<![CDATA[Students’ low achievement and persistent misconceptions in physics, particularly on capillary rise phenomena, suggest that conventional instruction is often insufficient for developing scientifically accurate mental models. Understanding capillary rise requires students to connect microscopic interactions, such as adhesive and cohesive forces, with observable macroscopic phenomena. Although this concept is important in physics and closely related to everyday experiences, research investigating students’ mental models of capillary rise remains limited, especially within Problem-Based Learning (PBL) contexts. Previous studies have focused mainly on conceptual understanding and learning outcomes rather than on the development of topic-specific mental models. This study aimed to examine the effect of PBL on students’ mental models of capillary rise concepts. A quasi-experimental method with a pretest–posttest non-equivalent control group design was employed. Participants were 78 eleventh-grade science students from two public senior high schools in Central Maluku, Indonesia, divided equally into an experimental group and a control group. Data were collected through mental model tests, interviews, and classroom observations. Quantitative data were analyzed using Analysis of Covariance (ANCOVA). The results showed a significant effect of the instructional model on students’ mental models (F = 8.793; p = 0.004; Partial η² = 0.116). Students who learned through PBL demonstrated greater improvement in constructing scientifically appropriate mental representations than those who received conventional instruction. These findings indicate that PBL promotes active engagement in problem-solving and collaborative inquiry, enabling students to build and refine conceptual understanding. This study contributes to physics education research by providing empirical evidence that problem-based learning supports the development of meaningful mental models in conceptually complex physics topics such as capillary rise.]]>
