Ross K. Galloway

Student-generated content: Using PeerWise to enhance engagement and outcomes in introductory physics courses

We describe the implementation and evaluation of an online tool to support student generation of multiple choice assessment questions within two consecutive semesters of introductory physics at the University of Edinburgh. We substituted a weekly homework for an assessment activity in which each student was required to participate in using the system. Engagement with the system was high, with contributions generally going beyond the minimum requirements. The quality of submissions was on average high, with the very best questions being remarkably detailed problems rather than exercises. We explore links between use of the online system and end of course examination score. We find that students with higher levels of activity in the system scored significantly higher marks on the exam; this effect was seen for students of lower ability as well as for the highest performing students.

Cross-field diffusion of electrons in tangled magnetic fields and implications for coronal fine structure

High-resolution images of the solar corona suggest that some degree of tangling exists in the coronal magnetic structure. We show that a very low level of such magnetic tangling is sufficient for Rechester-Rosenbluth diffusion to be the dominant cross-field plasma transport mechanism. This diffusive process, which moves particles rapidly across the field on tangled field lines, is thus likely to be a governing mechanism in controlling plasma structure in the direction perpendicular to the magnetic field. We generate model coronal loops with cross-field dimensions governed by Rechester-Rosenbluth diffusion and show that the cross-field transport is consistent with the observed widths of coronal magnetic loops. Together with observed loop morphology, these calculations allow us to constrain the degree of magnetic field disorder likely to be present in the corona, and in particular the degree of tangling as invoked in discussions of coronal heating.

Assessing the quality of a student-generated question repository

We present results from a study that categorizes and assesses the quality of questions and explanations authored by students, in question repositories produced as part of the summative assessment in introductory physics courses over the past two years. Mapping question quality onto the levels in the cognitive domain of Bloom’s taxonomy, we nd that students produce questions of high quality. More than three-quarters of questions fall into categories beyond simple recall, in contrast to similar studies of student-authored content in dierent subject domains. Similarly, the quality of student-authored explanations for questions was also high, with approximately 60% of all explanations classied as being of high or outstanding quality. Overall, 75% of questions met

Thermalisation and hard X-ray bremsstrahlung efficiency of self-interacting solar flare fast electrons

Context. Most theoretical descriptions of the production of solar flare bremsstrahlung radiation assume the collision of dilute accelerated particles with a cold, dense target plasma, neglecting interactions of the fast particles with each other. This is inadequate for situations where collisions with this background plasma are not completely dominant, as may be the case in, for example, low-density coronal sources. Aims. We aim to formulate a model of a self-interacting, entirely fast electron population in the absence of a dense background plasma, to investigate its implications for observed bremsstrahlung spectra and the flare energy budget. Methods. We derive approximate expressions for the time-dependent distribution function of the fast electrons using a Fokker-Planck approach. We use these expressions to generate synthetic bremsstrahlung X-ray spectra as would be seen from a corresponding coronal source. Results. We find that our model qualitatively reproduces the observed behaviour of some flares. As the flare progresses, the model’s initial power-law spectrum is joined by a lower energy, thermal component. The power-law component diminishes, and the growing thermal component proceeds to dominate the total emission over timescales consistent with flare observations. The power-law exhibits progressive spectral hardening, as is seen in some flare coronal sources. We also find that our model requires a factor of 7−10 fewer accelerated electrons than the cold, thick target model to generate an equivalent hard X-ray flux. Conclusions. This model forms the basis of a treatment of self-interactions among flare fast electrons, a process which affords a more efficient means to produce bremsstrahlung photons and so may reduce the efficiency requirements placed on the particle acceleration mechanism. It also provides a useful description of the thermalisation of fast electrons in coronal sources.

Using concept inventories to measure understanding

Abstract Measuring understanding is notoriously difficult. Indeed, in formulating learning outcomes the word ‘understanding’ is usually avoided, but in the sciences, developing understanding is one of the main aims of instruction. Scientific knowledge is factual, having been tested against empirical observation and experimentation, but knowledge of facts alone is not enough. There are also models and theories containing complex ideas and interrelationships that must be understood, and considerable attention has been devoted across a range of scientific disciplines to measuring understanding. This case study will focus on one of the main tools employed: the concept inventory and in particular the Force Concept Inventory (FCI). The success of concept inventories in physics has spawned concept inventories in chemistry, biology, astronomy, materials science and maths, to name a few. We focus here on the FCI and ask how useful concept inventories are for evaluating learning gains. Finally, we report on recent work by the authors to extend conceptual testing beyond the multiple-choice format.

Teacher-student discourse in active learning lectures: case studies from undergraduate physics

ABSTRACT In this paper we develop knowledge of the discourse that takes place between teacher and students in two large undergraduate classes which use a flipped, active learning approach. In flipped classes students encounter the content through pre-class resources, freeing up class time for more active engagement with the material. This results in increased opportunities for teacher-student interactions which may be beneficial for learning. Our aim here is to explore the nature and purposes of these dialogues. Two case studies from introductory physics classes at the University of Edinburgh are analysed through a sociocultural perspective. Three main purposes of dialogues are observed: (1) Involving students in sense-making, (2) Guided expert modelling and (3) Wonderment questions. We found that the dialogues predominantly use a triadic Initiation, Response, Feedback (IRF) format and are authoritative in nature, but work together to create an interactive learning environment that can be described as ‘ideologically dialogic’

How do approaches to solving open-ended problems vary within the science disciplines?

ABSTRACT This paper describes the results of a comparative study into the approaches used by science undergraduates when solving open-ended problems. This study adopted a pseudo-grounded theory framework to analyse six case studies, one from each of the science disciplines studied. The study involved 70 participants from 5 institutions solving open-ended problems using a think-aloud protocol. Analysis of the data identified a number of different approaches used by each subject group. Participants in psychology, pharmacy and sports rehabilitation used a greater number of novice-like approaches than participants in chemistry, physics and interdisciplinary science. The approaches used by physical science participants were very similar whereas those from pharmacy, sports rehabilitation and psychology were more varied and relied on students’ ability to relate to a familiar context. Evaluation of the relative quality of solutions showed variation with discipline.

Students as Co-creators: the Development of Student Learning Networks in PeerWise

PeerWise, an online tool that facilitates peer learning through student-generated content in the form of multiple-choice questions, was implemented in a large introductory university physics course. Interactions between students engaged in PeerWise were investigated using social network analysis. This showed that a dense and relatively equitable network was formed, giving students direct and easy access to the whole cohort through sharing and answering questions. A statistically significant correlation was found between students’ use of PeerWise and their performance in the end-of-course examination, even after taking into account their prior ability as measured by assessment prior to the start of the course. This suggests that students benefit from engaging with their peers, not only by sharing or answering a large number of questions but perhaps by being exposed to a wide range of question styles, levels, explanations and