<p><strong>Abstract:</strong> Laboratory-based learning is learning that aims to develop an understanding of scientific content, problem-solving skills, science skills and understanding. This study aims to determine the effect of guided inquiry laboratory on critical thinking skills in terms of students' initial abilities in the material reaction rate. The research design used was a quasi-experimental posttest. Sampling using cluster random sampling technique is the students of class XI semester 1 one of the public high schools in Malang City. Hypothesis testing used two-way ANOVA with SPSS 22 for windows. The results showed that there was an interaction between the learning strategy and the prior knowledge of students' critical thinking skills.</p><strong>Abstrak</strong><strong>:</strong><em> </em>Pembelajaran berbasis praktikum merupakan pembelajaran yang bertujuan mengembangkan pemahaman konsep kimia, keterampilan pemecahan masalah, ketrampilan dan pemahaman sains. Penelitian ini bertujuan untuk mengetahui pengaruh praktikum inkuiri terbimbing terhadap kemampuan berpikir kritis ditinjau dari kemampuan awal siswa pada materi laju reaksi. Rancangan penelitian yang digunakan adalah <em>quasi e</em><em>xperimental posttest</em>. Pengambilan sampel menggunakan teknik <em>cluster random sampling</em> adalah siswa kelas XI semester I salah satu SMA Negeri di Kota Malang. Hasil penelitian menunjukkan terdapat perbedaan kemampuan berpikir kritis siswa yang dibelajarkan dengan parktikum inkuiri terbimbing dan siswa yang dibelajarkan dengan praktikum verifikatif. Terdapat interaksi antara strategi pembelajaran dengan kemampuan awal terhadap kemampuan berpikir kritis siswa.

Sweet corn silk contains active compounds which act as an antibacterial. In this study, sweet corn silk extract was determined antibacterial activity in various solvents, Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). Extraction of sweet corn silk was conducted by maceration method. Antibacterial activity was tested with the disc diffusion method, then followed by MIC and MBC tests at 250; 125; 62.5; 31.25 and 15.625 mg/mL using liquid dilution method and drop plate method. The result showed that its inhibition zone against bacteria E. coli and S. aureus was 19.3 and 13 mm for ethanol extract, 9.3 and 12.3 mm for ethyl acetate extract, while the petroleum ether extract is also inhibited E.coli with its inhibition zone 2.67 mm but has no antibacterial activity on S. aureus. Ethanol extract had the MIC to E. coli and S. aureus was 125 mg/mL, while MBC was 250 mg/mL.