Penelitian ini bertujuan untuk Penelitian ini bertujuan untuk menganalisis adakah hubungan kemampuan berpikir kritis, sikap ilmiah siswa terhadap hasil belajar IPA sisw yang melaksanakan pembelajaran Problem Based Learning di kelas VIII SMP dan untuk membuktikan seberapa besar sumbangan relatif dan efektif kemampuan berpikir kritis, sikap ilmiah siswa terhadap hasil belajar IPA siswa yang melaksanakan pembelajaran Problem Based Learning di Kelas VIII. Penelitian ini dilakukan di SMP Negeri 1 Tarakan pada bulan April hingga Mei 2019. Jenis penelitian ini adalah korelasional dengan menggunakan pendekatan kuantitatif. Sampel penelitian ini sebanyak 181 siswa kelas VIII yang telah mempelajari materi cahaya dan optik. Pengambilan sampel dilakukan denganteknik Purposive Sampling. Instrumen yang digunakan adalah soal uraian untuk mengukur kemampuan berpikir dan hasil belajar serta angket untuk mengukur sikap ilmiah siswa. Data dianalisis dengan uji normalitas, uji linieritas dan uji hipotesis (uji regresi berganda), Hasil penelitian ini menunjukkan bahwa terdapat hubungan kemampuan berpikir kritis, sikap ilmiah terhadap hasil belajar. Hasil penelitian ini menunjukkan bahwa, sumbangan efektif pada variabel X1 sebesar 44% untuk sumbanagn efektif variabel X2 sebesar -0,44%. Sedangkan sumbangan relatif variabel X1 sebesar 100% dan sumbangan relatif variabel X2 sebesar -0,99%.

The purpose of this study is to analyze whether there is a relationship between critical thinking skills, students 'scientific attitudes toward science learning outcomes of students who carry out Problem Based Learning in class VIII SMP and to prove the contribution of relative and effective critical thinking skills, students' scientific attitudes towards Science learning outcomes of students who are learning Problem Based Learning in Class VIII. This research was conducted at Tarakan 1 Public Middle School in April to May 2019. This type of research is correlational using a quantitative approach. The sample of this study was 181 students of class VIII who had studied light and optical material. Sampling is done by purposive sampling technique. The instrument used is a problem description to measure thinking skills and learning outcomes as well as a questionnaire to measure students' scientific attitudes. Data were analyzed by normality test, linearity test and hypothesis test (multiple regression test), the results of this study indicate that there is a relationship between critical thinking skills, scientific attitudes toward learning outcomes. The results of this study indicate that, the effective contribution of the X1 variable is 44% for the effective contribution of the X2 variable of -0.44%. While the relative contribution of X1 variables is 100% and the relative contribution of X2 variables is -0.99%.