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…

Describes an inexpensive, easy-to-construct manometric device that is a substitute for an expensive commercial transducer that is sensitive to slight pressure fluctuations. An activity for demonstrating the importance of CO-2 as a humoral regulator of respiration is described. (Author/SA)

A technique is presented which utilizes wax moth larvae in a laboratory investigation of an insect virus. Describes how an insect virus can be used to introduce undergraduate biology students to laboratory work on viruses and several virological concepts. (SA)

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)

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)

For this 12-hour laboratory project students examine a model and explain why equipment is placed where it is, and then install some piping on the model. (BB)

Describes a laboratory activity which can be done with equipment normally available for introductory college courses. It measures the ratio of the radioactivity per unit mass of a unicellular alga to the radioactivity per unit mass of the medium in which it grows. (HM)

Describes an advanced undergraduate physics experiment which permits the measurement of ultrasound velocity and absorption in liquid systems. A description of the tasks the student is expected to perform is also included. (HM)

Discusses a demonstration in which the near and far focusing distances of a student volunteer are measured and his or her glasses prescription is computed. (HM)

Describes a demonstration in which the local inertial frame of reference can be obtained in the laboratory by allowing a cage to fall freely without rotation under the influence of gravity. (HM)

Described is a gel diffusion experiment that permits the completion of duplicate diffusion runs within a three-hour laboratory session. Information included for the short-duration gel diffusion experiment is the diffusion cell, the experiment, data treatment, and the expected results of the experiment. (Author/DS)

Two implanted slide techniques are described by which activity of proteolylic bacteria and the growth of algae in the soil can be readily studied by school students using simple apparatus and methods. Variations are suggested for studying the effects of agricultural practices and environmental conditions on the soil bacteria and algae. (Author/DS)