Penelitian ini bertujuan untuk menghasilkan LKS fisika berbasis inkuiri terbimbing yang memenuhi kriteria kelayakan (valid, praktis, dan efektif) untuk melatihkan keterampilan proses sains siswa pada materi Hukum Archimedes. Penelitian ini menggunakan jenis penelitian pengembangan dengan model ADDIE (Analysis, Design, Development, Implementation, and Evaluation). Subjek penelitian adalah 36 siswa kelas XI MIPA SMA Negeri 1 Porong. Teknik pengumpulan data adalah observasi dan angket. Validitas LKS ditinjau dari syarat didaktik, konstruksi, dan teknis berkategori sangat valid (didaktik 88%, konstruksi 88%, dan teknis 85%). Kepraktisan LKS ditinjau dari keterlaksanaan dan kendala pembelajaran berkategori sangat praktis dengan persentase keterlaksanaan pembelajaran 89% meskipun terkendala kurangnya waktu. Keefektifan LKS ditinjau dari hasil observasi keterampilan proses sains bermodus sangat efektif dengan skor rata-rata keterampilan mengamati 3,60 (sangat terampil); merumuskan masalah 3,50 (sangat terampil); merumuskan hipotesis 3,48 (sangat terampil); mengidentifikasi variabel 3,53 (sangat terampil); menganalisis data 3,50 (sangat terampil); dan membuat kesimpulan 3,48 (sangat terampil). Respon siswa terhadap LKS juga bermodus sangat baik sehingga dapat disimpulkan bahwa LKS fisika berbasis inkuiri terbimbing layak digunakan untuk melatihkan keterampilan proses sains siswa berdasarkan validitas LKS, kepraktisan penggunaan, dan keefektifan untuk melatihkan keterampilan proses sains.

Kata Kunci : LKS Inkuiri Terbimbing, Keterampilan Proses Sains,   Hukum  Archimedes

This research aims to produce physics student worksheets based on guided inquiry that worthy (valid, practical, and effective) to train students’ science process skills in Archimedes’ Law. This research uses a type of research and development with the ADDIE model (Analysis, Design, Development, Implementation, and Evaluation). The research subjects were 36 students of class XI MIPA in SMA Negeri 1 Porong. Data collection techniques are observation and questionnaire. The validity of student worksheets based on didactic requirements, construction requirements, and technical requirements is very valid (didactic 88%, construction 88%, and technical 85%). The practicality of the student worksheets based on implementation and learning constraints is very practical with the percentage of implementation learning 89% although constrained lack of time. The effectiveness of the student worksheets based on observation results of the science process process skills is very effective with an average score of observing skills 3.60 (very skilled); formulate a problem 3.50 (very skilled); formulate a hypothesis 3.48 (very skilled); identify variables 3.53 (very skilled); analyze data 3.50 (very skilled); and make a conclusion of 3.48 (very skilled). Student responses to student worksheets also very good so that it can be concluded that physics student worksheets based on guided inquiry worthy to used to train students' science process skills based on student worksheets validity, practicality of use, and effectiveness to practice science process skills.

Keywords : Guided Inquiry Worksheets, Science Process Skills, Archimedes’ Law