Popular Physics
In July 5th 2014 an occultation of Mars by the Moon was visible in South America. Citizen scientists and professional astronomers in Colombia, Venezuela and Chile performed a set of simple observations of the phenomenon aimed to measure the…
A Faraday cage is an interesting physics phenomena where an electromagnetic wave can be excluded from a volume of space by enclosure with an electrically conducting material. The practical application of this in the classroom is to block…
Infectious disease remains, despite centuries of work to control and mitigate its effects, a major problem facing humanity. This paper reviews the mathematical modelling of infectious disease epidemics on networks, starting from the…
A "space drive" is a hypothetical device that generates a propulsive force in free space using an input of power without the need for a reaction mass. Any device that generates photons (e.g., a laser) would qualify as a propellantless…
A modern elementary introduction to special relativity for advanced school children or first-year university students, in Russian. I try to demonstrate that relativity does not contradict common sense; on the contrary, it follows from…
This article provides some historical background and then reviews developments in string theory over the last twenty-five years or so. Both perturbative and non-perturbative approaches to string theory are surveyed and their impact on how…
A general relativistic description of a disk rotating at constant angular velocity is given. It is argued that conceptually this direct approach poses fewer problems than the special relativistic one. For observers on the disk, the geometry…
The use of compressed air cannons in an undergraduate lab provides a way to illustrate the cooperation of diverse physics concepts, such as conservation of momentum, the work-kinetic energy theorem, expansion of gas, air drag, and…
If one asked some friends where on the horizon they should expect to see the sunrise, half of the answers would be "in the east". Of course, something analogous would happen with the sunset and the west. However, sunrise and sunset…
We present a new robust setup that explains and demonstrates the quantum of electrical conductance for a general audience and which is continuously available in a public space. The setup allows users to manually thin a gold wire of several…
The ill-posed projectile problem of finding the source height from spattered droplets of viscous fluid is a longstanding obstacle to accident reconstruction and crime scene analysis. It is widely known how to infer the impact angle of…
We explore the gravitational dynamics of falling through planetary interiors. Two trajectory classes are considered: a straight cord between two surface points, and the brachistochrone path that minimizes the falling time between two…
The job of a physicist is to describe Nature. General features, hypotheses and theories help to describe physics phenomena at a more abstract, fundamental level, and are sometimes tacitly assigned some sort of real existence; doing so…
The volume of air that goes in and out of a musical instrument's sound hole is related to the sound hole's contribution to the volume of the sound. Helmholtz's result for the simplest case of steady flow through an elliptical hole is…
I discuss some interesting classroom demonstrations of diamagnetism and how this effect can produce levitation. The possibilities for hands-on demonstrations of diamagnetic and superconducting levitation are discussed. To conclude I discuss…
The first order equation relating object and image location for a mirror of arbitrary conic-sectional shape is derived. It is also shown that the parabolic reflecting surface is the only one free of aberration and only in the limiting case…
Our aim in this proposal is by using the Faraday's law of induction as a simple lecture demonstration to measure the Earth's magnetic field (B). This will also enable the students to learn about how electric power is generated from the…
Three separate questions of relevance to Major League Baseball are investigated from a physics perspective. First, can a baseball be hit farther with a corked bat? Second, is there evidence that the baseball is more lively today than in…
A discussion is given of Robert Brown's original observations of particles ejected by pollen of the plant \textit{Clarkia pulchella} undergoing what is now called Brownian motion. We consider the nature of those particles, and how he…
In this paper we show that with the help of accessible, teaching quality equipment, some interesting details of the motion of a gyroscope, typically overlooked in introductory courses, can be measured and compared to theory. We begin by…