As reporters and a Japanese television crew looked on, James Filatro, principal of P.S. 95 in Brooklyn, demonstrated to a kindergarten class what not to do when encountering a gun.

Filatro, a short, gray-haired man keen about making an impression, pretended to shoot himself in the face and dropped to the floor like a ton of bricks, knocking over furniture and a couple of students.After the demonstration, Filatro asked the 5-year-olds, "What should you do when you see a gun?"

"Don't touch it," they replied in unison. They had learned the lesson.

The media had descended on the elementary school in the Gravesend neighborhood to observe the board of education's new "Anti-Weapon Campaign" in action. Schools Chancellor Richard Green, in response to the growing number of guns being brought into city schools, launched an academic war on guns last week with lesson plans to be adopted by teachers from prekindergarten to 12th grade.

In the school year that ended last June, 1,916 weapons - including guns, knives, razor blades and brass knuckles - were confiscated from New York City students, compared with 1,495 in 1987. Those figures, the most recent available, reflect the fact that schools have not been immune to the dramatic rise in crime and drug use elsewhere. More alarming to educators and parents is that drugs and guns are accessible to children at startlingly young ages.

Last January, a 5-year-old boy, dubbed the "Pistol-Packin' Peewee" by the New York Post, brought a loaded .25-caliber handgun into a kindergarten lunchroom. At P.S. 257 in the Bronx, a first-grader brought a live bullet to class for show-and-tell.

"This is not about gun safety," board of education spokesman Bob Terte said. "Our message is: Don't touch a gun at all."

Terte said five of the city's 117 high schools have been selected as part of a pilot project in which security agents with hand-held metal detectors randomly screen students. Since classes started in September, nearly 200 weapons have been confiscated. Green wants to include 10 more schools in the metal-detection program, which would cost the board of education another $5 million.

Filatro said only one student has ever brought a gun to his school.

"Two years ago, a sixth-grader came in with two handguns," he said. "He was new. He came from Texas, and he wanted to show his friends.

"We're not saying guns are bad. Guns have a purpose," he said. "Butthere's no place for a gun in school."

That message comes across loudly and clearly from posters hung in the hallways and in every classroom. They read: "Be cool, no weapons in school" and "Life is grand without a gun in your hand."

The board of education published a booklet that is entitled "Don't Risk Your Education, No Guns in School" and includes teaching strategies and suggested lessons. It lists many statistics, including the sad fact that every day in the United States, two people under 18 are murdered with guns and another is killed accidentally with one.

For some streetwise students in Donald Kelleher's fifth-grade class, guns are an everyday reality. Asked by Kelleher why people want guns, the students answered quickly: Guns are for protection, are easy to get and convey a "cool" image. They agreed that drug dealers are most in need of guns.

"If you rip off their crack, they'll kill you," said 10-year-old Sam.

Sam, sitting at his desk with a stack of baseball cards, was asked by a reporter whether he had seen a gun. He nodded and said, "An Uzi." Sam said his 17-year-old cousin is a drug dealer and carries the Israeli-made weapon to protect himself.

"My brother is getting a gun from his friend," Sam said. His brother, 14, is in junior high and wants to protect himself, Sam said, because "this kid named Larry and his crew are always jumping him and his friends."

Asked what he would do if his brother ever brought home a gun, Sam thought for a moment and said, "I'm gonna tell my mother."