Student Understanding Of The Mechanical Properties Of Metals In An Introductory Materials Science Engineering Course

We report on initial findings of a project to identify, study, and address student difficulties in a university-level introductory materials science course for engineers. Through interviews of over 80 students and testing of over 300 students, we examined in detail student understanding of the mechanical properties of metals. Here we describe a number of student difficulties in understanding macroscopic properties of metals and the effects of simple processing on these properties. For example, many students have difficulty with basic definitions of mechanical properties. These difficulties include the notion that yield strength is independent of the cross sectional area of the material, the difference between the strength of a material and the stiffness of that material, and the actual definition of yield strength and Young’s modulus. Further, only half of the students recognized that drawing a metal through a tapered hole increases its strength and only half again of these students could give a simple, correct explanation as to why. All of these results are after traditional instruction that explicitly covered these topics. In order to address these difficulties, we are in the process of designing and field testing 45 minute in-class active learning group-work lessons, similar in structure and style to lessons shown to be effective in physics education research efforts.