bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of the Kinetic Theory of Gases. V. The Equation of State
Authors: Brush Stephen G.
Published: August 2005

Some early attempts to explain deviations from the ideal gas laws are discussed. After a general survey of 19th-century work on the equation of state, the work of Ritter (1846), Clausius (1870), and van der Waals (1873) is discussed in detail. Ritter used Poisson's formula to include the virial of interatomic forces in the caloric theory of gaseous pressure; Clausius introduced similar methods in the kinetic theory. Combined with the Maxwell-Boltzmann distribution law, the virial theorem provided a systematic procedure for calculating the pressure from any assumed force law. Van der Waals used more intuitive methods for taking account of the effect of finite molecular size and attractive forces. The success of his equation led to a large amount of work on the equation of state, but rigorous deductions from definite molecular models did not begin until around 1900.
Functional Dependence: Three Introductory Experiments
Authors: Romer Alfred
Published: August 2005

This paper describes a sequence of three experiments designed to initiate beginners in the particular methods of the physics laboratory. Attention is given to the rules for taking, recording, and analyzing data, and for reporting the conclusions drawn from them. The experiments progress from directness and simplicity at the start to a standard level of complexity as the laboratory techniques become more familiar. The sequence is organized around the topic of functional dependence, in each experiment the functional relationship expressed in a particular law of physics being tested by plotting the data in such a form as to give a straight-line graph. The experiments chosen are: (1) the extension of a spiral spring, which gives direct proportion; (2) the acceleration of a ball rolling down an incline, which gives a quadratic function; (3) the simple pendulum, which gives a different approach to the quadratic function, and makes possible the calculation of a known physical constant g.
Deuteronomy. Synthesis of Deuterons and the Light Nuclei during the Early History of the Solar System
Authors: Fowler William A. , Greenstein Jesse L. , Hoyle Fred
Published: August 2005

Abundances in terrestrial and meteoritic matter indicate that the synthesis of deuterons and of the isotopes of lithium, beryllium, and boron occurred during an intermediate stage in the early history of the solar system. In this intermediate stage, the planetary material had become largely separated, but not completely, from the hydrogen which was the main constituent of primitive solar material. Appropriate physical conditions were satisfied by solid planetesimals with dimensions of the order of 10 m and consisting of silicates and oxides of the metals embedded in an icy matrix. The synthesis occurred through spallation and neutron reactions induced in the outer layers of the planetesimals by the bombardment of high-energy charged particles accelerated in magnetic flares at the surface of the condensing sun. The importance of the (n,α) reactions on Li6 and B10 is indicated by the relatively low abundances of these two nuclei. Anomalous abundances of Xe129 and Ag107 observed in meteorites can be attributed to the decay of radioactive I129 and Pd107 produced in the planetesimals. The interval between the irradiation of the small planetesimals and the formation of large bodies in the solar system could not have exceeded 107 to 108 years.
A simple Fermi-Dirac integrating circuit
Authors: Hite Dennis , Boykin Timothy B. , Singh Nagendra , Shen Dashen
Published: August 2005

We present a simple circuit that performs Fermi-Dirac integration. The core of the circuit is a differential amplifier that we show is a model of a Fermi-Dirac system. The construction and characterization of the circuit requires students to apply knowledge of device physics, transistor circuit theory, and signal processing. The circuit construction is relatively simple and requires only a few components found in most electronics laboratories.
Interior Value Problems of Mathematical Physics. Part I. Wave Propagation
Authors: Masket A. V. , Vastano A. C.
Published: August 2005

The Laplace transform has been applied to solve a class of problems in wave propagation that are converse to the well-known time-dependent Boundary Value Problems (BVP). From a knowledge of time-varying conditions on a suitably restricted set of points interior to a region, it is possible to deduce time-varying boundary conditions. These standard situations in slab, cylindrical, and spherical geometry have been treated for the finite domain. The solution of an Interior Value Problem (IVP) in the semi-infinite domain explicitly demonstrates the formulation of an advanced solution in contrast to the retarded solution for a Boundary Value Problem. Corresponding problems in heat conduction will be discussed in a subsequent article.
Axiomatic Deduction of the General Lorentz Transformations
Authors: Schwartz H. M.
Published: August 2005

The general Lorentz transformations are derived on the basis of a set of postulates which are fully consistent with the underlying ideas of Newtonian mechanics, but which of course do not include the independent postulate of absolute simultaneity. Thus, the assumption of the constancy of the vacuum speed of light c is not introduced as a starting point. Instead, the given development leads to a universal critical velocity, and the two alternatives of its value being infinite or finite, correspond to the Newtonian and the relativistic kinematics, respectively, with the critical velocity identified with the experimental value c in the latter case.
A “Two Cultures” Physics Course
Authors: Bork Alfred M.
Published: August 2005

A physics course for students in the humanities is described. The course combines a detailed study of mechanics, particularly kinematics, with reading assignments stressing the interaction of science with art, literature, history, government, and other facets of contemporary society.
Simple Derivation of the Electron-Nucleus Contact Hyperfine Interaction
Authors: Rado George T.
Published: August 2005

