In an attempt to address the gaps in science outcomes (broadly defined), this synthesis highlights factors related to students' race/ethnicity, culture, language, and social class. Some studies examine relationships between these factors and student outcomes; particularly, experimental studies offer causal explanations of the impact of treatments or interventions on science outcomes. Others explicate underlying processes involving student diversity in science teaching and learning. In this section, we present the results of research focusing on classroom practices: (a) student characteristics and science learning, (b) science curriculum (including computer technology), (c) science instruction, and (d) science assessment. Studies addressing bilingual or ELL students are discussed within each section. Some studies addressed multiple topics and thus are included in more than one area. In describing specific studies, we address research questions, theoretical perspective or conceptual framework, methods (e.g., research setting, participants, data collection and analysis), results, and conclusions.