Ever since our nation first embraced the goal of mass schooling, it has faced the challenge of balancing the concern for educational quality with the desire to reach as many students as possible. Today, this dilemma is reflected in the dual aims of promoting high academic achievement while simultaneously pursuing educational equity for an increasingly diverse student population (Darling-Hammond, 1996; McLaughlin, Shepard, & O'Day, 1995). To achieve these aims, it is necessary to develop a knowledge base that situates recent advances in our understanding of educational processes within the realities of today's schools. This need is especially urgent, given the current climate of standards-based instruction, high-stakes assessment, and accountability. The literature review presented in this synthesis is a step in developing such an empirically based integration.

Knowledge about science and technology is increasingly important in today's world. Aside from the growing number of professions that require a working familiarity with scientific concepts and high-tech tools, the future of our society hangs in the balance of decisions that must be made on the basis of scientific knowledge. Documents on science education standards (American Association for the Advancement of Science [AAAS], 1989, 1993; National Research Council [NRC], 1996, 2000) represent the science education community's best efforts to define what constitutes science learning and achievement (see the summary in Lee & Paik, 2000; Raizen, 1998).