A simple derivation is given of the Fermi formula for the contact hyperfine interaction energy between the magnetic moment of a nucleus and that of the surrounding electrons. Considerably fewer mathematical and more physical arguments are used than in previous derivations. It is shown that the contact hyperfine field at the nucleus is necessarily equal to the magnetic induction in the interior of a sphere possessing a uniform electronic magnetization. The simplifications achieved in the present derivation do not seem to result in a loss of rigor, and they do not require the introduction of essentially new assumptions.
“Meta” Relativity
Authors: Bilaniuk O. M. P. , Deshpande V. K. , Sudarshan E. C. G.
Published: August 2005

In pre-relativity times, Thomson, Heaviside, and Sommerfeld, among others, had examined questions arising from the assumption that a particle may move faster than the velocity of light in vacuo. Such a hypothesis is reexamined in the framework of classical (nonquantum) theory of special relativity.
Construction and Use of a Fabry-Perot Interferometer
Authors: Hilton Wallace A.
Published: August 2005

The construction of a student-laboratory, Fabry-Perot interferometer is described, together with its use in three experiments. The first is a basic experiment for making some optical measurements. The second uses the interferometer to measure the index of refraction of a gas, and the third uses it to observe the Zeeman effect.
Electron Levels, Electrochemical Effects, and Thermoelectricity
Authors: Scott William T.
Published: August 2005

The concepts of cavity potential (electrostatic potential in a cavity in a conductor) and Fermi potential (energy per unit charge for an electron at the Fermi level) are defined and used to discuss the work function, contact potentials, Ohm's law, electrode-solution equilibria, and chemical emf's. With the introduction of the entropy transport per unit charge for electrons in a metal (S*), the Seebeck, Peltier, and Thomson effects are elucidated, and the fact that no emf exists at a thermal junction is made clear. Certain other common confusions are cleared up. It is suggested that use of this conceptual scheme will allow the basic physics of these important processes to be taught effectively in general physics courses.
Mechanical Conservation Laws and the Physical Properties of Groups of Motions in Flat and Curved Space-Times
Authors: Davis William R. , Katzin Gerald H.
Published: August 2005

The intimate relation of symmetry properties describable by groups of motions and the consequent conservation laws realizable for a particle in classical mechanics and in the mechanics of restricted and general theories of relativity are discussed in detail using elementary results of the theory of continuous groups. In addition, for the case of special relativistic mechanics the finite form of the groups of motions, underlying all of the possible constants of the motion of the form of first integrals linear in the momenta, are constructed and shown to be the inhomogeneous (i.e., including displacements) proper Lorentz transformations.
Vibratory Brownian Motion
Authors: Baxi M. R. S.
Published: August 2005

In this paper, we derive the general law for the Brownian motion displacement of a particle in a colloidal solution on the basis of a wave equation for energy, which adequately explains its vibratory character.
Interior Value Problems of Mathematical Physics. Part II. Heat Conduction
Authors: Masket A. V. , Vastano A. C.
Published: August 2005

In contrast to the solution of Interior and Boundary Value Problems (IVP and BVP) in wave propagation, it is not possible to provide the simplifications made available by the Heaviside wave-expansion technique for heat conduction. The application of the Laplace transform to IVP in heat conduction generally involves the explicit application of the inversion theorem— contour integration and the evaluation of residues at poles in the complex plane. Following the presentation of solutions to some representative IVP in heat conduction in slab, cylindrical, and spherical geometry, it is shown how a heat-conduction problem in the semi-infinite domain may be reduced to a case for the finite domain. The need for the application of integral equation techniques is thus avoided. A discussion of the connection between the IVP and BVP is presented on the subject of potential theory and the phenomenon of vision as an IVP in optics.
Apparatus Drawings Project. Report Number 31. A Versatile Mercury Reservoir for Demonstrating Properties of Gases and Vapors
Authors: Williams T. Walley
Published: August 2005

This article describes a simple apparatus for demonstrations of properties of gases and vapors requiring a mercury-filled tube. Its key features are a glass tube with a vacuum-tight valve on the top and a reservoir deep enough so the entire tube can be immersed in the mercury to expel the air. With the valve closed the tube can be used as a barometer. If some air is left in the tube, Boyle's law can be demonstrated. A simple modification of the valve allows the vapor pressure of volatile liquids to be measured.
Kepler's Third Law for Elliptical Orbits
Authors: Weinstock Robert
Published: August 2005

Two demonstrations of Kepler's third law for elliptical orbits are presented. Both assume the validity of Kepler's first two laws and a few simple facts concerning the geometry of the ellipse; one directly employs conservation of energy, the other the centripetal-force relation. But neither involves an elaborate use of the calculus.
A Geometrical Introduction to Special Relativity
Authors: Daubin Scott C.
Published: August 2005

