Redox reaction is a core concept in teaching and learning chemistry. This article explores a new method for balancing organic redox reactions that requires the balancing of both atoms and charges. The H+, O, H[subscript 2]O, and e- are used as balanced vehicles in two half reactions. A non-oxidation number approach can be applied to both molecular…

Morphology-dependent properties are significant in chemistry and material sciences. This laboratory experiment, designed for upper-division undergraduates in chemistry and related majors, emphasizes the concepts of the shape-controlled synthesis of crystal particles and the influences of crystal particle morphologies on their reaction…

The interference pattern between two harmonic oscillations with slightly different frequencies are called beats. The beats, as a combined motion, have two different periods, one approximately equal to the period of the original oscillations, and another that is significantly longer and is related to the variable amplitude of the motion. The main…

Oxidation number (ON) is taught as an electron-counting concept for redox reactions in chemistry curriculum. The molecular formula method, the Lewis formula method, and the structural formula method have all been used to determine ON. However, the task of assigning ON still poses problems for some teachers and students. This paper explores a new…

In this article, we construct a very simple double pendulum (the concept of a pendulum should be familiar to all beginning students of classical mechanics). Since a double pendulum has two degrees of freedom, we suggest that this pendulum can be used in the classroom environment to illustrate the concept of normal modes, and we use video software…

The reflection and refraction of light are more familiar to students than the reflection and refraction of sound. Reflection and refraction that occur during the transmission of sound waves are common phenomena in everyday life but are often difficult to understand during actual learning. In this study, we developed a sound reflection and…

The weight, one of the key concepts of physics education, still continues to be discussed among physics educators. Today, there are two main definitions as the 'gravitational' and 'operational', but there are differences even between them. It is important to know the different approaches found in textbooks in eliminating misconceptions and…

Ever wonder how an astronaut's mass is measured in space? Of course, a weight scale is of no use, because the astronaut and the scale are in free fall. Measuring the period of a spring mass oscillator is one way to measure mass. In this article, we will demonstrate a method to measure mass using a smartphone, a rubber band, and an app called…

Teaching special relativity to lower-division students is challenging because results such as time dilation, length contraction, and frame dependence of simultaneity are counterintuitive. The literature is extensive, so only a brief list is given here, with articles divided roughly between discussions of general principles and calculations applied…

Recently I took a walk through the physics demonstration room at Kenyon College, where I first started teaching in 1964. On an upper shelf was the little home-built apparatus in Fig. 1. This was used for one of two short single-concept films that I made in the 1970s. Both "The Magnus Effect" and "Optical Barrier Penetration"…

We sought to improve concept application in introductory mechanics by emphasizing causal statements (such as "forces change momentum") instead of laws (such as [delta]p=F[delta]t). Using student performance on a well-documented question, this intervention showed modest improvements. However, students in classes using recently introduced…

A drama model can be helpful to support children's understanding of some of the more abstract parts of the science curriculum. The drama models can usefully enhance children's understanding of scientific processes and concepts. They can help to link the practical activities with the conceptual understanding. The use of more than one way of…

This work provides a missing manual needed to understand permanent magnets (also known as "hard" magnets), the only source of "magnetic induction field B" (units of teslas), often called the magnetic field, that students are familiar with when they confront magnetic force acting on moving charges. Students see this magnetic…

A solenoid is a coil wound many times on a cylinder of length greater than its diameter. Solenoids are mainly used as electromagnets, because a magnetic field is formed when current flows through a solenoid. The solenoid described in secondary school and university textbooks is a single-layered solenoid. Further, textbooks and papers focusing on…

A simple experiment is described to compare the descent time between two vertically separated points when an object slides down tracks of varying shape. A surprising result is that the descent time is shortest when it follows a circular track rather than a cycloidal track. Cycloidal tracks are usually predicted to result in the shortest descent…