Discussed are the mechanisms of nuclear magnetic relaxation, and applications of relaxation times. The measurement of spin-lattice relaxations is reviewed. It is stressed that sophisticated techniques such as these are becoming more important to the working chemist. (CW)

Presented is an experiment to show the connection between spectroscopy and thermochemistry by examining the spectra of atomic sodium and diatomic sodium. Background information; a description of the apparatus; procedures; calculations; and energy diagrams are included. (CW)

Discussed are some of the issues which were considered when the International Union of Pure and Applied Chemistry revised its guide to notation in physical chemistry. Included are the choice between SI and non-SI units and choosing sensible names and symbols for quantities. (CW)

Described are demonstrations of the optical activity of two sugar solutions, and the effects of various substituents on acid strength using an overhead projector. Materials and procedures for each demonstration are discussed. (CW)

Examined are the illustrations and descriptions of the molecular structure of sulfur dioxide found in selected chemistry textbooks. Inconsistencies and incorrect information are indicated. It is suggested that molecules other than sulfur dioxide be used as examples of molecules for which resonance is important. (CW)

Applications of lasers to molecular absorption spectrometry, molecular fluorescence spectrometry, visible semiconductor fluorometry, atomic absorption spectrometry, and atomic fluorescence spectrometry are discussed. Details of the use of the frequency-doubled diode laser are provided. (CW)

Three aspects of quantum mechanics in modern chemistry are stressed: the fundamental structure of quantum mechanics as a basis of chemical applications, the relationship of quantum mechanics to atomic and molecular structure, and the consequent implications for chemical education. A list of 64 references is included. (CW)

Discussed are the substructures (subgraphs) of imaginary transition structures that provide an effective approach to the characterization of organic reactions. A comparison of conventional methods and this method is presented. (CW)

Compares the attributes of the silk from spiders with those of the commercially harvested silk from silkworms. Discusses the evolution, design, and effectiveness of spider webs; the functional mechanics of the varieties of silk that can be produced by the same spider; and the composite, as well as molecular, structure of spider silk thread. (JJK)

Presented is an activity in which students make models of viruses, which allows them to visualize the shape of these microorganisms. Included are some background on viruses, the biology and geometry of viruses, directions for building viruses, a comparison of cells and viruses, and questions for students. (KR)

Suggests using poetry such as James Maxwell's "To the Chief Musician upon Nabla: A Tyndallic Ode" as a vehicle for learning physics. Discusses the physics concepts alluded to in the verses of the poem. (MDH)

Describes a set of simple, inexpensive, classical demonstrations of nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) principles that illustrate the resonance condition associated with magnetic dipoles and the dependence of the resonance frequency on environment. (WRM)

Describes two activities to analyze unit-cell structures from a geometric viewpoint and invites students to apply their mathematical understanding to scientific phenomena. Students form models of the simple cube, a building block of crystalline structures, and a methane molecule. (MKR)

Offers a lesson for sixth-grade students where they study crystals in a science class; after looking at different types of crystals through a magnifying glass and microscope, the students sketch crystal formations in their science logs. Focuses on different repeating patterns enabling students to draw a repeated design of crystals from their logs.…

This paper reports the results of applying a particular analytical perspective to data from an interview study: a typology of learning impediments informed by research into learning and students' ideas in science. This typology is a heuristic tool that may help diagnose the origins of students' learning difficulties. Here it is applied to data…