Effects of Problem-Based Learning on Critical Thinking Ability and Science Learning Achievement of Grade 4 Students

Abstract

This research aimed to compare Grade 4 students’ 1) critical thinking ability before and after learning, 2) critical thinking ability after learning against the 70 percent criterion, 3) learning achievement before and after learning, and 4) learning achievement after learning against the 70 percent criterion, following problem-based learning instruction. This pre-experimental research employed a one-group pretest–posttest design. The sample consisted of 10 Grade 4 students at Wat Nong Khu Noi School in the second semester of the 2025 academic year, selected through cluster random sampling with the school as the sampling unit. The data collection instruments comprised (1) problem-based learning lesson plans, (2) a critical thinking ability test, and (3) a learning achievement test. Data were analyzed using mean, standard deviation, dependent-samples t-test, and one-sample t-test. The results revealed the following: 1) the students’ critical thinking ability after learning was significantly higher than before learning at the .05 level; 2) the students’ critical thinking ability after learning was significantly higher than the 70 percent criterion at the .05 level; 3) the students’ learning achievement after learning was significantly higher than before learning at the .05 level; and 4) the students’ learning achievement after learning was significantly higher than the 70 percent criterion at the .05 level. These findings can serve as guidelines for developing and improving problem-based learning instruction to effectively promote students’ critical thinking ability and enhance their learning achievement.