<![CDATA[Improving science process skills is one of the requirements of the Independent Curriculum, which emphasizes student-centered learning and positions students as active participants in the scientific inquiry process. However, these skills have not yet developed optimally, particularly in wave material that demands analytical thinking and practical skills. This study focuses on describing the improvement of students' SPS through the application of the guided inquiry model assisted by PhET Interactive Simulation to class VIII-G students at SMPN 3 Sidoarjo. The study used a quantitative approach with a one-group pre-test and post-test design, which was carried out through three main stages: administering a pre-test, implementing PhET-assisted guided inquiry learning, and administering a post-test. The instrument used was a SPS essay test covering five indicators: formulating problems, formulating hypotheses, identifying variables, interpreting data, and drawing conclusions. The results showed a significant increase in all indicators, which was reinforced by the results of the N-Gain analysis with a high category. The normality test showed that the data were not normally distributed, so the analysis was continued with the Wilcoxon test which produced an Asymp value. A significance level of 0.000 < 0.05 indicates a significant difference between the pre-test and post-test scores. Therefore, this study concludes that PhET-assisted guided inquiry is effective in improving students' science process skills on the topic of waves. ABSTRAK Peningkatan keterampilan proses sains menjadi salah satu tuntutan kurikulum merdeka yang menekankan pembelajaran berpusat pada murid serta menempatkan mereka sebagai pelaku aktif dalam proses penyelidikan ilmiah. Namun, kemampuan tersebut masih belum berkembang optimal, khususnya pada materi gelombang yang menuntut proses berpikir analitis dan keterampilan praktis. Penelitian ini berfokus untuk mendeskripsikan peningkatan KPS murid melalui penerapan model guided inquiry berbantuan PhET Interactive Simulation pada murid kelas VIII-G SMPN 3 Sidoarjo. Penelitian menggunakan pendekatan kuantitatif dengan desain one-group pre-test and post-test, yang dilakukan melalui tiga tahap utama, yaitu pemberian pre-test, penerapan pembelajaran guided inquiry berbantuan PhET, dan pemberian post-test. Instrumen yang digunakan berupa tes esai KPS yang mencakup lima indikator, yakni merumuskan masalah, merumuskan hipotesis, mengidentifikasi variabel, menginterpretasi data, dan membuat kesimpulan. Hasil penelitian menunjukkan adanya peningkatan signifikan pada seluruh indikator, yang diperkuat oleh hasil analisis N-Gain dengan kategori tinggi. Uji normalitas menunjukkan data tidak berdistribusi normal, sehingga analisis dilanjutkan dengan uji Wilcoxon yang menghasilkan nilai Asymp. Sig 0,000 < 0,05, menandakan adanya perbedaan signifikan antara nilai pre-test dan post-test. Dengan demikian, penelitian ini menyimpulkan bahwa guided inquiry berbantuan PhET efektif dalam meningkatkan keterampilan proses sains murid pada materi gelombang. ]]>
