Attempts to show that in the closed loops of cyclic structures the protons situated in conic regions above and below the ring will be shielded. Uses the diamagnetic and air stable octahedral tin(IV) complexes of porphyrins for study. Notes complexes crystallize easily and offer spectacular purple colors. (MVL)

Discusses the mechanism and the change of pH during the reaction. Notes that a dramatic rise in pH occurs when the reaction nears completion. Evaluates theories by other authors. (MVL)

Gives upper level chemistry students a better understanding of the application of lasers in the field of spectroscopy. Provides three experiments to demonstrate the thermal lens effect: determination of beam profile, cell position optimization, and pKa determination. (MVL)

Explains the development of a science program which was initiated to help students, parents, and other teachers appreciate science. Provides a list of materials needed, procedures, questions, and objectives for performing two of the 30 activities used in the project. (RT)

Demonstrates a variety of electrical phenomena to help explain atomic structure. Topics include: establishing electrical properties, electrochemistry, and electrostatic charges. Recommends demonstration equipment needed and an explanation of each. (MVL)

Describes two demonstrations (1) a dust explosion using a coffee can, candle, rubber tubing, and cornstarch and (2) forming a silicate-polyvinyl alcohol polymer which can be pressed into plastic sheets or molded. Gives specific instructions. (MVL)

Uses paper chromatography with food dyes to provide a simple and inexpensive basis for teaching chromatography. Provides experimental methodology and tabled results. Includes a solvent system comparison (Rf) for seven dyes and twenty-two solvents. (MVL)

Describes how to organize a student-directed laboratory investigation which is based on amphibian metamorphosis, lasts for nearly a term, and involves extensive group effort. Explains the assignment, student response and opinion, formal paper, and instructor responsibilities. (RT)

This article presents a variety of topics discussed in this column and at a biology teachers' workshop concerning the quality and value of lab techniques used for teaching high school biology. Topics included are Drosophila salivary glands, sea urchins, innovations, dyes and networking. (CW)

Provided are background information, equipment lists, and procedures for four activities for teaching aquatic ecology. Activities include "The Aquatic Food Chain Game"; "Two-Liter Aqua-Vivariums"; "A Sealed World"; and "Weaving a Web: Evaluation." (CW)

Contains articles on digestive enzymes in grasshoppers; bird and badger observation; reactions between hydrochloric acid and sodium carbonate solutions; observing the migration of ions; pupil's heating skills (Bunsen burners); photolysis experimentation; capillary kinetics; experience with trireme; connection circuits; special relativity; a…

Three articles focus on many classroom activities and experiments inspired by the voyage of two canoes, built of traditional materials, from Hawaii's Hilo Harbor in 1995. Nationwide, students followed daily satellite tracking, accessed the Internet for updated accounts of the canoes, talked directly with navigators, and watched television…

Describes the implementation and evaluation of a nondirected student research project that aimed at acquainting students with some of the procedures used by physicists in the real world. Outlines specific project designs used by the students. (JRH)

Presents an alternative to the use of a radar to determine how fast an individual can serve a tennis ball. Equipped with a tape recorder and a Macintosh computer, students determine the velocity of a tennis ball by analyzing the sounds and echoes heard on the court. (ZWH)

Discusses 5 innovative experiments conducted by Rutherford in early 1900s utilizing the 30 milligrams of radium salt he personally carried from Europe to Canada in 1903. Traces his work with alpha particles from his original results which determined their nature, charge, and mass, to his technique of backscattering which helped to advance…