Some of the basic ideas of special relativity are developed through graphical representation of the results of two “thought experiments” with moving rods. The influence of the postulates of the theory on the geometric properties of the figures representing “experimental” data is described. From the figures the length contraction is derived directly. Time dilation and conservation of space-time intervals and space-time volume follow as corollaries.
Analogy between Nuclear Chain Reacting Systems and Vibrating Strings and Membranes
Authors: Pabbi Shiv Datt
Published: August 2005

The analogy between the one-group theory of nuclear chain reacting systems and vibrating strings (or membranes) with similar geometry and boundary conditions is developed and some examples are considered. This should be useful as a class demonstration and may also help to give an idea of reactor buckling of assemblies with complex geometry.
A Demonstration of the Magnetic Mirror Effect
Authors: Allen Ronald J.
Published: August 2005

A description is given of the magnetic mirror effect exhibited by charged particles spiralling into a converging magnetic field. The apparatus makes use of a commercial electron tube filled with an inert gas, originally designed for measuring the specific charge of the electron. The necessary field configuration is provided by an ordinary bar magnet. Measurements of pitch angle at various points of the particle trajectories were made from photographs of the spiral orbits. The magnetic field strength corresponding to these points was determined independently from extensive field measurements carried out near the end of the bar magnet. The ratio of field strengths at two different points of the particle trajectory as a function of the spiral pitch angles at those points is compared with theory.
Homogeneous Nucleation of Vapor Condensation. I. Thermodynamic Aspects
Authors: McDonald James E.
Published: August 2005

In absence of all foreign materials or wall surfaces, phase transitions of the type vapor-to-liquid or liquid-to-solid are blocked by an activation-free-energy barrier. The latter arises from surface-free energy increases resulting from appearance of embryos of the more condensed phase. The thermodynamics of this type of phase transition are examined in Part I for the particular case of vapor condensation, a case for which theory and experiment now stand in tolerably good agreement. In Part II, kinetic aspects will be considered.
An American Physicist's Year in Europe: Henry A. Rowland, 1875–1876
Authors: Rezneck Samuel
Published: August 2005

Henry Augustus Rowland was born in Honesdale, Pennsylvania, in 1848, into a family of ministerial tradition, but he himself at an early age displayed an inclination toward and precocious gift for scientific experiment. The first twenty-seven years of his life were spent in self-preparation for a scientific career, although formally trained as a civil engineer at Rensselaer Polytechnic Institute, where he also taught physics. In 1875 occurred his “discovery” by Daniel C. Gilman, founder and first President of the new Johns Hopkins University, then in search of a suitable faculty. Now came his great opportunity, which Rowland eagerly seized upon, to spend a year in Europe, on salary from Johns Hopkins. Rowland's zealous and rewarding exploitation of this opportunity is the theme of this article. Rowland's letters and travel journal supply abundant material revealing how he traveled widely across Europe from Ireland to France, to Germany, Switzerland and Austria, and everywhere he visited the physical laboratories. He met many of the European men of science, inspected their facilities, and actually performed an important experiment in electromagnetism in Helmholtz's laboratory in Berlin. His critical commentary provides a unique survey of the state of physics in Europe at this time. In May, 1876, Rowland returned to America, unusually well-informed and self-assured, to assume the responsibilities of his new position as the first professor of physics in the Johns Hopkins University, where he built a distinguished scientific career for himself, broken off unhappily by his premature death in 1901.
Observables of Relativistic Particles
Authors: Garrido L. M. , Sesma J.
Published: August 2005

We study the most general unitary transformation that transforms the Hamiltonians of particles of spins 0, 12, or 1, into Hamiltonians containing even or odd matrices only. We present also the expressions for the position operators for each transformation that are valid for the three kinds of particles mentioned above.
Density Matrix Representations
Authors: Patterson J. D.
Published: August 2005

The relations between the ordinary density matrix, the density matrix in the coordinate representation, the Löwdin density matrices, the Dirac density matrix, and other density matrices are traced. The roles of pure and mixed cases, equilibrium and nonequilibrium situations, and single- and many-body representations are considered.
Studies of the Electronic Structure of Covalent Semiconductors by EPR
Authors: Bemski G.
Published: August 2005

This paper reviews the basic theory of impurity states in semiconductors as applied to “shallow donors” in silicon. It points out the role of the electron paramagnetic resonance (EPR) technique in investigating such states in silicon and the relation of experiments to the theory.

