The learning process only focuses on the material by memorizing concepts, students do not use LKPD to do practical work optimally, so the biology learning process in schools does not encourage students to practice critical thinking skills. This study aims to improve students' critical thinking skills by using the PBL learning model combined with STEM-based worksheets on environmental pollution conceptin class 10th SMA Negeri Bireuen district. The approach used is experimental design, the method used is quasi-experimental, with a pretest-posttest design non-equivalent control group design. Population in class 10th IPA SMAN 1 and SMAN 2 Peusangan designed 252 people. The sampling technique used was purposive sampling technique. The research sample was 140 students. The number of samples in the experimental class was 71 people and 69 people in the control class. The instrument used was a reasoned multiple choice question accompanied by a rubric. The data analysis used was n-gain and independent t-test. The results showed that the critical thinking skills obtained was 0.93, with an increase in class critical thinking skills including the high category. The results of the independent sample t-test obtained Sig. (0,000) α (0.05) then Ha is accepted, so it is suggested that there are differences in the critical thinking skills of students between the experimental class and the control class on environmental pollution material in class X SMAN Bireuen. The implementation of PBL learning model combined with STEM-based LKPD can improve students' critical thinking skills on environmental pollution material in class 10th SMA Negeri Bireuen Regency.

The learning process only focuses on the material by memorizing concepts, students have not utilized worksheets to do practical work optimally, so the biology learning process in schools does not encourage students to practice critical thinking skills. This study aimed to determine the effect of implementing STEM-based student worksheets in improving students' critical thinking skills at SMP Negeri 1 Peusangan, Bireuen Regency. This study used a pretest-posttest control group design. The study population was 88 VIII grade students of SMP Negeri 1 Peusangan. The research sample consisted of 67 students. The sample is determined through the purposive sampling technique. The researcher determines the class of the research sample using purposive sampling. The taking of the experimental class and the control class is determined by looking at the standard deviation of the results of the homogeneous pretest of students (the ability of homogeneous students). Critical thinking skills are measured by multiple-choice questions with reason. It is used to determine the increase and difference in the critical thinking skills of students. Analysis of N-Gain test data, paired sample t-test, and independent sample t-test. The results showed that the implementation of STEM-based LKPD could improve students' critical thinking skills on excretory system material in class VIII of SMP Negeri 1 Peusangan. In addition, there are differences in the KBK of students between the experimental class and the control class on the excretory system concept in class VIII of SMP Negeri 1 Peusangan.

Implementation of learning in class 11th MAN 1 and MAN 2 Banda Aceh City Students only get information without going through discussion activities, students who are not brave enough to express ideas or ideas, so that students are not trained in using their critical thinking skills. This study aims to determine the improvement of students' critical thinking skills through the application of the STEM-based discovery learning model to the motion system concept. The research approach used is quantitative with the type of pre-experimental research. The research design used is the one-group pretest-postest design. The population was all of 11th grade students, amounting to 292 people. The sampling technique used was a total sampling. The sample in this study consisted of 292 students. The instruments in this research were pretest and posttest multiple choice questions with reasoned. Data analysis consisted of normality test, paired sample t-test at a significant level of 0.05 and n-gain. The results of the paired sample t-test obtained tcount 48 and value (ρ.001), so it was concluded that there were differences in critical thinking skills and learning outcomes of students before and after learning with the application of the STEM-based discovery learning model to the motion system concept. The results of the n-gain test using the Meltzer formula showed that the gain in critical thinking skills was 0.85, so there was an increase in critical thinking skills with a high category.

Critical thinking skills are competencies that are expected to be possessed by every student in 21st century learning. One of the efforts that can be made to improve students' critical thinking skills is to apply the flipped classroom learning model. This study aims to determine the effect of students' critical thinking skills through the application of the blended learning model of the flipped classroom. The research approach used is quantitative with a quasi-experimental type of research, the research design used is pretest-posttest non-equivalent control group design. Sampling used a total sampling technique from the entire population of 102 students of class XI IPA at SMAN 1 Peulimbang. The instrument used to measure critical thinking skills is in the form of essay questions accompanied by an assessment rubric. Data on critical thinking skills were analyzed by parametric statistics using the independent sample t test. The results showed that the value of < 0.05, then there was an effect of students' critical thinking skills after the application of the blended learning model of the flipped classroom on the respiratory system material

The learning process has not emphasized the development of skills; this is because in learning students tend to memorize concepts so that learning outcomes and self-efficacy are not trained optimally. The formulation of the problem in this study is: is there a difference in learning outcomes and student self-efficacy between the use of the Problem Base Learning model combined with the E-STEM-based Student Worksheet with the Problem Base Learning model on environmental pollution material at MAN Banda Aceh? This research is quantitative with an experimental research approach. The research design used was pretest-posttest control group design. The population of this study was all students of class X MAN 3 Banda Aceh, totaling 84. The sampling technique used a total sampling of 84 students. The instrument used to measure learning outcomes is multiple choice questions using 30 questions and self-efficacy is measured using a questionnaire. Data analysis of learning outcomes and self-efficacy of students using independent sample t-test at a significant level of 0.05. The results showed that there were differences in student learning outcomes and self-efficacy after applying the Problem Base Learning model combined with the E-STEM-based Student Worksheet on environmental pollution materials at MAN Banda Aceh