Discusses the development of the Rutherford-Bohr atom. Indicates how the objectives of the historian may differ from those of the retrospecting or historicizing physicist. (Author/SK)

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)

Reviews the developments in S-matrix theory over the past five years which have made it possible to derive results characteristic of quark models without any need to postulate the existence of physical quarks. In the new approach, the quark patterns emerge as a consequence of combining the general S-matrix principles with the concept of order.…

Comparisons are made for the particle-in-a-box, the harmonic oscillator, and the one-electron atom. A classical uncertainty principle is derived and compared with its quantum-mechanical counterpart. The results are discussed in terms of the statistical interpretation of the uncertainty principle. (Author/BB)

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)

Describes the structure of a set of computer programs (DITRAN) that translate the text of conversational exchanges appropriate for elementary physics discussions into an operational computer-based dialog. Dialogs produced in this manner are designed as a series of templated subprograms. The structure of a simple template is reviewed. (Author/TS)