The transition between electrons localized at these impurities and those free to conduct is also discussed in relation to silicon. Finally, an example of EPR experiments on conduction electrons in InSb is also given, completing the range of investigations from the localized to completely free electrons in covalent semiconductors.
Strobe Photography with the General Radio 1531—A Strobotac
Authors: Eldridge David C. , Skinner Edward M. , Tsepas James
Published: August 2005

The new General Radio Strobotac, a stroboscopic tachometer, has been a useful tool for high school science projects and as a teaching aid. In addition to its use for multiflash it can be employed as a single-flash unit, being easily triggered by a beam of light, a sound wave, or by simple contact. The treatment is comprehensive, covering the photography of shock waves, standing waves, splashes, and ripple tank phenomena.
Intensity-Time Variations of the Cosmic Radiation
Authors: Lockwood J. A.
Published: August 2005

Observations of the cosmic radiation arriving at the earth show that both the energy spectrum and total intensity of particles change with time. A brief survey is presented of the major changes in the flux of relativistic particles, with representative data from nucleonic detectors. The rigidity dependence and attenuation for the long-term change and transient variations are discussed. Some data for the sudden increases which represent solar injection are shown. The investigation of these intensity-time variations yields information about the electromagnetic state of the earth-sun region.
Demonstration of the Electric Fields of Current-Carrying Conductors
Authors: Jefimenko Oleg
Published: August 2005

The making of the two-dimensional printed circuit type models of current-carrying conducting systems and the use of these models for demonstrating the electric fields of current-carrying conductors is described. The models are produced by drawing the systems under consideration on glass plates using a transparent conducting ink. The electric lines of force inside and outside the elements of these models are demonstrated with the aid of grass seeds strewed upon them.
Beginning a Study in Elementary School Science
Authors: Karplus Robert
Published: August 2005

Several professional scientists at the University of California in Berkeley have established a collaboration with educators to study problems of science teaching in the elementary schools. The objective is to help educators prepare a scientifically and psychologically sound program for elementary school science instruction. Scientific subject matter is presented in an inductive problem-solving approach. The first year's experience with laboratory use of some teaching materials prepared with the guidance of the committee members revealed many problems, but was greatly encouraging as well.
Strange Carnot Cycles; Thermodynamics of a System with a Density Extremum
Authors: Thomsen John S. , Hartka Theodore J.
Published: August 2005

Sommerfeld has given an apparent case of a perpetual motion machine of the second kind. This consists of a Carnot engine employing liquid water and operating between the normal and anomalous regions of thermal expansion. His explanation of the paradox is shown to be incomplete when the temperature of maximum density is pressure-dependent. To analyze this case a simple thermodynamic model for a substance with a density extremum is given; this model yields a reasonable approximation to the data for water. Standard thermodynamic properties of the system are computed and useful approximate forms given. Various Carnot cycles and a non-trivial “two-process” cycle are then shown in the p−T, T−s, and p−v planes. Sommerfeld's paradox is resolved by showing that a Carnot cycle qualitatively similar to that in his problem involves expansions for both isothermal processes. Theoretical implications of the analysis and applications to sound waves and shock waves are briefly discussed.
Specific Heat of a Particle in a Box
Authors: Rosenstock Herbert B.
Published: August 2005

The specific heat of a free particle in a cubic box with reflecting walls is found to be a function of variable η = 2mL2kT/ℏ2 (m = mass of particle, L length of box, T = temperature, k and 2πℏ Boltzmann's and Planck's constants). For large η the specific heat approaches the classical equipartition value dk/2 (d = dimensionality), for small η it approaches zero as T−2 exp (−const T−1), and in between, at η = 9π, it has a maximum, (9/8) (dk/2).
Measurement of Surface Energies of Alkali Halide Crystals
Authors: Norman S. L. , Zwicker E. F. , Grossweiner L. I.
Published: August 2005

The surface energies of several alkali halide crystals were measured by two techniques which are within the capabilities of the undergraduate physics laboratory. One method involves slow cleavage and the other involves impact cleavage under a falling weight. The experimental findings are comparable to previously published results.
Microwave Zone Plates
Authors: Brown Thomas B.
Published: August 2005

A microwave zone plate not only illustrates some of the principles of optical (visible light) zone plates but exhibits also interesting differences which are due primarily to the wide aperture which is required for a practical microwave zone plate. These properties have been studied for a zone plate which was designed with four clear zones to focus 12-cm waves from a source 125 cm away to an equally distant image point and was constructed by pasting aluminum foil zones onto a sheet of cardboard. This zone plate operates by reflection as well as by transmission. The experimental data are analyzed in terms of wide aperture theory which is developed in an appendix.
Apparatus Drawings Project. Report Number 23. Impulse-Driven Torsional-Mechanical Oscillator
Authors: Marcley Robert G.
Published: August 2005

A simple impulse-driven torsion pendulum for studying the transient and steady-state characteristics of resonant mechanical oscillators is described. The moving system has a natural period of about 2 sec and is fitted with a coaxial hollow cylinder and a reservoir of oil for applying a damping torque that is proportional to the angular velocity of the pendulum. This damping is continuously variable between almost zero (air) and critical. The driving impulses, which are approximately square waves, are derived from simple electronic circuits that permit the period between pulses to be continuously varied from approximately 0.05 to 4 sec. Detailed information on the mechanical system and electronic circuits is given.
Elementary But Exact Treatment of a Dipole Ring
Authors: Santarelli Vincent
Published: August 2005

