Classes for Grade IX, X, XI will continue till 13th April

Cheryl Hollinger has taught Advanced Placement biology at Central York High School in Pennsylvania for 17 years, plenty of time to see what isn't working. The amount of material covered is "overwhelming," she says; the 1,280-page textbook "is way too big to go in depth." Students go through the motions of their lab assignments without grasping why, and "the exam is largely a vocabulary test."

That all changes this fall, however, with a new curriculum that lasers in on just three body systems (down from 11); requires fewer but more creative biology labs, and entails an AP exam assessing reasoning skills rather than factoid recall. "I'm excited," says Hollinger, who welcomes the prospect of getting students "to think and act like scientists."

[Check out the rankings of the Best High Schools.]

Students and parents, get set for the next wave of education reform, which is about to raise expectations. Data from 2009 show that only 38 percent of U.S. 12th graders performed at or above proficiency in reading, and only 26 percent were proficient in math. The goal, say experts, is to better prepare high schoolers for the rigors of college and a competitive world economy, and to create a pipeline of native talent for the millions of STEM jobs going begging—in science, technology, engineering, and math.