This article describes a novel, hands-on method to qualitatively determine the extent of microbial activity in topsoil using ordinary blank paper. Appropriate and scalable for the high school and college level, these experiments expose students to some of the challenges facing environmental researchers and also contribute to curriculum development…

Describes a simple photometer capable of measuring small light intensities over small areas. The inexpensive, easy-to- construct instrument is intended for use in a student laboratory to measure the light intensities in a diffraction experiment from single or multiple slits. Typical experimental results are presented along with the theoretical…

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…

Qualitative analysis schemes are used in undergraduate laboratory settings as a way to introduce equilibrium concepts and logical thinking. The main component of all qualitative analysis schemes is a flame test, as the color of light emitted from certain elements is distinctive and a flame photometer or spectrophotometer in each laboratory is…

Suggests teaching strategies for overcoming the lack of student understanding of the principles of the bubble photometer by helping students compare the bubble photometer with the weighing method, develop the concept of assumptions, and resolve cognitive conflicts. Uses an interactive activity to help students expose their preconceptions.…

Includes description of a light meter, photometer, fluid flow apparatus, and acoustic grating. (RH)

Describes a number of pieces of equipment for physics. Included are a pendulum, Archimedes' Principle apparatus, solar photometer, and anharmonic motion. (RH)

Describes the construction and use of an inexpensive colorimeter that reliably estimates the phosphorus concentrations in water. Presents a two-step modification to an existing photometer. (SAH)

This transition, observed with an inexpensive ultraviolet photometer, is a potentially useful experiment for an advanced freshman class because it introduces several concepts of general physical interest. (DF)

An iodometric assay that allows the ground-level ozone concentration to be determined with an inexpensive sampling apparatus and a homemade photometer is described. This laboratory experiment applies a variety of different fundamental concepts including oxidation-reduction chemistry, the ideal gas law, and spectroscopic analysis and also provides…

The use of harmful organic solvents in classrooms has become a critical issue of concern in the field of chemistry education. This article describes a classroom activity at a high school in which an acrylic fabric was used as the extraction medium in the analysis of the detergent concentration in water instead of organic solvents. Dyes were used…

Describes differences in the construction of a colorimeter and a photometer. Gives examples of ways in which light-measuring instruments can be used by biologists. These examples can be used either as class experiments or as individual projects. (GS)

Describes the following: an electric circuit for an expensive photometer, an amplifier circuit capable of demonstrating many aspects of behavior of free and driven oscillators, and finally a projection recording system which uses an unmodified XY or XT recorder and a separate overhead projector. (GA)

Traces the development of instruments used in spectrophotometry. Discusses how spectrophotometric measurements are made. Describes the color comparator, the filter photometer, and the spectrophotometer. Outlines the evolution of optical systems, including light sources, the monochromator, the photodetector, double-beam optics, and split-beam…