Two children play at washing dishes in a tiny sink. "Phooosh," one says, as he pretends to turn on the toy faucet. Nearby, another boy stomps on a wad of green Play-doh and then marvels at the imprint of his tennis shoe. A fourth child, glum and red-eyed, sulks by himself in the corner.

To a casual observer, the 11 children in Classroom 6 at Dumfries Elementary School look like any other group of preschoolers on the first day of class.

But this collection of youngsters is what educators call "at risk." Their educational and social skills trail behind those of other children their age. Many scored below 50 percent of the median on a skills test, and none scored higher than 75 percent. Some had trouble identifying objects, such as kites, or naming a color or repeating simple phrases.

Middle-class families often send their children to preschool, sometimes even earlier than age 4. Youngsters with severe physical and learning disadvantages can also attend a special county preschool program.

But for some of the children of Dumfries, one of Prince William's poorest communities, there is nothing. In a county where officials say the average school has about 6 percent of its students on the school meal program and some have almost none, about a third of the pupils at Dumfries Elementary come from homes that meet the federal income guidelines of less than $24,000 a year for a family of four to qualify for free or reduced meals.

And if the parents don't have the time or inclination to aid their offspring's development, then they hit kindergarten already behind.

"If you're behind on the first day of school, what is your opportunity to catch up?" asked Mary Parrish, who oversees Prince William County schools' federal grant program.

Giving these children a chance to catch up is what the preschool class at Dumfries, dubbed Great Start after the much-lauded Head Start program, is attempting to do.

"Those children become the ones who may fail at some point," said Principal Nicolette Rinaldo. "We're trying to prevent failure. Our goal is to make children successful."

Funded by federal Chapter 1 money, the program kicked off last week at Dumfries and Yorkshire schools. The county has also applied for Head Start grants and, if successful, would expand its at-risk preschool program to six more schools next semester. County schools are providing the classrooms and bus service.

Parrish said 13 elementary schools were determined to have educationally needy populations, with Dumfries and Yorkshire the neediest. Officials surveyed the communities to find out how many eligible children were around and then screened them to find the 32 at greatest disadvantage.

The preschool regimen is designed to build basic skills, foster a love of learning and spur parental involvement. They get breakfast and lunch at school and will be given books to take home every week.

"As you look at the children, you don't see any difference," Parrish said, as a child in a Bart Simpson "Watch it, Dude" T-shirt scampered by. One child cried and ran behind his mother when class began; another put on his backpack and stood by the door 30 minutes before the end of school, eager to join his sister in a different room. A couple of children refused to eat the pizza lunch.

But beyond calming first-day jitters, Parrish said, the class should enable the children to express themselves better, and by the end of the year, they should be well-prepared to start school on an equal footing with their peers.

"Next year when they're attending kindergarten, they're going to be very different children," she said.