bluuebunny/crossref_metadata_2025 huggingface dataset:
On the interpretation of indirect tests of Coulomb’s law: Maxwell’s derivation revisited
Authors: Fulcher L. P. , Telljohann M. A.
Published: March 2005

The potentials of two concentric conducting spherical shells are calculated under the assumption that the force between two point charges varies as rδ−2. Maxwell’s result for small δ, which is required to interpret modern experiments, is obtained. The derivation uses only basic ideas of electrostatics and elementary calculus. The upper limits for δ that can be set by various experiments are also discussed.
An experiment on skin effect
Authors: MacDougall J. W.
Published: March 2005

Two experimental apparatus which may be used for laboratory or classroom demonstration of the skin effect phenomenon are described. The first apparatus shows the decrease of a magnetic field as it penetrates a thickness of metal. The second demonstrates the decrease with depth of current in a wire.
Operator techniques in three dimensions
Authors: Smith Charles Ray
Published: March 2005

Dirac bra and ket notation is developed for three-dimensional space. A number of transformations, closure relations, and projection operators are discussed in some detail. The formal results are applied to examples pertaining to homogeneous isotropic and anisotropic systems, as well as to sums over photon polarization degrees of freedom. Most of the discussion is tailored for the student before his exposure to operator methods of quantum mechanics.
Thermionic emission experiment using a phototube
Authors: Pearlstein Edgar , Swift Gregory , Wright Kenneth
Published: March 2005

An advanced undergraduate laboratory experiment is described for studying thermionic emission. The cathode of a type 922 photodiode is used as the emitter, over a temperature range from room temperature to 80 °C. The thermionic emission current varies by a factor of 3000 over this temperature range, enabling good determination of the work function of the cathode, which can be compared with the photoelectric work function. The experiment requires no specialized apparatus.
Superconductivity in the advanced laboratory
Authors: Behroozi F. , King K. R.
Published: March 2005

Two simple experiments in superconductivity suitable for the advanced undergraduate laboratory are described. A homemade variable-frequency oscillator is employed in a conventional cryostat to measure the superconducting transition temperature of tin using a resonant-tank-circuit method. The setup is further used to obtain the superconducting–normal phase diagram for tin in the presence of a magnetic field. Enough experimental details are provided to enable a nonspecialist to duplicate the setup and perform the experiments.
Can local measurements resolve the twin paradox in a Kerr metric?
Authors: Hall Donald E.
Published: March 2005

The twin paradox has been strengthened in recent versions by putting both twins in free fall throughout. It is then less obvious that there are observable differences in their experiences. This article further considers Markley’s proposal for twins in oppositely directed circular orbits in the equatorial plane outside a rapidly rotating massive object. Experiments are discussed that would enable each twin to distinguish which way he is revolving. They can then agree as to which will age less, so that the paradox is still resolvable. It is argued that these experiments must include at least one interaction between the observer and some part of spacetime outside the immediate vicinity of his own worldline.
Particle accelerators and the fundamental constants
Authors: Kalmus P. I. P. , Jones R. B.
Published: March 2005

As an instructive exercise in elementary quantum physics, we explore the relationship between the sizes of circular particle accelerators and the fundamental constants of nature.
Precision falling body experiment
Authors: Blackburn James A. , Koenig R.
Published: March 2005

By replacing optical position sensors with electrical contact switches and by using an integrated-circuit timer with digital readout, the time required for a ball bearing to fall may be measured consistently to about 0.1 msec. The acceleration of gravity may then be determined to better than one part per thousand.
Quantitative measurement of the Doppler shift at an ultrasonic frequency
Authors: Nerbun R. C. , Leskovec R. A.
Published: March 2005

Two ultrasonic transducers, the receiver stationary at the end on a linear air track, and the source mounted on a moving glider, are the basis for a Doppler shift experiment. The source frequency and the shifted receiver frequency are fed into a digital phase detector circuit which produces an output difference frequency with a sinusoidal waveform. This Doppler shift frequency can be measured directly and compared with the shift predicted from theory.
Resource Letter EMAA-2: Laboratory experiences for elementary astronomy
Authors: Kruglak Haym
Published: March 2005

Prepared at the request of the AAPT Editorial Board for Resource Letters. This is one of a series of Resource Letters on different topics intended to guide college physicists, astronomers, and other scientists to some of the literature and other teaching aids that may help improve course contents in specified fields. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one Letter on some of the main subjects of interest. Comments on these materials as well as suggestions for future topics will be welcomed. Please send such communications to Professor Aaron Owens, Editor, Resource Letter Board, Department of Physics, Kenyon College, Gambier, Ohio 43022.

N o t a t i o n: The letter E after an item number indicates elementary level; the letter I indicates intermediate level; and the letter A indicates advanced material. An asterisk (*) indicates those references we feel to be especially helpful.

