<![CDATA[Critical thinking remains a major challenge in elementary science education, as many students experience difficulty identifying problems, selecting relevant information, justifying their reasoning, and drawing logical conclusions. This study aimed to examine differences in critical thinking skills between students taught through the Problem-Solving learning model assisted by Questions Box Challenge media and those receiving conventional instruction, as well as to determine the model’s effect on critical thinking skills. A quantitative quasi-experimental approach with a nonequivalent control group design was employed. The participants comprised 50 fifth-grade students at SD Negeri Harjosari 01, with 25 students in Class V-A assigned to the experimental group and 25 students in Class V-B assigned to the control group. The study was conducted from May to July 2026 over three learning sessions on the human respiratory system. Data were collected through essay-based pretests and posttests, questionnaires, observations, interviews, and documentation. The test instrument consisted of 15 items developed according to Ennis’ critical thinking indicators. Data were analyzed using normality and homogeneity tests, an independent-samples t test, and simple linear regression. The experimental group achieved a higher mean posttest score than the control group (75.60 vs. 63.00), and the independent-samples t test indicated a statistically significant difference between the groups (p < .001). Regression analysis further demonstrated a significant effect (tcount = 8.059 > ttable = 2.011, p < .001), with the learning model explaining 57.5% of the variance in students’ critical thinking skills. These findings demonstrate that integrating problem-solving stages with question-based media can effectively strengthen students’ abilities to interpret problems, analyze relevant information, justify responses, and formulate logical conclusions. The study contributes empirical evidence supporting interactive problem-solving instruction as a practical strategy for improving critical thinking in elementary science classrooms.]]>
