Jill Garrett sensed the difference within minutes of teaching her first class at the BASIS DC public charter school in an old building on Eighth Street NW. The seventh-grade students were eager for a challenge. They quickly made clear her lesson was too easy.

They knew, after all, that by the end of high school, they each would have to take at least seven college-level Advanced Placement courses, an almost unheard of requirement.

Anyone can get into BASIS DC, yet the school demands more of students than any high school, public or private, in the city. Some parents and teachers love this. Some who reject the option think it is too much.

BASIS founders Michael and Olga Block have so far set up 31 small, radically challenging schools that operate as charters — public schools independent of school districts — and in seven cases as private schools, including one in McLean and two in China.

The Blocks, both economists, started their first school in Tucson. Olga did not think American schools measured up to those she attended in her native country, the former Czechoslovakia. Michael noticed students educated abroad did better in his college classes.

Garrett, 32, is now head of school at BASIS DC, sharing leadership of 585 fifth- to 12th-graders with Portia Cameron, also 32, head of operations. They have 41 teachers. The school’s student body is 39 percent white, 35.8 percent black, 8.5 percent Hispanic, 8.4 percent Asian/Pacific Islander and 8 percent multiethnic. Sixteen percent of students are from low-income families.

The school is too new for The Washington Post’s America’s Most Challenging High Schools list, but its AP demands are more than other District schools. St. Anselm’s Abbey School, which requires at least five AP courses, usually has the highest AP test-taking rate. Last year, BASIS DC, not yet at full strength, gave 2.52 AP tests (which last more than three hours) per high school student, compared with 2.46 for St. Anselm’s.

Some educators think it is wrong for a public charter school to have standards so high that intimidated students and their parents do not apply. Yet I cannot think of a reason ordinary public school children should not have a chance to get as much out of high school as private and magnet school students do.

“BASIS DC is not for everybody. It is perfect for those who accept the challenge,” said Berhan Dargie, who has two children at BASIS DC. Sanam Naraghi Anderlini said at the school her two daughters’ “eyes and brains just lit up.” They have learned time management and effective studying skills, she said.

BASIS schools have many idiosyncrasies. By law, charter schools may not charge tuition. But BASIS DC, like other BASIS schools, says on its website, “We request an annual contribution of at least $1,500 per student, or a monthly pledge of $150” to attract the best teachers. That is very unusual for charters. BASIS officials say fewer than half of parents contribute.

Arizona Republic journalist Craig Harris reported May 7 on the finances of BASIS schools. He found 71 percent of the $84 million in state funds collected last year by BASIS Charter Schools, a tax-exempt nonprofit corporation, to operate 20 Arizona charter schools went to BASIS.ed. That is a private company owned by the Blocks.

BASIS.ed paid school staff members at the Arizona schools and used 11.75 percent of all school revenue for financial, legal, recruiting, professional development, construction management and other services usually performed by school districts.

Last December, Harris reported, property records showed the Blocks made a $1.68 million down payment on an $8.4 million condominium in New York, where they have two private schools. They also own homes in Tucson and Scottsdale, Ariz.

In a March letter to BASIS parents, BASIS.ed executives said, “The Blocks have put their heart and soul — and personal money — into growing BASIS Curriculum Schools for more than twenty years. To claim that they should not profit from their life’s work is unkind and, frankly, un-American.”

The Blocks have launched an experiment in accelerated education for anyone. The passing rate on AP tests for BASIS DC students last year was 57.5 percent, the national average. If taxpaying BASIS DC parents are pleased with the school, that is good enough for me.