The Effect of the Problem-Based Learning Model on Biology Learning Outcomes in the 8th Grade Science Class at SMP Negeri 19 Palu

Research background: The low student achievement in biology at SMP Negeri 19 Palu specifically regarding the human respiratory system is attributed to the conventional teaching methods still employed by teachers. Purpose and scope of the article: This study examines the effect of the Problem-Based Learning (PBL) model on students’ learning outcomes in biology, specifically regarding the human respiratory system. Method: This study used a quasi-experimental design with a quantitative approach. The research design employed was a nonequivalent control group design using two groups: an experimental group (Class VIII D) consisting of 25 students who received the PBL model, and a control group (Class VIII C) consisting of 25 students who received conventional instruction, with pretests and posttests administered to both groups. Result: The experimental class achieved an average posttest score of 80.36, which was higher than that of the control class, which scored 73.04. The N-Gain score for the experimental class was 0.56 and for the control class was 0.52; both fall into the moderate category, but the experimental class showed a higher increase. It has been empirically proven that the Problem-Based Learning (PBL) model has a significant effect on learning outcomes, as evidenced by the posttests of both classes, the N-Gain scores, and student and teacher activities. Conclusion: The PBL model can improve learning outcomes more significantly than the conventional model; therefore, it is highly recommended for application to other biology science materials at the junior high school level.