Describes a procedure for the qualitative analysis of aluminum subgroup cations designed to avoid failure to obtain lead or barium chromate precipitates or failure to report aluminum hydroxide when present (due to staining). Provides a flow chart and step-by-step explanation for the new procedure, indicating significantly improved student results.…

Describes an experiment on the simultaneous determination of chromium and magnesium by spectophotometry modified to include the Generalized Standard Addition Method computer program, a multivariate calibration method that provides optimal multicomponent analysis in the presence of interference and matrix effects. Provides instructions for…

Describes a microscale laboratory course in which students perform many classic organic reactions using only one-hundredth to one-thousandth the amount of starting material usual in student experiments. Reduction of toxic chemicals concentration in laboratory air and savings in chemical costs and experimental time are benefits of the novel course.…

Discusses use of the fine-beam cathode-ray tube to investigate strength and direction of the earth's magnetic field, simulating discussion between student and teacher as the equipment is set up and the experiment done. Provides diagrams and illustrative photographs to aid in equipment set-up and measurement. (JM)

Describes an inexpensive and versitile interface which can be readily adapted to many on-line experimental projects in scientific fields by educators who are not computer experts. Hardware and software requirements are noted. (JN)

Discusses instructional strategies and activities designed to help students learn to recognize patterns and to create models to explain patterns. These include laboratory investigations and an exercise in which students are challenged to find the model used for the classroom seating arrangement. (JN)

Background information (including optical properties of inorganic materials) and procedures are provided for an experiment which introduces students to preparation of a doped semiconductor; phosphorescence; gettering procedures; reducing atmospheres; and use of a high-temperature furnace with associated thermocouples, temperature controllers, and…

Examines techniques used to make ultrasensitive spectroscopic measurements. They include excitation, thermal lens, photo acoustic, and ionization spectroscopies. Guidelines and methods are provided for each technique; common uses and applications are explained. (DH)

Describes an apparatus developed for photochemical studies, particularly those involving the fluorescence of halogenated acetones. The apparatus is constructed from equipment normally found in a moderately sized physical chemical laboratory. Also provides background information on some aspects of the photophysics of halogenated propanones. (JN)

Describes a set of experiments (for senior-level biochemistry students) which permit evaluation and estimation of rate and equilibrium constants involving an intermediate in the alpha-chymotrypsin mediated hydrolysis of ortho-hydroxy-alpha-toluenesulfonic acid (I). The only equipment required for the experiments is a well-thermostated double beam…

The use of a microcomputer as the basis of a multichannel analyzer (MCA) system is described. Principles of microcomputer MCA, choice of microcomputer, input-output port, data display, MCA program, and interrupt routine (with flowchart) are the topic areas considered. (JN)

Equipped with simple sensors and software, a microcomputer can become a microcomputer-based laboratory (MBL). Discusses the value of MBL's and provides three programs which preview the new MBL kits available for science classes. A list of commercially available MBL's (with product names, current prices, and other information) is also included. (JN)

Suggests a simple technique for collecting and observing human hair roots to compare structure, function, and variation. Students extract their own hair samples and view them using a 40-power microscope objective. Differences between active/inactive phases of hair growth are readily observed. (The activity can be adapted for younger students.) (DH)

Project CHEMLAB has prepared a database which focuses on laboratory experiments suitable for high school through graduate or professional school levels. The scope of the project, the structure of the database, database features, and computer searching are discussed. (JN)

The value of the genus Nematodius in teaching is not widely realized. Presented is a brief biological outline of the organism (including geographical distribution and reproductive cycle/behavior) and its use in student investigation of selective predation. (Author/JN)