ABSTRACT
A teacher/mentor is sometimes an expert in the sense that they know the content domain in which they have to teach or mentor students, even though they may not be an expert at pedagogy. Nevertheless, as a content expert, s/he can teach in at least three different ways: (1) by modeling and demonstrating to a large number of students, in the context of a classroom, how a problem is solved or how a chemical reaction can be produced, without any verbal interactions with the students; (2) by explaining verbally some difficult concepts or how a problem is solved; and (3) by guiding and interacting with a specific student through extended dialogue to understand a concept or to solve a problem, with other students observing such interactions. In short, there are many ways that teachers/mentors can deliver instruction even though they may not be an expert at pedagogy. The question is, which method of instruction is best for students' learning?
