Describes an apparatus designed to investigate molecular motion by means of light scattering. Light from a He-Ne laser is focused into a cell containing a suspension of polystyrene spheres. The scattered light, collected on the photosurface of a photomultiplier tube, is analyzed. The apparatus won first prize in Demonstration Lecture Apparatus in…

The use of toluidine blue as a stain for plant tissues is advocated. Directions for hand-cut tissue staining are provided. (PEB)

The temperature at which the onset of coordinated segmental motion begins is called the glass-rubber transition temperature (Tg). Natural rubber at room temperature is a good example of a material above its Tg. Describes an experiment examining the response of a typical polymer to temperature variations above and below Tg. (Author/JN)

Cerenkov counting is a useful technique for assaying medium/high energy beta emitters in aqueous solutions. Advantages of the technique include: (1) simple sample preparation; (2) being able to handle large volume of aqueous solution for counting; and (3) absence of chemical quenching. Cerenkov counting is also less expensive than other methods.…

Five commonly used selection criteria were studied to determine their relationship to nine teaching behaviors of 112 preservice teachers in laboratory preschools. Results indicate that the commonly used factors for selecting and hiring preschool teachers are moderately useful indicators of certain behaviors that comprise teaching. (JOW)

Suggesting that selected research activities be integrated into engineering technology programs to give students experiences in new technology, this article discusses a project incorporating teaching, research, and service. A photograph and description of the solar experiment unit resulting from the project are provided. The unit runs on air,…

Describes procedures for preparing acetylacetonate complex of cobalt(II), followed by spectrophotometric analysis to characterize the material, with additional characterization methods supplied by students to provide open-ended dimension for the experiment. (SK)

Measurement of the time dependence of the flow of charge constitutes the procedure known as chronocoulometry. Although the technique is useful in a variety of electrochemical measurements, the discussion focuses on the evaluation of reactant adsorption, the application for which the technique was originally devised. (JN)

Discusses the nature of pulse voltammetry, indicating that its widespread use arises from good sensitivity and detection limits and from ease of application and low cost. Provides analytical and mechanistic applications of the procedure. (JN)

Describes basic characteristics of the electrochemical cell. Also describes basic principles of electrochemical procedures and use of these concepts to explain use of the term "primarily" in discussions of methods primarily responsive to equilibrium cell potential, bulk ohmic resistance, and the Faradaic impedance. (JN)