The problem addressed in the study was whether 10- and 11-year-old children, collaborating within a computer-supported classroom, could engage in progressive inquiry that exhibits an essential principal feature of mature scientific inquiry: namely, engagement in increasingly deep levels of explanation. Technical infrastructure for the study was provided by the Computer-Supported Intentional Learning Environment (CSILE). The study was carried out by qualitatively analyzing written notes logged by 28 Grade 5/6 students to CSILE's database. Results of the study indicated that with teacher guidance, students were able to produce meaningful intuitive explanations about biological phenomena, guide this process by pursuing their own research questions, and engage in constructive peer interaction that helped them go beyond their intuitive explanations and toward theoretical scientific explanations. Expert evaluations by three widely recognized philosophers of science confirmed the progressive nature of students' inquiry. © 2003 Wiley Periodicals, Inc. J Res Sci Teach 40: 1072–1088, 2003