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…

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 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…

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…

In this work, we made a simple electronic tool called a 'magnetic polarity detector' which can determine the magnetic poles of permanent magnets or electromagnets. We used it in some student experiments in the physics laboratory. For example, determining the magnetic poles of permanent magnets and a current-carrying coils or electromagnets.…

Telelab, an implementation of remote labs 2.0, is open-source and freely available for non-commercial use. The platform consists of sensors that collect data, smartphone apps that transmit data and videos from anywhere, and a web app that provides a user interface to view, analyze, and control remote experiments. Based on this platform, any…

Student understanding of the laws that describe the flow of a fluid is often hampered by a defective knowledge of basic classical mechanics (kinematics, statics, dynamics, and conservation laws) and by wrong common-sense ideas about quantities related to fluids, such as velocity and pressure. A pedagogical discussion about the Venturi effect,…

Sound is an interesting topic for physics lessons at all ages. However, it is difficult to illustrate this ubiquitous phenomenon and many models do not adequately represent the properties of sound and thus promote unwanted conceptions. The experiment presented here avoids this by visualising sound itself with the help of the schlieren technique.…