Development of Inorganic Molecular Shape Model Using 3D Printer to Strengthen Student's Conceptual Understanding

This research aims to develop a product in the form of an inorganic molecular shape model using 3D printer, analyze validity, practicality, effectiveness product, and strengthen students' conceptual understanding product. The method is Research Development (R&D) based on Analysis, Design, Development, Implementation Evaluation (ADDIE) model. supporting instruments for this are instrument validation sheets, readability questionnaires, pretest-posttest questions, question during trial, observation sheets understanding, student response questionnaire results showed that developed was following ADDIE because five stages were carried out systematically; being has very high validity with average percentage 96.88%; practicality 95.17% which categorized as practical, 94.69% effective; can shown indicators achievement trial 90.61% result 94.69%, both belong category. There increase pretest value 33.93 post-test 63.99. Rasch analysis after consistency answers 0.71 (quite good), quality items 0.93 (very interaction between 0.68 good). be used topic shape.