Abstract
Abstract The research aims to produce a valid, practical and effective chemistry learning devices based on a blended learning model to improve student critical thinking skills. The 4D development model was applied in this study. Testing of learning devices and tests of critical thinking skills are carried out on the tenth-grade students at high schools in the city of Mataram, West Nusa Tenggara, Indonesia. The one group pretest-posttest design was applied as a research design. The results showed that the validity of the developed chemical learning devices based on the blended learning model had an average value of syllabus, lesson plan, teaching materials, and critical thinking instruments were 82%, 86%, 72% and 70%, respectively. The practicality of the learning devices is tested through a blended learning processes. The chemistry learning devices have a practical criteria with a scoring percentage of 78%. Furthermore, the chemistry learning devices are effective in promoting critical thinking skills. The inprovement of students’ critical thinking can be seen from the increasing of their score from 55.3 to 82.2. In conclusion, the developed chemistry learning devices based on the blended learning model are valid, practical and effective criteria, and its applicable to promote students’ critical thinking skills.