Beth A. Lindsey

Student understanding of energy: Difficulties related to systems

Choosing a system of interest and identifying the interactions of the system with its environment are crucial steps in applying the relation between work and energy. Responses to problems that we administered in introductory calculus-based physics courses show that many students fail to recognize the implications of a particular choice of system. In some cases, students do not believe that particular groupings of objects can even be considered to be a system. Some errors are more prevalent in situations involving gravitational potential energy than elastic potential energy. The difficulties are manifested in both qualitative and quantitative reasoning.

Student ability to apply the concepts of work and energy to extended systems

We report results from an investigation of student ability to apply the concepts of work and energy to situations in which the internal structure of a system cannot be ignored, that is, the system cannot be treated as a particle. Students in introductory calculus-based physics courses were asked written and online questions after relevant instruction by lectures, textbook, and laboratory. Several difficulties were identified. Some related to student ability to calculate the work done on a system. Failure to associate work with the change in energy of a system was also widespread. The results have implications for instruction that aims for a rigorous treatment of energy concepts that is consistent with the first law of thermodynamics. The findings are guiding the development of two tutorials to supplement instruction.

Combining two reform curricula: An example from a course with well-prepared students

Many studies have separately documented the benefits of research-based curricula and pedagogical methods. Here, we report on the effects of adopting a reform curriculum (Matter and Interactions) in conjunction with a pedagogical tool designed and validated in the context of a traditional treatment of mechanics (Tutorials in Introductory Physics). We document the need for targeted interactive engagement materials (such as the tutorials) even in a course with a population of students who are extremely well-prepared in physics. We describe the modifications necessary to successfully incorporate Tutorials in Introductory Physics into a course using Matter and Interactions, and we present data documenting the success of this approach.

Assessing students’ metacognitive calibration with knowledge surveys

“Calibration” is an aspect of metacognition that describes how well students assess their own knowledge. One tool that can help to assess student calibration is the knowledge survey (KS). On a KS, students rate their confidence in their ability to answer questions related to course content. A comparison of a student’s confidence level with their actual performance on course exams gives an indication of the student’s metacognitive calibration. We report on a study that explores students’ responses to a KS in introductory physics and chemistry courses serving both STEM and non-STEM populations. In many courses, Delta (the difference between KS-score and final exam score, a measure of calibration) was anti-correlated with final exam performance. No relationship was found between Delta and students’ scientific reasoning abilities. We also report preliminary findings on how calibration differs for questions of a quantitative nature vs. those of a more conceptual nature.