<![CDATA[Students' chemistry learning outcomes remain relatively low, especially in the colloidal system material, which is considered difficult to understand due to a lack of active student involvement in the learning process. The Problem-Based Learning (PBL) model is an innovative approach that can improve student learning outcomes by presenting real problems that encourage students to think critically, analytically, and actively in finding solutions. This study aims to examine the effect of the PBL model on student learning outcomes in the colloidal system material for class XI at SMA Negeri 1 Palu. The type of research used is a quasi-experiment with a Nonequivalent Control Group Design. The research sample consisted of two classes: class XI-3, the control class, and XI-4, the experimental class, each with 36 students. The research instrument was a multiple-choice learning-outcome test consisting of 15 questions, validated by an expert and found to have 82% validity. Pretest and posttest data were analyzed using the SPSS program version 26.0. The t-test results showed a p-value of 0.043 < 0.05, so H0 was rejected, and H1 was accepted. Thus, it can be concluded that the application of the Problem-Based Learning (PBL) model significantly improves student learning outcomes in colloidal systems. This study provides empirical evidence that the application of PBL can increase active involvement and student learning outcomes, and can serve as a reference for teachers in developing more contextual and student-centered chemistry learning strategies.]]>
