Discusses the application of the rule of allowing the car in front to have a two-second lead. Notes that as speed doubles, stopping distances increase by four. Provides a table of stopping distances including reaction distance, braking distance, total stopping distance, and two-second rule distance. (MVL)

Presents data from two studies determining the validity of various measures of physical activity in preschool children. One explored how certain measures of activity predicted observed behavior. The other examined the Caltrac motion sensor's predictive validity. Results indicate the Caltrac monitor is sensitive to children's individual differences…

Assessed infants' detection of relative motion between a target and its surrounding static reference features in two experiments. Found evidence for 8- and 20-week-olds' detection of a moving target, and a target and surrounding reference features moving in opposite directions. Twenty-week-olds detected a target that moved faster and in the same…

Seven experiments involving a total of 203 college students explored a form of object-specific priming and established a robust object-specific benefit that indicates that a new stimulus will be named faster if it physically matches a previous stimulus seen as part of the same perceptual object. (SLD)

Reviews two projects studying the nature of mental representations of space induced entirely by language. The first project investigates perspective in descriptions of large-scale (e.g., convention center, town) space. The second project investigates mental representations of objects located immediately around the body. (37 references) (KRN)

Discusses how the Galilean balance equilibrium model can be used in the physics classroom to provide students with a model of intelligibility that would unify their thinking about motion and, at the same time, provide them with a general procedural schema for solving motion problems. (ZWH)

A procedure for estimating the speed and distance of plane, assuming the speed of sound and the velocity of the plane are constant, is described. (KR)

A procedure for measuring the speed of light using the assumption that the frequency of light remains unchanged as it moves from one medium to another is presented. A laser with a known wavelength and frequency in air was used as a light source. (KR)

A task involving movements with either hand to near or far targets was employed with 16 adults with mental retardation (9 of whom had Down's syndrome). Specific features of the movement were precued. Both groups were able to use advance information to reduce movement preparation time and were not limited by a fixed-order movement preparation…

Examined whether young infants produced differentially organized hand and arm actions in relation to affective expressions when the infants were presented with social and nonsocial stimuli. (PCB)

Explains the physics behind some of the apparently puzzling aspects of the motion of a person riding a snake-board (a skateboard with independently pivoted axles). (Author/WRM)

Measured nonword reading, exception word reading, and performance with Ternus apparent movement displays (the perception of which is believed to depend upon the magnocellular and parvocellular pathways) in dyslexic children and children without reading difficulties. Found that Ternus task performance was related to nonword reading ability but not…

Describes a bubble activity related to the concepts of force and motion. Uses soap solutions for the task and evaluates students according to their performance in the problem solving process and garnering investigation results, which are conceptually based. Promotes and assesses science process skills. (Contains 20 references.) (YDS)

Calculates the angular velocity of a spinning top without the simplifying assumption found in most textbooks that the total angular momentum is solely along the symmetry axis. (WRM)

Interactive digital video enables computer visualization techniques that help students to collect, analyze, and model two-dimensional motion data. This article describes and evaluates five activities developed for the physics classroom with the use of this technology in mind. Activities explore concepts such as space, time, frames of reference,…