Hartford, Conn. ? For incoming freshmen at western Connecticut’s suburban Brookfield High School, hefting a backpack weighed down with textbooks is about to give way to tapping out notes and flipping electronic pages on a glossy iPad tablet computer.

A few hours away, every student at Burlington High School near Boston will also start the year with new school-issued iPads, each loaded with electronic textbooks and other online resources in place of traditional bulky texts.

While iPads have rocketed to popularity on many college campuses since Apple Inc. introduced the device in spring 2010, many public secondary schools this fall will move away from textbooks in favor of the lightweight tablet computers.

Apple officials say they know of more than 600 districts that have launched what are called “one-to-one” programs, in which at least one classroom of students is getting iPads for each student to use throughout the school day.

Nearly two-thirds of them have begun since July, according to Apple.

At Burlington High in suburban Boston, principal Patrick Larkin calls the $500 iPads a better long-term investment than textbooks, though he said the school will still use traditional texts in some courses if suitable electronic programs aren’t yet available.

“I don’t want to generalize because I don’t want to insult people who are working hard to make those resources,” Larkin said of textbooks, “but they’re pretty much outdated the minute they’re printed and certainly by the time they’re delivered. The bottom line is that the iPads will give our kids a chance to use much more relevant materials.”