It is a natural context for a number of learning interactions. As part of our support for this form of service learning, we developed a tutoring handbook. Students learn by teaching. Teach it to a tenth grader. Some aspect or other of any college course could be relevant and interesting to younger students.
Students learn while teaching.
Through reflection, a student tutor can observe many aspects of the process and context of learning and problem solving. Just about every facet of human life plays out vividly in any school classroom, making it a good field to develop student powers of observation and interpretation in several disciplines. The ongoing relationship between tutor and tutee also gives students a perspective on a child's view of the larger world. A few eliciting questions can go a long way. Finally, a quick form for assessing the tutoring experience.