The partition function of a ring of dipoles interacting only in pairs is derived in an elementary manner. The resulting exact expression is used to derive the thermodynamic behavior at very high and low temperatures. It is shown that an even number of antiferromagnetic dipoles is thermodynamically equivalent to any number of ferromagnetic dipoles at all temperatures as far as the average energy and entropy are concerned.
Apparatus Drawings Project. Report Number 24. Platinum Wedge Blackbody
Authors: Marcley Robert G.
Published: August 2005

The apparatus described is a platinum wedge that can be used as a source of both black and non-blackbody radiation. The wedge, 118 in. long with an included angle of 9°, is formed from 0.001-in. platinum foil and heated by passing an electric current through it. Less than 50 w of power are needed to produce temperatures of ca 1500°K. The wedge attains thermal equilibrium rapidly so that measurements of several widely separated temperatures are practical during a normal laboratory period. Evacuation of the apparatus housing to a pressure of approximately 0.001 mm Hg essentially eliminates conduction and convection effects. Two windows allow examination of the wedge cavity and one external surface. This apparatus, while designed for experiments on optical pyrometry and the spectral emissivity of a metal, might be easily adapted to experiments on the spectral distribution of blackbody radiation.
Classical Models of Radiative Decay
Authors: Kaufman Charles , Winter Rolf G.
Published: August 2005

Classical models for radiative fundamental particle decay are examined. Calculations are presented for radiative nuclear beta processes, pion decay, and muon decay. At least some features of the photon spectra are obtained correctly for these examples.
The Role of Experimental Work
Authors: Neher H. V.
Published: August 2005

The difficulties in making the physics laboratory truly a part of the education of students are considered. The tendencies toward the use of less standardized equipment and toward allowing more freedom to the students are resulting in improvements, but they, in turn, introduce new problems—those of cost, of the preparation of laboratory assistants, and of the prevention of over-specialization at an early stage. Among the activities that offer hope for the improvement of our laboratories are the work of the AAPT Committee on Apparatus, especially the Apparatus Drawing Project. Broad specifications of the requirement for good instructional apparatus and laboratory instructions are outlined, and instructors are encouraged to engage in a continuous process of change in their laboratories. Finally, some of the educational achievements of well-run experimental work are listed and discussed.
Some Results of a Survey Made in Preparation for the Conference on Curricula for Undergraduate Majors in Physics
Authors: Phillips L. W.
Published: August 2005

About 250 physics departments that offer an undergraduate physics major but do not have a Ph.D.-level graduate program replied to a general questionnaire dealing with departmental programs and practices. Results presented here are derived primarily from those sections of the questionnaire dealing with various aspects of the curriculum for physics majors: the introductory course taken by physics majors, intermediate level courses, the role of independent study and research, and specific degree requirements, together with some estimates as to further (post-baccalaureate) education and eventual careers of graduated majors.

Some more general data on physics major enrollments and faculty sizes, derived from publications of the American Institute of Physics, are also included.
Toward a More Effective Introductory Laboratory
Authors: Dayton Irving E.
Published: August 2005

The use in the introductory laboratory of research-type notebooks rather than formal reports is discussed. Experience has shown that this technique emphasizes physics rather than peripheral aspects of the laboratory, and that the laboratory becomes an integral and effective component of the introductory course.
Apparatus Drawings Project. Report Number 25. Whirlygig: A Conical Pendulum for Centripetal Force Experiments
Authors: Marcley Robert G.
Published: August 2005

The apparatus described is a conical pendulum that has a small mass m fixed to a cord that passes over a pulley attached to a hollow vertical shaft. A larger mass M is suspended from the end of the cord. The pulley is located so that the cord hangs vertically along the axis of rotation of the shaft. When the small mass rotates about the shaft axis, it assumes a dynamically stable orbit consistent with m, M, and ω, its angular velocity. The slight offset of the pulley permits the cord to drag the pulley-shaft assembly around in synchronism. M, m, and T (the tension in the cord) are constant so that the free length of the cord will adjust itself to reflect changes in ω. Since the apparatus is fixed to a rigid base and frictional losses are very low, accurate and reproducible data may be easily obtained. Information needed for constructing the low-friction components is given.
Elementary Theory of Resonance Scattering
Authors: Downs B. W.
Published: August 2005

Elastic scattering by a spherically symmetric potential is discussed in terms of a partial-wave analysis in which the phase shifts do not appear explicitly. The resonance structure of the scattering amplitude is more evident in this analysis than it is in the usual phase-shift analysis. The resonance structure is discussed, and the connection of the formalism with that of Kapur and Peierls is established.
Electromagnetic Fields of a Charge and Isotropic Medium in Relative Motion
Authors: Diesendruck L.
Published: August 2005

