In a slow sweep, Diana Prout's right leg separates itself from the floor. Extended behind her, it rises -- past pretty, past the point of pain. Pausing, it rises more. An inch past possibility, it stops.

"No-no-no-no-no-no -- that won't do. Get that leg up," demands Fabian Barnes, director and resident despot of the D.C. Art Works' Dance Institute of Washington summer program.

Twenty-four students -- ages 12 to 21, a third of whom have never taken a dance class -- blink. Mesmerized by Prout's demonstration of what they'll all attempt momentarily, they watch as, obediently, the leg rises more. And stays there.

"That's nice, Diana -- very musical," says Barnes. Prout -- a 21-year-old Howard University student whose three years of ballet experience make her the class standout -- relaxes her leg. Human again, it grazes the floor.

"Okay, everybody else to the barre," orders Barnes. Not missing a beat, they comply. Seconds later, 25 pointed feet begin the ascent.

Clearly, something is wrong here. Where's the gum-smacking, the ennui, the back-talking associated with today's teens? Nine days after Barnes's six-week program began, the students -- most of them District residents who earn minimum wage through the Mayor's Summer Youth Employment Program by being here -- are into this. Into the sweat and frustration, the challenge of being put through their paces by a couple of real, dance-for-their-supper professionals.

Barnes and co-instructors Dean Anderson and Robert Garland, who will teach modern dance starting July 28, are principal dancers with the Dance Theatre of Harlem (assistant instructor Jenne Franklin, a District native, has been studying in New York with DTH for three years). When DTH went on a six-month hiatus in March because of financial difficulties, Barnes suggested a city-sponsored professional-level dance school for District kids. A month later, D.C. Art Works Executive Director Ulysses Garner approved the proposal, allotting studio space at the Stables Art Center downtown. Student auditions were held in May and June.

Everybody here works hard for the money. Barnes and Anderson, a girl with a wild ponytail attests, "don't play." Pacing the class, they point out the tiniest faux pas. "Point your FEET, Michael!" Barnes commands a barefoot boy. "I SEE you, Reprina!" Smiling, Anderson asks a girl too shy to raise her head when she flubs a move, "What's on the FLOOR?"

The young dancers love it. Class is "hard but not impossible," says Morenike Efuntade, 19, a student at Prairie View A&M University in Texas. "People would pay to get an opportunity like this."

"It's a struggle for me -- I'm not strong enough to do {the ballet}, have to build my body up," says Erynne Dowe, 14. "I look around -- like at Diana, who's very good -- and I guess I'm envious. But it makes me work harder. You know, I don't think I've ever been challenged to the point where I have to work to my fullest capacity."

Prout -- whose longing to become a professional dancer is dimmed by one consideration -- the money ("I mean, I want to be comfortable") -- glances at her instructors.

"My teacher in {her hometown of} New Orleans was good -- but {Anderson and Barnes} are so much better... . They push you. Like etiquette -- all the girls' hair has to be confined; no bangs that droop in your face. No gum. Colors -- they don't like loud colors... . If you forget a step, Mr. Barnes digs it out of your head."

Suddenly, she's imitating him: "Remember what we did three days ago?" she booms. "What was it? Define it. Show it to me."

Back at the barre, students with varying degrees of skill are showing it to him. They've just finished an on-their-backs jazz workout to Sheena Easton, in which 50 legs scissored the air like spandexed windshield wipers. Barnes studies them, comments as they dip and sway.

"Now, Erynne," he whispers to a visitor, "{DTH director} Arthur Mitchell would love her -- those long limbs."

"And she," he continues, nodding toward at a voluptuous girl whose baby face hasn't caught up with her body, "is the perfect example of the importance of a willingness to learn. She may not have been born with the perfect dancer's body, but sometimes they're the ones who make it."

They're moving now to a piano's peremptory beat. Up, down, up again. Clutching the barre, they circle from the waist, straighten and extend their arms ceilingward. Their eyes fix on the beauty of their hovering fingers.

If barely trained bodies can do these limber, unimagined things, the dancing suggests, young minds must have a similar potential.

"Of course," says Reprina Washington, 14, a Largo High School sophomore who lives in Southeast. "All your life, you're going to have to deal with difficult things, and you can't give up. ... I enjoy this because it's hard."

"Of course," adds instructor Barnes. "I'm tenacious in everything I do, and I got that from dance. You walk better. You carry yourself better. You have a better opinion of yourself. In today's world, there's so much going on that I didn't have to contend with when I was a kid. ... Crack. Or the girls and teenage pregnancy. A lot of what they learn here -- discipline, setting goals, working to achieve something -- will help them."

He laughs. "Plus, they're too tired to get into trouble when they leave me. They go home and soak."

During lunch break, the kids -- who will perform at the Duke Ellington School of the Arts at the program's end -- sprawl on the floor outside the studio, munching Chinese takeout. They talk about why they do this.

"I don't think I'm gifted," says Jonathan Jackson, 19, one of three young men in the class. "But it's good, seeing if I can extend myself to the maximum point."

It's the joy, sighs Prout, of "seeing what I can do. Putting people in awe -- 'Wow, how does she get her leg up so high?' The pleasure that you're doing something right; you didn't mess up, it was fabulous."

Explanations don't come as easily to Chanee Johnson, 13. She stands there, face contorted, stuck in the effort of explaining the "why" of ballet. "I feel," she begins and stops. But her arms, curled in front of her midsection, begin to arc outward in a long extension, as if to finish the sentence. "I feel -- emotions and feelings and I express it while I'm dancing. Happy and loving and stuff. Dancing makes me smile."

Now, unconsciously, she's in the classic dancer's pose -- toes turned out, her arms a brown halo above her head.

"Dancing makes me feel -- beautiful. It gives me beauty."