After weeks of planning and construction, Luke Schafer, 12, and Cory Byrne, 12, both of Rockville, assembled their handmade submarine by the side of a tank at the Naval Surface Warfare Center, Carderock Division, in Bethesda and placed it in the water.

"We tested the motor a couple of times but never in water," Luke said.

When the boys put their sub in the water it floated on the surface, so they added weights to gain neutral buoyancy, which is the state of not floating or sinking that is ideal for submarines like the ones constructed by the boys and their classmates at Earle B. Wood Middle School in Aspen Hill.

The class visit to the naval facility and use of one of its tanks for testing the boats was the culmination of a unit called Sea Perch. It was part of a pilot program at Wood that combines science, technology, engineering and math that is offered at the school and is enhanced by visits from engineers working at the Carderock facility.

"This is giving the kids a real world experience in science to prepare them to be work and college ready in the sense of possible careers," Principal Jeanie Dawson said. "It's made science come alive."

Twenty-four seventh-grade students and teacher Jerry Bush visited the center Jan. 27 for a day-long field trip and work session.

"It's cool to get your feet wet with engineering and see where you can go," Kellen Cremins, 13, of Rockville said. "I'm looking forward to seeing how my sea perch works."

The class is an elective that offers units on digital art, Internet gaming, computer-aided design and drafting in addition to the robotics unit that includes the Sea Perch project, Bush said.

The day included a tour of the facility, which was opened in 1939 and has tanks used by the Navy to test the sea worthiness of ships.

"I've never seen anything like it, the basins are huge," Kellen said. "The handmade boats looked really realistic. I thought it was really cool they could miniaturize it to see how it would work."

The highlight of the day, though, was when the students got to test their models by placing them in a 4-foot-deep rectangular tank and run them through their paces.

Professionals, including Toby Ratcliffe, an ocean engineer who is outreach coordinator with the National Defense Education Program, Damien Bretall, a mechanical engineer, and Lauren Russell, a marine architect, went to Wood to work with the students as they built their submarines and were at the launch for consultation and support.

A few of the submarines needed last-minute adjustments, but before long all the students had launched and powered up their boats.

"We didn't expect it to do a bunch of tricks, so it's doing about what we expected. It goes up and down, backward and forward. The best part is it goes really, really fast," Joey Cornwell, 12, of Rockville, said.

The testing included a "mission."

Students placed wand magnets on their submarines and had to troll the bottom collecting magnets Ratcliffe had planted.

The mission's success was noted by shouts of "we got one," or the tally of how many magnets were collected on one sweep. Five seemed to be the top number.

"This is great fun and very engaging. Sea Perch is probably the best thing we've done so far,'" Melody Dastanlee, 12, of Rockville, said.

Seventh grade students from Earle B. Wood Middle School test submarines they built Wednesday, January 27, 2010 at the Naval Surface Warfare Center in Bethesda.