Describes a thin film rectangular dielectric waveguide and its laboratory use. Discusses the theory of uniaxial thin film waveguides with mathematical expressions and the laboratory procedures for a classroom experiment with diagrams. (Author/YP)

Describes experiences, or "lab puzzles," which will help students develop problem-solving skills in a laboratory setting. Outlines procedures for developing techniques, setting boundaries, and finding the number of molecules of water in Lake Erie. (RT)

Studies the polarization effect on water by cations and anions. Describes an experiment to illustrate the polarization effect of sodium, lithium, calcium, and strontium ions on the water molecule in the hydration spheres of the ions. Analysis is performed by proton NMR. (MVL)

Develops a lab experiment for introductory instrumental analysis that requires interference studies and optimizing of conditions. Notes the analysis of the aspirin is by visible spectrophotometric assay. Gives experimental details and discussion. (MVL)

Describes a laboratory experiment designed to encourage laboratory cooperation among individual undergraduate students or groups. Notes each student contributes results individually and the exchange of data is essential to obtain final results. Uses the polarographic method for determining complex metal ions. (MVL)

Describes a laboratory experiment that measures the amount of ascorbic acid destroyed by food preparation methods (boiling and steaming). Points out that aqueous extracts of cooked green pepper samples can be analyzed for ascorbic acid by a relatively simple redox titration. Lists experimental procedure for four methods of preparation. (MVL)

Presents two experiments: the first one measures the heat of an exothermic reaction by the reduction of permanganate by the ferris ion; the second one measures the heat of an endothermic process, the mixing of ethanol and cyclohexane. Lists tables to aid in the use of the solution calorimeter. (MVL)

The purpose of this study was to determine the concerns of Texas science teachers about the 40 percent laboratory time rule just prior to enforcement and at the end of its first year of implementation. The methodology, results of the first and second years, conclusions, and implications for teaching science are discussed. (KR)

For a two-year period, 32 secondary students gifted in the areas of mathematics and science participated in a curriculum which incorporated higher-level thinking skills and more real-life laboratory experiences into mutually reinforcing mathematics and science lessons. After the program, participants scored higher on mathematics and science…

In this article, the authors present a classroom experiment that was developed to introduce middle school learners to the carbon cycle. The experiment deals with transfer of CO[subscript 2] between liquid reservoirs and the effect CO[subscript 2] has on algae growth. It allows students to observe the influence of the carbon cycle on algae growth,…

The use of complex instruments for chemical analysis is becoming increasingly important. Unfortunately, because of school budgetary constraints, many students are not exposed to these methods until they reach the college level. When students do have access to sophisticated instruments, they often view them as black boxes, with little or no…

Stomata are the pores on leaves through which carbon dioxide, oxygen, and water vapor are exchanged with the atmosphere. Researchers have found that leaf stomatal densities change in response to several environmental variables, including humidity, light intensity, and atmospheric levels of carbon dioxide, a greenhouse gas (Van Der Burgh, Dilcher,…

Although the theory of evolution is the foundation of modern biology, students too rarely have an opportunity to watch selection operate in natural populations of animals. This lack may be partially responsible for the unfortunate ignorance of many people regarding the significance of evolution in biology. Laboratory exercises that directly study…

This collection of lesson plans designed for teachers of 4th- through 12th-grade students utilizes an assortment of teaching strategies for topics related to coal and the coal industry. Activities cover the following topics: coal formation; coal identification; "the geologist's dilemma" (a supply and demand activity); geologic time and…

This document describes ways to work with DNA and host organisms in precollege classrooms. The guidelines are intended to assist the teacher who already has training in working with microbes, DNA, and associated chemicals. The contents of the guidelines include: (1) Permitted DNA molecules, vectors, and recommended host organisms for constructing…