R e p r i n t s: When ordering, request Resource Letter EMAA-2. Enclose 75 cents per copy (not in stamps) together with a stamped and self-addressed envelope and send to Melba Phillips, Acting Executive Officer, American Association of Physics Teachers, Graduate Physics Building, SUNY at Stony Brook, Stony Brook, New York 11794.
Thomson’s monopoles
Authors: Adawi I.
Published: March 2005

The angular momentum L of the electromagnetic field due to an electric point charge e, and a magnetic point charge (pole) g, is calculated by several methods to obtain J. J. Thomson’s result that L=eg/c, and L is directed along the line joining the electric monopole to the magnetic monopole. The relation to Dirac’s monopoles is discussed, and particle size is considered.
On phase shift analysis of one-dimensional scattering
Authors: Formánek J.
Published: March 2005

The problem of phase shift analysis of one-dimensional scattering is investigated. It is shown that conditions required by Eberly are not sufficient for guaranteeing parameterization of scattering amplitude by phase shifts. The weak point of Eberly’s reasoning is indicated, and the missing condition is specified.
Etiquette in the laboratory
Authors: Ogborn Jon
Published: March 2005

The author offers, for those newly entering laboratory society, a simple guide to the proprieties and niceties of conduct therein. Customs dealt with include: making an entry to the laboratory; its arrangement and the nature of the tasks it provides; the proper manner of discovering the nature of those tasks; the fashion after which it is appropriate to regard the manuscript provided; correct behavior in the conduct of the experiment, and the necessities to be observed in recording its outcome; all this, together with more general advice about comportment in the laboratory and the benefits which may be obtained from it. [Editor’s note: The editors have already drafted a letter of response for correspondents who will take this article seriously—and another for those who do not!]
Analog between optical waveguide system and quantum-mechanical tunneling
Authors: Tsai Tung-lin , Thomas G.
Published: March 2005

The analog between an optical waveguide coupler and the quantum-mechanical double-well problem is established. Well-known results of the quantum-mechanical system are applied to the waveguide system. This way of thinking of the waveguide system provides a quick understanding of the coupling mechanism and provides new interpretations of results obtained from Maxwell’s equations. Just as ray opticals give insight into certain types of optics problems, we believe that the tunneling interpretation will give new insight into the field of guided light waves.
Ohmic electrical conductivity in a magnetic field
Authors: Arora V. K.
Published: March 2005

A quantum-mechanical theory using a density matrix for electrical conductivity in the presence of a magnetic field is described. The conventional methods using the Boltzmann transport equation are not satisfactory because the magnetic field introduces a curvature in the free path of an electron. The expectation value of the current density and the components of the conductivity tensor in a magnetic field are obtained. The advantages of the density matrix in electric transport problems with a magnetic field are discussed.
Miniature magnet for electron spin resonance experiments
Authors: Rupp L. W. , Wittig K. R. , Walsh W. M.
Published: March 2005

Commercially available permanent magnets have been incorporated in a compact and inexpensive structure providing both field sweep and modulation suitable for electron spin resonance at microwave frequencies.
Quantum mechanical momentum operators and Hamilton’s variational principle
Authors: Brownstein K. R.
Published: March 2005

The Euler–Lagrange equations in classical field theory are not covariant with respect to a transformation of independent variables. A modified covariant version of these equations is presented. The modification consists of replacing the partial derivative ∂/∂qi by the Hermitian quantum mechanical momentum operator pi conjugate to the coordinate qi. This momentum operator is given by pi=−ih/[∂/∂qi+(1/2) ∂/∂qi(lnJ)], where J is the Jacobian of the transformation.
Runge–Lenz vector for nonrelativistic Kepler motion modifed by an inverse cube force
Authors: Heintz W. H.
Published: March 2005

The Runge–Lenz vector is determined in a rotating coordinate system, for nonrelativistic Kepler motion modified by an inverse cube force. In the rotating coordinate system the problem reduces to that of nonrelativistic Kepler motion. Using the Runge–Lenz vector it is shown how to obtain the classical orbit equation and the quantum mechanical energy eigenvalues. Attention is confined to classical motion between two turning point method can be extended to other kinds of motion that are possible in this force field.
Numerical experimentation with stellar model atmospheres
Authors: Hill Stephen J.
Published: March 2005

The use of a computer in the undergraduate astrophysics course is useful in presenting the radiative transfer processes in a stellar atmosphere. The students experiment on a computer model to determine how the properties of the star, the temperature and opacity, determine the nature of the observed spectrum of a star. Sample results of the students’ experimentation are presented.
Design of an inexpensive pendulum for study of large-angle motion
Authors: Schery Stephen D.
Published: March 2005

The design of a pendulum that can demonstrate the dependence of period on amplitude is described. Common laboratory supplies are used for construction, and timing is done with a stopwatch. A small computer may be used for theoretical analysis without need for detailed study of differential equations, elliptic functions, or perturbation theory. Agreement between experimental data and theory to 1 part in 103 is conveniently obtainable.
Bound-state eigenvalues of the square-well potential
Authors: Murphy R. D. , Phillips J. M.
Published: March 2005

