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Reasoning about the concept of electric charge, and the meaning of the term &quot;net charge&quot; in particular, presents a greater learning challenge than students and instructors might initially recognize. This may be due in part to subtleties in the use of positive and negative signs to characterize complementary charges, rather than to indicate that the quantities are greater than or less than zero. In this talk, we discuss the nuances of electric charge as a physical quantity and situate it in a body of work by mathematics and physics education researchers to characterize the uses and meanings of signs. We then describe preliminary research that illustrates the effect of wording differences on student reasoning about electric charge as a signed quantity and discuss implications for instruction.

AAPT SM 21

Electric charge as a signed quantity

negative sign

mathematical reasoning

electric charge

Join AAPT and Physics Educators worldwide in developing and strengthening your professional connections by attending the 2021 AAPT Virtual Summer Meeting. AAPT meetings are a great way to reflect on your teaching, recommit to best practices and re-energize your career with new research, products, and techniques.

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Reasoning about the concept of electric charge, and the meaning of the term "net charge" in particular, presents a greater learning challenge than students and instructors might initially recognize. This may be due in part to subtleties in the use of positive and negative signs to characterize complementary charges, rather than to indicate that the quantities are greater than or less than zero. In this talk, we discuss the nuances of electric charge as a physical quantity and situate it in a body of work by mathematics and physics education researchers to characterize the uses and meanings of signs. We then describe preliminary research that illustrates the effect of wording differences on student reasoning about electric charge as a signed quantity and discuss implications for instruction.

technical paper

Instead of written homework, I collect videos of students doing and explaining their work. I'll talk about why I do this, the value of seeing the process in addition to the product, and the logistical problems and solutions I've come across. I do this for small and big classes, lectures and labs, theory and coding. The biggest upsides are a much better understanding of the students' understanding along with a dramatic reduction in cheating. Typical videos are 3-5 minutes in length and I watch them at double speed. This allows me to grade up to 1000 videos per class per semester.

The value and logistics of student-submitted videos for homework

The Classical Mechanics course taught at BC in Fall 2020 used a hybrid of model of class instruction, combining students learning remotely and students attending in person into a single synchronous class. Past offerings of this course used hands-on lab experiments to engage students in mathematical modeling of oscillators and other mechanics topics. To give all the learners a uniform experience, lab experiments in 2020 were replaced with group video analysis projects, integrating lecture, experiment, and computation. The videos were used to scaffold increasingly nuanced computational models. For example, for oscillations, student videos of everyday objects oscillating were solicited and exploited as a “hook” to introduce modeling of undamped springs, and the discrepancies between theory and experiment were used to motivate damped models. This structure was inspired by Brian Lane’s “Capture, Code, Compare” activities.

Labs in Intermediate Mechanics: Combining Student-Made Videos with Computational Modeling

This talk provides an introduction to the mission, features, and types of articles in the American Journal of Physics with a goal of helping potential authors understand how to prepare a submission.

Publishing in the American Journal of Physics

Visual pop culture has been employed for physics education because novel examples from visual pop culture can capture students’ attention. Although widely enjoyed by people around the world, Japanese animation (Anime) has been used less frequently than other types of visual pop culture. In this presentation about our recent paper published in “The Physics Teachers”, we introduce how Anime examples can be used to teach fluid mechanics concepts including buoyant force, drag, lift, and key dimensionless numbers such as Reynolds number. This approach was employed in an undergraduate-level fluid mechanics class, and many students were positive about using Anime for teaching fluid mechanics because the examples provided a break from the normal methods of teaching and students were more engaged with the content that they learned. Therefore, Anime has the rich potential as a source of instructional examples that illustrate concepts from fluid mechanics and other areas of physics.

Using Japanese Animation (Anime) for Teaching Fluid Mechanics

Surface charges direct the flow of current through conductors. In anthropomorphic terms, they tell the current where to go and where not to go. As acknowledged by Professors Griffiths, Jackson, and Chabay and Sherwood, surface charges have been difficult to calculate. This paper presents a new way to calculate surface charges in which the surface of the conductor is covered with pixels which hold the surface charge. The pixels (referred to as "sensing pixels") sense the electric fields produced by all the other charges in the system and adjust their internal charge until steady state is reached. Importantly, sensing pixels allow students (and researchers) to understand why surface charge distributions, however calculated, look the way they do by asking the simple question: "What would a sensing pixel sense?" As Professor Sherwood kindly wrote to the author, this can make such counterintuitive phenomena as the accumulation of charges at edges, intuitive.

Surface Charges from a Sensing Pixel Perspective

Looking back, it has been a year like no other for The Physics Teacher. I will shine a spotlight on some of our recent content such as the exciting collection of articles on sex, gender and physics teaching, while also reflecting on some of the metrics we use to measure what we produce. In addition I will attempt to convey some glimpses of possible future feature items in TPT.

TPT Highlights from a Challenging Year

In our presentation, we discuss gender inequality in the physics classroom. Diversity strengthens science, but in most physics classrooms female students are disadvantaged both directly and indirectly: extensive research shows that they are undermined, viewed as less capable, and have less successful experiences both in terms of learning and identity formation. In this article and presentation, written in partnership between a male high school physics teacher and a female student from his 2018-2019 12th-grade physics class, we describe a two-week period in which we worked together to try to change the culture of our physics class.

The Elephant in the (Class)Room: Discussing Gender Inequality in Physics

The Physics Teacher focuses on teaching introductory physics at the high school, two- and four-year college, and university levels. Typical topics include innovative physics demonstrations, new ways of doing lab experiments, ideas for presenting difficult concepts more clearly, suggestions for implementing newer technology into teaching, historical insights that enrich the physics course, and suggestions for using results from physics education research, all focused on teachers in the introductory physics classroom. I’ll discuss our newest process for submitting manuscripts and what to expect after you submit your work.


Submitting a manuscript to The Physics Teacher

The biological cell exhibits a fantastic range of behaviors, but ultimately these are governed by a handful of physical and chemical principles. Here we explore simple theory, known for decades and based on the simple thermodynamics of mixtures of ideal gases, which illuminates several key functions performed within the cell. Our focus is the free-energy-driven import and export of molecules, such as nutrients and other vital compounds, via transporter proteins. Complementary to a thermodynamic picture is a description of transporters via "mass-action" chemical kinetics, which lends further insights into biological machinery and free energy use. Both thermodynamic and kinetic descriptions can shed light on the fundamental non-equilibrium aspects of transport. Our biochemical-physics discussion will remain agnostic to chemical details.

Key biology you should have learned in physics class

The conceptual development of student understanding of weight
Xiangqun Zhang and Lei Bao
Existing research has reported persistent difficulties among students at all levels in understanding the concepts involving weight and gravitation. In the literature and textbooks, there are two versions of weight definition in terms of (1) the gravitational force applied on an object and (2) the force applied on the supporting object. The latter is often referred to as the operational definition of weight, which describes the process of weighing an object. Studies have also demonstrated that using the operational definition in teaching can improve student understanding of the concepts involving weight, gravitation, and weighing. However, in the Chinese middle school physics curriculum, the gravitational definition of weight is mandated and universally implemented in instruction. To investigate the impact on student learning from using the gravitational definition of weight, a post-instruction survey is conducted to examine students’ conceptual understandings of weight. The results will be discussed and compared to the literature.


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