This month's cover shows a satellite view of sediment being deposited into the Coral Sea by a river. Articles in this issue discuss a broad range of applications of chemistry to our physical, chemical, biological, and geological surroundings, including endangered species, water analysis, herbicides in soils, and the natural selection of various elements for biogeochemical systems.

Environmental Chemistry

The Fraser fir has recently experienced severe dieback at high-elevation sites in the southern Appalachians, partly as a result of acid rain. Woosley and Butcher (page 1592) have developed several experiments that focus on this species, analyzing for metals, volatiles, and chlorophyll in the fir's foliage. Solomon, Oliver-Hoyo, and Hur (page 1581 *) describe how to generate acid-rain gases for use in overhead projector demonstrations. An extremely broad view of environmental chemistry is taken in the book by Williams and Fraústo da Silva that is reviewed by Kauffman on page 1559 *.

Environmental problems also lend themselves to inquiry-based learning. Krow and Krow (page 1583 *) have used disposal of low-level radioactive waste as the focus for a problem-based learning module that will be useful in interdisciplinary courses and in many chemistry courses. Myers (page 1585 *) has developed a laboratory problem-solving exercise that involves identifying samples of bottled water by chemical analysis. Drinking water is also the subject of a discovery-oriented experiment by Hage et al. (page 1588) that uses capillary electrophoresis to determine nitrate and nitrite in a variety of water samples.

Sipos (page 1603) has developed a simple analysis for dissolved oxygen using a Clark oxygen sensor that is appropriate for a sophomore course. Quach et al. (page 1595) have developed an instrumental analysis experiment in which gasoline is analyzed by GC-MS for methyl-t-butyl ether and benzene. Application of HPLC to determination of polycyclic aromatic hydrocarbons in cigarette smoke is described on page 1599 by Wingen, Low, and Finlayson-Pitts.

Sediments, soils, and carbonate minerals are important components of our environment. Christensen et al. (page 1605) describe an experiment in which hydrogen sulfide and acid-soluble metallic sulfides can be analyzed in sea-floor sediments by means of low-cost electroanalytical techniques. Precise determination of CO₂ content of carbonate minerals is described by Pile et al. beginning on page 1610, and soil-water distribution of agricultural chemicals is the subject of an environmental lab by Dolan, Zhang, and Klarup (page 1609).

Agricultural chemicals and drugs often depend on specific enantiomers for their activity, and Valenzuela, Green, and Dahl (page 1590) report an experiment designed to introduce this idea. Ferguson (page 1615) has developed a quantitative HPLC analysis of a psychotherapeutic medication, and Inda et al. (page 1618) report an immunodotting assay for detecting cow-milk adulteration of sheep milk.

Chemical Kinetics

Novak (page 1574) has developed a series of questions for assessing knowledge of chemical kinetics that do not require calculus and concentrate on conceptual issues. El Seoud and Takashima (page 1625) report an experiment on hydrolysis of methyl chloroformate that is designed to teach techniques in chemical kinetics. Brown, Tyson, and Weil (page 1632) describe an experiment in which NMR line shapes are used to determine the rates of exchange processes. Dwyer, Norman, and Jasien (page 1635) combine 2D EXSY and computational chemistry to determine rotational barriers in push-pull ethenes. Vitz (page 1661) has developed spreadsheet templates that allow rapid plotting and curve fitting of kinetic data, thereby freeing students to more thoroughly consider the concepts involved.

Research in Science and Education

A number of papers this month describe research that will be of interest to teachers of chemistry. Wai et al. (page 1641) describe a variety of chemical reactions in supercritical carbon dioxide that have practical applications. Ezrahi et al. (page 1648) describe the phase behavior of multicomponent systems in terms of triangular and tetrahedral diagrams. Rudman (page 1646 *) provides a comprehensive overview of conversions of temperature among the four main extant scales (Celsius, Fahrenheit, Kelvin, and Rankine), and at the same time reviews use of the equation of a straight line, y = ax + b. Towns et al. (page 1653) describe an experiment in using the World Wide Web for teaching physical chemistry, and Burke, Greenbowe, and Windschitl (page 1658) report on development and evaluation of instructional computer animations.

The State of Chemical Education

In this the last issue of our 75th year, we have collected historical reports, opinions, and prognostications from a broad range of people in chemical education. You will find these in the Chemical Education Today section, pages 1518 through 1550 *. We hope that you find them interesting, enjoyable, and thought provoking.

* designates articles of special
interest to high school teachers.