Five clowns from the Ringling Brothers and Barnum & Bailey Circus juggled, flipped and twirled their way through a recent program at the Penn Hills branch of Greater Pittsburgh YMCA aimed at introducing kids to the science of the circus.

Some of the 4- and 5-year-olds giggled and clapped Friday while others took a more reserved stance, staring at the five performers before them. One, Anthony DelMastro, 4, of Penn Hills, wouldn't even look at the clowns for the first minutes of the program.

But by the end of the show, as the clowns sat on the floor with the 20 or so children, he agreed the clowns really weren't scary. The children warmed to the visitors, and some even asked questions.

To add to the fun, the clowns gave each youngster a bag full of stickers and toys, something Anthony liked a lot. He shook his head "no" when asked if he were still afraid.

That hesitancy by young children around clowns isn't unusual at all, said Dan Berkley, a New Jersey native who is the host clown for the science program they put on at schools and other facilities across the country. The 23-year-old graduate of Bates College in Maine, who has a bachelor's degree in physics, has been with the circus about a year.

"It's outside their experience," he said.

Ringling Brothers and Barnum & Bailey has been sponsoring the program for several years, and it is designed so children can see how much fun science can be. The clowns perform tricks to illustrate the laws of gravity, balance and rotational velocity.

A new show is developed each year, and work on the 2006 version will begin in a few weeks.

"There is a lot of physics in circus acts," Mr. Berkley said. The children at Friday's program were probably too young to realize that, he said, but they did watch with rapt attention as two clowns juggled shiny bowling pins and another kept seven balls in the air.

Some spun plates on skinny sticks and another balanced a metal folding chair on his red nose.

One more did a series of flips from one end of the gymnasium, where the program was held, nearly to the other. Then he did it again.

Pratfalls were part of the show, too, but not as many as during a regular big top event.

This was, after all, a special performance, with a higher aim: to teach as well as entertain.

The circus came to town on a 52-car train last week for shows at the Mellon Arena.

The Penn Hills visit was the only circus outreach program held on this stop, and it was the first time the program was held there.

"We didn't have the room [before]," explained Peggy O'Brien, who is senior program director for the Penn Hills Y.

Space is available now because a just-completed $3.8 million building and renovation project quadrupled the size of the facility, something the Y board wanted to showcase when members decided to stage the outreach program at a Pittsburgh Y facility.

Before, things as exciting as a circus had to be done as a field trip, not a visit.

All in all, Christine Lovett, a Penn Hills mother, thought the whole thing was a good idea.

Her older son, Ronnie, 4, was part of the Y-Tots preschool class that hosted the clowns, and her younger son, Andrew, almost 3, accompanied her as they watched the program.

Both boys had been to the circus before, and, while they'd reserved judgment on the clowns, both had told their mother what they had enjoyed being a part of the bigger audience at the "real" circus.

"They liked the animals the best," Mrs. Lovett said.