Presents a laboratory demonstration that helps students understand the concept of microscope calibration. (JRH)

Describes a low-cost four-color LED photometer developed to overcome the rising cost of laboratory equipment used in general chemistry labs and introduce instrumentation at the undergraduate level. The photometer detects absorbance at selected wavelengths of visible light but retains the advantages of a dual-beam system. The unit is compact and…

Describes two variations of an air sampler and analyzer that are inexpensive to construct, easy to operate, and designed to be used in an educational program. Variations use vacuum cleaners and aquarium pumps, and white facial tissues serve as filters. Samples of air pollution obtained by this method may be used from early grade school to advanced…

Describes the function of the various parts of the microscope and their integration in the formation of an optical image. Presents a procedure for setting up a microscope to obtain maximum resolution and contrast for each objective lens at all magnifications. (JRH)

Describes the Packard's Falling Body Apparatus, invented by John C. Packard, which is essentially an inclined plane combined with a simple and elegant method of measuring the relative time of descent of a steel ball. (JRH)

Describes an experiment combining qualitative and quantitative information from hydrogen nuclear magnetic resonance spectra. Reviews theory, discusses the experimental approach, and provides sample results. (JM)

Describes three situations in which computer software was used in a chemistry laboratory. Discusses interfacing voltage output instruments with Apple II computers and using spreadsheet programs to simulate gas chromatography and analysis of kinetic data. Includes information concerning procedures, hardware, and software used in each situation. (CW)

Studies the polarization effect on water by cations and anions. Describes an experiment to illustrate the polarization effect of sodium, lithium, calcium, and strontium ions on the water molecule in the hydration spheres of the ions. Analysis is performed by proton NMR. (MVL)

Describes a photochemistry experiment designed to introduce photochemical techniques and experience free radical chemistry. Selects Nuclear Magnetic Resonance spectroscopy for the analysis. This activity is suggested for use in an upper level undergraduate organic course. (MVL)

Describes an advanced NMR project that can be done with a 60-MHz continuous-wave proton spectrometer. Points out the main purposes are to give students experience in second-order NMR analysis, the simplification of spectra by raising the frequency, and the effect of non-hydrogen nuclei on proton resonances. (MVL)

Describes a method for using nuclear magnetic resonance to observe the effect of electronegativity on the chemical shift of protons in similar compounds. Suggests the use of 1,3-dihalopropanes as samples. Includes sample questions. (MVL)

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)

ChemSource is designed as a strategy to help preservice and inservice high school chemistry teachers promote student learning more effectively. Its major premise is that well-designed laboratory investigations are an important avenue for cultivating student interest, engagement, and meaningful learning in chemistry. The SourceBook component of…

Presents a method of constructing short range transmitters suitable for sensing the temperature in eggs, nest cavities or other applications. Provides a list of materials, circuit diagram, and assembly instructions. (CW)

Presented are five ideas for A-level biology experiments using a laboratory computer interface. Topics investigated include photosynthesis, yeast growth, animal movements, pulse rates, and oxygen consumption and production by organisms. Includes instructions specific to the BBC computer system. (CW)