The determination of the thickness of a sludge blanket in primary and secondary clarifiers and in gravity thickness is important in making operational control decisions. Knowing the thickness and concentration will allow the operator to determine sludge volume and detention time. Designed for individuals who have completed National Pollutant…

Describes an experiment which can be used to test for the use of accelerants in the origin of a fire. Involves distillation and gas liquid chromatography to identify the accelerants, thus combining two experiments ordinarily included in the beginning organic laboratory. (SLH)

Describes the use of student projects within a traditional biology laboratory class to incorporate openness, inquiry techniques, and student choice into course teaching. Included is a list of sample investigations. (CC)

Discusses advances made in chemical analysis instrumentation used in environmental monitoring. This first of two articles is concerned with analytical instrumentation in which detection and dispersion depend ultimately on the properties of gaseous molecules. (JR)

Suggests two uses for the programmable calculator in the freshman chemistry laboratory: as a means of determining whether or not a student's raw data from a laboratory experiment fall within acceptable tolerance limits; and as a means of checking the reliability of unknowns and grading on quantitative experiments. (MLH)

Describes a "feedback course" offered at Brown University, in which undergraduates redesigned the introductory organic chemistry laboratory. The students specified objectives for the ideal lab, then devised laboratory experiments. Laboratory safety was stressed, all dangerous reagents and solvents were eliminated, and toxicological data were…

Discusses some of the most important structural features found in modern chemical laboratories, including building shapes, floor plans, and window utilization. (MLH)

Discusses an experiment in freer language laboratory use in which oral communication was elicited with the help of illustrations, vocabulary, and a model. (Text is in French.) (AM)

Describes an experiment wherein the student can demonstrate the existence of all the thiocyanato chromium complexes, estimate the stepwise formation constants, demonstrate the robustness of chromium III complexes, and show the principles of paper electrophoresis. (GS)