THE EFFECTIVENESS OF PROBLEM-BASED LEARNING ON DEVELOPING STUDENTS' CRITICAL THINKING ABILITY

Critical thinking is one of the most important 21st century skills that students must have. One of the instructional methods considered to be capable of fostering students' critical thinking development is Problem-Based Learning. This study was designed to investigate the effectiveness of problem-based learning on developing students' critical thinking ability in Physics. The participants of this pre-experimental study with one-group pretest-posttest design were 35 tenth-grade students at a senior high school in South Sulawesi Province, Indonesia. In this study, problem-based learning was implemented in Physics class on Heat lessons for four weeks. The syntax of the learning process included: 1) orienting students to problem; 2) organizing students to study; 3) assisting students to conduct independent or group investigations; 4) developing and presenting the work; and 5) analyzing and evaluating students' problem-solving process. Test of critical thinking ability was administered in pre-test and post-test. The categories of critical thinking assessed were students' ability to: 1) identify or formulate questions; 2) analyze arguments; 3) ask and answer questions for explanation or clarification; 4) induce and judge inductions; and 5) make and judge value judgements. Apart from the test, a Likert-Scale questionnaire was also used to find out the participants' motivation in learning Physics. The finding of this study showed that problem-based learning was effective on developing students' critical thinking ability. This could be seen from the results of N-Gain analysis of students' pre-test and post-test scores where the obtained scores falled into middle category. The study also revealed that students' motivation in learning Physics was classified into high category. The findings prove that problem-based learning can be used as one of learning methods to develop students' critical thinking ability in Physics.