Electrification by rubbing different materials is a well-known phenomenon with a history that began more than five centuries B.C. ago. However, simple experiments can lead to contradictory or inconsistent results, and the history of this phenomena is plagued with non-intuitive results. For example, triboelectric charging by rubbing identical…

What happens when a perfectly elastic ball collides with a completely inelastic ball? It is shown that the outcome depends on the stiffness of each ball. A standard textbook problem in mechanics is to calculate the outcome of a head-on collision between two balls using conservation of momentum and kinetic energy. It is easily shown that the…

The mathematical form of the magnetic field due to a current loop, and the fact that it is identical to the electric field due to an electric dipole in the far field, are fundamental to our understanding of electromagnetism. While undergraduate level electromagnetism textbooks usually derive the electric field from an electric dipole, few derive…

Physics II is an undergraduate course on basic electromagnetism that I teach for engineers, and it includes topics from optics as a natural application. Among the many challenges of conducting video lectures during the local restrictions of the SARS-CoV-2 epidemic was finding demonstration material. In this article, I describe how these…

The measurement of the charge-to-mass ratio, e/m, of the electron is a fundamental part of any study of electricity and magnetism. It is possible to use an apparatus designed to measure e/m for other things, including investigations of electron flow through a near vacuum, measuring a work function, and even exploring some quantum mechanics…

In an earlier article I argued that much of what used to be called "modern physics" stems from the intersection of two earlier technologies: high vacuum and high voltage. In this article I will discuss the induction coil, invented in the 1830s, reinvented in the second half of the 19th century, and still used today to produce the high…

In this paper I describe an interactive Gauss's law computer simulation using the GlowScript programming environment. The simulation calculates a point charge's electric field at locations on the surface of a Gaussian cube and displays the electric field in GlowScript's 3D graphics window. The point charge can be moved, and the electric field…

In one of the Faraday's experiments an electric current is induced in a conducting loop when a magnet in front of it moves towards or away from the loop. While the direction of circulation of the electric current in the loop has only two options, it depends on three experimental conditions that generate eight cases. Even though the Faraday law or…

Exploding pumpkins with rubber bands remains a popular demonstration of the conversion of spring potential energy into kinetic energy. Videos of laughing and squealing children and adults being pelted with pumpkin fragments have millions of hits on YouTube, and the activity has even been featured on talk shows like "The Tonight Show Starring…

Recently, small computer fans have been demonstrated to be an effective method for teaching simple resistive circuits both qualitatively and quantitatively. The current through the fans is related to the rotational speed of the fans and allows multiple senses to be engaged (touch, sight, and hearing). Methods for learning simple circuits in an…

An electric motor converts electrical energy into mechanical work and an electric generator converts mechanical work into electrical energy. The symmetry between the motor and generator naturally leads to questions about creating a perpetual motion machine. The allure of this question has inspired textbook problems, physics education articles, and…

The law of conservation of momentum can be applied to a wide range of processes whether it is the collision of subatomic particles, rocket propulsion, or the recoil of a cannon. In this experiment two technologies, the Arduino microcontroller and a PASCO smart cart, are used to create a movable rubber band launcher. The Arduino microcontroller is…

In this work, we will describe a Peer Project Learning assignment focused on the STEM project-based learning activities where students build a custom board game with a series of constraints that guide them to learn (and later teach) about the main concepts of an electromagnetism physics course for undergraduate students.

A previous journal article established that a hanging Slinky's restoring force is due only to the coils between the support and the Slinky's center of mass (hereafter COM). Correspondingly, it is expected the Slinky's elastic potential energy (hereafter EPE) is associated with only those coils; however, there is no confirming experimental…

Physics experiments powered by a universal serial bus (USB) connection are becoming increasingly common. With teachers going through so many batteries each year, USB-powered physics provides an economical and environmentally friendly alternative. In this article, the authors discuss several ways that USB power can provide a convenient way to do…