Tujuan penelitian ini untuk menghasilkan Lembar Kegiatan Peserta Didik berbasis Problem Based Learning pada materi perubahan lingkungan  yang layak (valid) untuk melatihkan keterampilan berpikir kritis siswa yang layak secara teoritis. Alasan LKPD perlu dikembangkan dengan model pembelajaran Problem Based Learning karena dinilai mampu untuk memacu keterampilan berpikir kritis siswa. Keterampilan berpikir kritis diartikan  keterampilan peserta didik baik dalam proses maupun kemampuan untuk memahami konsep, menerapkan, mensintesis, dan mengevaluasi informasi yang diperoleh, serta membantu menyelesaikan masalah sehingga perlu dilatihkan. Para peserta didik diarahkan untuk merumuskan masalah, membuat hipotesis, hingga membuat solusi untuk menyelesaikan masalah yang telah disajikan. Penelitian ini menggunakan model pengembangan 4D tanpa disseminate yaitu hanya define, design, develope, bahkan tahap uji coba pun tidak bisa dilaksanakan karena penelitian ini dilaksanakan pada waktu pandemi Covid 19. Data penelitian diperoleh melalui metode validasi. Parameter penelitian meliputi kelayakan teoritis berdasarkan hasil dari validasi LKPD, data yang diperoleh dianalisis secara deskriptif kuantitatif dan kualitatif. Berdasarkan hasil analisis dan penelitian disimpulkan bahwa LKPD berbasis Problem Based Learning pada materi perubahan lingkungan ini layak nilai validitas sebesar 3,62 rincian nilai mean dari masing-masing aspek; penyajian (3,67), isi (3,67), dan bahasa (3,50)  dengan kategori sangat valid, sehingga layak digunakan dalam kegiatan pembelajaran.Kata Kunci: Lembar Kegiatan peserta didik, Problem Based Learning, berpikir kritis.

This study aims to develop LKPD based on Problem Based Learning on material changes in the environment that are feasible (valid) to train students' critical thinking skills. The reason this LKPD was developed with the Problem Based Learning learning model is because this model is considered capable of spurring students' critical thinking skills. Critical thinking skills themselves are defined as skills that need to be trained in students both in the process and in the ability to understand concepts, apply, synthesize, and evaluate information obtained, and help solve problems. Students are directed to formulate problems, make hypotheses, to make solutions to solve the problems that have been presented. This study uses a 4D development model without dissemination, namely only define, design, develop, even the trial phase cannot be carried out because this research was conducted during the Covid 19 pandemic. The research data was obtained through the validation method. The parameters in this study include theoretical feasibility based on the results of the validity of LKPD. Based on the results of the analysis and discussion, it was concluded that the development of LKPD based on Problem Based Learning on this environmental change material deserves a validity value of 3.62 with a very valid category and can be used as a teaching material to train students' critical thinking skills on environmental change material.

Keywords: students worksheet, problem based learning, validity