SOME OF THE STUDENTS ARE AFRAID of what will happen once they leave the woods. Which is why today, in a cozy classroom yurt whose bare wooden tables and sparse bookshelves are more Little House on the Prairie than Ivy League, Adirondack Semester program director Cathy Shrady is helping 12 St. Lawrence University students brainstorm about how they'll cope with their return to the "real" world.

There's talk about slowing down, taking more walks, gathering for reunion dinners, and continuing to use "sound-cue reflection"—an exercise that involves taking three deep breaths and pausing to reflect when they hear a self-designated trigger sound (a bird's call, maybe, or a twig's snap). Some hope to reach out to the unenlightened: "Face-to-Face, Not Facebook" is the slogan they propose for a poster, or possibly a line of bumper stickers.

Nearly four months ago, these students traded smart phones, keg parties, and indoor plumbing for handwritten letters, quiet dinners, and a composting toilet named Clive. They've been living and learning in a wooded idyll called Arcadia (a classical reference to "the border between tilled land and wilderness"), near Lake Massawepie in New York's Adirondack Mountains. The campus consists of seven yurts nestled among towering hemlock and white pine trees, with rough paths cutting through a carpet of pine needles, ferns, moss, and mushroom-studded tree stumps.

Though idealistic, the Arcadians aren't naive. They know they're about to return to a culture in which many of their peers check e-mail and Facebook before getting out of bed in the morning.

They are right to be scared.

The Adirondack Semester is like a study-abroad program, even though its participants never leave New York State. Instead, they journey back in time. Their days are filled with chores that haven't concerned most 19-year-olds since pioneer days: drawing water from the lake, shoveling waste from the toilet, and slaughtering, plucking, and cooking a chicken.

"Instead of going out on Friday nights, you knit by the wood stove," sophomore Courtney Davis says. Indeed, she is wearing a hand-knit cap, its neon tassel lending her the visage of a sprite. Davis is a field hockey player who grew up in the suburbs of Albany, New York, where she had access to three shopping malls within 20 minutes of home. Here at Arcadia, she joined her classmates in purging 10 percent of their belongings early in the semester. These are the things she misses from home: ice cream, her mother, and watching movies on a comfy couch.

The encampment's spartan accommodations lack rock posters and stereos and water bongs. Fashion is utilitarian, makeup nonexistent. It's a struggle to find a mirror among the students' meager personal effects.

In addition to their classes, students stay busy by taking turns cooking meals, cleaning common areas, and gathering wood and water. It's common to hear them laughing and singing as they work. No one sleeps in or shirks duties. If someone forgets to collect and purify the lake water, the group goes thirsty.

They find ways to entertain themselves with the materials at hand. Tom Roseen, a tall, dark-haired sophomore with an interest in woodworking, is building a fort. He started assembling the stick-and-leaf structure during his "solo experience" (a night spent alone in the wilderness), and he's continuing the project for fun. "I just enjoy building it," he says.

Their curriculum complements the outdoor experience, with classes like Natural History: Ecology of the Adirondacks, Land-Use Change in the Adirondacks, and Creative Expressions of Nature. "What's the difference between hardwood and softwood?" ecology professor Brad Baldwin asks, before diagramming the cellular structure of a tree on the classroom yurt's whiteboard. "Which would you rather start a fire with? Which would you rather carve?" The answers come easily, as students draw on their experiences in woodworking class and consider the logs that fuel the room's stove. Later, during an experiment that involves measuring the strength and density of different types of planks, Roseen correctly identifies several wood types by smell alone.

During another lesson, Baldwin explains what they can expect from "lake turnover," the seasonal change in water stratification. Then the discussion shifts from local to global: how melting glaciers could affect the density of seawater and potentially lower temperatures in the U.K. The class almost shivers in response. The students know what it's like to be out on an upstate New York lake when the November sun's setting and the wind's picking up. It's hard science presented with the immediacy of visceral experience.

More than anything, the Arcadians are learning how to focus on the natural world rather than a virtual approximation of it. They notice things like the movement of the stars across the sky. Every two weeks, sophomore Luke Reed uses a protractor to measure the shifting positions of constellations as summer turns to fall turns to winter. Sophomore Lindsay Houston uses her free time to paddle out on a canoe and observe the habits of a family of beavers.

"I've spent a lot of time doing homework on the beach," Davis says. "There's a campsite down there that we've named 'the library.'"

As the semester draws to a close, no one's really sure how they'll fare back home, even though they've all created reentry plans. Perhaps the scariest possibility is that Arcadia won't be lost in a quick, violent flash but will gradually fade, like calloused hands turning soft. Missy Wirth, the only senior in the program, likens the scenario to the myth that if you put a frog in a pot of cold water and slowly increase the heat, the frog won't realize it's being boiled. Like that poached amphibian, she worries, "this will slowly die."

During lunch—leftover onion soup, homemade bread, cheese, apples, and tea—Davis, Chris Biles, and Emilie Wetzel recall some of the semester's social highlights: a pirate-themed dinner, a Sadie Hawkins date night (to which Davis invited her date via a message scrawled on Clive's wall). Then their attention is drawn to the male students who are fooling around with a tape measure, wrapping it around their chests. Biles and Wetzel join them. Wirth spots the reporter's notebook and says, "Guys, she's taking notes!" Everyone laughs.

Before joining the fun, Davis turns and, with the gravity of a sage, gives a face-to-face status update: "I'm the happiest that I've ever been."