Discusses the contributions made by the field of quantum electrodynamics to the understanding of positroniums. (MLH)

The concept of a "picture superiority effect" is discussed. Examined are a number of perceptual considerations that need to be given to picture construction. Parameters which appear to attract the learner's attention to a picture are considered. (CW)

Discusses the change in pressure as a balloon expands. Describes the pressure change in a spherical soap bubble and a rubber membrane on the tube. Provides demonstrations when two balloons are connected by a tube. Lists five further reading materials. (YP)

Examines college students' perception of an interactive videodisc learning system as an alternative to the conventional laboratory for learning biology skills and concepts taught under classroom laboratory conditions. Reports that the videodisc instruction gave more experimental and procedural options and more efficient use of time than the…

Presents a procedure by which cytokinins are used to induce a population of dividing and differentiating cells on the cut surface of the roots of an intact plant. Includes the method used, results, and suggestions for a variety of variables that may be tested. (RT)

The difference in time between the emission and reception of light is called the "lookback" time. This article explores implications of lookback time and explains some of the puzzling questions posed by the scientific observation of cosmic history. Provides several pictures and diagrams. (YP)

Described is the construction and use of an osmometer that is low in cost, easy to make, and durable. Materials needed and procedures are outlined. Diagrams show an assembled instrument and individual parts. (RT)

Examines whether content area textbook passages could be rewritten so that middle grade students' main idea comprehension ability was enhanced. Finds that after reading rewritten text versions, some students could compose significantly more passage main ideas, and all students could compose significantly more paragraph main ideas. (MM)

Discusses the need for quality science books for children and the role that awards could play in promoting superior books. The American Institute of Physics Award, the American Nature Study Society's Eva L. Gordon Award, and the New York Academy of Sciences Award Program are described. Award-winning publishers and authors are listed. (31…

Two studies investigated the placement of interesting details in a text by asking 276 undergraduate students what they could recall after reading a text about a physicist and his scientific work. Placement of detail did not affect recall, but overall interestingness of the text did affect recall. (SLD)

Describes the building of a list of constructed-impact factors (CIF) for biomedical journals not included in the 1996 editions of the "Journal Citation Reports." The online retrieval from the host DIMDI of the data needed for impact-factor calculation is described. The top 100 (of 338 titles, ranked according to their CIFs) are…

Investigated whether HIV-prevention program planners sought out science in designing interventions and, if not, where they gathered prevention information. Surveys of program mangers nationwide indicated that three important sources of information were peers and colleagues, departments of public health, and the Centers for Disease Control and…

Lists directions for creating some laboratory equipment that makes it easier for students to assess the rate at which an enzyme is modifying its target (substrate). (WRM)

Examines problems associated with children's use of science text, the implied literacy demands of learning science from currently available science books and schemes, and the extent to which the current interpretation of literacy advocated by the National Literacy Strategy encompasses the skills needed to learn science from a book. Includes…

The advent of cheaper SLR digital cameras and associated software has allowed the rapid creation of digital images. We explain three simple techniques that allow the generation of micrographs. A further technique is described that allows the production of an image from a full section of the microscope slide. Class sets of micrographs greatly…