be brought to bear on novel problems. Modeling approaches have the advantage of avoiding the content-process debates that have plagued science education over the years. One cannot model without modeling something, so when students are engaged in modeling, reasoning processes and scientific concepts are always deployed together.

Most existing research on modeling has been conducted with units or courses that do not span more than one school grade. (For example, Stewart and colleagues have developed high school courses in evolutionary biology and genetics; Reiser et al., 2001; White and Frederikson, 1998; Raghavan et al., 1995; and Wiser, 1995 have developed units for middle school grade students.) On a longer time scale, Lehrer and Schauble (2000) have initiated and studied a school-based program in which science teaching and learning is organized over grades 1-6 around modeling approaches to science (see Box 4.8). Data from this project include paper-and-pencil “booklet” items administered to intact classes of students, yearly three-hour detailed student interviews, and “modeling tasks” completed by small groups of students. Producing these items was itself a challenging task, since students were learning forms of mathematics not routinely taught in elementary grades. The items that were developed were based on evolving data about children’s understanding of ideas in geometry, measurement, data, and statistics. The student achievement data showed strong student gains; for example, from the first to the second year of the project, effect sizes by grade were 0.56 (Grade 1), 0.94 (Grade 2), 0.43 (Grade 3), 0.54 (Grade 4), and 0.72 (Grade 5).

Argumentation Bazerman (1988), Lemke (1990), Kuhn (1989), and others have pointed out that science entails mastering and participating in a particular form of argument, including relationships between theories, facts, assertions, and evidence. This characterization of science explicitly acknowledges that science is not just the mastery of knowledge, skills, and reasoning but also participation in a social process that includes values, history, and personal goals. This view of science informs the ongoing work of Warren and Rosebery (1996), for example, who focus on classroom discourse organized around argumentation in science (see Box 4.9). Once again, researchers are supplementing their reports of teachers’ professional development with careful measures of student learning. These measures are