Feynman mentioned to us that he understood a topic in physics if he could explain it to a college freshman, a high school student, or a dinner guest. Here we will discuss two topics that took us a while to get to that level. One is the relationship between gravity and time. The other is the minus sign that appears in the Lagrangian. (Why would one…

This article first notes the misinterpretation of a common thought experiment, and the misleading comment that "systems tend to flow from less probable to more probable macrostates". It analyses the experiment, generalizes it and introduces a new tool of investigation, the simplectic structure. A time-symmetric model is built upon this structure,…

An experiment using [superscript 1]H NMR spectroscopy to observe the kinetics of the acylase 1-catalyzed hydrolysis of "N"-acetyl-DL-methionine has been developed for the organic laboratory. The L-enantiomer of the reactant is hydrolyzed completely in less than 2 h, and [superscript 1]H NMR spectroscopic data from a single sample can be worked up…

This commentary disagrees with a recent submission (Cheung, D. "J. Chem. Educ. 2009, 86," 514-518) questioning the value of the Le Chtelier principle (LCP). Cheung points out that the LCP fails to predict the proper change in a small set of chemical equilibria. This commentary argues that the LCP has great qualitative utility in correctly…

A novel experiment for the extraction of lycopene from tomato paste by foam fractionation is described. Foam fractionation is a process for separating and concentrating chemicals by utilizing differences in their surface activities. Extraction of lycopene by foam fractionation is a new method that has not been previously reported in the…

Although the presentation of quantum mechanics found in traditional textbooks is intellectually well founded, it suffers from a number of deficiencies. Specifically introducing quantum mechanics as a solution to the arcane dilemma, the ultraviolet catastrophe, does little to impress a nonscientific audience of the tremendous paradigmatic shift…

Surprisingly, spectator ions are responsible for unexpected kinetics in the biphasic copper(II)-aluminum displacement reaction, with the rate of reaction dependent on the identity of the otherwise ignored spectator ions. Application of a published kinetic analysis developed for a reaction between a rotating Al disk and a Cu(II) ion solution to the…

An approach is presented that utilizes a spreadsheet to allow students to explore different means of calculating and visualizing how the charge on peptides and proteins varies as a function of pH. In particular, the concept of isoelectric point is developed to allow students to compare the results of their spreadsheet calculations with those of…

Adding Mentos to an open bottle of Diet Coke can produce a fountain of liquid and froth extending several metres high. This activity can engage a wide audience of learners in a relevant and meaningful way, provide a model for creative science teaching, and help to develop learners' attitudes towards school science as a subject. In this paper, the…

For the last quarter century the author's professional interest has been almost exclusively the population of highly able, gifted and talented children and young people. His attention has been particularly focused on the "why," "what" and "how" aspects of providing for their exceptional educational and social emotional needs. Given his article was…

Before the advent of microcomputer-based labware (MBL), "time-of-flight" measurements for the speed of a transverse pulse on a string required elegant apparatus. This paper describes how to use an off-the-shelf MBL force sensor and a computer to perform the measurement. The data shown in this paper were collected using Vernier Software's wireless…

This study explored Bangladeshi science teachers' conceptions of nature of science (NOS) with a particular focus on the nature of (a) scientific knowledge, (b) scientific inquiry and (c) scientific enterprise. The tentative, inferential, subjective and creative NOS, in addition to the myths of the scientific method and experimentation, the nature…

Over the last two decades, science educators and science education researchers have grown increasingly interested in utilising insights from the sociology of scientific knowledge (SSK) to inform their work and research. To date, researchers in science education have focused on two applications: results of sociological studies of science have been…

An advanced undergraduate laboratory experiment is outlined which uses a dye laser to map out the chromatic dispersion curve of a polymethyl methacrylate (PMMA) optical fibre. Seven different wavelengths across the visible spectrum are employed using five different dyes. The light pulse is split into two pulses, one to a nearby photodetector and…

This paper presents a simple method for calculating Clebsch-Gordan coefficients for the tensor product of two unitary irreducible representations (UIRs) of the rotation group. The method also works for multiplicity-free irreducible representations appearing in the tensor product of any number of UIRs of the rotation group. The generalization to…