We investigated a very long chain falling from the pile on the edge of a table to the floor both experimentally and theoretically. In this very simple and novel configuration we showed that the velocity of the chain quickly converges to its asymptotic value, and that the steady-state velocity is proportional to the square root of the height of the…

The measurement of the charge-to-mass ratio, e/m, of the electron is a fundamental part of any study of electricity and magnetism. It is possible to use an apparatus designed to measure e/m for other things, including investigations of electron flow through a near vacuum, measuring a work function, and even exploring some quantum mechanics…

Our first experience of dimension typically comes in the intuitive Euclidean sense: a line is one dimensional, a plane is two dimensional, and a volume is three dimensional. However, following the work of Mandelbrot, systems with a fractional dimension, "fractals," now play an important role in science. The novelty of encountering…

Tumescence in cadaveric dissection involves the introduction of fluid into interstitial spaces to assist in the separation of natural tissue planes and the preservation of delicate structures. With a hand surgeon's perspective, the senior author brought this technique into the cadaver lab. The infusion helped transform desiccated and adherent…

Diffraction refers to a kind of optical phenomena which occurs when light approaches an element (object or aperture) whose features are in the range of the illuminating wavelength (small apertures, sharp edges). It can be explained by means of the undulatory nature of light or also geometrically by using simple ray optics. Diffraction phenomena…

In this paper, a simple method is described for visually demonstrating that the wavelength of light reduces when entering a medium of higher refractive index. When a violet laser (405 nm) is reflected off the surface of a Blu-ray disc (track spacing 320 nm) diffraction cannot occur since the wavelength is greater than the track spacing. However,…

Students determine the iron mass in dietary supplements using four colorimetric assays. These colorimetric assays were selective for Fe[superscript 3+]. It was complexed by thiocyanide, salicylate, gallic acid, and Fe(CN)[subscript 6][superscript 4-], forming blood-red, red, violet, and blue complexes, respectively. The [lambda][subscript max] of…

Applying the idea of green chemistry, we extended an esterification teaching experiment with isoamyl alcohol and acetic acid and reused isoamyl acetate in the transesterification reaction with KOH as the catalyst. As a result, isoamyl alcohol was produced and could be reused for the teaching experiment. The simplified experimental method achieved…

Benzoin, an [alpha]-hydroxy ketone, is stereoselectively reduced by sodium borohydride to yield hydrobenzoin, the stereochemistry of which is determined by acetalization and analysis of the derivative by NMR spectroscopy. This classical experiment has been enhanced by modern spectroscopic and computational analysis to enable students to…

A new experiment for use in introductory nanotechnology courses is described. This experiment allows students to fabricate metallic wires with microscale lateral dimensions and nanoscale vertical dimensions. Fabrication occurs in the capillaries of polydimethylsiloxane (PDMS) stamps modified with hydrophilic polymers. This experiment provides…

A set of inexpensive and pedagogically rich experiments focusing on S[subscript N]1, E1, and E2 reactions have been updated to include modern computational and spectroscopic analyses. The S[subscript N]1 experiment involves treatment of "tert"-amyl alcohol with hydrochloric acid to generate the corresponding alkyl chloride, which is used…

A laboratory experiment that involves the synthesis, characterization, and application exploration of a metal-organic framework (MOF) has been developed for first-year undergraduates in the Faculty of Engineering at National University of Singapore. The desired MOF material was prepared from commercially available reagents in a facile…

Biodiesel is an important biomass, largely employed in the transport sector and produced from vegetable oils. Additionally, waste cooking oils may be reused to produce biodiesel fuel, minimizing environmental pollution. A laboratory experiment that affords a widespread way to discuss degradation concepts and tools for used vegetable oil…

When injecting dye into a vortex, one finds that the dye remains captured around the vortex core over minutes, despite the fact that the vortex (and the dyed region) is strongly time-dependent. According to a recent theory, three-dimensional time-dependent vortices should be defined as rotating, material-holding regions of the fluid. Vortices…

Carbohydrates are an essential group of molecules to the organic chemistry classroom providing molecular relevance to a common ingredient in chemical biology. While the meticulous elucidation of the carbohydrate structures by Fischer and others is an engaging topic in the lecture, there are few laboratory experiments that can emulate carbohydrate…