HACKENSACK, N.J. — Spend a while at Pascack Hills High School in Montvale, one of the first in New Jersey to hand every student a laptop, and you’ll likely hear a teacher tell students to "forty-five it."

That means closing laptops halfway during a lesson — to a 45-degree angle — so they aren’t tempted to surf the Internet, check email or shop for shoes. It’s one of many techniques savvy teachers are adopting to keep the attention of a generation easily sidetracked by an unprecedented bounty of technology.

As a growing number of schools let iPads, laptops and cellphones enter the classroom, some teachers say they’re shouldering a new role as electronics police. Teachers warn constantly that abused devices will be confiscated. Some continually roam behind the back row to see who is watching what. And in a step that smacks of Big Brother, some have programs that monitor all their students’ screens at the same time, and shut off the computer of anyone goofing off.

In interviews with a dozen teachers, many talked about the tensions between embracing the digital era’s enormous benefits for instruction and worrying about the drawbacks. A survey released last month by the Pew Research Center reflects these conflicting feelings: 77 percent of middle and high school teachers who have advanced students said the Internet and digital search tools have had a "mostly positive" impact on their research projects. Even so, 64 percent said digital technologies "do more to distract students than to help them academically."

A two-day conference starting today at River Dell Regional High School will focus on how to make the best use of laptops, tablets and other devices in class, and how to keep kids engaged. About 140 educators from around the country, including 60 from New Jersey, are expected to attend.

It’s organized by Project RED (for Revolutionizing Education through Technology), whose leaders argue that using computers properly can boost test scores, prevent dropouts and even save money by cutting costs for textbooks and copying. The group was founded by Intel, the chip maker.

Ann Flynn, director of education technology at the National School Boards Association, said these tools should lead to less lecturing by teachers and more hands-on projects by students. Few districts, however, follow the rough rule that about a third of the budget for new hardware should go toward teacher training. "Teachers really need to have a different set of skills and teach in a different way," she said. "It’s not about tossing the stuff in the classroom and expecting magic."

Pascack Hills High School, a high-achieving school in an affluent district, issued individual laptops to students nine years ago. Now it spends more than $1 million a year to lease 2,503 Apple MacBooks for $413 per student, and educators from as far as New Mexico, Nebraska and Australia have visited to see them in action.

On a recent morning, small groups of students clustered around laptops as they used software to graph sound waves made by various musical instruments.

Their teacher, Brendan Field, said laptops enabled them to tackle complex assignments they couldn’t otherwise pursue but that the potential for distraction was a "huge problem." He allowed each team to have only one laptop open, and barred note-taking on laptops in the belief that pencils and paper were more efficient for math.

"It’s a teacher’s responsibility to enforce good habits" with technology, Field said. "They’re tempted and will do what you let them do. I do try to police it."

"It’s a problem with adults at work, too," he added. "It’s not kid-specific."

Some teachers say they have to do more of a song and dance to keep students engaged than in the past, and must work harder to show how the material is relevant to their lives.

"You have to put on a show, and make sure there are multiple activities each period," said Michelle Gaeta, a Pascack Hills math teacher. "It was different with my teachers. You knew you had to pay attention."

Despite teachers’ efforts, many students readily acknowledge sneaking off-topic peeks at their screens.

Michael Vercellone, a senior and student government president at Pascack Hills, said that although he loved his Science, Ethics, Technology and Society course, and was interested in a class discussion of Japanese doctors torturing World War II prisoners for medical research, he couldn’t help reading an irrelevant Wikipedia entry on parasitic botflies.

"It creeped me out. They get inside you," Vercellone said. He dismissed any concern that he might miss important academic points this way. "I can pay attention and do two things at once. Most of us are good at multitasking."

Many teachers say the benefits of laptops in class dramatically outweigh the costs. In an interdisciplinary history and English class, teacher Owen Haveron spoke about how juniors discussing "The Great Gatsby" could quickly check online what it meant to buy stock on margin. "That instant information can really add to conversations," he said.

But for some teachers, that immediate gratification has hazards. The Pew Research Center’s survey, done in conjunction with the College Board and National Writing Project, found that 76 percent of 2,067 middle and high school teachers "strongly agree" with the assertion that search engines conditioned students to expect to find information quickly and easily. For many students, it said, research means Googling.

In the survey, only 22 percent of teachers felt students showed patience and determination in looking for information. Pam Schwarz, a social studies teacher at Pascack Hills, said it was hard to teach students persistence and the value of intellectual struggle in the face of Google’s ease.

"If they don’t get an answer in a minute of searching they get frustrated," she said. She requires that some information on research papers come from "actual books" so students have to hunt through the library for different sources and multiple perspectives.

Most teachers agree that students need more help navigating the Internet wisely, said Kristen Purcell at Pew’s Internet & American Life Project, who led focus groups of teachers.

"Students aren’t being taught the skills they need to make smart choices, like assessing the quality of the information they see online and being able to recognize bias," she said. Teachers reported that too often, these skills were touched on in a piecemeal fashion, and left to English teachers to fit in when possible. "The education system has to figure out who will teach these skills and when," Purcell said. "We’re behind the ball in digital literacy."

Schools around North Jersey have varying policies toward devices. Some bar students from carrying cellphones during the day, while others allow them only at certain times or locations. Some teachers encourage using a smart phone app for a graphing calculator, for example, saving families the expense of buying one. Some schools allow access to Twitter, while others block it, saying it’s too addictive. Almost all bar Facebook.

Those pushing for broad, innovative adoption of new devices argue that students have to be nimble with them to survive in an increasingly high-tech environment, and must learn how to harness their own powers of concentration.

"You and I passed notes when we were in school," said River Dell Superintendent Patrick Fletcher. "Kids always had ways of distracting themselves."