<![CDATA[Penelitian ini bertujuan untuk menghasilkan LKS sains yang memenuhi syarat validitas, kepraktisan dan efektivitas dengan setting model pembelajaran PBL untuk meningkatkan keterampilan berpikir kritis dan keyakinan diri siswa SMP. Pengembangan LKS ini mengacu pada model pengembangan 4-D yang disarankan oleh Thiagarajan et al. (1974) yaitu define, design, develop dan disseminate. Validasi instrumen dan produk dilakukan oleh dua orang tenaga ahli dan sebelas orang praktisi. Kepraktisan dinilai oleh guru dan siswa, dan data keefektifan didapatkan dari 38 orang siswa. Metode analisis data dilakukan dengan analisis deskriptif kuantitatif terhadap validitas dan kepraktisan LKS. Efektivitas LKS dilakukan dengan one group pretest posttest design. Efektivitas LKS dianalisis dengan uji t pihak kanan. Hasil penelitian menunjukan (1) LKS dinyatakan valid dengan skor rata-rata validitas 3,40, (2) LKS dinyatakan praktis dengan skor rata-rata kepraktisan 3,30, (3) LKS dinyatakan efektif untuk meningkatkan keterampilan berpikir kritis dengan thitung > ttabel (13,407 > 1,684) dan (4) LKS dinyatakan efektif untuk meningkatkan efikasi diri siswa dengan thitung > ttabel (16,838 > 1,687). Berdasarkan hasil penelitian dapat disimpulkan bahwa LKS sains telah memenuhi syarat validitas, kepraktisan, dan efektivitas dengan setting model pembelajaran PBL untuk meningkatkan keterampilan berpikir kritis dan efikasi diri siswa SMP.Kata Kunci : Lembar Kerja Siswa, Problem Based Learning, Keterampilan berpikir kritis, Efikasi diri The purpose of this research was to produce a science student worksheet (LKS) that fulfills validity, practicality, and effectiveness requirements based on problem based learning model setting to improve junior high school students’ critical thinking skill and self-efficacy. The development of this student worksheet (LKS) was based on 4D development model suggested by Thiagarajan et al. (1974) they are define, design, develop and disseminate. The tests in this student worksheet were validated by two experts and eleven practitioners. The practicality was scored by the three teachers and the students, and the effectiveness data was acquired from 38 students. The data analysis method was done by using descriptive quantitative analysis toward the validity and the effectiveness of the student worksheet (LKS). The student worksheet effectiveness was done by using one group pretest posttest design. The student worksheet effectiveness was analyzed by using right side t-test. The result of the research shows that (1) the student worksheet (LKS) is valid with average score of the validity is 3.40, (2) the student worksheet (LKS) is practical with average score of the practicality is 3.30, (3) the student worksheet (LKS) is effective to improve students’ critical thinking skill with tcount > ttabel (13,407 > 1,684) and (4) the student worksheet (LKS) is effective to improve students’ self-efficacy with tcount > ttabel (16,838 > 1,687). Based on the result of this research, it can be concluded that science student worksheet (LKS) has fulfilled validity, practicality, and effectiveness based on problem based learning model setting requirements to improve students’ critical thinking skill and students’ self-efficacy.keyword : Student Worksheet, Problem Based Learning, Critical Thinking Skills, Self-efficacy]]>