The transcendental equations that determine the bound-state energy eigenvalues of the one-dimensional square well and the s states of the three-dimensional well are cast into a form that can easily be solved to high accuracy on a pocket calculator. Numerical examples of various one-dimensional wells and the deuteron are presented.
Victor Weisskopf: Oersted Medalist for 1975
Authors: Haynes Sherwood K.
Published: March 2005

Remarks by the Chairman of the Committee on Awards in presenting Victor F. Weisskopf the award of the 1975 Oersted Medal in recognition of his notable contributions to the teaching of physics.
AAPT Distinguished Service Citations—February 1976
Authors: Haynes Sherwood K.
Published: March 2005

The American Association of Physics Teachers conferred Distinguished Service Citations on eight outstanding contributors to physics education: Walter Eppenstein, Rennselaer Polytechnic Institute; Kenneth W. Ford, New Mexico Institute of Mining and Technology; Anthony P. French, Massachusetts Institute of Technology; Wallace A. Hilton, William Jewell College; Melburn R. Mayfield, Austin Peay State University; Betty L. Pollack, University of Oklahoma; Frederick Reif, University of California, Berkeley; Julius H. Taylor, Morgan State University. The presentations were made by Sherwood Haynes, retiring past President of the Association, at its annual business session on 5 February 1976 in New York City.
Physically important integrals without calculus
Authors: Reif F. , Larkin Jill H.
Published: March 2005

Many physically important spatial integrals, such as those needed for finding electric or magnetic fields, can be calculated by a simple method based on elementary geometry, without the need to use the techniques of the calculus or advanced theorems (such as Gauss’s or Ampere’s laws). The method is practically useful, can provide physical insights, and is suitable for mathematically unsophisticated students in introductory courses. We explain this method by applying it to calculate the electric fields due to a uniformly charged plane, line, and spherical surface.
Speed of light determined by microwave interference
Authors: Bergel L. , Arnold S.
Published: March 2005

Microwaves are reflected from a fixed and a moving object and mixed in a diode detector. The Doppler beat frequency across the detector is used to drive a spark generator which issues sparks along an air track. The speed of light is easily obtained to three places from the microwave frequency and the average distance between the sparks. An inexpensive Gunn diode serves as both microwave source and detector.
Contact potentials between metals: History, concepts, and persistent misconceptions
Authors: Fisher Leon H. , Varney Robert N.
Published: March 2005

Some early and not easily available history of contact potentials between metals is presented. A discussion is given of how the existence of a characteristic potential difference between metals was established. This discussion presents some idealized experiments and then analyzes the historic work in terms of them. From experiments, it is shown that the measured potential difference lies between two points that are respectively just outside of the two metals in contact. Certain points are brought out that are not often found in the literature. (i) Bennet discovered contact charging of dissimilar metals significantly earlier than Volta did. (ii) Nothing in 19th (or 20th) century physics discloses experimentally the internal potential difference between two dissimilar metals in contact. (iii) Many 19th century physicists, including Maxwell, thought that the Peltier effect disclosed the value of the internal potential difference between dissimilar metals in contact. Later analysis showed that Maxwell was wrong. (iv) The belief that contact potentials were solely electrolytic, arising from damp contacts, recurred well into the 20th century but was almost completely abandoned following the advent of high-vacuum technology. It recurs occasionally with no justification in the 1940’s and 1950’s.
Comparison of the treatment of electricity in the SAPA, SCIS, and ESS elementary school curricula
Authors: Stefanich Greg P.
Published: March 2005

The treatment of electricity in each of the three most widely used National Science Foundation sponsored elementary science programs (SAPA, SCIS, and ESS) is examined. A first impression tends to leave one with the feeling that the approaches parallel each other; however, each program is quite different in its orientation, and the treatment of subject matter is quite different. The author has selected the concept of electricity to illustrate these different approaches in a comparative setting.
Interference pattern of a cylindrical glass tube
Authors: Maddox W. C. , Koehn B. W. , Stout F. H. , Ball D. A. , Chaplin R. L.
Published: March 2005

Reflection of coherent light from a cylindrical glass tubing gives many interference fringes which extend around the tube for more than 180° from the incident beam direction. These fringes have a spacing which varies with angle. The cause of this interference pattern is the superposition of the reflections from the outer and inner surfaces of the cylinder. Excellent agreement is obtained between experimental and theoretical results of the magnitude of the fringe separation as a function of angular direction.
Establishing an undergraduate research program in physics: How it was done
Authors: Cohen Samuel A. , MacVicar Margaret L. A.
Published: March 2005

