The most common type of homopolar motor comprises a cylindrical neodymium magnet, a battery, and a non-ferromagnetic frame rotating around the battery. Here, the author substituted a coiled spring for the frame. Due to this change, a new and intriguing effect emerges, the axial buzzing of the spring during its rotation. This paper describes the…

We only became aware of the existence of bed prism spectacles when a student brought them to the classroom and asked us about how they work. The device proved to be a fertile source of curiosity among the students, and, to be properly understood, it required us to develop a comparison between reflection in a typical mirror and total internal…

A glass filled with carbon dioxide gas upside down on a plate of water constitutes an excellent demonstration of the solubility of gases. If the water level on the plate is maintained the CO[subscript 2] will slowly dissolve and the column of water will rise inside the glass, without quite reaching the ceiling, before an opposite process sets in:…

Should entropy and energy be emphasised as relevant concepts for biology education? This question will be discussed, highlighting the ways in which the concepts of entropy and energy can contribute to a better understanding of biological processes. Organisms are open systems. Therefore, the chosen perspective is different from the traditional…

Diagrams and photographs (or computer simulations) should not replace effective observations of the wave properties that can be illustrated using a ripple tank, but they can provide support when discussing and revising what has been observed. This article explains and illustrates a route towards successful photography, which is much easier with…

The classic jumping ring apparatus consists of a coil with an iron core that extends out of the coil. A copper or aluminum ring placed over the iron core jumps upward when AC power is applied to the coil. In this paper we will examine a modified design of the jumping ring apparatus, called the "long-coil design." It allows the ring to…

This article focuses on an illusion due to our perceptions regarding competing coordinate systems or frames. I share an interesting anecdote and then explain aspects of its origin, referencing other similar illusions in the literature. Although it is difficult to experience the phenomenon without visiting the hill, I have some suggestions to…

In biochemistry, the trivial names of chemical compounds constitute a significant part of scientific language. Understanding the etymology of the names may be important for the association of these names with actual compounds and thus be a valuable teaching tool. The citric acid cycle (Krebs cycle) is a central metabolic pathway in most living…

The non-SI unit sverdrup, named to honor Norwegian oceanographer and meteorologist Harald Ulrik Sverdrup (1888-1957), is adopted for quantifying large-scale volume transport by oceanographers, meteorologists, and atmospheric physicists. The sverdrup is used to appraise the volumetric rate of evaporation, precipitation, runoff, transport of ocean…

It is common in introductory physics to show that in the absence of air drag an object dropped from rest will reach the level ground at exactly the same time as one that is projected horizontally from the same height. However, the situation is different in the presence of a speed-dependent drag force, as either object may hit first or they may hit…

If a body is in equilibrium under the action of three non-parallel coplanar forces, the forces must be concurrent, that is, must meet at a single point. Specific examples are provided here to illustrate the validity of this statement by the use of free-body diagrams as well as during the discussion of equilibrium and moments. These cases are…

In our everyday life, it seems that magnetic phenomena are restricted to ferromagnetic materials or electromagnetism caused by electric currents. From a physics point of view, we know that this everyday experience is contrary to the nature of magnetic phenomena. If one regards the magnetic properties of the elements of the periodic table in their…

We have designed a simple Arduino-based experiment to study free fall. The experimental data associated to the free and vertical fall movement of a brass saucer are gathered with the help of an ultrasonic distance sensor and an Arduino board. The position-time curves obtained from different initial heights are then plotted and the acceleration of…

Ambient ionization mass spectrometry enables rapid in-situ analysis of a plethora of analytes that are relevant to the forensic and defense communities. As the arsenal of ambient ionization techniques, aimed at solving specific targeted problems, continues to expand, the adoption of these techniques into non-academic settings has been relatively…

This qualitative case study delved into students' understanding and positioning while they participated in solving an authentic, conceptually-based problem in a high-school chemistry class. Verbal and nonverbal cues, particularly gestures, offered broader awareness of students' engagement in sensemaking during the learning experience. The…