If students collect trash out of an urban streambed, they are providing a valued service to the community as volunteers. If students collect trash from an urban streambed, analyze their findings to determine the possible sources of pollution, and share the results with residents of the neighborhood, they are engaging in service-learning.
In the service-learning example, in addition to providing an important service to the community, students are learning about water quality and laboratory analysis, developing an understanding of pollution issues, and practicing communications skills. They may also reflect on their personal and career interests in science, the environment, public policy or other related areas. Both the students and the community have been involved in a transformative experience.
Other examples could be to perform an environmental study for a local government or community organization; conduct a conservation project in a recreation area or park; tutor secondary students in biology; serve as a judge for a science fair; present an interactive seminar for an elementary or secondary school science class or club; organize a neighborhood beautification project or work at the SD City College Garden ( Seeds @ City Urban Farm).