The need for students’ worksheets is felt urgent and very necessary, especially when the covid-19 pandemic. Therefore, through this research a Student Worksheet (SW) will be developed and the application to increase the understanding of the Sound Wave concept in Middle School students. The development of SW uses a Research and Development approach through the ADDIE model. SW limited trials were conducted on high school students. This research was conducted in 2 cycles of 4 meetings, each of which consisted of 4 stages: planning, implementation, observation and reflection. In addition, the feasibility of the learning tools used, the feasibility of learning, classroom management and students’ responses to learning were examined. Trials on limited samples, test student learning outcomes, teacher skills and student responses. Data analysis method used is descriptive method. Results that being analyzed with descriptive statistics it was found that the use of Lab Virtual PhET SW can improve student learning outcomes and teacher skills in the learning process in each cycle.