In the fall of 1969, MIT extended an open invitation to all of its undergraduate students to join the professional research activities of the faculty. This undergraduate research program rapidly increased in size, scope, impact, and diversity. In this article we report on the Undergraduate Research Opportunities Program (UROP) in the MIT Physics Department: the philosophy and objectives of the Physics program, its organization, rules, funding, growth, atmosphere, problems, and accomplishments. By the end of its first three years, Physics UROP included more than 50% of all the undergraduates enrolled in physics. Evaluations of UROP by faculty, administrators, and students were uniformly enthusiastic. This article presents the outline of how Physics UROP was established and how it evolved. Now in its seventh year, UROP has survived to maturity without becoming a cumbersome bureaucracy.
The rise and fall of PSI in physics at MIT
Authors: Friedman Charles P. , Hirschi Stanley , Parlett Malcolm , Taylor Edwin F.
Published: March 2005

Small-scale trials of the Personalized System of Instruction (PSI) in physics at MIT under the sponsorship of the Education Research Center were followed by adoption of large-scale introductory PSI courses in the Department of Physics. After four semesters, all introductory physics PSI courses were suspended. This study investigates what happened. We point out organizational difficulties in going from small- to large-scale use of the PSI method. We also identify certain conflicting perceptions among participants and observers that contributed to the suspension. The study, we hope, is an example of an informative ’’postmortem’’ of a type much needed in higher education.
Significant physics content and intellectual development—cognitive development as a result of interacting with physics content
Authors: Renner John W.
Published: March 2005

Increasingly during the past 20 years intellectual development has been recognized as the central purpose of education. The Piagetian model of intellectual development tells us that each student must engage a subject in a manner appropriate to his or her present stage of development if he or she is to advance to the next stage of development. When applied to college physics teaching, this theory implies that the large fraction of introductory physics students who are at the concrete operational stage of development must observe physical phenomena directly while they themselves are manipulating the equipment. Only in this way can they progress to the formal operational stage that characterizes professionals in the field.
Resource Letter RC-1: Cosmology
Authors: Ryan Michael P. , Shepley L. C.
Published: March 2005

Prepared at the request of the AAPT Editorial Board for Resource Letters. This is one of a series of Resource Letters on different topics intended to guide college physicists, astronomers, and other scientists to some of the literature and other teaching aids that may help improve course contents in specified fields. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one letter on some of the main subjects of interest. Comments on these materials as well as suggestions for future topics will be welcomed. Please send such communications to Professor Aaron Owens, Editor, Resource Letter Board, Department of Physics, Lake Forest College, Lake Forest, Illinois 60045.

N o t a t i o n: The letter E after an item number indicates elementary level; the letter I indicates intermediate level; and the letter A indicates advanced material. An asterisk (*) indicates those references we feel to be especially helpful.

R e p r i n t s: When ordering, request Resource Letter RC-1. Enclose 75 cents per copy (not in stamps) together with a stamped and self-addressed envelope and send to Melba Phillips, Acting Executive Officer, American Association of Physics Teachers, Graduate Physics Building, SUNY at Stony Brook, Stony Brook, New York 11794.
Implementing a course on the physics of music
Authors: Shonle John I.
Published: March 2005

This paper provides information to aid in starting a course in musical acoustics. The selection of topics for lecture, a project-mode laboratory, texts, references, equipment, and lecture demonstrations are covered.
A differential equation for the energy eigenvalues of relativistic hydrogenic atoms, and its solution
Authors: Epstein Saul T.
Published: March 2005

By using various general theorems, differential equations for the energy are written down for Klein–Gordon and Dirac hydrogenic atoms. When coupled with the fact that in the nonrelativistic limit one must get the Bohr formula, these equations are shown to determine the exact energy eigenvalues. Also, in the case of the Klein–Gordon equation, a recursion relation is derived from which the average values of powers of the radius can be found.
Numerical methods for solving two transcendental equations which appear in Fraunhofer diffraction
Authors: Henry Dennis C.
Published: March 2005

The intensity distribution in a Fraunhofer single-slit diffraction pattern is described by transcendental equations of the form x=C sinx and x=C tanx. The first equation appears in the solution for the width of the central maximum of the pattern. The second results from an attempt to locate the positions of the secondary maxima. Students who are used to explicit (closed) solutions of equations are often distressed by the apparent need for trial-and-error methods. Graphical solutions give a good ’’feel’’ for the situation, but are not satisfying to those who would like greater precision. Numerical methods, which rely only on introductory calculus, can be easily applied. Algorithms employing pocket calculators are presented.
Giant dipole state in the deuteron in simple models
Authors: Zamick L.
Published: March 2005

By assuming a Serber interaction and either asymptotic or Hulthen wave functions for the deuteron, we can easily obtain the mean energy of the dipole state of the deuteron. We do this in two ways: first, we construct the dipole state as a bound state in the continuum and, secondly, we use the photodisintegration cross section. The results for the bound state calculation agree with the continuum calculation.
Sound and light in the arts
Authors: Day Donald K.
Published: March 2005

