COOLIDGE HIGH SCHOOL, at the northern corner of the city of Washington, marked a quiet but significant success this week. For the first time, some of its students took the advanced placement examination in English. This year is the first that Coolidge has offered an advanced placement course--another indication that the city's schools are now moving toward more challenging, and demanding, programs for their best students. Next year, Coolidge will add advanced placement chemistry. Since AP courses are taught at the college level, one incentive is that most colleges give credit for them. Coolidge's principal, James E. Campbell Jr., says that he's prepared to consider AP courses in any subject in which as many as five students sign up.

High schools in Washington, and throughout this area, are now trying to do two difficult things at once. They are trying to increase the range of possibilities for their best students and, meanwhile, raise the standards for all their students. Coolidge is one place where you can see this double purpose at work. While adding the AP courses, Coolidge and all of the the city's high schools will tighten sharply the basic requirements for graduation. In science and mathematics, for example, this year's seniors must pass only one course in each to get a diploma. But the youngsters who graduate in 1984 must pass two courses in math, two in science, one in a foreign language and one more than the present four in English.

The AP English course was not easy to fit into Coolidge's curriculum, at a time when the school's enrollment is running higher than expected and the faculty is being cut. But other English teachers agreed to take somewhat larger classes, to accommodate the new course with its 18 students. It's not only for the AP students, incidentally, that the courses are getting more challenging. Susan Gordon, who teaches the AP class, has four other classes of seniors and currently some of them are working on Shakespeare's sonnets. One recent exercise had the students writing sonnets of their own, and several of the more successful results are up on Mrs. Gordon's bulletin board.

Readers of this page hardly need to be reminded that curriculum standards in high schools here, as in much of the country, went sadly slack in the great wave of educational experimentation that began in the late 1960s. Now, at schools like Coolidge, under teachers like Mrs. Gordon, curriculum is moving in another direction. If you worry about things like the country's scientific competence, the quality of its culture and the ability of young Americans to use their native language--and there is plenty to worry about--it's worth knowing that there are high school teachers who share these concerns and are doing something about them.