These brief summaries are designed to help readers easily see which articles will be most valuable to them. The online version contains links to the articles.
Letters to the editor
“Entropy production diagrams”
Ramandeep S. Johal
92(9), p. 647. https://doi.org/10.1119/5.0226811
“It is time to honor Emmy Noether with a momentum unit”
Geoff Nunes, Jr.
92(9), p. 647. https://doi.org/10.1119/5.0229624
Resource letter ALC-1: Advanced laboratory courses
Walter F. Smith
92(9), p. 648. https://doi.org/10.1119/5.0209841
For many undergraduate students, the advanced laboratory course is instrumental in their development into experimental physicists. Over the past two decades, the advanced laboratory course has seen a renaissance with over 250 articles written describing experiments that can be adapted and adopted for these courses. This Resource Letter provides a detailed list of resources spanning books and articles to organizations and vendors that support advanced laboratory courses.
Data science education in undergraduate physics: Lessons learned from a community of practice
Karan Shah, Julie Butler, Alexis V. Knaub, Anıl Zenginoğlu, William Ratcliff, and Mohammad Soltanieh-ha
92(9), p. 655. https://doi.org/10.1119/5.0203846
Are you interested in adding data science concepts to your physics curriculum, but unsure where to start? If so, you may be interested in the new Data Science Education Community of Practice that offers guidance, inspiration, and resources for physics teachers like you, along with the results of faculty and industry surveys highlighting the skills that will be most useful to your students.
Application of the heat equation to the study of underground temperature
Mathis Caprais, Oriane Shviro, Ugo Pensec, and Hermann Zeyen
92(9), p. 663. https://doi.org/10.1119/5.0196139
Frequently, modeling the three-dimensional world is too challenging for a class exercise, and we instead teach students using unrealistic one-dimensional problems. So it is wonderful when a one-dimensional model turns out not only to be fairly accurate but also to have real-world implications. That is the case with heat flow through the soil, which can be treated with a one-dimensional model and which is important to energy-efficient solutions such as underground housing and ground-source heat pumps. This paper finds the underground temperature as a function of depth through measurements, analytical solutions, and computational solutions. These solutions can form the basis for a very interesting class assignment. In addition to considering heat transport through conduction, the model also includes heat transport through the flow of rain water.
A linear-algebraic derivation of the Lorentz transformation
Phil Schwartau
92(9), p. 670. https://doi.org/10.1119/5.0216153
Physics instructors know there are many ways to derive the Lorentz equations, and we all have our favorites. But take a look at this one, and you may find a new favorite. Appropriate for special relativity courses, as long as the students have some familiarity with linear algebra.
Photon under repeated transverse Lorentz boosts: An apparent paradox
Tugdual LeBohec
92(9), p. 674. https://doi.org/10.1119/5.0193902
Could two observers see the same photon traveling in opposite directions? It doesn't seem possible without introducing faster-than-light travel or causality issues, yet all you need is a few successive perpendicular Lorentz boosts to arrive at a frame of reference where the photon momentum direction is reversed. The author introduces this new special relativity paradox and its resolution, offering new ways to think about the symmetries of the Lorentz transformation and pedagogical motivations for the Wigner rotation.
Remarks on the yield of fission bombs
J. M. Pearson and B. Cameron Reed
92(9), p. 680. https://doi.org/10.1119/5.0166291
Both awe-inspiring and terrifying, a nuclear explosion is a spectacular display of microscopic physics profoundly affecting the human scale. This paper explores the physics of nuclear explosions and addresses the counter-intuitive fact that the total energy released by a fission bomb is independent of the energy released in a single fission. While this was known to the scientists who developed the atomic bomb, much of their work is classified and their knowledge remains inaccessible to the general public. With only a few historical documents to go on, the authors of this article attempt to recreate a calculation by Manhattan Project scientists and clearly show why the total energy yield is independent of the energy released by each fissioning nucleus. This article will be of interest to readers interested in nuclear physics, or in the history of the Manhattan Project.
