Provides four questions and answers relating to topics in environmental chemistry as well as six reader comments relating to questions presented in previous issues. (SL)

Describes a method of acquainting physics and astronomy students with the general theory of relativity. (SL)

Presents a parallel treatment of the same phenomena by two approaches (steady-state approximation and approximate solution of the appropriate diffusion equation) to clarify the physical meaning of the important radiation boundary condition in the diffusional derivation. (JN)

Discusses three topics that have been improperly applied to the acidic precipitation issue. They are: (1) use of the pH scale; (2) acidity; and (3) solution equilibria of strong and weak acids. Implications for instruction are considered. (JN)

Describes a freshman chemistry experiment in which students separate and identify commonly used drugs by thin-layer chromatography. Materials needed, procedures used, and typical results obtained are included. (JN)

Describes a low-cost ($120) device which eliminates plasma lines in Raman spectra. The device consists of two prisms and two mirrors which are held in a symmetrical relationship to one another so that a particular position will allow only one wavelength to pass through on a given axis. (JN)

Discusses a problem (on page 523 of "College Physics," by Sears, Zemansky, and Young, published by Addison-Wesley, 1980) concerning light bulbs and resistance. Shows why the assumption of constant resistance is unrealistic and provides guidelines for revision. (DH)

A rapid sequencing method for ribosomal RNA was applied to the resolution of evolutionary relationships among Metazoa. Describes the four groups (chordates, echinoderms, arthropods, and eucoelomate protostomes) that radiated from the coelomates. (TW)

Presented is an introduction to the interpretation of electron spin resonance spectra of organic radicals. The article is written for undergraduate college students. (RH)

Outlined is a procedure for analyzing the ground electronic state of the iodine molecule by using information provided by "hot" bands, observed in the absorption spectrum of iodine vapor. (RH)

Presented are three methods for dealing with chemical problems involving reaction stoichiometry. (RH)

Discussed are a brief explanation of the function of the vortex tube and some applications for the chemistry laboratory. It is a useful and inexpensive solution to many small-scale laboratory heating and cooling applications. (RH)

Outlined is the history of superconductivity and described are the physical and chemical principles upon which it rests. Some possible applications of superconductors are considered. (RH)

Described is a student preparation of YBa2Cu3O8-x, a classroom demonstration of its superconductivity, and an analytical chemistry experiment dealing with the oxidation state of copper in the material. (RH)

Investigated a persistent error among introductory college biology and genetics students, namely, that amino acids are produced by genetic translation (protein synthesis). Contributors to this misconception were revealed through multiple-choice items and interviews. Implications for education are discussed with specific steps suggested to correct…