PENINGKATAN KEMAMPUAN BERPIKIR KRITIS DAN PENALARAN SISWA SMP MELALUI MODEL PEMBELAJARAN PROBLEM BASED LEARNING (PBL) PADA KONSEP PEMANASAN GLOBAL

Penelitian ini bertujuan untuk menghasilkan informasi mengenai bagaimana peningkatan kemampuan berpikir kritis dan penalaran siswa, serta bagaimana tanggapan siswa terhadap pembelajaran konsep pemanasan global melalui model pembelajaranProblem Based Learning (PBL). Sampel penelitian adalah siswa Sekolah Menengah Pertama (SMP) kelas IX (Sembilan) sebanyak 220 siswa. Metodepenelitian yang digunakan yaitu quasi eksperimen dengan desain penelitian pre test – post test control group design. Instrumen penelitian yang digunakan berupa tesuraian dan kuesioner. Data penelitianberupanilaipre test, post testdanN-gain, data tersebutdianalisissecarastatistikmenggunakanuji Mann-Whitney.Data tanggapansiswadianalisissecaradeskriptif.Hasilpenelitianmenunjukkan model pembelajaranProblem Based Learning (PBL)dapatmeningkatkankemampuanberpikirkritisdanpenalaransiswa.Peningkatankemampuanberpikirkritisdanpenalaransiswa yang mengalamipembelajaranmenggunakan model Problem Based Learning (PBL)lebihtinggidanberbedasignifikandengansiswa yang mengalamipembelajarantidakmenggunakan model Problem Based Learning (PBL). Data hasilkuesionermenunjukkan 78,4 % siswamenyatakan persetujuannya bahwa model pembelajaran Problem Based Learning (PBL) dapat meningkatkan kemampuan berpikir kritis, 77,9% siswa menyatakan persetujuannyabahwa model pembelajaranProblem Based Learning (PBL) dapat meningkatkan kemampuan penalaran siswa, dan 79,9% siswa menyatakan persetujuan nya bahwa model pembelajaran Problem Based Learning (PBL)dapat diterapkan untuk pembelajaran konsep pemanasan global. ;--- The aim of this research is to analyze how is improvement of students’ critical thingking and reasoning skill, also their responses towards instruction of global warming concept through Problem Based Learning (PBL) model. Sample of this research consist of 9th grade of junior secondary school students as much as 220 students. Method that was used in this research is quasi experiment with pre test – post test control group design. Research data that were collected consist of pre test, post testscore and N-gain score, data were analyzed statistically through Mann-Whitney test. Students’ response data were analyzed descriptively. The result shows that Problem Based Learning (PBL) improved students’ critical thinking and reasoning skill. The improvement of students’ critical thinking and reasoning skill that learn through Problem Based Learning (PBL) was higher and significantly different with students who did not learn through Problem Based Learning (PBL). Questionnaire data shows that Data 78,4 % of students stated their agreement that Problem Based Learning (PBL) could improve critical thinking skill, 77,9% of students stated their agreement that Problem Based Learning (PBL) could improve their reasoning skill, and 79.9% students agreed than Problem Based Learning (PBL)can be applied to instructionof global warming concept