106 JIPF (JURNAL ILMU PENDIDIKAN FISIKA) p-ISSN: 2477-5959 | e-ISSN: 2477-8451 Vol. 6 No. 2, May 2021, Page 106-114 This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. Improving Students’ Critical Thinking Skills Trough Contextual Teaching and Learning Science Module Siti Nur Hasanah 1 , Widha Sunarno 2 , Baskoro Adi Prayitno 3 Universitas Sebelas Maret, Indonesia 1,2,3 snhasanah@student.uns.ac.id 1 , widhasunarno@gmail.com 2 , baskoro_ap@uns.ac.id 3 Received: June 30 th , 2020. Revised: October 22 nd , 2020. Accepted: October 27 th , 2020 Keywords : Critical Thinking Skills; Contextual Teaching and Learning; Science Module ABSTRACT This study aims to determine the effectiveness of the science module based on the contextual learning approach (CTL) in improving the critical thinking skills of junior high school students. The research method used was a quasi- experimental study involving 30 students in the experimental class and 30 students in the control class from a junior high school in Surakarta. The data collection technique was done by measuring students' critical thinking skills before (pretest) and after learning using the Science module (posttest). The instrument used was a critical thinking skill test based on Facione's critical thinking skills indicator. The improvement of students 'critical thinking skills was analyzed using a pretest-posttest gain score and followed by an independent sample t-test to determine the significance of the difference in the average increase in students' critical thinking skills. The results showed that the use of a science module based on a contextual learning approach could improve students' critical thinking skills, with a score of 0.46, or in the category of moderate improvement compared to control class students, with a score of 0.29, or in the low improvement category. Meanwhile, based on the results of the t-test the average gain score of the two classes shows a significant difference in the improvement of critical thinking skills between students who are taught using the Science module and students who are taught using conventional modules. INTRODUCTION Critical thinking skills are one of the skills needed to face globalization and internationalization in the 21st century [1]. Critical thinking skills are also considered as one of the foundations of learning in the 21st century [2]. Critical thinking skills are needed to analyze things that are needed in the decision- making process or determine better actions and careful consideration. Facione defined several skills, including critical thinking skills: interpretation, analysis, inference, evaluation, explanation, and self- regulation skills [3]. In an academic context, students need critical thinking skills to explore deeper knowledge and find the relationship between the theory studied and the arguments students have [4]. It