated in the same class is seen as a symbol of the diversity Columbia strives to project.

But racial tension is becoming more of an issue. In recent years, the number of black students in the school district has eclipsed the number of white students even though Maplewood and South Orange still are majority white. In the past year, the district has been sued twice for discrimination: once by two former black students who said they were mistreated by teachers after a food-fight in the cafeteria, and also by a group of teachers, mostly black, who accused the principal, who is white, of racial bias.

The superintendent of the district, Peter P. Horoschak, acknowledged that there were, in a sense, two Columbias. The de facto segregation is most visible at the extremes.
Statistics for this year show that while a Level 5 math class, the highest, had 79 percent white students, a Level 2 math class, the lowest, had 88 percent black students.
Levels 3 and 4 tend to be more mixed, though a school board member, Mila M. Jasey, said, "Some white parents tell me that they know their kid belongs in a Level 3 class but they don't want them to be the only white kid in the class."

Though parents and students are granted some input, students are supposed to be placed in levels primarily based on grades and test scores. Many black students complain that they are unfairly relegated to the lower levels and unable to move up.

Quentin Williams, the 17-year-old leader of the Martin Luther King Association at the school, calls it "contemporary segregation." He said that his organization, one of the largest on campus, had tried to meet with the administration over the issue several times but "got the runaround."

So in mid-March his group planned to walk out of school. They even had the backing of several parents, who volunteered to help. As the date approached, Quentin, a senior, said he felt "a lot of pressure coming in from a lot of different angles."

Student leaders eventually decided that holding an assembly would give them a better opportunity to publicly confront administrators, especially the principal, Renee Pollack. At the assembly, which was mandatory for all students, she stood in front of the student body and apologized for saying anything that might have been construed as insensitive.

Ms. Pollack said later that complaints about her were being spread by teachers on her own staff.

"They were trying to manipulate the kids in order to get at me," said Ms. Pollack, who has been the principal for three years and is up for tenure this month.

The flashpoint of the assembly came when Nathan Winkler, a skinny, intense senior who says he wants to be governor some day, grabbed the microphone and announced that he had no sympathy for people in lower levels because all it took was hard work to move up.

His short outburst was like a cleaver, splitting the student body in two. Many blacks booed him. Many whites cheered. He was then accused of using the term "you people" in his speech - though he did not, according to a videotape of the assembly. After the assembly, he said, he was stalked in the hallways.

He now admits that he spoke out of fear.

"I felt extremely isolated during that assembly," he said. "For the first time I was aware of being part of the minority. White kids are outnumbered at Columbia. I knew that, but I hadn't really felt it before."

Student leaders and administrators are now discussing ways to narrow the so-called achievement gap, like granting students more say in which level they are in; better identifying which level students belong in; expanding a summer school program for students who want to take upper level classes. Administrators say they had been working on all this before the walkout threat.

"But the students forced the issue," Ms. Pollack acknowledged.

Ms. Pollack also pointed out that this year, more students of color from Columbia have been accepted into Ivy League universities than white students, with two Hispanic, three black and two white students gaining early admission.

The debate over leveling here boils down to fairness. Is it fair just to ensure equal access to upper level classes? Or does fairness go farther than that and require administrators to truly level the playing field so that the racial makeup of upper classes better resembles the racial makeup of the school?

Stewart Hendricks, a senior whose father is from Guyana and whose mother is Swiss, said that some teachers do seem to have lower expectations for black students but that he did not let them get him down.

"The purpose of high school is to prepare you for the real world," he said. "And in the real world, you can't listen to other peoples expectations, because in the real world, people are just waiting for you to fail."

Because of his mixed racial heritage, he said, "I guess you can say I'm in the middle of all this."

And in a way, that is why he sympathizes with the principal.

"She's got an entire black population that wants to get rid of the leveling system and an entire white population who would leave this town if they did that," he said. "What's she supposed to do?"