Enhancing Critical Thinking and Scientific Attitudes through PBL in Excretory System for XI Grade Students

This study aims to determine the improvement in critical thinking skills, the enhancement of scientific attitudes, and the relationship between critical thinking skills and scientific attitudes of students through the implementation of the Problem-Based Learning (PBL) model in the excretory system material for Grade XI students at SMA Negeri 1 Tanah Luas, North Aceh. This research is a Classroom Action Research (CAR) conducted in two cycles during the second semester of the 2024/2025 academic year, with 24 student participants. Data collection techniques included critical thinking skills tests, scientific attitude questionnaires, and observations, while data analysis was conducted using descriptive quantitative and inferential methods with the aid of SPSS software. The results show that students' critical thinking skills improved from an average of 63.45 in Cycle I to 80.88 in Cycle II, with an N-gain value of 0.43 (moderate category), and the classical completeness increased from 50.00% to 83.33%. Scientific attitudes also improved across all indicators: objectivity increased from 53.23% to 81.04%, critical thinking from 51.15% to 82.60%, openness from 58.02% to 77.92%, perseverance from 62.29% to 76.35%, and curiosity from 61.04% to 83.02%. The correlation test results show a significant relationship between critical thinking skills and scientific attitudes, with an r value of 0.685 (p < 0.05) in Cycle I and r = 0.412 (p < 0.05) in Cycle II. Based on these results, it can be concluded that the implementation of the PBL model is effective in improving students' critical thinking skills and scientific attitudes, as well as strengthening the relationship between the two.