Evolving mental models of electric circuits

This is a case study of a 16 year old student, alias "Susan", discussing her thinking with a tutor during hands-on investigations of electric circuits. Susan had not studied any physics. To facilitate complex learning, her experiments were designed to foster model building in a series of small steps. Each step revised only one of Susan's alternative conceptions, so that most of her model was always available to support reasoning during an episode of conceptual change.