When you enter Therese Johnston's classroom at George Washington Junior High in Alexandria, it looks at first like any other junior high science lab.

There are posters of the solar system, plants and minerals. In the back of the room, two tanks, one filled with tadpoles and the other with a rat named Splitter, sit under cabinets filled with assorted artifacts.

But beyond the blackboard and books are learnings not so obvious to the eye. Johnston is not only educating her students in life science, but also in environmental awareness.

"The direction of this class has really changed over time," said Johnston, who has been teaching for 30 years. "Just in the last few years, students have become more concerned and more involved in the environment. Now, environmental awareness is part of the curriculum."

Because of these environmental concerns, many of Johnston's students say science means more to them today than ever before.

"I was concerned about the environment before I started this class," said eighth-grader Jenny Kane. "But Mrs. Johnston teaches us about the problems in the world and shows us that we can make a difference."

"It's hard for people our age," added classmate Kathryn Reukauf, "because when people find out how old we are, they think we're not serious."

A look at what they're doing outside the classroom shows that many of Johnston's students, like Jenny and Kathryn, are very serious about the environment.

Take for example a group of students, led by two seventh-graders, who are studying alternatives to Styrofoam in the school cafeteria as well as setting up school assemblies to tell students how to recycle. They also have spoken to city officials about setting up a recycling site on the school's back parking lot.

Or four other students, who after going on a class field trip to the National Zoo, now spend Saturday mornings there in front of the animals' compound informing zoo visitors about the pachyderm's danger of extinction.

Then there was the group who protested to the city council last year, seeking to ban tuna from Alexandria schools because dolphins are often killed in fishermen's nets. Two days after presenting a petition to the council, tuna was yanked from the menu.

And finally there is the boat: a 31-foot Bolger Gloucester schooner being built by Johnston's students in the school's annex building. When completed, the light two-sail craft will hold five to six people and will fold in half for easy transport. Most likely the class's largest undertaking, the boat is expected to be finished in April and will be used to study wildlife and pollution on the Potomac.

"The boat is important for several reasons," said Johnston, who came up with the idea last year. "One, the students will be able to use it to study first-hand the wetlands along the river and Chesapeake Bay, as well as the pollution. They will be able to test the water themselves and to catalog fish and birds.

"Two, if the kids build it, it gives them a vested interest in using it," she said.

Beginning in November, about 30 students have gotten together on most Saturday mornings to construct the wooden craft. Plans for the boat were donated by Leigh Ross, a local resident who also oversees the work. Although they still lack vital parts of the boat, such as the sails, the money raised so far for construction was donated. The boat is expected to cost about $2,000 to $3,000.

Seventh-grader Ruth Van de Water said, "The boat is just another thing we do in this class. We learn about the environment and have fun too."

Johnston said everything she teaches is to get students involved. "I want to teach them something that will last beyond the classroom," she said. "They are still idealistic at this age, and they want to do something for others in the world rather than just for themselves."