Uncovering and repairing crystal structure misconceptions in an introductory materials engineering class

The crystal structure of a metal plays an important role in its relationship to its macroscopic properties as well as atomic mechanisms of structural change. As such, students need to have an ability to visualize planar crystal atomic packing features, but often find it difficult. Thus, the research question here is, "How can a student\´s baseline knowledge and misconceptions of planar atomic packing features for different metal structures be measured and how well can instruction promote conceptual change and misconception repair." Answering this question will provide insight for developing more effective pedagogy for crystal structures. A multiple-choice survey with six items was developed using misconceptions from students\´ pencil and paper sketches of face-centered cubic (FCC) and body-centered cubic (BCC) atoms on (100), (110), and (111) planes. Pretests and posttests of the survey were administered to students in a Spring 2012 introductory materials engineering course. Misconceptions that were revealed included: missing atoms, extra atoms, misplaced atoms, "non-touching atoms where they should touch" and "touching atoms that should not touch". Students\´ difficulty in solving increased from (100) to (110) to (111) planes for both BCC and FCC structures. Details of the survey instrument and results are described in the paper.