The aim of this study was to investigate the effects of activities developed based on a four-step constructivist approach on students' understanding and explaining real-life problems about reaction rate concepts in chemistry. The study was carried out with 41 eleventh grade students, from two different classes attending a secondary school in Turkey. Two classes were randomly designated as experimental and control groups. While teaching the subject, a four-step constructivist approach was used for the experimental group whereas in control group, students were taught by the traditional method. Teaching activities in both groups were observed by one of the researchers. In both groups, Real-life Relating Test (RRT), including the phenomena that students observe in their daily life about reaction rate concepts was implemented before and after the intervention. Also semi-structured interviews were conducted with 13 students chosen from the both groups. At the end of the study, it was determined that the intervention which was carried out based on a four-step constructivist approach helped more the students in explaining real-life problems in a scientific way and provide more lasting learning than traditional approach. It is suggested that such activities should be used in other abstract or problematic concepts in chemistry.