Describes a method of staining that makes details clear and dispenses with the time-consuming use of chemicals. The Rheinberg differential color illumination, (or optical staining) is strikingly beautiful and is especially useful with living or nonliving unstained, transparent specimens. Color photographs of sample specimens are included.…

Two laboratory procedures in experimental chemotaxonomy are outlined for determining the presence of betalains in genera representing different plant families. A list of materials and equipment needed is provided. (DC)

Describes modification of a gas viscometer to produce a low cost instrument with high precision and safe design. Three tungsten electrodes are mounted in the viscometer using graded glass seals and a ball trap is inserted between mercury reservoir and all external stopcocks. Also describes modifications in experimental procedures. (Author/JN)

Describes an experiment in which parameters from an "ab-initio" potential are used to calculate vibrational-rotational energy levels and construct a "stick spectrum" for the overtone emission of the hydroxyl radical. Provides background information on ab-initio spectrum, experimental procedures, and analysis of data. (Author/JN)

Describes a three-hour liquid chromatography experiment involving rapid separation of colored compounds in glass columns packed with a nonpolar absorbent. Includes apparatus design, sample preparation, experimental procedures, and advantages for this determination. (SK)

Provides a gas chromatography experiment that exercises the quantitative technique of standard addition to the analysis for a minor component, methyl salicylate, in a commercial product, "wintergreen rubbing alcohol." (CS)

Outlines and discusses procedures for the preparation of lucigenin, a powerfully chemiluminescent compound. Major techniques (requiring three 4-hour sessions) involving nucleophilic and electrophilic aromatic substitution, nucleophilic aliphatic substitution, reductive coupling, and oxidation reactions include steam distillation, decolorization…

A simple polarographic method is used to obtain continuous oxygen dissociation curves under a variety of conditions using a Clark oxygen electrode system. (Author/SK)

Provides background information on and experimental procedures for the preparation of sulcatol, an insect chemical. Includes physical properties of sulcatol derivatives and time required to complete experiments in the undergraduate organic chemistry laboratory. (Author/SK)

A survey of freshman chemistry laboratory manuals identified 15 questionable laboratory procedures, including the use of potentially hazardous chemicals. Alternatives are suggested for each hazard discussed (such as using a substitute solvent for benzene). (SK)

The acid-catalyzed hydrolysis of N-vinyl pyrrolidone provides a simple spectrophotometric kinetic experiment to introduce general acid catalysis, solvent isotope effects, and other aspects of ionic reactions in solution in advanced courses. The Bronsted equation and concept of linear free-energy changes is also covered. (SK)

Concludes that in the laboratory, participants' conversation behavior is not discernably affected by videotaping, no matter how overt or obvious the taping procedure is. Study focuses on behaviors out of conscious awareness: gestures, head nods, speaking turns, self or object manipulations, and shifts to reclining posture or to forward lean. (PD)

The National Research Council has published a comprehensive report on procedures for handling hazardous chemicals and on other aspects of laboratory safety. By early 1981, the Occupational Safety and Health Administration intends to present preliminary proposals for safety in chemical research laboratories. (WB)

Discusses distillation of liquid mixtures with the emphasis on experimental work. A number of experiments, intended for chemistry secondary school teachers in the United Kingdom, are included. (HM)

Describes an experiment which makes use of a number of concepts from geometrical optics. The apparatus and method which is intended for students in elementary college physics classes are included. (HM)