The trajectory of a ball in air is affected by aerodynamic drag and lift. In general, the trajectory needs to be calculated numerically since the acceleration varies with time in both the horizontal and vertical directions. If the trajectory remains approximately parabolic, then simple analytical solutions can be found, giving useful insights into…

Teaching special relativity to lower-division students is challenging because results such as time dilation, length contraction, and frame dependence of simultaneity are counterintuitive. The literature is extensive, so only a brief list is given here, with articles divided roughly between discussions of general principles and calculations applied…

Simulation of physics phenomena is an indispensable part of experimental studies. Undergraduate and postgraduate physics students are often introduced to the simulation of various phenomena as one of the most important pedagogical tools. In this document, we demonstrate the simulations of the two-body decay of a particle and equilibrium states in…

A loop-the-loop experiment usually involves a ball rolling around a vertical loop. A different version of the experiment is described where a nut was allowed to slide around a vertical loop. In both experiments there is a large decrease in kinetic energy when the ball or the nut first enters the loop.

Bounded by the statements of Feynman and Galileo, I describe certain tricks that can be useful for the teaching of physics. In particular, I describe the calculation of the center of mass (centroid) of an arc of circumference and a circular sector. For this purpose, I also use Pappus's theorems. An Appendix is available with Archimedes' method to…

Experimental results are presented concerning the motion of a ball that bounces up an incline a few times then bounces back down again. The number of bounces up the incline is typically small since the speed of the ball in a direction parallel to the incline decreases rapidly, not only during each bounce but also while the ball is in the air. The…

In the movie Gravity, American astronaut and scientist Dr. Stone (Sandra Bullock) is on a spacewalk when tragedy suddenly strikes. An ever-increasing field of debris caused by a destroyed spy satellite damages the Hubble and Space Shuttle and quickly wipes out their mission. Dr. Stone spends the rest of the movie trying to find a ride back home.

A Slinky is a loose helical coil spring and is a well-known educational toy. In this paper a model for a Slinky is presented. The Slinky is represented as a sequence of rigid half coils connected by torsional springs. A range of Slinky configurations in static equilibrium are calculated. Where possible the torsion spring model is compared with the…

In physics education, the topic of electromagnetic induction is an important but also challenging topic for many students. The early introduction of formulae, e.g., Faraday's law of induction, seems to hinder rather than to foster the understanding of the topic's underlying principles. In this paper, we present the basic idea for a teaching…

It has long been suspected by general relativists that physicists who do not specialize in general relativity (GR) believe that special relativity (SR) is incapable of modeling dynamics within accelerated reference frames. Consequently, many physicists may conclude that certain phenomena, such as time dilation due to acceleration, can only be…

We describe a simple, intuitively appealing interpretation of the observed ellipsoidal shape of the rotating Earth: it is that surface everywhere perpendicular to the net force upon it.

The study of coordination complexes in general and inorganic chemistry courses is facilitated by theoretical frameworks such as crystal field theory (CFT) and ligand field theory (LFT). The angular overlap model (AOM) is alternative approach that quantifies metal-ligand interactions based on the geometric configuration of a given complex. In this…

Resonance is an important, and rather dramatic, phenomenon in physics. The mechanical case of a mass-spring oscillator is generally the first example that students encounter in introductory courses. In electromagnetism, the resonance in driven RLC circuits is presented in analogy with mechanics, since the mathematical equations describing them are…

Ion transport, involving the diffusion and migration of ions within the electrolyte, stands as a fundamental concept in electrochemistry and serves as the driving force for electrochemical reactions. Electric double layers are critical in the fields of electrochemical energy storage and chemical conversion, constituting a central focus of…

The Wilson cloud chamber is an apparatus used for detecting and observing the trails of alpha/beta rays or even cosmic rays in saturated gas conditions. The principle of this device is based upon the powerful ionization of the aforementioned rays within the medium. This article will provide instruction for creating a classic version of the cloud…