Describes a study that used the ordered-tree technique to investigate knowledge change across the first semester of a college course in organic chemistry. Finds that over the course of the semester, students' knowledge trees became more similar to those of their professors. Discusses possible assessment uses for the ordered-tree technique.…

Details ab initio crystal orbital calculations using all-trans-polyethylene as a model. Describes calculations based on various forms of translational symmetry. Compares these calculations with ab initio molecular orbital calculations discussed in a preceding article. Discusses three major approximations made in the crystal case. (CW)

In this article, the third part of a series, the results of ab initio polymer calculations presented in part 2 are discussed. The electronic structure of polymers, symmetry properties of band structure, and generalizations are presented. (CW)

Explores neurochemical events in the extra cellular space of the brain by use of in vivo voltammetric microelectrodes. Reports dopamine concentrations and pathways, and discusses techniques used for analysis. Recognizes current problems and future directions for research. (ML)

Describes statistical analyses of tests used for organic chemistry classes and attempts to pose a model to explain the results. Concluded that students who possess a slight grasp of a concept actually have less of a chance of answering an item correctly than those who merely guess. (CW)

Highlights aspects of safety that are unfamiliar to most laypersons and to many chemists as well. Presents findings that may lend themselves to presentation in chemistry classes. Details flammability tests, vapor space hazards, and the special case of gasoline containers. Provides experimental data relating vent area and internal pressure. (CW)

Argues for the introduction of a college level safety course for chemistry majors and surveys college catalog offerings to determine course status in American Chemical Society approved departments. Concludes that six percent of approved departments offer a formal safety course. (ML)