Describes some impurity-related optical properties of semiconductors, with special emphasis on the luminescence of zinc sulfide (ZnS). Presents and interprets five experiments using a ZnS screen, ultraviolet lamp, transparent Dewar liquid nitrogen, and a helium/neon gas base. Includes application of luminescence measurements to archaeology. (SK)

Describes an experiment providing an experimental introduction to vibrational spectroscopy and experience in using an elementary vacuum line. The experiment, using a gas cell charged with methanol, is completed in a three-hour laboratory period and is directed toward understanding vibrational spectroscopy rather than the diagnostic value of the…

Presents background information, materials needed, and experimental procedures to study enzymes dependent on pyridine nucleotide coenzymes (NAD/NADH). The experiments, suitable for advanced organic or biochemistry courses, require approximately 10-15 hours to complete. (SK)

Describes an experiment to analyze commercial analgesic preparations (pain relievers) by silica gel thin layer chromatography, followed by preparative (thick) layer chromatographic separation and spectroscopic analysis. Key difference from similar experiments is that students are responsible for devising suitable solvent systems for the thin layer…

Mechanical properties (stress-strain relationships) of polymers are reviewed, taking into account both time and temperature factors. Topics include modulus-temperature behavior of polymers, time dependence, time-temperature correspondence, and mechanical models. (JN)

Describes a series of experiments which a group of 12- to 14-year-old students developed and conducted as they attempted to design a solar panel. Includes an outline of their building procedures. (DC)

A general discussion of prediction and the use of models as a means of understanding reality is provided, focusing on the application of mathematical models to various scientific disciplines and its role in experimentation. (DC)

Describes a lysozyme assay for use in the biology classroom to teach enzymology. Provides background information, materials and methods, sources of lysozyme, and evaluation of the assay. (DS)

Discusses the role, importance, and benefits of performing demonstrations in physics. Suggests that actual demonstrations are more valuable than those presented on films or videotapes. (SK)

Presents the author's viewpoints on the role, benefits, and mechanics of performing physics demonstrations. Suggests that teachers keep a demonstration file. Indicates that demonstrations can be set up in showcases or in hallways. (SK)

Describes kinetics experiments completed in a single two-hour laboratory period at 25 degrees Centigrade of nitrito to nitro rearrangement, based on the recently discovered base-catalysis path. Includes information on synthesis and characterization of linkage isomers, spectrophotometric techniques, and experimental procedures. (SK)

Presents a simple, economical model of circulatory behavior that illustrates the effect of changes in cardiac output, peripheral resistance and compliance on arterial blood pressure. (CS)

Describes a laboratory scale reactor that determines the kinetics of a gas-solid catalytic reaction. The external recycle reactor construction is detailed with accompanying diagrams. Experimental details, application of the reactor to CO oxidation kinetics, interphase gradients, and intraphase gradients are discussed. (CS)

Describes a physical chemistry experiment involving the analysis of the spectrum of benzene vapor in which the resolution in terms of wave length is a limiting factor. (CS)

He-Ne laser experiments suitable for an undergraduate laboratory are described. The topics covered are cavity stability, self-mode-locking coherent interactions between pulses and laser medium, and spontaneous transverse mode locking. (Author/DS)