Students who come each week to the Prince George's County school system's Howard B. Owens Science Center in Lanham are encouraged to touch, push and probe the exhibits -- from the hot-air balloon to the laser machine to the snakes.

The Owens center, opened in 1978 and named for a former supervisor of secondary school science who first proposed the idea in the 1960s, is the only science center in the country that serves a single school district. Its programs complement classes in physics, biology, chemistry and astronomy at all grade levels.

Director Hays B. Lantz Jr. says exhibits are designed to lift science out of the abstract and into the hands of the 500 students who come each week. "I want this place to be saying, 'Hey, this is science, and it's exciting,' " Lantz said. "If it doesn't say that to you, then I've failed miserably."

Last week, Addie Strain and Beth Raabe, both 15, came to the center with their Northwestern High School biology class to do work in physiology, learning such diverse skills as measuring heart rates and dissecting frogs. The structured program was "okay," they said, but they preferred to go off on their own to try out the laser exhibits and look at the animals -- especially the live alligator from South America.

The center, Strain said, is "a lot more interesting than school. . . . It's got a lot more equipment and a lot of different stuff."

The two-story center next to DuVal High School has more than 100 exhibits, including a parabolic mirror that moves in and out and creates strange configurations.

All the exhibits are meant to be manhandled by students, said design specialist Addison Likins. All of the mechanical projects turn off on their own, however, because "kids have a tendency to forget to do that."

In addition to Lantz and Likins, the center has six full-time teachers, two instructional aides and nine part-time staff members who assist with administrative work. The center operates on an annual budget of $418,000.

The showpiece is the planetarium, which has a dome 55 feet in diameter and an audio-visual system that has 60 slide projectors and 17 speakers. The planetarium, which can represent the night sky from any point on earth, is open to the public on Friday nights for an admission fee of $1.50 for adults and 75 cents for children.