Describes experiments that illustrate a number of general principles such as pattern identification, displacement chromatography, and salting-out adsorption, plus an experiment that demonstrates that identification by chromatography alone is impossible. Illustrates that chromatography is still possible with quite simple means, notwithstanding the…

Presents activities that can be used to introduce thin-layer chromatography at the undergraduate level in relatively less developed countries and that can be performed with very simple and commonly available apparati in high schools and colleges. Activities include thin-layer chromatography with a test-tube, capillary feeder, burette, and rotating…

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…

Presents an interview protocol used to identify and evaluate students' conceptions of plants which is an invitation to participate in the third national study exploring elementary students' science conceptions. (YDS)

Describes an experiment to demonstrate a simple method for measuring fungus growth by monitoring the effect of temperature on the growth of Trichoderma viride. Among the advantages that this experimental model provides is introducing students to the importance of using the computer as a scientific tool for analyzing and presenting data. (AIM)

Describes an exercise used as a follow-up activity to a lecture presentation exploring the basic methodology and theory of shoot tip cultures. Utilizes a factorial experimental design which allows for the determination of the effects of each factor alone and in combination with each other. Other concepts emphasized include dependent and…

Examines the relative effectiveness of the traditional lab method and the microcomputer-based laboratory (MBL) for improving student understanding. Examines three areas of achievement: graphing interpretation skills, and interpreting motion graphs and understanding of motion. Results indicate that MBL laboratories are more effective than…

Describes several ways to partially levitate permanent magnets. Computes field line geometries and oscillation frequencies. Provides several diagrams illustrating the mechanism of the oscillation. (YP)

Outlines procedures for demonstrating and preparing a permanent slide of sister chromatid exchanges and recombination events between the two chromatids of a single chromosome. Provides the name of an additional resource for making preparations of exchanges. (RT)

Presents a laboratory exercise that uses a simple imaging technique to illustrate the profound effects that living roots exert on the pH of the surrounding soil environment. Achieves visually stimulating results that can be used to reinforce lectures on rhizosphere pH, nutrient availability, plant tolerance of soil acidity, microbial activity, and…

Describes a laboratory method to allow students to complete electrophoresis and staining of DNA samples within 1 45-minute classroom period. (MKR)

Describes the use of a digitized video image system in conducting radically different projectile experiments. Presents a detailed example of its use and discusses the advantages and disadvantages of using digitized video images. (JRH)

Describes an experiment that uses the ultrasonic transducer for demonstrating the Fourier components of waveshapes such as the square and triangular waves produced by laboratory function generators. (JRH)

Describes an experiment designed to help understand the effect of the curvature of the laboratory equipment support (cylindrical rod instead of knife-edge) on the frequency of oscillation of pendula. (ZWH)

Involves students in a study designed to examine the interaction between children's observations of light and shadows and their developing theories in the context of a series of lessons in a third-grade classroom. Results suggest that student's observation of light led to the development of a limited theory about light that was largely useful in…