We compared students’ self-reported perception of learning with their actual learning under controlled conditions in large-enrollment introductory college physics courses taught using 1) active instruction (following best practices in the discipline) and 2) passive instruction (lectures by experienced and highly rated instructors). Both groups received identical class content and handouts, students were randomly assigned, and the instructor made no effort to persuade students of the benefit of either method. Students in active classrooms learned more (as would be expected based on prior research), but their perception of learning, while positive, was lower than that of their peers in passive environments. This suggests that attempts to evaluate instruction based on students’ perceptions of learning could inadvertently promote inferior (passive) pedagogical methods. For instance, a superstar lecturer could create such a positive feeling of learning that students would choose those lectures over active learning. Most importantly, these results suggest that when students experience the increased cognitive effort associated with active learning, they initially take that effort to signify poorer learning. That disconnect may have a detrimental effect on students’ motivation, engagement, and ability to self-regulate their own learning. Although students can, on their own, discover the increased value of being actively engaged during a semester-long course, their learning may be impaired during the initial part of the course. We discuss strategies that instructors can use, early in the semester, to improve students’ response to being actively engaged in the classroom.

Nearly every introductory physics or chemistry course includes live lecture demonstrations, which can range from simple illustrations of a pendulum to elaborate productions with specialized apparatus and highly trained demonstrators. Students and instructors often consider "demos" to be among the highlights of these classes. Yet, in some situations demos may be cumbersome, inaccessible, or otherwise unavailable, and online video demos could offer a convenient alternative. We compared the effectiveness of live demonstrations with online videos under controlled conditions in the first semester of an introductory physics (mechanics) course. Students were randomly assigned to view either a live or video version of two demos. The same instructor presented both versions of the demo using an identical script, keeping the same time on task across both conditions, but with small differences in presentation appropriate to the medium. Compared with the students who saw the live demos, the students who watched the online videos learned more, and their self-reported enjoyment was just as high. We discuss reasons why videos helped students to learn more, including that they are more likely to make correct observations from the video. These results suggest that videos could provide students with an equally effective learning experience when live demos are unavailable. Indeed, even when live demonstrations are available, it may be beneficial to supplement them with online presentations.

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We discuss our work toward the construction of a light-shell effective theory (LSET), an effective field theory for describing the matter emerging from high-energy collisions and the accompanying radiation. We work in the highly simplified venue of 0flavor scalar quantum electrodynamics, with a gauge invariant product of scalar fields at the origin of space-time as the source of high-energy charged particles. Working in this simple gauge theory allows us to focus on the essential features of LSET. We describe how the effective theory is constructed and argue that it can reproduce the full theory tree-level amplitude. We study the 1-loop radiative corrections in the LSET and suggest how the leading double-logs in the full theory at 1-loop order can be reproduced by a purely angular integral in the LSET.

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