Freshman Evie Fachon’s lesson plans for teaching biology to children at Roxbury’s Yawkey Boys and Girls Club included arts, crafts and games. The teaching methods differed from those used by professors in her classes at Northeastern, but the science was surprisingly similar.

“In class we learned about a lot of really advanced topics that were accessible to us because we’re biology students and we’ve been studying this for years,” said Fachon, who discussed her teaching strategy after she presented her work during Thursday’s Service-Learning Expo in the Curry Ballroom. “So the real challenge was taking that information and not dumbing it down, but finding a way to make it accessible to a different audience.”

Teaching difficult concepts in an understandable way is an important tenet of a service-learning course, said Gail Begley, director of the University Pre-Health Program and the instructor of Fachon’s service-learning course, “Inquiries in Cellular and Molecular Biology.”

“It’s easy to talk about science when you’re using jargon and these big complicated ideas,” Begley said. “But if you can explain it to someone without using all that, then you really know the material.”

Thursday’s event in the ballroom was the Center of Community Service’s first  showcase of service learning. In previous years, Northeastern had hosted an end-of-semester breakfast that featured student, faculty and community speakers.

Service learning at Northeastern is a form of experiential learning that links academic courses to community-based organizations. Students engage in hands-on service roles and projects, applying concepts they learn in the classroom to address community needs.

“What we wanted to do this year was give more students and faculty members the chance to show off their work and their research,” said Kristen Doggett, director of the Center of Community Service. “At an event like this, you’re really able to see just how many ways our service-learning classes are interacting with the community, whether they’re working with students in the classroom or after school or working with our partners to develop new programs or initiatives.”

Over the course of the fall semester, more than 500 graduate and undergraduate students completed nearly 20,000 hours of community service. Many of the service-learning course’s 33 teaching assistants were recruited after excelling in a prior service-learning course.

CJ Schmidt, for example, a sophomore mechanical engineering major, took a service-learning class last year and returned this fall as an assistant. He helped engineering students teach engineering design principles to seventh and eighth graders at Orchard Garden Middle School in Boston’s Roxbury neighborhood.

“I think the saying that in order to learn something really well you have to teach it is a completely accurate phrase,” Schmidt said. “You learn about engineering design in class, but until you are familiar enough with the concepts that you can teach them yourself — and make it fun for middle school students — you don’t fully know it.”

Susan Freeman, the associate academic specialist who teaches the engineering course, noted that service learning enhances students’ knowledge about a subject and introduces them to new neighborhoods and experiences.

“The schools and community centers these students volunteer with may not be far away — just a short ride on a city bus — but they’re in areas that Northeastern students may never have otherwise gone,” Freeman said. “And when the course is over, so many of my students are eager to go back, joining us even when they don’t need to be there for class or credit. They’re passionate about the community and they’re passionate about these topics.”