This paper describes an elementary one-semester course in the physics of sound and light with an emphasis on applications in art, music, photography, and theater. The course has succeeded in attracting a substantial number of students with an interest in one or more of the above areas. The structure and composition of the course may therefore be of interest to physics departments in other institutions.
Particle motion in ion cyclotron wave fields
Authors: Liemohn H. B. , Duane B. H.
Published: March 2005

The interaction between charged particles and circularly polarized electromagnetic waves propagating parallel to a static magnetic field is an important problem in classical plasma physics owing to possible energy exchange at the cyclotron resonance. The nonlinear motion of ions in such fields is known to be described by elliptic functions, but the physics is obscured by the complicated expressions. The properties of the particle trajectories are much more transparent in the perturbation–expansion solution derived here. For small wave amplitudes the solutions are valid for an extended time and the resonance effects are clearly evident. The initial phase between the particles and wave fields emerges as an important condition on the motion. Potential applications of the results in magnetospheric physics and plasma fusion devices are briefly discussed.
360° reflection holography
Authors: Hsue S. T. , Parker B. L. , Monahan M.
Published: March 2005

As an extension of 360° transmission holography, two methods of making 360° reflection holograms are presented. Image reconstruction of the holograms for the two methods is described.
Classroom demonstration of the vibration of a bowed string
Authors: Dale E. Brock
Published: March 2005

An overhead projector has been modified for stroboscopic illumination for the purpose of demonstrating the vibration of a string excited by a violin bow. The vibrational pattern is clearly delineated, as are differences caused by insufficient or excessive bow force. A regime of oscillation is noted at high bow force and low speed in which alternate waves are reflected from the bow and the bridge so that the vibration transmitted to the bridge is about an octave below the fundamental frequency of the string.
Singular motions of asymmetric rotators
Authors: Harter William G. , Kim Chong C.
Published: March 2005

An apparatus is described that shows clearly and quantitatively the spectacular motion of free rotating rigid and semirigid bodies moving near their inertial singularities. A geometric construction is shown that makes the theory of this motion clear.
Computer interfacing: An undergraduate course for scientists and engineers
Authors: Peters Philip B. , Settle Frank A.
Published: March 2005

An interdisciplinary course has been designed and developed whose intent is to teach the basic principles of interfacing a small digital computer to laboratory apparatus. This course is available to science and engineering majors at the junior or senior level and has been team taught by instructors in several different disciplines. It is not an electronics course, but many of the current concepts in digital electronics are treated so that the student may understand the mechanics of the construction of an interface. The primary emphasis is on laboratory experience. Hardware requirements are not stringent, and it is possible to assemble a single laboratory station for as little as $4000.
Self-diffusion experiment using a neutron generator
Authors: Benenson R. E. , Rimawi K. , Chaitin M. , Goldenberg S. , Kaplan D.
Published: March 2005

A measurement of the coefficient of self-diffusion of xenon or krypton gas is described as an advanced undergraduate or early graduate student experiment. The radioactive tracer production is part of the experiment, and modern nuclear counting and analysis techniques are employed. Diffusion is very easily observed, and quite precise results are possible, except for a puzzling result in xenon at pressures near 1 atm.
Determination of absolute D* for photovoltaic infrared detectors: An advanced undergraduate experiment
Authors: Houlihan John F. , Mifsud Lewis
Published: March 2005

Various factors which affect an accurate determination of the detectivity of infrared detectors are analyzed, and an advanced undergraduate laboratory exercise which considers a number of these factors and is suitable for solid state physics or device-oriented electrical engineering courses is discussed.
Polar intensity profile of elliptically polarized light
Authors: Mayes Terrill W.
Published: March 2005

Many textbooks on optics discuss the phenomenon of elliptically polarized light but do not present diagrams which depict the intensity a phototube would measure as an analyzer is rotated through 360° in a field of elliptically polarized light. In this paper an equation is derived which gives the polar intensity profile for this situation. The theoretical results are then compared with experimental data.
Gravitational radiation: Sources
Authors: Campbell William B. , Morgan Thomas A.
Published: March 2005

A useful expression for the tidal gravitational field due to a radiating source is found. In electromagnetic theory the electric field E in the radiation zone is determined by two time derivatives of the component of the dipole moment which lies in the plane perpendicular to the line of sight. This result generalizes in a natural fashion for the tidal gravitational field E. The gravitational field in the radiation zone for several physical systems of interest is determined. A critical discussion of the applicability of the linear theory of gravitation and of the long-wavelength or quadrupole approximation is given.
The Robert A. Millikan Lecture Award 1976
Authors: Guernsey Janet
Published: March 2005

The AAPT Awards Committee selected Tung Hon Jeong to receive the Robert A. Millikan Lecture Award for 1976. This award, which is given for ’’notable and creative contributions to the teaching of physics,’’ was presented at the annual summer meeting, held at the University of Missouri–Rolla in Rolla, Missouri in June 1976.
De Broglie’s thesis: A critical retrospective
Authors: MacKinnon Edward
Published: March 2005

