We investigated how different levels of information presented by various technologies affected secondary students' understanding of acid, base, and pH concepts. Secondary students who were selected for the study had just completed their study of acid–base chemistry. No attempt was made to provide further instruction. We analyzed changes in the understanding of individual students by constructing concept maps from the propositions that the students used in interviews conducted before and after a series of acid–base titrations. After the initial interview, students were divided into three groups. Within each group, students individually performed the same set of titrations using different technologies: chemical indicators, pH meters, and microcomputer-based laboratories (MBL). After the titrations were completed, all students were interviewed again. We found that students using MBL exhibited a larger positive shift in their concept map scores, which indicates a greater differentiation and integration of their knowledge of acids and bases. The chemical indicator students exhibited a more moderate positive shift in their concept map scores, and the pH meter students exhibited a smaller positive shift. We also found that the MBL students constructed more inappropriate links in their concept maps than the chemical indicator or pH meter students. However, we speculate that this increased number of inappropriate links indicates a high level of involvement with the technology. We therefore argue that the level of information offered by the technology affected students' understanding of the chemical concepts.