Newton's third law of motion: Elusive even among graduate engineering students

Abstract

Some Fundamental Laws of Physics remain elusive even to graduate engineering students, as they cannot understand them well enough to apply them correctly to most situations. Newton's 3rd Law of Motion is one of them, as this present study shows. The "Force Concept Inventory" (FCI) questionnaire was given to graduate engineering students as a pre-assessment at the beginning of the "Scientific Foundations of Engineering" course, which is part of the Gordon Engineering Leadership program and aspires to deepen the understanding of the fundamental laws of science that underlie all engineering disciplines. Two weeks after the students participated in a 2.5-hour session on reviewing classical mechanics, part of which focused on the conceptual understanding of Newton's Laws of Motion, especially the third Law, the same questionnaire was given to them as postassessment and the results, including the correct answers, were discuss after the post-test. The students showed remarkable improvement. The results of this study and the pedagogical approach used, which the author has developed over a number of years as part of Professional Development courses for Middle and High School STEM Teachers, will be presented and discussed. This approach is consistent with the research findings on How People Learn. Although it is encouraging to see such a great improvement in the students' understanding of the laws of motion after only a couple of hours of interactive teaching, what is of even greater interest is to see if the teaching approach that was used was adequate to reverse the students' misconceptions regarding Newton's Laws of Motion, especially the 3rd Law, permanently or if with time the students fall back to their pre-conceptions. A delayed post-assessment using the same FCI questionnaire was administered to the same graduate students six months later completely unexpectedly and without any prior notice that such an assessment would be conducted. The results, which are presented, analyzed and discussed in the paper, strongly indicate that the teaching methodology used results in reversal of misconceptions that lasts at least six months, suggesting that this change may be permanent.