Fourth, while they recognize the central role of involving students in the culture of scientific practice to build scientific knowledge, they do not fully articulate how students’ participation in science practices can be integrated with learning about science concepts. Finally, although many standards documents include at least the first three of the four strands of scientific proficiency that we use to organize this report, these strands are generally described separately, so the crucial issue of how advances in one strand are linked to and support children’s learning in the other strands is not addressed.
As currently described and enacted in U.S. K-8 science classrooms, curriculum—the sequence and series of tasks and assignments posed to students—rarely builds cumulatively and in developmentally informed ways, from students’ early knowledge and resources toward scientifically accepted theories and concepts. Although there are some curricular materials that pursue this approach, they tend to cover a limited slice of content and are often restricted in duration to periods spanning a few to several weeks of instruction. It is highly unlikely that brief periods of uncoordinated instruction are going to achieve the goal of helping students generate a scientifically informed epistemology, a deep and well-structured knowledge base, and a firm understanding of the purposes and methods of science.
Analyses of science curricula in the United States indicate that they are generally poorly designed for the purpose of effective knowledge building. Evaluations recently conducted under the leadership of the American Association for the Advancement of Science (AAAS) Project 2061 staff suggest that the major commercial textbook series, which do at least take a multiyear perspective to sequencing instruction, have major flaws of various kinds, including content, motivation, and attention to student prior conceptions (Kesidou and Roseman, 2002). The AAAS analysis indicates that curriculum is rarely framed around the big ideas. Indeed, the big ideas are largely lost in the curriculum. Roseman, Kesidou, Stern, and Caldwell (1999), authors of the AAAS report, concluded (p. 2):
[T]he textbooks covered too many topics and didn’t develop any of them well. In addition, the texts included many classroom activities that either were irrelevant to learning key science ideas or didn’t help students relate what they were doing to the underlying ideas.
Valverde and Schmidt’s (1997) comparison of U.S. science curriculum with the 10 countries performing best on the tests of science achievement in the Trends in International Mathematics and Science Study provide further support for the AAAS conclusions, as well as the results of these curricular