Science Learning Tools Project Based Learning (PjBL) Model With STEM Approach To Improve Mastery of Junior High School Student's Concepts on Environmental Pollution Materials

The study aims to determine the effect of using the science learning tools Project Based Learning (PjBL) model with the STEM approach in increasing creativity and conceptual mastery of junior high school students. The research method used is quasi-experimental. The design in this study is one group pretest-posttest design. The population of this research is class VII in one of the state junior high schools in Surakarta. The research sample consisted of 44 students. The instrument used was the concept mastery test instrument consisting of 20 questions on the subject of environmental pollution. The data analysis technique used in this study is the t-test. Based on the result of the feasibility test of the science learning device, namely syllabus 3.8, RPP 3.44, teaching materials 3.67, LKPD 3.54, assessment instrument 3.63 with the category average is very feasible to use. The result of data analysis, the average N-gain of the experimental class was 0,63 with a medium category, and the control class 0,21 with the low category. The result of the t-test showed that there were differences in the mastery of concepts between the experimental class using the PjBL model of natural science learning tools and the STEM approach with the class without using these tools.