The P3E learning model (Organizing, Investigation, Presentation, and Evaluation) with a contextual approach isja science learning model designed to train students' critical thinking skills based on constructivism theory. The purpose of this study was to analyze the effectiveness of the P3E learning model with a contextual approach to learning Natural Sciences (IPA) to train the critical thinking skills of elementary school students. This research used one group pre-test post-test design for elementary school students in the fourth grade of the school year 2018-2019. Critical thinking skills in this study were measured using the indicators Facione (2004). The data analysis technique used was Paired test, n-gain, and Independent test. The results of the study prove that: (1) There is an increase in critical thinking skills of fourth grade students at = 5%. (2) Average n-gain of critical thinking skills in the high category; l (3) There is a significant difference between the natural science critical thinking skills in all classes, and (4) Students respond very positively. Therefore, the P3E learning model with a contextual approach has been shown to be effective on natural science learning has been proven to be effective to improve the critical thinking skills of primary school students.

Keywords : P3E, Contextual Approach, Critical Thinking.