The electromagnetic potentials and fields of a charge and an isotropic dielectric medium in uniform relativistic motion are derived for the following cases: charge at rest, medium moving; charge moving, medium at rest; charge and medium moving. The electric displacement D is found to be always radial, and the magnetic field intensity H is found to be always proportional to the cross product of charge velocity and position vector. The electric field intensity E and the magnetic flux density B depend on the medium velocity in general. The approximations to low velocity result in a modification of the medium velocity by Fresnel's dragging coefficient. The superoptic case results in a conical region for real fields and radiation at the Cherenkov angle.
Some Applications of Hypervirial Theorems to the Calculation of Average Values
Authors: Epstein J. H. , Epstein S. T.
Published: August 2005

Hypervirial theorems are used to compute various average values for the nonrelativistic hydrogenic atom, the isotropic harmonic oscillator, and the relativistic hydrogenic atom. In the latter case many new results are found.
Matrix Representation of Thermodynamics of Multicomponent Systems
Authors: Carroll Philip Joseph , Kyame Joseph John
Published: August 2005

The extension of a matrix representation for the thermodynamics of a multicomponent system is demonstrated. Specific applications of these matrices are made to stability conditions and phase transitions.
A Restatement of the Zeroth Law of Thermodynamics
Authors: Thomsen John S.
Published: August 2005

Turner's proof of the Zeroth law as a consequence of the second law is examined and two criticisms are noted. It is also pointed out that most conventional statements of the Zeroth law do not necessarily imply that temperature is a scalar. A new formulation is given and two corollaries are stated; one of these is the usual form of the Zeroth law. The restrictions thus imposed on permissible temperature scales are briefly discussed.
Experimental Evidence for the Second Postulate of Special Relativity
Authors: Fox J. G.
Published: August 2005

It is pointed out that the extinction theorem of dispersion theory, for which an elementary derivation is given, shows that an incident light wave is extinguished at the surface of a dielectric. This may mean that information about the velocity of light from a moving source would be lost if the light passed through intervening transparent, stationary material before it was measured. All past laboratory measurements to verify the constancy of the velocity of light from moving light sources and mirrors and from extraterrestrial sources were made only after the light had passed through stationary material. Double stars, especially close binary pairs, are surrounded by a common envelope of gas which may contain enough matter to extinguish the direct light from the stars. Thus de Sitter's proof of the constancy of the velocity of light may not be conclusive. It is concluded that there may not exist any sure experimental evidence for the second postulate of special relativity.
Films for Students of Physics, Supplement I
Authors: Weber Robert L.
Published: August 2005

Some 220 films useful for instruction in physics are added to the 450 in the 1960 listing. These lists, which include foreign films, are intended to be helpful to those planning future films, as well as to instructors seeking suitable films for classroom use in school and college.
Basic Semiconductor Devices
Authors: Daly Raymond A. , Hill Bert J.
Published: August 2005

A simplified approach to the construction of semiconductor devices is outlined in this paper. Detailed techniques and procedures for making diodes and transistors during the time allotted in typical laboratory periods are described.
A History of the Electric Wind
Authors: Robinson Myron
Published: August 2005

The electric wind was one of the earliest manifestations of the gaseous discharge to have been discovered and a subject of active investigation among electrical experimenters of the eighteenth and nineteenth centuries. Today, after a period of relative neglect, interest in this phenomenon has been revived. Recent publications consider the practicability of applying the wind mechanism to fluid pumps, high-voltage generators, loudspeakers, thermoelectric converters, and other devices. The historical background of the electric wind from the earliest times is presented here together with a selected bibliography.
Apparatus Drawings Project. Report Number 27. Apparatus for Investigating the Properties of Sound Waves
Authors: Marcley Robert G.
Published: August 2005

The apparatus described was developed for undergraduate investigation of some of the properties of waves, such as wavelength, phase, interference, and diffraction, using acoustic waves as the medium of instruction. Thin plates, pierced by various apertures, are irradiated by a beam of essentially plane acoustic waves, at about 15 000 cps, obtained from an inexpensive horn-type “hi-fi” tweeter mounted in an enclosure with absorbent interior walls. The radiated energy is examined with a boom-mounted crystal hearing-aid earphone, used as a microphone, that feeds a tuned preamplifier and cathode ray oscilloscope. Utilizing undamped resonances, above the normal operating range of the transducers, insures high sensitivity at a trivial cost, while simple phase-measuring techniques further improve resolution and sensitivity. The apparatus, developed for a 950-student freshman laboratory, can be operated with five setups in a room with completely negligible interaction, and constructed at a low cost for both components and labor. Information on construction is given.
Francis Weston Sears: Oersted Medalist for 1961
Authors: Olsen Leonard O.
Published: August 2005

Remarks made by the Chairman of the Committee on Awards for 1962 during the presentation ceremony of the Oersted Medal to Francis Weston Sears in recognition of his notable contributions to the teaching of physics.
The Most Important Thing
Authors: Sears Francis W.
Published: August 2005

Response of the Oersted Medalist to the American Association of Physics Teachers, January 25, 1961
The Arrow of Time
Authors: Gold T.
Published: August 2005

The time symmetry of the physical laws is discussed. The asymmetry in all statistical processes is found to be related to the tendency for radiation to diverge and that in turn is related to the expansion of the universe. No asymmetry is contained in the laws of electrodynamics, and the choice of the retarded potentials is not a time unsymmetrical step.

