Abstract
This research is an experimental study which aims to see the effect of plant classification practicum activities in improving student’s logical framework and inference skills. The subjects of the study is junior high school students who were randomly selected. The collected data was analyzed using Z and t tests to see the significance of the average student’s score. The criteria for the significance of practicum activities are achieved if the results of the Z and t test calculations differ significantly and the average students score is ≥ 75 students, as well as the number of students who get those score is > 65 students. The results showed that average students’ performance score were 78.2 and 83.1. While question score were 79.5 and 79.2. As well as the results of X and t test calculations show there were a significance in students' grades. Thus the practical activities of plant classification effectively develop the framework of logic and inference skills of students.