Abstract-This study aims to produce a teaching material in the form of guided inquiry based worksheet and to evaluate its validity, practicality, and effectiveness. The research was conducted using Research and Development (R&D) model.
Development model that is used in this research is a 4-D model (define, design, develop, and disseminate). Validity analysis resultshowed that moment kappa value is 0.91, which can be categorized as very high. Practicality analysis result based on teachers response and students showed that practicality value is 0.82, which can be categorized as very high. From effectiveness test, the gain score of student's learning outcome before and after using worksheet in learning is 0.54, which can be categorized as intermediate and mean of students activity presentation in each meeting is 81%, which can be categorized as very effective. Based on the data, it can be concluded that guided inquiry based worksheet on colligative properties solution are valid, practical, and effective.