The aim of this study was to construct a laboratory activity about magnetic properties of matter based on Discovery Laboratory Approach (DLA) and to investigate its effectiveness based on student opinions and observations. The study was conducted with sixteen freshman students in primary science education department. The study was utilized the case study approach and document analysis methods, in this process observation and interview forms were used in order to collect data. The DLA activities were performed with "Experiment worksheets" consecutively previously, during and after the laboratory discussions took place. Also, students' behaviors were determined while conducting the worksheet. Finally interviews were conducted with the students about the effectiveness of the activity. It is concluded that the DLA approach is an effective way of teaching science concepts.