If a ball rolls in a circular path on a horizontal surface at constant speed then its horizontal rotation axis changes direction with time. A simple experiment is presented showing that the torque applied to the ball is equal to the rate of change of its angular momentum, even though the magnitudes of its angular velocity and angular momentum…

Purpose: Most neural and physiological research on stuttering focuses on the fluent speech of speakers who stutter due to the difficulty associated with eliciting stuttering reliably in the laboratory. We previously introduced an approach to elicit stuttered speech in the laboratory in adults who stutter. The purpose of this study was to determine…

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…

Inspired by a commercially produced scattering experiment that was popular beginning in the 1960s, we have developed a Nerf-projectile-based educational activity to demonstrate the basics of particle scattering experiments.

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…

Course-based undergraduate research experiences (CUREs) offer an expanding avenue to engage students in real-world scientific practices. Increasingly, CUREs are instructed by graduate teaching assistants (TAs), yet TAs may be underprepared to facilitate and face unique barriers when teaching CUREs. Consequently, unless TAs are provided…

Many aspects of electrochemical education, such as electroanalysis demonstrations, require three-electrode-cell experimental setups. Many researchers and educators use screen-printed electrochemical electrodes, which are miniature and disposable but are relatively expensive and use proprietary fabrication components. The present article describes…

High school students and students in the first years of college have difficulties in understanding the topic of stoichiometry and, in particular, the concept of limiting reactant. Proposals aimed at overcoming these learning obstacles tend to focus on analogies, and there are few sequences that approach teaching from an experimental perspective.…

Although diffusion is the subject of beginning chemistry classes, there are a variety of experiments, such as the spread of perfume in the classroom, that are often "incorrectly" explained by diffusion alone. To eliminate this common misconception, a recently published method is modified to determine the diffusion constant of hydrogen…

Exposure to real-life applications of quantitative analysis techniques based on two gas chromatography (GC) experiments was provided to a large cohort of sophomore-level students. In one experiment, students assessed blood alcohol content by internal standardization using a homemade headspace system similar to methods implemented in forensic…

We describe a series of three experiments in which students develop a model system for measuring the LC50 of household substances, using grass seed as the model organism. Students use statistical methods to compare two samples (using chi-square and Student's "t"-tests), conduct a two-level multifactor experiment to look at multiple…

The aldol condensation reaction is one of the many synthesis reactions carried out in second semester organic chemistry laboratories. This reaction was integrated into a novel experiment requiring students to synthesize dibenzalace tone derivatives using the crossed-aldol condensation by reacting different types of benzaldehyde derivatives with…

Oxygen reduction reaction (ORR),as a multielectron electrode reaction, is an important electrochemical reaction in the field of electrochemical energy storage systems. Herein, a new advanced electrochemical laboratory experiment is designed for undergraduates to master the preparation of oxygen reduction catalytic electrode. Students can use…

We present a modernization of the undergraduate physical chemistry laboratory experiment for determining the speed of sound in various gases from resonant frequencies in a spherical resonator. The resonator (schematic IR = 7.5 cm) is constructed by 3D printing with eco-friendly poly(lactic acid), a commercially viable alternative to traditional…