An analytic approximation of the solution to the differential equation describing the oscillations of a simple pendulum at large angles and with initial velocity is discussed. In the derivation, a sinusoidal approximation has been applied, and an analytic formula for the large-angle period of the simple pendulum is obtained, which also includes…

Unlike many other topics in basic physics, series and parallel resistances are rarely noticed in the real life of an ordinary individual, making it difficult to design a laboratory activity that can simulate something familiar. The activities described here entail minimal costs and are based on a puzzle-like game of tracking wire connections. A…

A differential magnetic circuit (magnetic bridge) is described. The circuit separates the magnetic field sensor and the sample under study. A Hall probe serves as the sensor. The signal from the sensor can be enhanced by concentrating the magnetic flux. The magnetic bridge works even with dc magnetic fields. The device is used for displaying…

This paper analyses the real origin and nature of scientific errors against claims of science critics, by examining a number of examples from the history of electricity and optics. This analysis leads to a conclusion that errors are a natural and unavoidable part of scientific process. If made available to students, through their science teachers,…

This article presents a guided-inquiry (GI) hands-on determination of Fe in food samples including plantains, spinach, lima beans, oatmeal, Frosted Flakes cereal (generic), tilapia fish, and chicken using flame atomic absorption spectroscopy (FAAS). The utility of the GI experiment, which is part of an instrumental analysis laboratory course,…

Our aim in this proposal is to use Faraday's law of induction as a simple lecture demonstration to measure the Earths magnetic field (B). This will also enable the students to learn about how electric power is generated from rotational motion. Obviously the idea is not original, yet it may be attractive in the sense that no sophisticated devices…

A piezoelectric material generates an electric potential across its surface when subjected to mechanical stress; conversely, the inverse piezoelectric effect describes the expansion or contraction of the material when subjected to some applied voltage. Piezoelectric materials are used in devices such as doorbell buzzers, barbeque igniters, and…

In this article I support and extend the ideas presented by J. Brent Friesen in his article "Saying What You Mean; Teaching Mechanisms in Organic Chemistry" ("JCE" November, 2008). I emphasize "telling the truth" about proton transfers. The truth is that in aqueous acid most reactions are subject to "specific" acid catalysis: the only kinetically…

Students in the second-semester organic chemistry laboratory perform a Wittig reaction between butylidenetriphenylphosphorane (an ylide) and benzaldehyde and determine the relative percentages of the cis and trans isomers of the 1-phenyl-1-pentene product. Because of the highly reactive nature of this unstabilized ylide, students are introduced to…

Ronald J. Gillespie, the inventor of the Valence Shell Electron Pair Repulsion (VSEPR) model, relates how his career as researcher in Christopher Ingold's laboratories started. Gillespie developed a passion for chemistry and chemical education, searching for more appropriate and interesting ways to transmit the essential knowledge and enthusiasm…

Science education research can be categorised into three broad dimensions: knowing science, doing of science and learning about the nature of science. The concerns, doubts and relative importance of each of these aspects in relation to students' learning are debated in the literature. The findings of the empirical research carried out in New…

Microfluidics, the manipulation of fluids in channels with micron dimensions, has emerged as an exciting new field that impacts the broad area of nano/microtechnology. This is an important area to train the next generation of chemical engineers. This paper describes an experiment where students are given a problem to design a microfluidic mixer…

Environmentally benign chemistry is an increasingly important topic both in the classroom and the laboratory. In this experiment, students synthesize divanillin from vanillin or diapocynin from apocynin, using horseradish peroxidase and hydrogen peroxide in water. The dimerized products form rapidly at ambient temperature and are isolated by…

We report a simple, inexpensive, visual, and environmentally friendly S[subscript N]2 reaction appropriate for the second-year organic chemistry laboratory that illustrates stereospecificity, dependence of water solubility on the state of ionization, optical activity, and effect of diastereotopic protons in [superscript 1]H NMR spectroscopy. The…

This paper presents an experiment in which students determine the mass sensitivity of three crystal quartz resonators, designed to be carried out in "Physics Laboratory II" at the Institute of Experimental Physics, University of Wroclaw. The authors discuss the process of setting up the experiment and the results of the measurements.…