Describes an undergraduate physical chemistry experiment in which the acid catalyzed hydrolysis of sucrose is used to determine the catalytic coefficient of the hydronium ion, the catalyst in this reaction. (MLH)

Prefaced by an interpretation of American preschool studies, a semihistorical approach is used in presenting findings from preschool experiments from the West Riding Educational Priority Area project in England, with a purpose being to suggest some alternatives and to sketch a framework for explaining the conflicting results. (ND)

Analyzes the effects of age, sex and family composition on students' preferences for the sex and birth order of their offspring. (LS)

Discusses difficulties encountered in the determination of the thermal conductivity of a gas. Provides analyses of one particular set of data. (CP)

Details construction of an inexpensive electronic auditory device in which the resistance in parallel with the device is inversely proportional to the frequency of sound produced. (CP)

Describes an activity involving a transparent water filled box and a plane mirror in which the refraction of light rays is demonstrated. (CP)

Describes an undergraduate biochemistry experiment that utilizes gel electrophoresis of a crude extract and the partially purified gel filtrate. (MLH)

Describes an exercise that teaches Mendelian inheritance using human traits which students find exciting and relevant. (LS)

Describes an experiment, using a soap bubble raft, intended to provide insight into the orderly packing of spherical objects and the properties of metallic crystals. Also describes a solubility product experiment which uses barium hydroxide. (MLH)

The use of atomic absorption techniques to determine heavy metals in trace amounts is demonstrated by analyzing a solution of human hair digested in nitric acid. (MLH)

Describes qualitative and quantitative experiments using ion exchange columns; after introductory exercises the students determine the total ion concentration in sea water and blood plasma. (MLH)

The stoichiometry of the reaction between potassium chromate and barium chloride is determined by analysis of precipitates by mixing various amounts of both solutions. (GS)