PENGEMBANGAN LEMBAR KEGIATAN SISWA (LKS) BERORIENTASI GUIDED DISCOVERY UNTUK MELATIHKAN KETERAMPILAN BERPIKIR KRITIS SISWA PADA MATERI ASAM BASA KELAS XI SMA (DEVELOPMENT OF STUDENT ACTIVITY SHEET ORIENTED GUIDED DISCOVERY TO PRACTICE STUDENT CRITICAL THINKING SKILL ON ACID BASE MATERIAL FOR SENIOR HIGH SCHOOL GRADE XI)

Tujuan penelitian ini adalah (1) mendeskripsikan kelayakan LKS ditinjau dari kriteria isi, penyajian, kebahasaan dan kegrafikan, (2) melatihkan keterampilan berpikir kritis siswa, serta (3) mendeskripsikan respon siswa ditinjau dari kriteria isi, penyajian, kebahasaan dan kegrafikan. Jenis penelitian merupakan penelitian pengembangan (R&D). Rancangan pengembangan LKS menggunakan model ASSURE menurut Heinich, Molenda, dan Russel (1996). Sasaran penelitian adalah LKS yang dikembangkan. Instrumen yang digunakan lembar telaah, validasi, angket respon siswa, soal pemahaman konsep dan keterampilan berpikir kritis. Sumber data adalah dosen kimia, guru kimia, 30 siswa kelas XI SMA. Data dianalisis secara deskriptif. Hasil penelitian berdasarkan data hasil validasi, masing-masing kriteria kelayakan pada seluruh LKS memperoleh persentase antara 66,66% – 100%, sehingga LKS yang dikembangkan dikategorikan layak. Keterampilan berpikir kritis interpretasi, analisis, inferensi, dan penjelasan dikategorikan berturut-turut sangat baik (87,60% – 100%), sangat baik (92,50% – 94,33%) baik (71,33% – 72,33%) dan sangat baik (90,00% – 93,33%). Berdasarkan data hasil angket respon siswa masing-masing kriteria memperoleh persentase antara 76,66% – 100%, sehingga LKS yang dikembangkan dikategorikan layak. Kata kunci: LKS, guided discovery, keterampilan berpikir kritis The aim of this research is (1) to describe the feasibility of student activity sheet which determine by criteria of content, presentation, language, and graphical;(2) to practice student critical thinking skill; and (3) to describe the student response which determine by criteria of content, presentation, language, and graphical. The type of this research is R&D, design of student activity sheetusing ASSURE model by Heinich, Molenda, and Russel. The target of this research is the student activity sheet that had been developed.The instruments which used in this researchwere analysis sheet, validation sheet, student response questioner, question of comprehension concept and student critical thinking skill. Source of data were obtained by chemistry lecturer, chemistry teacher, as well as 30 students class XI Senior High School. The analyzed of data was done descriptively. The results of the validation data, each of the feasibility criteria on student activity sheet has the percentage 66.66% - 100%, so student activity sheet that have been developed categorized as feasible. Critical thinking skills of interpretation, analysis, inference, and explanations are categorized in respectively by very good (87.60% - 100%), very good (92.50% - 94.33%) good (71.33% - 72.33 %) and very good (90.00% - 93.33%). Based on data from student questionnaire responses of each criterion has percentage between 76.66% - 100%, so the student activity sheet that have been developed categorized as feasible. Keywords: student activity sheet, guided discovery, critical thinking skil