A new system for tracking a metal ball rolling on the slope of the touch panel of a tablet computer was developed. The widespread introduction of tablets in educational environments allows the use of a convenient dynamic measurement in schools.

Experiments involving RC circuits are an integral part of introductory physics courses. Previous articles using RC circuits describe determining the charge on a Van de Graaff generator, measuring currents and voltages in a charging RC circuit using a multimeter or an Arduino, measuring the decay constants of complex RC circuits, and using the…

A smartphone is a powerful learning aid in the hands of a large section of students around the world. The camera of the phone can be used for several learning purposes apart from its obvious purpose of photographing. If the focal length of the lens of the camera can be determined, several experiments in optics can be performed with it. In some…

The early 20th century marked a number of transformational experimental and theoretical discoveries in physics. Among them is one that is often neglected in the introductory physics curriculum, which revolutionized our understanding of the molecular world. Evidence for the thermal motions of atoms was first observed by Perrin in 1909, which had…

George M. Hopkins (1842-1902) wrote a series of articles on demonstrating physical phenomena in the "Scientific American" during the last years of the 19th century. These were collected in a book, "Experimental Science," that was first published in 1890, with revisions in 1892 and 1902. It must have been well received, for the…

Gravity bends light. One can argue this by reasoning that a beam of light should travel in a curved path when viewed from within an accelerating frame of reference, and then invoking Einstein's principle of equivalence, which asserts that the effects observed in an accelerating frame of reference are indistinguishable from the effects observed in…

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…

We demonstrated that an optimally designed pinhole camera can be used as an astronomical tool to observe the libration and apparent diameter change of the Moon at night. The libration and apparent diameter change of the Moon were observed using a handmade pinhole camera with a diameter of 0.65 mm and a focal length of 400 mm. It was found that the…

Nearly everyone, including physics students, finds rainbows to be fascinating and much has been written about them. For example, in a 2020 paper, Kenneth Ford sets forth the basic theory of rainbows created by water droplets at the level of geometric optics and uses a graphical approach to address the question of the relative intensities of the…

Atwood invented a machine in the 1780s that enabled him to observe the motion of a falling body as slowly as desired. This machine was equipped with the necessary means to measure the distance covered by the body and the time taken. With this data, it was possible, in addition to studying the falling motion, to calculate the local gravitational…

In this paper, we utilize the readily known theory of the ideal transformer to furnish a self-contained qualitative explanation on the AC-powered Thomson jumping ring (TJR) experiment.

We investigated a very long chain falling from the pile on the edge of a table to the floor both experimentally and theoretically. In this very simple and novel configuration we showed that the velocity of the chain quickly converges to its asymptotic value, and that the steady-state velocity is proportional to the square root of the height of the…

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…

Our first experience of dimension typically comes in the intuitive Euclidean sense: a line is one dimensional, a plane is two dimensional, and a volume is three dimensional. However, following the work of Mandelbrot, systems with a fractional dimension, "fractals," now play an important role in science. The novelty of encountering…

Electromagnetism is a complex topic for students at different educational levels. Perhaps one of the reasons for this is that students are unable to visualize the forces, fields, currents, and other electromagnetism key concepts that are related to the topic. Most teachers address this difficulty by including the use of some technological…