Creating pleasant musical sounds by vibrating the strings of musical instruments such as guitars and violins is the result of the type of instrument played as well as the mastery of the player. This article explains the physics of vibrating strings caused either by a bow drawn over them or by being plucked, and provides a simple analysis to…

This article highlights some of the challenges in explaining simple substituent effects on keto-enol equilibria, particularly to an undergraduate audience. Quantum-chemical calculations were performed to identify the role of intramolecular hydrogen bonding, inductive effects due to electron-withdrawing groups, and cross-conjugation on the…

Many high school and first-year university courses include discussion of the magnetic effect of currents. Frequently discussed textbook examples include long, straight wires, circular current loops, and solenoids, partly because these examples are tractable mathematically. The solenoid naturally leads to discussion on magnetic materials since it…

Basis vectors e[subscript alpha] play a useful role in special and general relativity. In particular they allow an expansion of the vectorial spacetime interval dl along infinitesimal curvilinear coordinate differences dl = e[subscript alpha]d[Xi][superscript alpha]: (thus the definition e[subscript alpha] = dl/d[Xi][superscript alpha]). In this…

Dilute guarana´ ("Paullinia cupana") powder aqueous extract is a soft drink that contains three structurally related methylxanthines (MXs), caffeine (CF), theobromine (TB), and theophylline (TP); CF is present in a large excess. Literature data show that values of [lambda][subscript max] and [epsilon][subscript max] of these three MXs…

Frozen peas and carrots are commonly available in grocery stores in the United States. The carrots are cut into cubes roughly 8 mm on a side, while the peas are roughly spherical with a diameter of about 6 mm. They are prepared together in water that is brought to a boil. The peas and carrots, which are initially mixed together, separate as the…

White light refracted by a glass edge or a prism might be split into the colors of the rainbow but, when restricted by a suitable arrangement of edges, might also yield a sequence of colors complementary to the rainbow. We studied the creation of these color fields experimentally with a setup consisting of RGB light-emitting diodes that cover all…

We investigated potential drivers of interest in topic-context and topic-activity combinations, as well as interactions between the different elements of situational interest in evolutionary biology. High school students (n = 982, age 17 years) were asked to rate their interest in two sets of items consisting of topic-context and topic-activity…

Despite extensive conceptualization of ions as hard spheres in most textbooks, solid-state structures are more accurately modeled as overlapping soft spheres that better reflect the size of the ions. The corresponding soft-sphere ionic radii of alkali and halide ions can be empirically established from the partial molar volume of the ions in…

One particular challenge in chemistry learning is developing students' atomic level understanding of chemical processes. It is necessary to help students learn how to critique atomic models rather than accept them as ''truth.'' In this study, we used a resources-based framework to examine how students made sense of macroscopic level information to…

In the museum wing of the Greenslade house is a clock with a two-second pendulum about one meter long. This ticks once per second, and every time it passes through dead center it completes an electrical circuit. When I came to Kenyon in 1964, this system was used to send signals to a series of telegraph relays, which ticked once per second.…

The inhibition of porcine pancreatic lipase by the drug orlistat was studied through a series of activities that combine experimental and computational procedures. The enzymatic activity of the lipase was determined by measuring enzyme kinetics and calculating parameters such as K[subscript m] and V[subscript max] from experimental data. Assays of…

This paper reports the first empirical investigation of the hypothesis that epistemic appraisals form part of the structure of concepts. To date, studies of concepts have focused on the way concepts encode properties of objects and the way those features are used in categorization and in other cognitive tasks. Philosophical considerations show the…

The experimental investigation of Newton's law of universal gravitation requires expensive and sensitive equipment. Therefore, it is often not possible to conduct such an experiment within a typical physics class. An alternative is to investigate the universal gravitation law by using simulations. In this paper, we are presenting such an augmented…

The history of particle physics can be considered nothing less than a huge triumph for science. Over the course of a little more than a century of effort, our understanding of the world of atomic and subatomic physics went from a vague understanding of atoms, to one that is much more detailed. Early in this hundred-year-long period, we learned…