Understanding exotic black hole orbits using effective potentials
Steven Pakiela, Brett Bolen, Benjamin P. Holder, Monica Rizzo, and Shane L. Larson
92(9), p. 686. https://doi.org/10.1119/5.0149655
Newtonian orbital mechanics is clean and orderly, with bound orbits being closed ellipses. Relativistic effects spoil this simplicity; in a weak gravitational field (e.g., the solar system), general relativity famously predicts orbital precession. In the strong gravitational field near a black hole, orbits can become tumultuous, appearing chaotic and unpredictable. “Zoom-whirl orbits” are extreme examples of this behavior, where the orbiting object plunges close to the black hole, whirls around it many times, and then heads back out to a larger radius. The authors of this article demonstrate how these complex orbits (which are of interest in gravitational wave astronomy) can be understood using the undergraduate physics of effective potentials. Computational tools are also developed and are freely provided to anyone interested in studying gravitational wave signatures from such orbits. Readers interested in black holes and relativity (and who have been intimidated by advanced mathematical treatments elsewhere in the literature) will find this article fascinating and instructive.
Probing coherent phonons in the advanced undergraduate laboratory
Nicholas J. Brennan, Joseph Peidle, Anna Wang-Holtzen, Jieping Fang, Kathryn Ledbetter, and Matteo Mitrano
92(9), p. 693. https://doi.org/10.1119/5.0190019
This paper provides an introduction to modern time-domain spectroscopy using ultrafast lasers, an experimental technique used to observe fundamentally important phenomena in condensed matter physics as well as in other fields. As a specific example, the authors demonstrate the generation and detection of coherent phonons in three solids. The paper provides an undergraduate-accessible discussion of the theory of coherent phonon spectroscopy in terms of classical harmonic oscillator physics. Then, a relatively low-cost ultrafast pump-probe spectroscopy system and the experimental procedures that the authors use in their experiment are described. Finally, typical experimental data and analysis methods are presented. This laboratory experiment is a welcome addition to the undergraduate physics curriculum, introducing a system that is suitable for examining a variety of ultrafast and nonequilibrium phenomena in an advanced instructional laboratory.
Bringing graphene into the undergraduate classroom
Andrew Seredinski, Tedi Qafko, Nathanael Hillyer, and Alexander Norman
92(9), p. 703. https://doi.org/10.1119/5.0164700
An experiment that introduces students to ultrathin graphene is presented. In this experiment, students fabricate a sample consisting of few-layer graphene flakes atop of a silicon wafer substrate using the mechanical exfoliation method and then use a microscope to acquire images of the sample under white-light and LED illumination. The images are analyzed to produce optical contrast values (a measure of the reflectance of the graphene flakes) as a function of illumination wavelength, and these experimental values are compared to a theoretical model for optical contrast based on thin-film interference, yielding a value for the graphene flake's layer thickness. This experiment is designed for advanced instructional laboratory and upper-level optics courses. It may also be simplified into a qualitative introductory physics laboratory, demonstration, or outreach workshop activity.
Bose and the angular momentum of the photon
Kirk T. McDonald
92(9), p. 711. https://doi.org/10.1119/10.1119/5.0229168
The year 2024 is the 100th anniversary of the publication of Bose's paper on quantum statistics, the submitted version of which, according to several sources, postulated the existence of photon's angular momentum. This Note provides a brief summary of the state of knowledge of both quantum mechanics and electromagnetism at that time, pointing out that, “The process of ‘discovery’ of novel concepts in physics is seldom crisp, and many people must become involved before a new idea is well accepted.” Readers will appreciate the detailed references that enable further exploration.
Comment on “Which is greater: eπ or πe? An unorthodox physical solution to a classic puzzle”
Roderick M. Macrae
92(9), p. 717. https://doi.org/10.1119/5.0221403
In a recent paper [Am. J. Phys. 92(5) 397–398 (2024)], Vallejo and Bove used the second law of thermodynamics to show that eπ > πe by imagining a finite body of initial temperature π placed in contact with a reservoir at temperature e. This comment on that work explores the situation more generally, showing that the result depends upon neither the value of π nor the second law. Rather, Vallejo and Bove's result is a limited proof of the second law in the case of their particular example. Appropriate for thermodynamics students at all levels.
Review of Beautiful Experiments: An Illustrated History of Experimental Science by Philip Ball
Rena J. Zieve, Reviewer
92(9), p. 719. https://doi.org/10.1119/5.0231571
