The purpose of this study was to investigate how two female students participated in science practices as they worked in a multimedia case-based environment: interpreting simulated results, reading and writing multiple texts, role-playing, and Internet conferencing. Using discourse analysis, the following data were analyzed: students' published web posters, Internet conferencing logs between American and Zimbabwean university students, and a focus group interview. Three constructs supported the development of these students' identities in practice: (a) multimedia cases creating emotional involvement; (b) authoring web posters, and role-playing situated in cross-cultural social networks; and (c) altruism associated with relevant global topics. The investigators argue that educators and developers of online learning environments consider social contexts, authoring, and opportunities for cross-cultural interaction to support participation in science practices. (Contains 9 figures, 4 tables, and 1 note.)