A simple and economical system that allows one to obtain the characteristic "I-V" curve in solar cells is presented. It is a computer-controlled system suitable as an instrumentation project for students who are learning about photovoltaic systems. This system is based on the use of an "R-3R" ladder circuit as a variable…

The article presents the results of an experimental study on the motion of a neodymium magnet on an inclined duralumin plate. During experiments, the time of motion was measured, and the steady-state velocity of the magnet motion was determined. To measure the time, a robotic set was used, which made it possible to measure the time of the motion…

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…

Systematic errors are unfortunately common in analyses performed by students in teaching laboratories. Quality control (QC) tools are required to detect and solve bias in laboratory analyses. However, although QC has become routine in real-world laboratories, it is still rarely applied in teaching laboratories. For this reason, systematic errors…

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.…

Smartphones are currently proposed as potential portable laboratories to perform a wide variety of physical experiments for teaching purpose. However, the frequent lack of clarity about the ease of replication of the experiments and on their accuracy often limits their effective use. In this work we deeply compare several smartphone-based…

One of the main topics of elementary physics is the idea that every material is composed of "little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one other." These particles could be atoms or molecules. Atoms are the smallest part into…