We present a simple experiment that allows us to demonstrate graphically that the intensity of sound waves is proportional to the square of their amplitude, a result that is theoretically analyzed in any introductory wave course but rarely demonstrated empirically. To achieve our goal, we use an audio signal generator that, when connected to a…

The question from the title is raised because in almost all introductory physics courses/textbooks the atmospheric pressure has been attributed to the weight of the column of air from a given level in the atmosphere up to its top. "Air is pressing on air." However the same textbooks, in the chapter on the kinetic theory of gases, tell…

Ever increasing technological progress opens novel opportunities concerning educational activities, and the ability to use the technology effectively is one of the 21st century's most demanding skills. The Partnership Forum for 21st-Century Skills (P21) states that no organization can achieve satisfying results without using technology and…

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…

To stimulate the intellectual curiosity of elementary school students, we conducted a workshop in distance education aimed at exploring the microscopic world inside a cell. In this workshop, elementary school students motivated to learn more on the subject of science analyzed movies of the Brownian motion of micrometer-sized particles suspended in…

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…

A simple experiment is described to verify the current dependence of Ampère's law for a long straight current-carrying conductor. A narrow and long rectangular multi-loop design is used to increase the strength of the magnetic field in between the long sides. As expected, the magnetic field is found to be linearly proportional to the electric…

The study of buoyancy is common in physics classrooms. In the last 20 years, several educators have described, theoretically and experimentally, buoyant forces and Archimedes' principle, both in "The Physics Teacher" and elsewhere. However, as far as I know, no one has reported on the pedagogical implications and experimental results of…

This paper describes an experiment with two touching rotating disks, whose movement is followed by video analysis. Within the disks' movements, there are intervals with sliding and intervals without sliding, that is, intervals with frictional forces between the touching surfaces and intervals without it. This system configuration allows for…

Optical polarization phenomena are omnipresent in physics, chemistry, biology, and technology. Studying optical polarization is best done through an interdisciplinary approach that combines biology and technology, which usually makes things more interesting to students. Seeing Haidinger's brush for the first time can be an exciting discovery for…

For science students doing traditional laboratory experiments, often it may feel as if the apparatus and experiment have been specifically chosen for good results. They suspect that the science they are learning in the classroom will not match nearly as well in the real world. However, many educators have observed that student motivation and…

One of the main topics of elementary physics is the idea that every material is composed of "little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one other." These particles could be atoms or molecules. Atoms are the smallest part into…

In this article, the dynamics of a traditional toy, the yo-yo, are investigated theoretically and experimentally using smartphone sensors. In particular, using the gyroscope the angular velocity is measured. The experimental results are complemented thanks to a digital video analysis. The concordance between theoretical and experimental results is…

Transistors are semiconductor devices that form the basis of today's electronic technology. Following the first step of developing a point-contact transistor developed by Walter Brattain and John Bardeen in 1947, the development of the junction transistor by William Shockley in early 1948 opened the way for rapid progress in electronic technology.…

The Michelson interferometer is one of the key experiments in modern physics when it comes to the topic of interference (Box 1). Experiments using interferometry have a high historic relevance as well as uses in current areas of research (quantum erasers, gravitational wave detection) and are used in higher education. Because of the high cost of…