The UV--vis absorption of cyanine dyes is a common experiment in many physical chemistry teaching laboratories. As part of the analysis, students are often asked to hypothesize why the predicted absorption differs from the measured values and why dyes which are predicted to have the same absorption have measured values which differ from each…

In school chemistry, the oxyhydrogen or "Knallgas" reaction is used to provide evidence of hydrogen gas in the squeaky pop test. However, the test actually indicates the presence of an explosive gas mixture of hydrogen and oxygen (oxyhydrogen gas) rather than pure hydrogen. The sheer observations of an explosive reaction and the…

The preparation of ethyl acetoacetate is a distinctive, century-old classic organic chemistry laboratory project. Ethyl acetate and sodium metal (sodium ethoxide) are reacted by Claisen ester condensation to produce the sodium salt of ethyl acetoacetate and then obtain the refined product by acidification as well as washing, drying, and…

Nowadays there is a concern to improve the quality of education by including an interdisciplinary approach of concepts and their integration in the curriculum of scientific disciplines. The development of microbial fuel cells as a potential alternative for production of renewable energies gives undergraduate students the challenge of integrating…

In the environment, communication among microorganisms is a key aspect of their lives. Through communication, single cells of a microbial population can coordinate their gene expression and, in consequence, their physiology. Quorum sensing systems (QS) are one of these mechanisms that allow this communication through the production and detection…

At-home chemistry experiments are increasingly important to enable high-quality online and hybrid instruction. These class modalities provide significant challenges and also dramatically expand the accessibility of education to those who work or care for family during traditional school hours or have significant commutes to campus. This work…

A multistep assembly of gold nanoparticle self-assembled monolayers (SAMs) on glass surfaces is proposed, as a third-year undergraduate experiment. The process includes self-assembly (SA) and electrostatic self-assembly (ESA) methods, which are central approaches in modern surface and materials engineering. The products are analyzed using…

The physics' subject aims to provide the student with a broad understanding of the physical phenomena that occur around them every day and introduce them to the scientific search. The use of experiments in the teaching of the subject contributes to the understanding of these phenomena, the development of skills and critical thinking and has many…

Students often perceive school science as purely theoretical, overloaded with facts, and mostly disconnected from their school, home, and community life. One way to bridge the disconnection between school science and lived experiences, and support students in realizing the relevance of science to their everyday life, is by enabling them to…

The importance of teaching the Luria-Delbrück experiment to biology students is increasingly recognized by educators, and improved pedagogical methods for teaching the classic experiment have been proposed and tested in the classroom. However, there are still obstacles that impede the proper teaching of the classic experiment. This note proposes…

A new system for tracking a metal ball rolling on the slope of the touch panel of a tablet computer was developed. The widespread introduction of tablets in educational environments allows the use of a convenient dynamic measurement in schools.

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…