Strategi Lightening The Learning Climate Menggunakan Media Poster Untuk Meningkatkan Kemampuan Berpikir Kritis Siswa Di SMP Muhammadiyah 1 Kartasura 2020/2021

This study aims to describe the implementation, effectiveness, constraints and solutions of the Lightening The Learning Climate strategy using Media Posters to improve critical thinking skills in class VIII-B students of SMP Muhammadiyah 1 Kartasura in the 2020/2021 academic year. This study uses Mixing Methods or a combination of qualitative and quantitative methods with a Sequential Explanatory design. Data collection techniques using observation, questionnaires and interviews. The validity of the data in this study used triangulation of sources and techniques. Data analysis using flow model. Quantitative approach using Pre-experimental with One Group Pretest Posttest Design. The test instruments in this study are validity and reliability. The validity test uses the product moment formula and the reliability test uses the KR.20 formula. The requirements test in this study is normality using the Lilliefors formula and homogeneity using Bartlett. The results of this study are providing material through a whatsapp group, then giving group assignments that will be presented through google meet with the application of the Lightening The Learning Climate strategy using poster media. The effectiveness of students in implementing the strategy showed an average pretest score of 24.50 to 62.75 in the posttest, so it can be said to be quite effective. Based on the results of the analysis, tcount is greater than ttable 5,826 > 2,086. Constraints faced are the limited time and student situations that are difficult to direct. While the solution that can be done is to give warnings and direct students through the WhatsApp group before the activity is carried out. The hypothesis proposed in the form of Ho is rejected and Ha is accepted, meaning that there is a difference between before treatment (pretest) and after treatment (posttest). These differences indicate an increase in the average value of the pretest with the posttest. Thus, it can be concluded that the application of the Lightening The Learning Climate strategy using poster media can improve critical thinking skills in class VIII-B students at SMP Muhammadiyah 1 Kartasura