Presented is a practical scheme to enable introductory biology students to investigate the mechanism by which urea is synthesized in the liver. The tissue-slice technique is discussed, and methods for the quantitative analysis of metabolites are presented. (Author/SL)

Described is a simple apparatus to determine acceleration due to gravity. It utilizes direct contact switches in lieu of conventional photocells to time the fall of a ball bearing. Accuracies to better than one part in a thousand were obtained. (SL)

Discusses precaution in handling laboratory chemicals and research animals. Gives references, suggested readings, and a table showing fire hazard properties of some flammable liquids. (MLH)

The agencies listed in this document are amending the Federal Policy for the Protection of Human Subjects, which was published in the Federal Register on June 18, 1991, to change all references to the Office for Protection from Research Risks (OPRR) to the Office for Human Research Protections (OHRP); revise the footnote found at the end of…

This interpretive study of the implementation of a school-based assessment scheme of biology practical work in Hong Kong examines the struggles of three teachers with the issue of fairness in relation to their classroom actions. Though the teachers' discourses were dominated by, and their classroom actions were pre-eminently influenced by, the…

Describes the experimental procedures used for detecting DNA and RNA synthesis in xenopus cells by autoradiography. The method described is suitable for senior high school laboratory classes or biology projects, if supervised by a teacher qualified to handle radioisotopes. (JR)

Describes an experiment designed to provide the opportunity for studying some of the parameters affecting the stability of Vitamin C in various environments, and to acquaint the student with an experimental procedure for studying simple reaction kinetics and the calculations of specific rate constants. (Author/JR)

An atomic absorption spectrophotometric method is described for the rapid analysis of lead dioxide candles exposed to ambient air containing sulfurous pollutants. (Editor/JR)

The study was conducted to evaluate divergent physics laboratories in accomplishing objectives of Commission on College Physics. A questionnaire was used to collect data from students. Analysis revealed students in divergent laboratories had more opportunity to choose or design their own experiments and develop a model for data interpretation. (PS)

Describes the principles and uses of thermoluminescence technique in dating of pottery and ceramic pieces and establishing the authenticity of artifacts. (CC)

Describes a microbiological experiment designed to study the competition between two species of bacteria. Experimental procedures and data obtained in conducting this experiment are provided, together with a discussion of the results. (JR)