Comments on this issue's article by Ward, Vela, and Hass on children's category learning. Suggests that aspects of the authors' methodology may have led them to underestimate holistic processing. (PCB)

Discusses the application of methodological techniques to social science Web experiments, and suggests topics in library and information science most conducive to research on the World Wide Web. Topics include causal inference; the Web as a venue for research; Web experiments versus laboratory experiments; and internal, construct, and external…

Presents a laboratory activity designed to be a botanical autotutorial tour of a supermarket, meant to increase students' appreciation of the role that botany plays in the production of food. (WRM)

Examines student attitudes towards biochemical experiments and their effect on student learning. Finds that biochemical experiments in the medical curriculum are valuable, but efforts should be directed more towards the development of students' attitudes and approaches to the exercise. (Author/CCM)

Describes how to determine the mass of a gas in a flexible, lightweight container and argues that the buoyant force of air needs to be taken into account. Recommends the use of mylar and describes equipment preparation. (DDR)

Describes a set of laboratory activities in which students construct a model for the relationship between potential difference (measured in volts) and current (measured in amperes) in a DC circuit with a single resistor. (SAH)

Introduces the chicken wing project in which students assess the microbial contamination of chicken wings for the safety of foods. Uses the colony counting technique and direct wash fluid examination for determining the microbial contamination, and investigates methods to reduce the level of microbial contamination. (Contains 14 references.) (YDS)

Explores using corn seeds to demonstrate plant growth and development. This experiment allows students to formulate hypotheses, observe and record information, and practice mathematics. Presents background information, materials, procedures, and observations. (SAH)

Explains the teaching opportunities, especially in science activities and laboratory experiments, of using technology in science classrooms. (YDS)

Describes a chemistry demonstration on freezing point depression wherein students investigate the effects of adding various substances to ice water. Includes instructor information and a student activity sheet. (YDS)

Presents a 10-hour chemistry experiment using copper sulfate that has three steps: (1) purification of an ore containing copper sulfate and insoluble basic copper sulfates; (2) determination of the number of water molecules in hydrated copper sulfate; and (3) recovery of metallic copper from copper sulfate. (Author/YDS)

Describes an activity comparing incandescent bulbs and LEDs powered by dc and ac voltage sources to illustrate properties of matter and the interactions of energy and matter. Includes both instructor information and student activity sheet. (Author/YDS)

Explains a three week laboratory experiment on the gel separation of peroxidase, which is the most well-known isozyme, from beans. Includes suggestions on the laboratory management. (Contains 13 references.) (YDS)

Explains how to use galvanotaxis and mutagenesis experiments to study Paramecium's swimming behaviors and ion channel functions. (YDS)

Describes a molecular biology laboratory in which students study the role of the enzyme polygalacturonase in the softening of tomatoes during ripening by developing their own hypotheses and designing their own experiments. (MM)