Undeterred by workmen installing windows and sawing wood two floors below, Lei Kendale got on with the business at hand: Teaching his new fourth-grade students the "Code of Civility" they were expected to honor.

Pointing to the blackboard, he asked the uniformed boys and girls, "What's the word?" then snapped his fingers. "Responsibility!" they answered. He moved to the next word, snapped again and the response came back louder, "Respect!" And so it went this week in the opening days of the new Robert Louis Johnson Arts & Technology Academy Public Charter School for kindergarten through fifth grade in Northeast Washington.

Across town, at the Booker T. Washington Public Charter School for Technical Arts in Northwest Washington, the construction work was closer and louder. With the buzzing of electric saws filling the air in the partially built room, 22 teenagers sat in chairs with no desks as they began a high school program of traditional subjects and training in the construction and building trades.

The schools--both works-in-progress--are two of 10 public charter schools opening this and next week in the District. They join 19 others already in operation, part of a public education movement that advocates say will have a profound impact on education in the nation's capital.

The District, where two charter schools began operating in fall 1996, now has the fastest-growing charter school movement of any city in the country. With a congressional mandate that allows 20 new schools to open each year, proponents say it may not take long before the number of independent charter schools comes close to rivaling the city's 145 traditional public schools, which serve about 71,000 students.

There are more than 1,100 charter schools across the country, with some 250,000 students. There were about 3,500 students in D.C. charter schools last year, and supporters say enrollment could double this year.

The learning-amid-construction atmosphere is typical of new charter schools, which operate with public funds, are free to students and enjoy a great deal of autonomy.

Proponents say that such schools offer parents an option within the public system and will force traditional schools to improve to keep students. Opponents say charter schools drain resources from traditional schools, making it difficult for them to improve.

Charter school programs in the District are diverse--so much so that they don't all have regular 180-day school years. Cesar Chavez Public Charter High School in Northwest Washington, for example, operates on a 221-day year and gives students only a month off for summer vacation. Some schools are designed for children with learning disabilities, adjudicated youths and high school dropouts. Others emphasize technology, math and science, language immersion, the arts or vocational training.

Booker T. Washington, which has about 100 students in grades 9 through 12, offers training in trades including carpentry, plumbing, electrical wiring and bricklaying as well as computer skills. It also has a night program for adults.

"The school offers me a chance to learn the skills I am interested in," said Alicea Bland, 18, a senior who last year attended a charter school that didn't reopen this year. She opted for charter schools, she said, because her neighborhood public high school has no vocational training, an example of how vocational education in the District has all but disappeared in recent years.

Students at Booker T. Washington said the first few days there were marked by disorganization, with staff members feeling their way through what many liken to the start-up of a new business. But the students said they expected improvements and were willing to take a chance on the new school.

Booker T. Washington was founded by Ed Pinkard, a construction and real estate consultant who said he wants to fill the city's vocational education gap. Robert L. Johnson was started by parents who were upset in 1997 when D.C. school officials closed their neighborhood elementary school. They won approval to open a charter school in the same building.

Both schools are experiencing the same first-year growing pains most charters face.

"I sympathize with those people just starting to open schools now because I was there a year ago," said Irasema Salcido, founder of the well-regarded Cesar Chavez high school, now in its second year and located in the same building as Booker T. Washington.

"It is hard, impossibly hard. You can't imagine the difficulties," she said. "Now, the second year is very different. We are not dealing with the unknowns. . . . You know what you have control over and what you don't."