Students' understanding of the objectives and procedures of experimentation in the science classroom

As part of a project to identify opportunities for reasoning that occur in good but typical science classrooms, this study focuses on how sixth graders reason about the goals and strategies of experimentation and laboratory activities in school. Collaborating with teachers, we explore whether reasoning can be deepened by developing instruction that capitalizes more effectively on the classroom opportunities that arise for fostering complex thinking and understanding. The design of the study includes (a) a baseline interview probing students' understanding of experimentation in the context of a standard, 40-min ''hands-on'' activity that is part of the standard sixth-grade curriculum; (b) a 3-week teaching study, in which five teachers, informed by the cognitive science research concerning the development of scientific reasoning, designed and taught a special experimentation unit in their classrooms; and (c) a series of follow-up interviews, in which students' understanding of experimentation was reexamined. The findings from the two learning contexts-one more supportive of student reasoning than the other-inform us about the kinds of reasoning that are developing in middle-school students and the forms of instruction best suited to exercising those developing skills.