Chemical kinetics is an extremely important concept for introductory chemistry courses. The literature suggests that instruction in chemical kinetics is often teacher-dominated at both the secondary school and tertiary levels, and this is the case in Thailand--the educational context for this inquiry. The work reported here seeks to shift students from passive learning to more active, student-centred learning and involved some 413 first year undergraduate science students in Thailand. Drawing on inquiry-based learning, the participants were asked to design an experiment investigating the reaction of acids and bases. The research findings suggest that participants were able to explain the changes of the rate of a chemical reaction, and developed good conceptual understanding of chemical kinetics both qualitatively and quantitatively. It also showed this more active teaching approach, which is radically different from normal teaching in Thailand, was an enjoyable experience for the students. (Contains 3 tables and 5 figures.)