<![CDATA[Abstract Critical thinking skills are essential competencies in 21st-century learning, particularly in science education. However, preliminary observations indicate that students’ critical thinking skills are still low due to teacher-centered learning, resulting in suboptimal achievement of critical thinking indicators. This study aims to determine the effect of the Problem-Based Learning (PBL) model on students’ critical thinking skills in the topic of food chains. This research employed a quasi-experimental method with a nonequivalent pretest-posttest control group design. The sample consisted of 50 students, including 25 students in the experimental class and 25 students in the control class. The instrument used was an essay test based on Facione’s critical thinking indicators. Data were analyzed using paired sample t-test and independent sample t-test. The results showed that the average posttest score of the experimental class (67.80) was higher than the control class (39.70). The independent sample t-test showed a significance value of 0.000 < 0.05, and the effect size was 2.54 (very large category). It can be concluded that the Problem-Based Learning (PBL) model has a significant effect and is more effective than Inquiry-Based Learning (IBL) in improving students’ critical thinking skills. Keywords: Problem-Based Learning, Critical Thinking Skills, Science Learning, Elementary Education Abstrak Keterampilan berpikir kritis merupakan kompetensi abad ke-21 yang penting dikembangkan dalam pembelajaran IPAS. Namun, hasil observasi menunjukkan bahwa kemampuan siswa masih rendah karena pembelajaran cenderung berpusat pada guru sehingga capaian indikator keterampilan berpikir kritis belum optimal. Penelitian ini bertujuan untuk mengetahui pengaruh model Problem-Based Learning (PBL) terhadap keterampilan berpikir kritis siswa pada materi rantai makanan. Penelitian ini menggunakan metode kuasi eksperimen dengan desain nonequivalent pretest-posttest control group design. Sampel penelitian berjumlah 50 siswa yang terdiri atas 25 siswa kelas eksperimen dan 25 siswa kelas kontrol. Instrumen penelitian berupa tes uraian berbasis indikator keterampilan berpikir kritis. Teknik analisis data menggunakan uji paired sample t-test dan uji independent sample t-test. Hasil penelitian menunjukkan bahwa rata-rata nilai posttest kelas eksperimen sebesar 67,80 lebih tinggi dibandingkan kelas kontrol sebesar 39,70. Hasil uji independent sample t-test menunjukkan nilai signifikansi sebesar 0,000 < 0,05 serta diperoleh nilai effect size sebesar 2,54 dengan kategori sangat besar. Dengan demikian, dapat disimpulkan bahwa model Problem-Based Learning (PBL) berpengaruh signifikan dan lebih efektif dibandingkan model Inquiry-Based Learning (IBL) dalam meningkatkan keterampilan berpikir kritis siswa. Kata kunci: Problem-Based Learning, keterampilan berpikir kritis, IPAS, pendidikan dasar.]]>
