Reviews trends in liquid chromatography including apparatus, factors affecting efficient separation of a mixture (peak sharpness and speed), simplified problem-solving, adsorption, bonded phase chromatography, ion selectivity, and size exclusion. The current trend is to control chemical selectivity by the liquid phase. (Author/JN)

Use of gradient elution techniques in high performance liquid chromatography (HPLC) is often essential for direct separation of complex mixtures. Since most commercial controllers have features that are of marginal value for instructional purposes, a low-cost controller capable of illustrating essential features of gradient elution was developed.…

Describes an inexpensive means for determining proximate analysis of coal, and by use of this data, its energy content. Pyrite content is also obtained by utilizing magnetic properties of iron. The simple device used makes the experiment suitable for the undergraduate laboratory. (Author/JN)

A controversy has arisen as to whether instrument vendors are providing sufficient information about instrument-associated software to permit users to understand invisible data transformations going on inside of the equipment. Topics addressed include software protection, user modifications, and publishing software. (Author/JN)

Describes a simple and inexpensive pyrolysis gas chromatography (PGC) system constructed from items available in undergraduate institutions. The system is limited, accepting only liquid samples and pyrolyzing "on the fly" rather than statically and not allowing for reductive pyrolysis. Applications, experiments, and typical results are included.…

Presents the uses of pocket calculators, programmable calculators, and microcomputers in teaching of statistical physics in unit 9 of the Nuffield advanced physics course. (SK)

Cathodoluminescence is visible light emitted from a specimen when it is bombarded with electrons. A technique known as cathodoluminescence petrography can provide information especially useful in studies or courses related to mineralogy and petrology. The technique is briefly presented, along with examples to illustrate typical results. (Author/WB)

Provides instructions for building an inexpensive apparatus that measures the thrust of a model rocket engine as a function of time. (CS)

A technician auto analyzer (consisting of six modules: sampler, multichannel peristaltic pump, dialyser, heating/incubation bath, colorimeter, and recorder) was modified by using key modules and substituting standard equipment for others; spectronic 20 with homemade flow cell for colorimeter module. Descriptions and diagrams of the apparatus are…

Crushed glass and a Rhodamine B solution are used in a one-dimensional optically scanned column experiment to study the dispersion phenomenon in porous media. Results indicate that the described model gave satisfactory results and that the dispersion process in this experiment is basically convective. (DC)

Describes an inexpensive, low-pressure liquid chromatography pump, slurry filler, stainless steel columns, and injector system suitable for the undergraduate laboratory or routine analysis. Includes sectional diagram of the pump and construction diagram of the preparative columns. (Author/SK)

The use of a logarithmic amplifier preceding an oscilloscope's vertical amplifier is described for physics teachers who want to demonstrate the exponential decay nature of some phenomena. (Author/SA)

Intended for the elementary teacher who lacks science teaching experience, this article presents tips for finding background information and for stocking a portable "science lab" with everyday materials. It also outlines 10 easy experiments. (SJL)

Describes an apparatus to be used in a visual presentation of simultaneous, independent motions and their resultants. The apparatus is best suited for representing a boat and stream, but could be modified to represent a plane in a moving air mass. (Author/DS)

Briefly discusses new instrumentation in the field of analytical chemistry. Advances in liquid chromatography, photoacoustic spectroscopy, the use of lasers, and mass spectrometry are also discussed. (CS)