The articles in this issue all focus, in one way on another, on how learners reason about scientific problems. The learners vary in age and ability, from elementary school children to college students. There are also many differences among the problems that the learners address in these studies. Despite these differences, the studies in this issue are connected by a number of common themes that illustrate the state of research about scientific reasoning today. Four of those common themes are discussed below.
Reasoning as Sense-Making in Complex Domains
All of these studies engaged students in reasoning about complex, scientifically significant problems. They all portray scientific reasoning as a sense-making activity that requires conceptual understanding as well as algorithmic competence. The articles by Frederickson, White, and Gutwill, and by Lin and Lehman are particularly interesting in this respect. We have traditionally taught students to solve the problems they address (quantitative current flow problems and designing controlled experiments) by following clearly specified rules. Yet, the most successful treatments focused on reasons rather than rules. Students were able to solve the problems better when they thought about why they set up a particular experiment or why current and voltage reached a particular steady state in a circuit.