Some of the important modern developments of thin-layer chromatography are introduced. Discussed are the theory and instrumentation of thin-layer chromatography including multidimensional and multimodal techniques. Lists 53 references. (CW)

Described is an experiment which illustrates pseudo-first-order kinetics in the fading of a common indicator in an alkaline solution. Included are background information, details of materials used, laboratory procedures, and sample results. (CW)

Discusses when alternating and magnetic fields are independent. Provides examples of experiments involving mains hum and the detection of induced signals. Describes electric circuits and oscilloscope displays. (Author/YP)

Describes the mechanism of bicycle computers functioning as speedometers and timers. Discusses why the computers do not display the continuously changing readings and show the correct values at higher speeds. (YP)

Describes an experiment producing a visible spectrum with inexpensive equipment available in the physics classroom. Discusses some related equations, apparatus settings, and instructional methods. (YP)

Described is a simple technique for isolating DNA from halophilic bacteria. Materials, procedure, and additional experiments are outlined. It is stated that the DNA obtained will be somewhat contaminated with cellular proteins and RNA. Offers a procedure for greater purification. (RT)

An exercise that uses a common bacterium, E. coli, in great numbers, to detect a demonstrable change in the ability of some cells to become resistant to the common antibiotic streptomycin is presented. The procedure for preparing and pouring the gradient antibiotic plates is provided. The advantages of using the Basic Fuchsin in the agar are…

Evaluates the traditional method of intercalating theoretical and seminar classes with laboratory practical work. Proposes a new schedule where students get problem-based learning of theoretical concepts during the first half of the course, and plan and execute a laboratory project during the second half. (Author/CCM)

Describes how scientists use representations and tools in the chemistry laboratory. Derives implications from these findings for the design of educational environments. (Author/CCM)

Demonstrates how leaf slices provide an inexpensive material for illustrating several fundamental points about the biochemistry of photosynthesis and respiration. Presents experiments that illustrate the effects of photon flux density and herbicides and carbon dioxide concentration. (DDR)

Reviews the interests and inventions of Robert Bunsen. Describes the constant water level bath, suction pump, absorptiometer, and diffusiometer. Contains 16 references. (DDR)

Points out the need to educate undergraduate chemical engineering students on chemical process safety and introduces the content of a chemical process safety course offered at the University of Iowa. Presents laboratory experiments demonstrating flammability limits, flash points, electrostatic, runaway reactions, explosions, and relief design.…

Describes the study of dung-inhabiting or coprophilous fungi to illustrate basic lab techniques and fundamental ecological concepts. Contains 24 references. (WRM)

Presents methods that can be used to isolate the enzyme tyrosinase and to assay its activity. Lists instructions for a laboratory activity that has variable but frequently dramatic results. (WRM)

Using microbiology activities in the classroom is an effective way for teachers to address National Standards in the life sciences. However, common microbiology activities that involve swabbing doorknobs and hands are too risky due to the likelihood of culturing human pathogens. In addition, making sterile media and maintaining sterile conditions…