Louis de Broglie’s doctoral thesis developed a concept of waves associated with material particles that was soon incorporated into wave mechanics and later supported by experimental demonstrations. De Broglie’s original development, however, relied on an incorrect identification of two quite different relations: the relation between the velocity of a particle and the relation between the group velocity of a wave packet and the velocity of individual waves in the packet. A clarification of this difference and its historial significance is followed by a tentative account of the reasons why de Broglie’s well-known formula proved successful, though the theory supporting it rested on a conceptual confusion. Finally, this development and clarification are related to some of the difficulties involved in the attempts top fashion a coherent interpretation of quantum theory.
Singular potentials in one dimension
Authors: Andrews M.
Published: March 2005

In quantum mechanics of one dimension it is shown for potentials which become infinite at a point but are continuous elsewhere, that the singularity acts as an impenetrable barrier if the potential is not integrable up to the singularity, but if the potential is integrable the behavior is not essentially different from that of a potential which does not become infinite.
Analogy between optical rays and nonrelativistic particle trajectories: A comment
Authors: Arnaud J. A.
Published: March 2005

The identification, medium refractive index n = nonrelativistic particle velocity v, in the analogy of geometrical optics with nonrelativistic particle mechanics is physically correct and useful, but can easily be misinterpreted. The conditions under which the analogy holds are outlined. The significance of Descartes’s mechanical models is also discussed.
Canonical transformation to the free particle
Authors: Glass E. N. , Scanio Joseph J. G.
Published: March 2005

It is shown how to find some canonical transformations without solving the Hamilton–Jacobi equation. The canonical transformation from the harmonic oscillator to the free particle is constructed and used as an example of transformations which cannot be maintained when going from classical to quantum systems. The group of canonical transformations which can be carried over to quantum mechanics is discussed.
Maintaining enrollments in physics with declining university enrollments
Authors: Baldwin Thomas O.
Published: March 2005

The general education program in the Department of Physics at Southern Illinois University (Edwardsville) is described in considerable detail. Enrollments in courses and student credit hour production have been maintained in spite of an overall decline in university enrollments. The paper concludes by discussing the implications of general education courses for staffing in physics departments.
On some properties of γ matrices
Authors: Dumais Jean-François
Published: March 2005

The problem of the order, reducibility, and equivalence of systems of γ matrices is discussed from a presumably original point of view. The method proposed has the pedagogical advantage of being simple and self-contained. In particular, the questions of order and reducibility are treated without any use of group theory or of the theory of associative algebras. Finally, a simple systematic method is given for finding the matrices connecting different systems of 4×4 γ matrices.
On polynomial solutions of linear differential equations with polynomial coefficients
Authors: Si Do Tan
Published: March 2005

In the space of polynomials, the operators z and D=d/dz are known to be Hermitian conjugates with respect to the Bargman and Louck–Galbraith scalar products. From this property we obtain a method to study linear differential equations with polynomial coefficients. The conditions for obtaining polynomial solutions for these equations are found. Applications to the quantization of usual Schrödinger equations are given.
Multiple scattering theory with target nucleus antisymmetry
Authors: Austern N. , Tabakin F. , Silver M.
Published: March 2005

This article presents a pedagogic introduction to multiple scattering theory. Projectile–nucleus collisions are emphasized, and particular attention is given to the treatment of antisymmetry of the target nucleus wave function. The two standard renditions of multiple scattering by Foldy–Watson and by Kerman–McManus–Thaler differ primarily in the stage at which target nucleus antisymmetry is introduced and in the properties of the Hilbert space in which intermediate quantities are evaluated.
New light on old rays: N rays
Authors: Lagemann Robert T.
Published: March 2005

During the period 1903–1906, some 120 trained scientists published almost 300 articles on the origins and characteristics of a spurious radiation, the so-called N rays. Some new explanations are advanced for the extensive false observations and the deductions made from those observations. These are based on visits to Nancy, France, where the purported discovery was first announced and after which the rays were named, on an interview with a former assistant who knew some of the principals in the case, and on new archival information. Some of the misleading statements in the subsequent literature and oral history dealing with N rays are challenged, and additional information is provided on the original ’’discoverer,’’ René Blondlot.
Educational technology and university physics
Authors: Elton L. R. B.
Published: March 2005

Practicing teachers tend to concentrate their thoughts on the what and, to a lesser extent, the how of teaching. It is argued that such thoughts can be largely ineffective unless accompanied by a proper concern for the aims of the educational process and its evaluation. This concern is the prime task of the educational technologist. This paper analyzes the nature and purpose of this task.
Flexibly structured, inquiry-based, physical science course for education students
Authors: Quattrone J. J. , Courville G. E.
Published: March 2005

