<![CDATA[This study aims to improve the scientific reasoning skills of seventh-grade students in Class VII C at SMPN 1 Rambipuji through the use of Student Worksheets based on Socio-Scientific Issues (SSI) in science lessons covering ecology and biodiversity. The study employed the Classroom Action Research (CAR) method, conducted in two cycles comprising the stages of planning, implementation, observation, and reflection. The research subjects consisted of 32 students. Data collection was conducted through scientific argumentation ability tests, observations of student learning activities, and documentation. The results showed that the use of SSI-based worksheets was effective in improving students’ scientific argumentation skills. The percentage of students meeting the standard increased from 40.63% in Cycle I to 84.37% in Cycle II. The average score for students’ scientific argumentation skills also improved, rising from 73.44 in Cycle I to 82.59 in Cycle II. In addition, student learning activities increased from the “active” category to “very active.” The percentage of student learning activities rose from 71.5% in Cycle I, Session 1, to 91.5% in Cycle II, Session 2. Based on these results, it can be concluded that the implementation of Socio-Scientific Issues (SSI)-based worksheets is effective in improving students’ scientific argumentation skills and learning activities in science education. This approach also helps students become more active in discussions, express their opinions, and connect the learning material to real-world problems.]]>
