When grocery stores sell solutions of ammonia, they are labeled "ammonia"; however, when the same solution is purchased from chemical supply stores, they are labeled "ammonium hydroxide". The goal of this experiment is for students to determine which name is more appropriate. In this experiment, students use several different experimental methods…

This experiment investigates the methylation of 2-naphthol with dimethyl carbonate. The volatility of the substrates, products, and co-products allows the reaction to be performed using a continuous-flow gas-phase setup at ambient pressure. The reaction uses catalytic quantities of base, achieves high conversion, produces little waste, and…

Brewing beer provides a straightforward and robust laboratory counterpart to classroom discussions of fermentation, a staple of the biochemistry curriculum. An exercise is described that provides several connections between lecture and laboratory content. Students first extract fermentable carbohydrates from whole grains, then ferment these with…

Bruker SMART X2S is a portable benchtop diffractometer that requires only a 110 V outlet to operate. The instrument operation is intuitive and facile with an automation layer governing the workflow from behind the scenes. The user participation is minimal. At the end of an experiment, the instrument attempts to solve the structure automatically;…

In this article, the author offers cautionary advice to help avoid some tempting morasses to unwittingly fall into as well as some more solid ground to stroll along when composing institutional prose. Ultimately, drawing on concepts from the fields of business, linguistics, social psychology, and professional writing, the author wishes to…

This classroom activity connection demonstrates the differences between the effects of NaCl (a salt of monovalent metal ions) and CaCl[subscript 2] (a salt of polyvalent metal ions) on swollen superabsorbent polymer gels. Being ionic compounds, NaCl and CaCl[subscript 2] both collapse the swollen polymer gels. The gel contracted by NaCl reswells…

In "JCE" Activity #67, "Flame Tests: Which Ion Causes the Color?", Michael Sanger describes how to conduct flame tests with household items. We have used this activity in outreach settings, and have extended it in a variety of ways. For example, we have demonstrated large-scale strontium (red), copper (green), and carbon (blue) flames using only…

Unexpected events often distract us. In the laboratory, novel auditory stimuli have been shown to capture attention away from a focal visual task and yield specific electrophysiological responses as well as a behavioral cost to performance. Distraction is thought to follow ineluctably from the sound's low probability of occurrence or, put more…

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…

Diverse biological data may be used to create illustrations of molecules in their cellular context. I describe the scientific results that support a recent textbook illustration of a mitochondrion. The image magnifies a portion of the mitochondrion by one million times, showing the location and form of membranes and individual macromolecules,…

Introductory science courses often have laboratory components in which students are required to write formal lab reports as homework. These reports often have problems such as incorrect data analysis, mistaken conclusions, and unclear graphs, all errors that indicate that students often fail to understand the experiments. Plagiarism is also…

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…

Understanding lunar phases requires three-dimensional information about the relative positions of the Moon, Earth, and Sun, thus using a stereo display in instruction might improve student comprehension of lunar phases or other topics in basic astronomy. We conducted a laboratory (15 sections) on phases of the Moon as part of the introductory…

This paper presents a simple, cost-effective and robust atomic force microscope (AFM), which has been purposely designed and built for use as a teaching aid in undergraduate controls labs. The guiding design principle is to have all components be open and visible to the students, so the inner functioning of the microscope has been made clear to…