We have added two improvements to a self-luminous LED stroboscope (a flashing point-like projectile developed for introductory mechanics): downsizing by replacing heavy and risky batteries with a compact and safe capacitor of several Farads (a so-called Super-C) and wireless control via ordinary IR (infrared) communications. Consequently, the…

An alternative way of introducing magnetism at all levels of education is proposed. It is stressed that magnetism can be introduced through the interaction between current-carrying conductors giving the students, at the same time, the possibility to measure the magnetic permeability [mu][subscript o]. Focusing on currents instead of permanent…

Protein PEGylation refers to the covalent binding of polyethylene glycol (PEG) moieties to a protein and has been increasingly applied, mainly in the biopharmaceutical industry. This technique may increase bioavailability and stability by decreasing immunogenicity and proteolytic attack. Given the industrial interest and the relevance of this…

When Mentos candies are dropped into a bottle of Diet Coke, a foamy fountain jets out of the beverage container. It has previously been argued that ingredients found in Mentos candies significantly enhance this fountaining effect. Other previous work has demonstrated that the kinetics of foam production can be quantitatively monitored using a…

In this work we study the motion of a small metal ball along an inclined multi-slotted track. Specifically, the effect of the slot width on the ball speed at the lower part of the track is analyzed in detailed both analytically and experimentally. Experimental results are in satisfactory agreement with the theoretical model.

This paper describes an experiment with two touching rotating disks, whose movement is followed by video analysis. Within the disks' movements, there are intervals with sliding and intervals without sliding, that is, intervals with frictional forces between the touching surfaces and intervals without it. This system configuration allows for…

The Griess assay is widely used by regulation agencies as an official method for nitrite quantification in water and food samples. In Brazil, the official method, which has been used to determine nitrite in food, was described by Instituto Adolfo Lutz (283/IV) in 1984. It uses 8 mL of reactants and provides 50 mL (reactants plus sample) of waste…

Lampworking is a valuable skill for students in Chemistry and others in science, technology, engineering, and math (STEM) related fields. The activity described here provides instructors the resources to both learn and teach the fundamentals of lampworking. Soft glass, which can be shaped and fused with a Bunsen burner, is used to improve the…

The framework of ecosystem services (ES) and disservices (ED) has increasingly been used in various science, technology, engineering, and mathematics (STEM) disciplines, including soil science. The objectives of this study were to use ES/ED concepts to extend and test an existing lecture and laboratory exercise on soil organic carbon (SOC) in an…

The practical two-step synthesis of 1-phenylthiourea is reported here as an undergraduate experiment for the organic synthesis laboratory. The reactions involved in 1-phenylthiourea preparation are very useful didactic examples to illustrate concepts relating to carbonyl substitution and addition, the effect of pH on solubility of organic…

Optical polarization phenomena are omnipresent in physics, chemistry, biology, and technology. Studying optical polarization is best done through an interdisciplinary approach that combines biology and technology, which usually makes things more interesting to students. Seeing Haidinger's brush for the first time can be an exciting discovery for…

A quantitative titration of the amount of magnesium hydroxide in milk of magnesia using only items purchased in grocery and retail stores is reported. Either vinegar or a solution of food grade citric acid serves as the titrant, while food dyes advertised as being extracted from natural sources provide the end-point indicator. An inexpensive,…

The role and efficacy of the laboratory in chemical education have recently been a subject of renewed discussion as researchers are called upon to address the question of whether laboratory education lives up to expectations. The COVID-19 pandemic, which forced most of the global student population to temporarily adopt remote learning, offers an…

There has been dramatic growth in interest and research regarding organic photochromism in recent decades. Despite this, the topic is seldom addressed in the undergraduate chemistry curriculum. Herein, we present a straightforward and robust experiment for the second semester organic chemistry laboratory curriculum which combines multistep…

Surface chemistry impacts technology, advancing the development of new heterogeneous catalysts, semiconductor devices, and materials synthesis. Carbon surfaces are ubiquitous in various fields, and the surface reactivity can be altered by surface functionalization on the molecular scale, introducing functional groups, thus shifting their…