A method of plotting planes on stereonets is described including great circles, poles, and dip vectors. Teaching applications of dip vectors in engineering geology and structural geology are discussed. (CW)

Discusses merits of using sigma-pi model of ethylene as a teaching aid in introductory organic chemistry. The nonmathematical treatment of sigma-pi bonding is then extended to such phenomena as conjugation, hyperconjugation, Markovnikoff addition, aromaticity, and aromatic substitution. (SK)

Discusses the problem of symmetry avoidance using water as an historical example. Uses simple pi systems for the analysis. Provides methodology and examples. Investigates two naive arguments. (MVL)

Discussed is single crystal X-ray crystal structure analysis. A common link between the NMR imaging and the traditional X-ray crystal structure analysis is reported. Claims that comparisons aid in the understanding of both techniques. (MVL)

Discusses three broad classes of magnetic behavior: diamagnetic, paramagnetic, and ferromagnetic. Presents a simple lecture demonstration using an overhead projector to synthesize triiron tetraoxide and to show its interaction with a magnetic field and comparing it to a paramagnetic material. (MVL)

Finds that a logical application of the simple rules of the molecular orbital bonding theory for diatomic molecules predicted the existence of three spin isomers of the oxygen molecule: one triplet form with two unpaired electrons and two singlet forms with all electrons paired. (MVL)

Discusses a new method for determining the eigenvalues of the Schroedinger equation when the potential energy function does not have a simple form. Describes the mathematical methods and provides an application. Lists limitations to the method. (MVL)

Questions the use of the Reactivity Selectivity Principle (RSP) by teachers and authors of texts in discussing organic reaction mechanisms. Provides some applications and failures of the use of the RSP, reviews some quantitative aspects of the RSP, and discusses some of the rationalization of the RSP failures. (TW)

Addresses the requirements of high school students and noncrystallographers in lectures on crystals, diffraction, and structure analysis. Discusses basic understanding and a sequence that addresses these requirements. Suggests visual and descriptive teaching methods used in this effort. (CW)

Describes an experiment in which stretching a rubber band can be used to compare the statistical theory of rubber elasticity with its continuum mechanics counterpart. Employs the use of the equation of the state of rubber elasticity and the Mooney-Rivlin equation. (TW)

Background information, data input, data analysis, and advantages of using this method with this software are discussed. A flowchart of the event-trapping program structure and a printout of the program are included. (CW)

Discusses the composition and properties of various types of coal. Follows the origin of coal and amounts available in the ground. Explores the anaerobic decay needed to produce coal. Touches upon the greenhouse effect. (MVL)

Describes several common synthetic organic transformations involving alkenes, alcohols, alkyl halides, and ketones. Includes concepts on kinetic versus thermodynamic control of reaction, rearrangement of a secondary carbocation to a tertiary cation, and the effect of the size of the base on orientation during elimination. (MVL)

Uses simple pulse NMR experiments to discuss Fourier transforms. Studies the generation of spin echoes used in the imaging procedure. Shows that pulse NMR experiments give signals that are additions of sinusoids of differing amplitudes, frequencies, and phases. (MVL)

Describes a procedure for constructing point groups based on the symmetric parent molecules of methane and adamantane. Intended for use in teaching concepts such as subgroups and cosets to beginners in group theory. (TW)