The concepts of electronegativity and classical electronegativity scales are briefly described. Electronegativity scales have practical quantitative applications, and this work suggests activities which can assist students select the scales for use in chemistry applications. It provided examples of the use of an appropriate electronegativity…

An exciting recent development in chemistry has been the ability to control nanoparticle crystal morphology or shape. Nanoparticles of different shapes present different crystal surfaces (or facets) with respect to the surrounding environment. Synthetic control over nanoparticle morphology has enabled the study of the influence of surface facets…

If an empty coffee cup is spun on a horizontal surface about a vertical axis in an anti-clockwise direction, then the whole cup rotates slowly backwards, in a clockwise direction, about a vertical axis located outside the cup. Clues to this curious behaviour are presented by comparing it with other spinning objects.

How many vertical jumps does it take to jump off of a rotating merry-go-round (MGR)? The answer is hidden in the expression: "r[subscript n]" = "r[subscript 0]" (1 + ["beta superscript 2") ["superscript n/2"]. When you make a vertical jump on a train moving on a straight line at constant speed (inertial…

The relativistic addition of velocities is usually introduced early in the study of Einstein's special theory of relativity. The equations are simple enough, but randomly chosen velocities lead to unwieldy calculations that can dishearten the student. This paper presents tables of velocity components in two dimensions, composed of five or fewer…

A key concept in current fluid dynamics and its applications to biology and technology is a phenomenon known as wetting. Wetting is familiar from everyday life and is simply the ability of a liquid to stay in contact with a solid surface. The wettability depends on the properties of the liquid and the solid and can be characterized by the static…

One of the most important aspects associated with the modern production of chemicals is sustainability. To teach students and young scientists to design their research in the spirit of "sustainable development," students should be made accustomed to seeking solutions that are not only efficient and cost-effective but also safe and…

Science is the activity of studying the natural world in various ways to construct theories and models to explain phenomena. Windschitl et al. reported that model-based inquiry includes the connection between observable aspects of the target phenomenon and conjectured underlying causal processes. In addition, they insisted that learners are…

Modeling is a core practice in science and is a meaningful way to learn the subject. This article introduces a modeling-based approach that highlights the idea that modeling is an iterative process and integrates the fundamental parts of scientists' work and key suggestions for teaching through modeling. The lesson "The Structure and Function…

Quantum science is in the news daily and engages students' interest and curiosity. A fundamental quantum science concept that underpins medical imaging, quantum computing and many future technologies is quantum spin. Quantum spin can explain many physical phenomena that are in the lower secondary school curriculum, such as magnetism and light,…

Photochemical reactions are initiated by the absorption of light, triggering the chemical reactions and resulting in the formation of products. These reactions are generally performed using a freely available renewable source of energy-solar energy. Solar simulators mimic both the ultraviolet and visible regions of sunlight and hence can serve as…

The mathematical form of the magnetic field due to a current loop, and the fact that it is identical to the electric field due to an electric dipole in the far field, are fundamental to our understanding of electromagnetism. While undergraduate level electromagnetism textbooks usually derive the electric field from an electric dipole, few derive…

The rapid growth of personal electronics has promoted a surge of e-waste worldwide. Among the e-waste stream, waste printed circuit boards (WPCBs) contain a lot of recyclable valuable metals that can incentivize the recycling operation when recovered. This pedagogical exercise demonstrates a simple electrocatalytic metal recovery strategy that…

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…

"k[subscript cat]/K[subscript M]" is a fundamental kinetic parameter as important as "k[subscript cat]" in enzyme kinetics. Although the parameter provides critical information on how the enzyme lowers the energy barriers along the reaction pathway for catalysis, "k[subscript cat]/K[subscript M]" is frequently…