Discusses a laboratory exercise (suitable for the day before spring vacation) involving use of a hard-boiled egg to stimulate student responses to questions on the effect of adding salt to the water, formation of iron sulfide, ease of peeling, and gas laws. Additional experiments are included. (BC)

Errors in determining the effectiveness of mouthwashes, disinfectants, and other household products as antibacterial agents may result from using broth cultures and/or irregularly shaped bits of filter paper. Presents procedures for a better technique and, for advanced students, two additional procedures for introducing quantitative analysis into…

Describes an experiment involving the preparation of copper iodide that gives stoichiometric results. Materials needed and procedures are discussed along with ideas on different ways to analyze the data. Pertinent chemical equations are presented. (BC)

Explains a projectile motion experiment involving a bow and arrow. Procedures to measure "muzzle" velocity, bow elastic potential energy, range, flight time, wind resistance, and masses are considered. (DH)

To integrate a research/discovery component into one course, an experiment using the sea urchin embryo system is introduced because the teacher manages only one organism and students provide the variables. The materials, handling methods, and experimental methods of the experiment are described. (YP)

Identifies the characteristics and components of a quality laboratory program for secondary science students. Suggests approaches, questions, and activities that aim to provide challenging experiences in the sciences. Also provides a listing of recommended laboratory standards and procedures. (ML)

Discusses the rationale for using photochemistry to merge descriptive chemistry and molecular orbital theory in first-year chemistry courses. Includes procedures and safety information for various activities, demonstrations, and experiments involving photochemical reactions. (DH)

Briefly discusses the theory of fatigue, and describes ways in which the fatigue rate in humans can be measured in the classroom using a simple physiological instrument, the ergometer. (JR)