This paper describes the findings of an exploratory cycle of a design-based research project and examines the learning effectiveness of collaborative activities that are supported by the GroupScribbles (GS) software technology in two Singapore primary science classrooms. The students had ten weeks of GS-based lessons in science, which were co-designed by teachers and researchers to teach the curriculum by tapping on collaborative work in small groups as well as in the whole class. The results show that the GS classes performed better than non-GS classes as measured by traditional assessments. With GS, students were found to have more opportunities to participate in class discussions, and were exposed to diversified ideas. Analysis of data collected in the classroom as well as data on students' attitudes and perceptions indicate that GS facilitated students' collaborative learning, and improved students' epistemology and attitudes toward science learning. (Contains 6 tables and 5 figures.)