BELFAST, Maine — When most people pass a playground, all they see in the whirl of activity there is children having a great time.

But a group of science-loving teenagers who just finished eighth grade at the Troy Howard Middle School in Belfast sees something else in all that playful action: kinetic energy that can be transformed into electricity. And they made it happen by building a model of a merry-go-round that produces electricity with the help of a converter.

“Our goal was to make clean, renewable energy,” Sydni Moores of Belfast said. “And kinetic energy seemed like it would be easier to harness.”

She and classmates Joshua Chun of Belfast, Vincent Bonarrigo of Belmont and Grace Fitzjurls of Belfast have been working together for the past six months or so to develop a way to make that happen, and their hard work has paid off. The eighth-graders, who formed team “Power Play” to compete in the national eCYBERMISSION program, won top honors in Maine and also were awarded a $5,000 STEM in Action grant to turn their idea into reality — one of just five teams in the country to be so honored.

The eCYBERMISSION program is a web-based science, technology, engineering and math competition for middle school students that is sponsored by the U.S. Army. The Maine contingent traveled to Washington, D.C., on Monday, June 20, for an all-expense-paid trip to an affiliated educational event that was put on by the National Science Teachers Association. While there, they are competing with teams from around the country to win the 2016 People’s Choice Award.

“It is a great project,” Beth Haynes, a retired science and math teacher from the middle school who advised the team, said. “A number of these STEM in Action grants have actually been patented. I think it’s a wonderful competition.”

In order to participate, the Belfast-area teens first had to choose a real problem in their community they wanted to help solve. They settled on the need for clean energy, which is important locally and globally.

“There’s the energy crisis the earth is going through right now,” Chun said.

They researched energy and brainstormed ideas. At first, they envisioned making a whole playground that would generate electricity by using swings, slides, teeter-totters and a merry-go-round.

“There’s so much kinetic energy in a playground,” Chun said.

But as they kept at the project, they decided to start with just one element — the merry-go-round. As they helped to flesh out their idea and build the model, they realized that each team member brought something unique to the table.

“We found there are different things we’re good at,” Fitzjurls said.

They also learned that it’s important not to be discouraged by setbacks.

“Always stick with things,” Chun said. “If you do, you might go far.”

In addition to going to the nation’s capital to meet with other young scientists and elected leaders, the teens hope that one day soon they will be able to see their idea in action.

“We want to build these and put them all over the place,” Bonarrigo said.