The low learning outcomes for Physics subjects where the learning outcomes of students' Physics process skills cannot be said to be fully successful. However, students listen more, write what the teacher informs and do practice questions based on the examples given by the teacher. Learning is also filled with teacher lectures. so this happens because most students come to school empty. This study aims to determine the differences between students' physics process skills through the LKS based on Natural Exploration (JAS) on the subject matter of temperature and heat at SMAN. The sampling technique was carried out by conducting a normality test and homogeneity test in the population. From the test of the two classes, data was obtained which stated that the two classes were normal and homogeneous, which were the experimental class and the control class. The determination of the experimental class and the control class was determined by random sampling, namely by lottery. In classical completeness the indicator of process skills in the experimental class is declared complete and the control class is declared incomplete.