It is well known that the needle of a compass in a magnetic field deflects, and that a compass near a conductive wire carrying a stable electric current deflects its needle. The only explanation of this observation is that the current-carrying wire creates a magnetic field around it. The strength of the magnetic field at any point near the wire…

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…

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.

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-performance liquid chromatography (HPLC) experiments are an important part of the undergraduate analytical instrumentation laboratory courses and usually use commercial C18 silica-packed reversed-phase columns. In this experiment, a simple method of preparing SiO[subscript 2] core-shell packed columns was developed to enable students to…

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.…

After a time away from the classrooms and laboratories due to the global pandemic, the return to teaching activities during the semester represented a challenge to both teachers and students. Our particular situation in a Microbial Physiology course was the necessity of imparting in shorter time, laboratory practices that usually take longer. This…

The activity proposed in this study aims to investigate the equilibrium between the liquid and vapor phases in a mixture of water and acetic acid, both of which are volatile substances. High school students can easily determine the composition of the liquid phase and its corresponding vapor phase at equilibrium using a simple and conceptually…

The helium-plasma (HePI) ionization mass spectrometry method was used to track the formation of reaction products and consumption of reactants by continually monitoring the vapors in the reaction headspace in real time. Two examples of the application procedure are presented here: a nucleophilic acyl substitution reaction and a 1,4-nucleophilic…

An introductory experimental course to teach and assess basic organic synthesis and identification skills has been designed. The first work of this course, which is based on the well-known hydrazone formation reaction of benzaldehydes with Brady's reagent, is presented. The designed experiment has many advantages and perfectly matches the goal of…

Quinacridone red and violet are visually different colors, an observation confirmed by their visible reflectance spectra and CIE L*a*b* coordinates. However, their IR spectra are extremely similar. Though chemically identical, the two quinacridones are polymorphs. In this experiment, designed for and tested by nonscience majors, the pigments are…

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…