Rebecca Rosenblatt

Student difficulties with basic concepts in introductory materials science engineering

We report on findings of a project to identify specific student difficulties in a university-level introductory materials science course for engineers. This is the first part of a larger project to design and assess evidence-based curricular materials for this course. Through interviews, testing, and classroom observation of over 1000 students, we examined in detail student understanding of basic topics in materials science including topics such as atomic structure, mechanical properties, defects, diffusion, phase diagrams, failure, and the processing of metals. We identified four general areas in which students have difficulties: Student confusion of similar concepts, student difficulties with reasoning about concepts with more than one variable, student use of inappropriate models or analogies, and student difficulties with common graphs and diagrams used in materials science. We provide a number of specific examples of each category, focusing on the materials science of metals. While these student difficulties are interesting in their own right, a careful examination of these difficulties can also provide useful information for the design of instructional materials.

Toward a comprehensive picture of student understanding of force, velocity, and acceleration

Students’ difficulties with conceptual questions about force, velocity, and acceleration have been well documented. However, there has been no single systematic study of student understanding of all paired relations among the concepts of force, velocity, and acceleration. For example, a student who believes an object with a net force on it must be moving might not believe an accelerating object must be moving. In this paper, we describe the development of a test to build a more comprehensive picture of student understanding. We describe modifications to increase the validity of the test by reducing false positives and unwanted inconsistencies. We also report preliminary data suggesting that there are definite patterns in student understanding of the various relations between force, velocity, and acceleration. For example, there are a higher number of students reporting that force and velocity are directionally related then that acceleration and velocity are directionally related.

Group-work tutorials for an introductory materials engineering course

We report on findings of a project to improve student learning in a university-level introductory materials science course for engineers. In a related preparatory project, we identified student difficulties with basic topics in materials science through interviews and/or testing of over 1000 students at The Ohio State University. Here, we report on the implementation of concept oriented group-work lessons or “tutorials” designed to address student difficulties identified in our prior work and improve student understanding of core concepts in materials science. The lessons were designed for weekly 48 minute recitations in which students work together in small groups on the tutorials in the presence of teaching assistants who assess and facilitate student progress. To determine the learning outcome, we analyzed scores on the final exam and found that even accounting for the fact that slightly “better” students tended to attend recitations more often, there was a valued-added effect of the recitations on final exam performance. These results suggest that these recitation methods and materials are effective in teaching students the difficult and important conceptual materials which they were designed to address.

Student accuracy in reading logarithmic plots: The problem and how to fix it

Through extensive student testing and interviews, we found that the majority of university sophomore, junior, and senior engineering students in a standard introductory materials science engineering course have a variety of difficulties reading correct values from simple logarithmic graphs. For example, students often unknowingly interpreted the log scale as linear and were confused about the order of magnitude of a value in the negative exponent region. To address these issues, we used the results of our findings to develop and implement a set of online “essential skills” tasks to help students achieve a core level of mastery and fluency in reading log plots, a basic and critical skill for engineers. The online tasks were administered as for-credit homework assigned several times throughout the semester, and students spent 10-20 minutes on each assignment. Results of post-tests indicate that with this minimal practice, students were able to dramatically improve their accuracy in reading log plots compared to a control group with no log plot practice. Furthermore, testing one month after training demonstrated that student continued to retain the learned skill. Future development will focus on making these essentials skills task broadly available online and further improving effectiveness and usability.

Modeling students’ conceptual understanding of force, velocity, and acceleration

We have developed a multiple choice test designed to probe students’ conceptual understanding of the relationships among the directions of force, velocity, and acceleration. The test was administered to more than 800 students enrolled in standard or honors introductory physics courses or a second‐year physics majors course. The test was found to be reasonably statistically reliable, and correlations of test score with grade, course level, and the Force Concept Inventory were moderate to strong. Further analysis revealed that in addition to the common incorrect response that velocity must be in the direction of the acceleration or net force, up to 30% of students gave “partially correct” responses, for example that velocity can be either opposite to or in the direction of the acceleration or net force but not zero. The data also suggests that for some students their evolution of understanding may progress through this kind of partially incorrect understanding.