The redox reaction between dioxovanadium(V) and oxalate is proposed as a suitable system to analyze the kinetics of a twostep reaction mechanism using UV-vis spectroscopy. First, the spectra of dioxovanadium(V) and its reduced counterpart oxovanadium(IV) are compared and explained using the crystal field theory. The change in absorbance can be…

The Michelson interferometer is one of the key experiments in modern physics when it comes to the topic of interference (Box 1). Experiments using interferometry have a high historic relevance as well as uses in current areas of research (quantum erasers, gravitational wave detection) and are used in higher education. Because of the high cost of…

Different virtual chemistry laboratories (VCLs) have been developed with which students can perform and practice their practical and experimental work, thus increasing their learning before performing the same work in a real chemistry laboratory. In this paper, we present an analysis of the existing virtual chemistry laboratories by identifying…

The synthesis of 4-amino-3-nitrobenzoic acid methyl ester is a simple Fischer esterification reaction designed as an experiment for use in an introductory organic chemistry course. The compound was synthesized as a one-pot reaction within 30 min to 16 h, with 1 h producing a workable yield. The bright-yellow solid was purified using liquid--liquid…

We propose an experimental analogy to verify Kepler's second law using a spherical pendulum. We made a movie of a closed elliptical orbit of the pendulum and extracted the data position using the Tracker software. Analyzing the data, we measured the areas that the position vector sweeps showing the validity of Kepler's second law.

This work presents an experiment that seeks to simulate human color vision through electronic components in an attempt to build, together with the students, a cybernetic 'eye'. The limitation of the cybernetic eye developed here in relation to the standard human chromatic vision, which makes it a 'colorblind eye', is an argument to be explored by…

This paper demonstrates the use of smartphones in an experiment of light absorption and light scattering. The LED display and camera of the smartphone are used as the light source and as the detector, respectively. The color wheel is used to choose the color of the light source to be shone through the sample for analysis. The detector directly…

When we travel in a train moving at a certain velocity, we observe the stationary objects outside are moving backwards. These stationary objects seem to move due to a relative velocity. Consider that the stationary object outside the train is a man standing on the stationary floor watching a woman moving on a train. The woman on a train will see…

Semiconductor devices, usually made from silicon wafers, are present in the electronic gadgets that we use on a daily basis. In an introductory physics class, the textbook usually devotes a few pages to these devices and moves on. As a result, students may readily forget the material or fail to see how it relates to their lives. A solution is to…

This exploratory study aims to verify whether the current use of scientific experiments in the Moroccan high-school science curriculum meets students' needs for experimental scientific learning. For that purpose, a sample chapter of the official science textbook was analysed in detail. The analysis was carried out using a didactic model of the…

Heat transfer is a phenomenon well known from everyday life. It is intuitively connected to the properties of materials, that is, to the physics concept of thermal conductivity relevant for cooking or maintaining the constant temperature in rooms, even without being familiar to the underlying physics. However, measurement of thermal conductivity…

Keto-enol tautomerism is a fundamental concept that examines the migration of a proton between two constitutional isomers, the keto and enol tautomer. Many experiments have been proposed to understand the concept behind Meyer's Rule, which states that the keto tautomer is favored as the solvent polarity increases. However, all the experiments have…

This note is about 1000 words in length. We have been taught that this much information is contained in a single picture. But, Fig. 1 is so rich that four separate ideas can be obtained from it! The figure appears in "The Boy's Playbook of Science" by John Henry Pepper. Pepper tells us that this shows an "assistant standing on the…

This chapter illustrates the main warning signals that could help us to detect the flaws of an explanation in physics: internal contradiction (two examples); direct contradiction of a law of physics (one example); indirect contradiction of a law of physics (one example); logical incompleteness of an explanation (three examples); overgeneralization…

The COVID-19 pandemic posed significant challenges for practical teaching within the sciences. While many instructors adopted innovative alternatives to conventional practicals, many relied on digital approaches that did not give students hands-on experience. In this study we evaluate the use of 'at home' practical kits used in first year physics…