Tujuan dari penelitian ini adalah mendeskripsikan Lembar Aktivitas Peserta Didik (LAPD) dengan model pembelajaran Inquiry untuk meningkatkan kemampuan berpikir kritis pada materi faktor-faktor yang mempengaruhi laju reaksi yang layak dalam aspek valid, praktis, dan efektif. Penelitian dengan model pengembangan ADDIE (Analyze, Design, Development, Implement, dan Evaluate) ini hanya dilakukan hingga tahap development (pengembangan) dan implementasi awal dan berfokus pada 5 indikator berpikir kritis yaitu interpretasi, analisis, evaluasi, inferensi, dan eksplanasi. Penelitian ini dilakukan di SMA Negeri 19 Surabaya dengan subyek penelitian 26 peserta didik kelas XI. Berdasarkan hasil penelitian, LAPD dinyatakan layak ditinjau dari aspek validitas yang memperoleh modus sebesar 4 hingga 5 untuk aspek validitas isi dan modus sebesar 5 untuk aspek validitas konstruk. Kepraktisan ditinjau berdasarkan hasil lembar observasi aktivitas peserta didik dengan persentase sebesar 91,67% dan hasil lembar angket respon peserta didik sebesar 89,34%. LAPD dinyatakan efektif berdasarkan hasil dari Uji Paired t-test (one tailed) didapatkan p-value sebesar 0.000. Hal ini menunjukkan bahwa p-value < dari 0,05 yang berarti H₀ ditolak dan H₁ diterima sehingga dapat disimpulkan bahwa terdapat perbedaan yang signifikan penggunaan LAPD dengan model pembelajaran inquiry terhadap peningkatan kemampuan berpikir kritis peserta didik dan LAPD yang digunakan dinyatakan layak untuk meningkatkan kemampuan berpikir kritis peserta didik.

Kata kunci: LAPD, kemampuan berpikir kritis, inquiry, laju reaksi.

The purpose of this study was to describe the Student Activity Sheet (LAPD) with the Inquiry learning model to improve critical thinking skills on the material of factors that influence the reaction rate that are feasible in the aspects of validity, practicality, and effectiveness. This research with the ADDIE (Analyze, Design, Development, Implement, and Evaluate) development model was only carried out up to the development stage and initial implementation and focused on 5 indicators of critical thinking, namely interpretation, analysis, evaluation, inference, and explanation. This research was conducted at SMA Negeri 19 Surabaya with 26 class XI students as research subjects. Based on the results of the study, LAPD was declared feasible in terms of validity aspects which obtained a mode of 4 to 5 for the content validity aspect and a mode of 5 for the construct validity aspect. Practicality was reviewed based on the results of the student activity observation sheet with a percentage of 91.67% and the results of the student response questionnaire sheet of 89.34%. LAPD was declared effective based on the results of the Paired t-test (one tailed) obtained a p-value of 0.000. This shows that the p-value <0.05, which means that H₀ is rejected and H₁ is accepted, so it can be concluded that there is a significant difference in the use of LAPD with the inquiry learning model in improving students' critical thinking skills and the LAPD used is declared feasible to improve students' critical thinking skills.

Keywords: LAPD, critical thinking skills, reaction rate.