Time asymmetry appears to be confined to statistical tendencies resulting from the over-all expansion. The significance of the various symmetries in the physical laws is briefly discussed.
Experimental Deduction of the Law of Centripetal Force
Authors: Freeman Ira M.
Published: August 2005

A simple laboratory experiment using a pendulum suspended from an equal-arm balance is capable of furnishing data from which the form of the equation for centripetal force may be deduced.
Experimental Foundations of the BCS Theory of Superconductivity
Authors: Ginsberg D. M.
Published: August 2005

A description is given of the way in which experimental results are useful in understanding the origins of a successful theory of superconductivity. Some experiments are discussed which have been performed since the theory was presented. Of these, some provide striking support for the theory, while others indicate that details of the theory should be further refined.
Nonlinear Ruler
Authors: Bork Alfred M.
Published: August 2005

A ruler with a nonlinear scale focuses students' attention on certain problems associated with physical measurement. This paper describes a simple teaching device that has proved useful in elementary physics courses strongly emphasizing the philosophy of science.
What's Happening to Calculus?
Authors: Wisner Robert J.
Published: August 2005

This short article is an attempt to identify and classify some of the salient features of change in present day calculus instruction, with a view of the problems faced by physicists. It is meant to be a description of subtle but cumulative perturbations which are actually taking place. The classification of these changes is given in terms which are accompanied by examples, and a plea is made for understanding the reasons behind present trends. An appendix gives a sample of textbooks which the concerned physicist could examine with profit.
Simple Circuits for the Measurement of Magnetic Field Strength, Inductance, and Capacitance
Authors: Ainslie Donald S.
Published: August 2005

This paper discusses the use of the tangent galvanometer for magnetic measurements and describes circuit modifications, in the Maxwell inductance bridge and the Fleming and Clinton capacitance bridge, which have proven useful in undergraduate work.
Effective Electronic Mass Tensor, Electrical Conductivity, and Hall Effect for Spherical Energy Surfaces
Authors: Jan Jean-Pierre
Published: August 2005

The effective electronic mass tensor is calculated for spherical energy surfaces, and found to contain two independent coefficients. These are equal only if the energy function is quadratic. Electrical conductivity and low-field Hall coefficient are also calculated; they involve the first derivative of the energy function.
Simplification of Carathéodory's Treatment of Thermodynamics. II
Authors: Turner Louis A.
Published: August 2005

The simplified treatment can be based on the assumptions as to continuity made by Carathéodory. Although Landsberg is correct that the general conclusion that the change of entropy must always have the same sign involves a further unstated assumption, it does follow without further assumption that the change of entropy must have the same sign in all adiabatic changes away from initial states having the same entropy. The results for ordinary systems, however, remain the same.
Production of Instructional Films with University Facilities
Authors: Tendam D. J. , McLeod R. R.
Published: August 2005

A series of 20 sound motion picture films of physics lecture demonstration experiments was made with university facilities. This article gives a general description of film production methods as they appear to the physicist.
Ray Lee Edwards Ceremonial Volume
Authors: Zorn Jens C.
Published: August 2005

Former students of Professor Ray Lee Edwards presented him a ceremonial volume of reprints and letters as an expression of their affection and esteem at the 1962 Annual Meeting of the American Association of Physics Teachers.
Motion Subject to a Central Force: An Apparatus for Demonstrating Orbital Stability
Authors: Telfair David , Brooks John T.
Published: August 2005

The usual approach to the teaching of rotational motion in the introductory college physics course emphasizes centripetal acceleration and the rotation of rigid bodies about fixed axes.

The approach outlined below may be used to extend, and in part to supersede, the usual approach. It is intended to strengthen the student's insight into the concept of angular momentum, and his understanding of the orbital motion and orbital stability of planets and satellites. An analysis of the system is based on energy considerations and on a frame of reference which rotates with the system.

An apparatus is described by means of which one may demonstrate many of the characteristics of orbital motion and central forces.
The Senior Physics Laboratory Course at Dartmouth College
Authors: Davis William P.
Published: August 2005

The senior laboratory course in physics at Dartmouth College is described. Each staff member of the department actively participates in the course by assuming the complete responsibility for two or three experiments.
Maxwell's Solution of Kirchhoff's Laws and the Superposition Theorem
Authors: Gardner M. E.
Published: August 2005

A student laboratory experiment for the investigation of the superposition theorem and Maxwell's method of the solution of Kirchhoff's laws is described. The apparatus was designed to minimize the possibilities of making incorrect electrical connections.
Can Liberal Arts Colleges Produce Doctoral Candidates?
Authors: Priestley Herbert
Published: August 2005

