Describes a technique whereby qualitatively correct models of differentially rotating degenerate stars may be constructed by simple methods available to undergraduate students. (Author/JN)

Presents an elementary formulation of the work expenditure corresponding to walking, the most common physical exercise. The model described is included in a physics course for freshmen in physical education and physical therapy. (Author/JN)

Describes how many of the geometrical and physical properties of the binary elastic collision of two particles can be represented by an isoceles trapezoid in the velocity space. (BB)

A model of Brownian motion is discussed which includes viscosity effects. The model lends itself to Monte Carlo simulation and thus is suitable for an elementary physics laboratory experiment. (BB)

Focuses on difficulties linked to situations in physics involving two models--geometrical optics and wave optics. Presents content analysis underlining two important features required for addressing such situations: (1) awareness of the status of the drawings; and (2) the 'backward selection' of paths of light. (Contains 24 references.)…

Discusses two models of teaching science, content-centered and process-centered, and suggests a combination of the two to teach nonscience majors. (MKR)

Presents basic relations involving the concept of available energy that are derived from the local equations of nonequilibrium thermodynamics. The equations and applications of the local thermodynamic equilibrium LTD model are also presented. (HM)

Compares micro-rockets to commercial models and water rockets. Finds that micro-rockets are more advantageous because they are constructed with inexpensive and readily available materials and can be safely launched indoors. (CCM)

Investigates student reasoning about models of conduction. Reports that students often are unable to account for the existence of free electrons in a conductor and create models that lead to incorrect predictions and responses contradictory to expert descriptions of the physics involved. (Contains 36 references.) (Author/YDS)

Shows that the expansion of the universe and its hierarchical structure may solve the dark night sky paradox. Points out that Harrison's solution, and the expansion of the universe, are equally important in explaining the reduction of radiation density to the level we observe by night. (Author/GA)

Examines the concept of PdV work and the harmonic oscillator as an example of a thermodynamic system with properties analogous to an ideal gas. (SL)

The following animal characteristics are considered to determine how properties and characteristics of various systems change with system size (scaling): skeletal weight, speed of running, height and range of jumping, food consumption, heart rate, lifetime, locomotive efficiency, frequency of wing-flapping, and maximum sizes of flying and hovering…

Presents a simplified model that illustrates the behavior of radiometers in steady state operation, and implications of the law of interaction between a rarefied gas and a solid surface. (MLH)

Studies the role of context in students' uses of alternative conceptual models by using Newton's third law. Identifies four contextual features that are frequently used by students in their reasoning. Probes the effects of specific contextual features on student reasoning using a multiple-choice survey. (Contains 39 references.) (Author/YDS)