A flexibly designed set of units used to present a laboratory-centered, inquiry-oriented physical science course to education students is described. The activities in these units place the students into situations in which they must make sense out of their experiences, and provides the instructor with the opportunity to guide, evaluate and prescribe, according to the individual student’s interests, intellectual capabilities, and knowledge of science.
Establishing V=L (d
I/d
t) directly from experiment
Authors: Duffy Richard J. , Haber-Schaim Uri
Published: March 2005

By using a current that has a triangular waveform, students can investigate how the voltage across a field coil is related to the current. The inductive effects are seen to be proportional to the slope of the current, and the effects of resistance are clearly evident. The coil used has an inductance of 3.9 mH and a resistance of 1.3 Ω. An inexpensive circuit for producing a triangular wave is presented. It is assumed that students are familiar with the law of magnetic induction and that they can use an oscilloscope as a test instrument.
Theory of the chimney breaking while falling
Authors: Madsen Ernest L.
Published: March 2005

When a tall isolated chimney or smokestack is destroyed, usually a charge is detonated at its base and the chimney falls in the way a tree falls in that the base remains fixed. The typical photograph of the chimney falling shows it breaking as it falls at a point about one-third its length from the bottom. Application of Newton’s laws of motion to the problem of a long thin chimney of constant mass per unit length shows that there is a maximum bending torque exerted by the upper part of the chimney on the lower when the lower part consists of the lower one-third of the chimney.
Theory of hitches
Authors: Bayman Benjamin F.
Published: March 2005

If one end of a rope is tied to a pole and the other end is pulled, the hitch may slip or it may hold fast. In this paper, we present a method of predicting which will happen. The topology of the hitch determines an inequality involving the coefficients of friction characteristic of the rope and pole. If this inequality is satisfied, the different turns of the hitch press on each other, and on the pole, to produce a self-locking unit that can withstand an arbitrarily strong pull.
Discussion of the rigid rotator problem
Authors: Greenberg N. I.
Published: March 2005

A discussion of the rigid rotator is presented at a level which is appropriate for a basic quantum mechanics course.
Hamilton’s principle and approximate solutions to problems in classical mechanics
Authors: Schlitt D. W.
Published: March 2005

Ordinarily in classical mechanics Hamilton’s principle is used as a variational method to obtain the Euler–Lagrange equations of motion. In general these differential equations can be solved only by approximation methods. The Ritz method is a procedure for obtaining approximate solutions of problems expressed in variational form directly from the variational equation. Application of this method to problems in classical mechanics is discussed, and the example of a simple pendulum is examined in detail. The result is a perturbation series type of solution. Secular terms in the solution are avoided in a natural way.
Riemann curvature tensor and closed geodesic paths
Authors: Morganstern Ralph E.
Published: March 2005

It is shown how standard treatments of the change in a vector Δξi under parallel transport about a closed path in Riemannian spacetime lead to erroneous results if a complete circuit is made rather than just half a circuit followed by antisymmetrization. In fact a nonzero change in the vector is obtained upon returning to the initial point via the reversed path. The error in these treatments is shown to involve several aspects of the law of transplantation for a vector and the idea of path reversal in curved spaces.
The career oriented pretechnical physics project
Authors: Elliott Walt
Published: March 2005

A career oriented pretechnical physics curriculum was successfully tested in four Dallas high schools during the school year 1973–74. The curriculum consists of a set of minicourses from which students tailor a physics course to meet their personal interests, needs, and abilities. Although designed for self-pacing, the minicourses appear suitable for lock-step instructional modes. The experimenal minicourse students indicated that they liked physics better, preferred minicourse instruction to traditional instruction, were more positive in valuing their performance in learning physics, and exhibited physics knowledge comparable to that of the control group. Those schools using the minicourses experienced exciting gains in physics enrollments.
Group velocity in crystal optics
Authors: Nelson D. F.
Published: March 2005

We show, contrary to developments in prominent optics texts, that the assumption of a single-frequency wave does not eliminate the effect of frequency dispersion upon the energy transport (group) velocity nor upon the energy density.
Concept of temperature without the zeroth law
Authors: Home Dipankar
Published: March 2005

The present article consists of two parts: (1) criticism of the zeroth law, and (2) development of thermodynamics dispensing with the zeroth law. Two main criticisms of the zeroth law are (a) it is not an independent law of thermodynamics, and (b) it does not furnish even a qualitative objective definition of temperature. It is, therefore, asserted that the concept of temperature must not be introduced before the second law. How the second law can be used to give a complete objective definition of temperature consistent with the zeroth law is then discussed.
Humanistic physics: A course using paraphysical topics to illustrate the scientific method
Authors: Garrity Michael K.
Published: March 2005

Community-interest short courses in physics can be developed to increase awareness of the methods and principles of science despite the reluctance of the general public to explore the unfamiliar. Humanistic physics uses topics chosen from neuroscience and the study of the paranormal, as well as demonstrations and lectures given by informed individuals from other disciplines, to cultivate an appreciation for the power as well as the limit of the scientific method when applied to the synergistic nature of man and his reaction with his environment.
Half-life of thorium-232: a laboratory experiment
Authors: Chikkur G. C. , Umakantha N.
Published: March 2005