Considerable concern is now evident about the liberal arts college as a source of doctoral candidates in physics. Remedial steps have been proposed in the direction of research grants to provide incentives and funding for increasing staffs, special summer undergraduate programs for physics majors, and better articulation between college and graduate physics departments. These are reviewed in terms of their implications and feasibility, with the conclusion that the best hope for the immediate future lies in the recognition of good teaching as a desirable and creative activity at the college level, serious consideration of curriculum revision at the individual department level, and improved articulation between college and graduate school.
On Physical Geometry
Authors: Hubig Werner
Published: August 2005

The basic problem of physical geometry is to determine uniquely the geometry of physical spaces. According to Reichenbach, this can be done only after universal forces have been eliminated because such forces may impose any geometry upon a physical space by changing the measuring rods undetectably. An examination of his proof leads to a contrary statement: Universal forces may alter the shape of a physical space but they cannot change its geometry. Therefore, the geometry of a physical space can be determined uniquely from physical measurements after a unique system of space measurement has been established. As a consequence, the general theory of relativity in its present form seems no longer to be acceptable.
Projectile Motion with Damping Proportional to Velocity
Authors: Nadeau Gérard
Published: August 2005

The solution by vector calculus of the motion of a projectile subjected to a constant gravity force and to a damping force proportional to the velocity is used as the basis of a velocity diagram relating the initial and final velocities to the target range and the flight time. Such a diagram can be used to solve some problems of projectile motion.
Some Physical Aspects of Electron-Receiving-Tube Operation
Authors: Natapoff Marshall
Published: August 2005

This paper reviews some of the less frequently discussed physical aspects of the operation of an electron-receiving tube. The physical basis for the existence of the four main components of control grid current is included in this discussion. Some comments are also made on the phenomena connected with the heater and the effect of the new “dark heater” coating. The pressure exerted by the gases in a tube is considered, and the limitation on the highest value of this pressure consistent with reliable performance is indicated.
The Kepler and Rutherford Problems: A Geometrical Treatment
Authors: Livesey D. L.
Published: August 2005

The motion of a particle in an inverse-square field of force is described in terms of the potential energy, which depends on the distance r from the center of force, and the kinetic energy, which can be expressed in terms of an effective impact parameter h. In different cases the relations between r and h correspond to paths which are elliptic, parabolic, and hyperbolic. These results are based on elementary geometry, which is sufficient to derive Kepler's third law and the Rutherford formula for nuclear scattering of alpha particles.
On the Momentum Theorem for a Continuous System of Variable Mass
Authors: Thorpe James F.
Published: August 2005

Theorems of linear momentum are derived for a control system having an arbitrary motion in a continuous velocity field. The resulting equations are valid for a system of variable mass. By allowing the control system to be at rest, the usual equations of fluid mechanics are obtained as a special case; by allowing the control system to move with the fluid, the momentum equations for a system of constant mass are obtained as a special case. In this way, it is possible to discuss a common, but incorrect, conception of the momentum equation for a system of variable mass.
Forced Vibrations of a Harmonic Lattice in Quantum Mechanics
Authors: Band William
Published: August 2005

Schrödinger's equation is solved in an elementary fashion for a harmonic lattice subject to external forces that are functions explicitly only of time, and to damping forces proportional to velocity expectation values. The result shows that the response is a purely classical motion of the quantum mechanical probability distribution associated with the free lattice. The energy of the lattice is Eq + Ec, where Eq is any energy eigenvalue of the free undisturbed lattice existing before the external forces were applied, and Ec is the energy that would be obtained by classical mechanics for the response of the lattice to the disturbance. The energy propagates through the lattice as a purely classical wave motion superposed on any quantum mechanical background that may happen to exist.

Anharmonic coupling terms are needed to cause quantum excitations and produce thermal equilibrium within the lattice. The conventional treatment of energy transport as due to unidirectional normal modes is criticized.
Design of a low cost Zimm–Crothers viscometer: From theory to experiment
Authors: Courbin L. , Cristobal G. , Winckert M. , Panizza P.
Published: August 2005

To accurately measure low viscosities of liquids, we describe how a Zimm–Crothers viscometer works and how to build it. The viscometer involves the action of a rotating magnetic field on a metallic cylinder floating on the liquid to be studied. The principles of electromagnetism and fluid mechanics involved make the viscometer an excellent tool for undergraduate laboratory courses and for measuring the shear viscosity of low viscous fluids. We discuss the advantages and limitations of this inexpensive and easy to use apparatus compared to other classical techniques. Calibrations with Newtonian fluids are explained and experiments with Non-Newtonian materials are discussed.
Resource Letter MP-1: The Manhattan Project and related nuclear research
Authors: Reed B. Cameron
Published: August 2005

This Resource Letter provides a guide to literature on the Manhattan Project and related nuclear research. Books and journal articles are cited for the following topics: general works, technical works, biographical and autobiographical works, the German nuclear program, and technical papers of historical interest. A list of videos and websites dealing with the Manhattan Project, nuclear weapons, and nuclear issues is also given.