It is demonstrated that the halflife of 232Th can be determined by dissolving a known amount of Th(NO3)4⋅4H2O in a liquid scintillator and using a difference method to obtain the counting rate due to and particles.(AIP)
Eigenvalue estimates for numerical integration of the Schrödinger equation from the WKB approximation
Authors: Birx Daniel L. , Houk T. William
Published: March 2005

A simple application of the WKB approximation allows one to establish upper and lower bounds of estimated eigenvalues for cases in which the time-independent Schrödinger equation is not analytically solvable. The technique developed is applicable to nonsymmetric potentials as well as those with a finite number of discontinuities. The formal technique is most valuable when there is a high density of states and there is danger of missing eigenvalues in the solution. A computer implementation of the technique is presented to facilitate its application.
The Kepler orbit from initial conditions via the Lenz vector
Authors: Caplan S. , Fuerstenberg H. , Hayes C. , Kane D. , Raboy S.
Published: March 2005

The orientation and parameters of the orbit of a satellite under an inverse square law of force are obtained by use of the eccentricity vector, equivalent to the Lenz vector, from a typical set of initial conditions.
Einstein’s comprehensive 1907 essay on relativity, part III
Authors: Schwartz H. M.
Published: March 2005

This is the concluding part of the English rendition of Einstein’s 1907 essay on relativity, of which part I appeared in the June 1977 issue of this Journal and part II in the September 1977 issue. It consists of a direct translation of the last part of the essay, part V, entitled ’’Principle of Relativity and Gravitation,’’ and of a few added footnotes.
Determination of a planet’s diameter by occultation time—an introductory astronomy exercise
Authors: Hart Francis X. , Massey J. Steve
Published: March 2005

This paper describes an exercise developed for a liberal arts astronomy course in which the students obtain values for the diameter of Venus by timing the intervals between contacts in a videotaped occultation of that planet by the Moon. Approximate expressions relating the planetary diameter to this time interval are obtained for occultations of a planet in the crescent or gibbous phases. We note that classroom playback of certain videotaped astronomical events demonstrates clearly their dynamic nature.
Diffraction of a δ-function pulse at a half plane: the boundary pulse
Authors: Calvert J. B.
Published: March 2005

The diffraction of a plane δ-function pulse by a black half plane is treated by Stokes’ diffraction formula. The solution is a superposition of the incident pulse terminated at the geometric shadow boundary and a separate cylindrical boundary pulse exhibiting diffusion. The boundary pulse satisfies Lamb’s theorem, and its Fourier transform yields the monochromatic boundary wave. The mathematical reason for the π/4 phase shift is seen in the Fourier transform of the pulse tail. The character of the solution is sufficient to show that the boundary pulse originates at the edge of the diffracting aperture, and to illustrate clearly the kinematical aspects of diffraction at a black screen.
Application of the Dirac delta function to electric charge and multipole distributions
Authors: Namias Victor
Published: March 2005

We introduce the concept of equivalent volume charge density for all types of charge and multipole distributions, discrete as well as continuous. The equivalent volume charge density for point charges, point dipoles, and point quadrupoles is expressed in terms of the Dirac delta function and its derivatives. The equivalent volume charge density for surface charge distributions and surface dipole distributions is obtained by introducing a ’’surface delta function.’’ The well-known equivalence between a continuous distribution of dipoles within a specified volume and the volume and surface densities is derived directly by means of the delta function formalism. The same method is also applied to find the equivalent volume and charge distributions for a continuous distribution of quadrupoles confined in a specified volume.
Investigating the physical nature of the Coriolis effects in the fixed frame
Authors: Renault Jacques , Okal Emile
Published: March 2005

It is shown that investigating Coriolis effects in the fixed frame leads to a clearer understanding of their physical nature: the body carries along its initial velocity, larger or smaller than the velocity of its corresponding point during the motion. A simple but thorough calculation of some effects (the Foucault pendulum and the eastward drift of a falling body) is given.
Measurement of dielectric constants and capacitor dissipation using resonant circuits
Authors: Jupin W. R.
Published: March 2005

Using basic theory of resonant RLC, equivalent capacitor circuits, and primarily uncalibrated, readily available apparatus, one can determine the dielectric constants of liquids and measure capacitor dissipation. The experiment described is suitable for both an intermediate level electricity and magnetism laboratory course and, with extensions, a more advanced course in dielectric theory.
Tumbling motion of free three-dimensional wave packets
Authors: Woodsum Harvey C. , Brownstein K. R.
Published: March 2005

A ’’moment of inertia’’ tensor ℐ is defined for a quantum-mechanical wave packet. The time evolution of ℐ is investigated. It is shown that, for a free wave packet, the evolution of ℐ is identical in form to that for a system of noninteracting classical particles. Several results involving the tumbling motion of the principal axis system of ℐ are obtained.