bluuebunny/crossref_metadata_2025 huggingface dataset:
1962 Citations for Distinguished Service
Authors: Correll Malcolm
Published: August 2005

Since 1953, the American Association of Physics Teachers has annually cited some of its members for distinguished service to the teaching of physics. In the nine following years, thirty persons have been so recognized. The five citations presented on January 27, 1962, are quoted below.
On Certain Combinatorial Problems
Authors: Rosenstock Herbert B. , Maradudin A. A.
Published: August 2005

In a recent paper, McLachlan and Chamberlain have proposed and solved the following problem: To find the number W(n,m,M) of ways of distributing m indistinguishable objects into n boxes with no more than M in each box. We present in this paper two additional methods for solving this problem and give solutions to four problems proposed but not solved by McLachlan and Chamberlain.
Comparison of Simon's and Van de Graaff's Theories of the Electrostatic Generator
Authors: Subudhi K. S. , Tiwari P.
Published: August 2005

The essential differences between the Van de Graaff's and Simon's theories of the electrostatic generator have been pointed out. According to Van de Graaff's theory: (i) The sphere acts as a Faraday's ice-pail; (ii) the rise of voltage is linear with time; (iii) the voltage attainable in the generator is equal to the breakdown potential of the sphere if there is no leakage of charge through the insulating support, etc.; and (iv) the voltage is a constant independent of the spraying voltage. According to Simon's theory: (i) The basic principle is the Volta's condensing electroscope principle; (ii) the rise of voltage is exponential with time; (iii) the attainable voltage is proportional to the spraying voltage; and (iv) the constant of proportionality does not depend on the capacity of the sphere, but depends on the positions of the spraying point, collecting point, and the sphere. The experiments performed with our generator show that the results are qualitatively in accordance with the Simon theory.
Apparatus Drawings Project. Report Number 26. Vertical Circle Apparatus
Authors: Marcley Robert G.
Published: August 2005

This article describes a vertical circle apparatus, sometimes called a loop-the-loop, designed to assist undergraduate study of rotational kinematics and dynamics. A flat narrow strip of stainless steel is flexed into a 26-in.-diam circular plane loop that is rigidly fixed to a flat vertical plate. Metal spheres, that traverse the loop, are rolled down a 60-in. straight track inclined 45° to the horizontal. The velocity of the sphere can be determined by using a conventional spark timer and waxed paper tape. A section of the circle at the top can be removed to illustrate the concept of centripetal force. The apparatus is sturdy enough for undergraduate use and, with suitable modifications and shadow projection techniques, has been used for lecture demonstrations before an audience exceeding 5000 persons. The prototypes of this apparatus were constructed by college sophomores with only high school machine shop training. Information on construction details is given.
Simple Demonstration Experiments in the Abbe Theory of Image Formation
Authors: Kranjc Katarina
Published: August 2005

Some experiments demonstrating Abbe's theory of microscopic vision by simple microscope equipment are proposed. These include line and crossed gratings, dark field, and phase contrast observations. The paper concludes with a brief account of image formation as a problem in Fourier synthesis.
Anniversaries in 1962 of Interest to Physicists
Authors: Barr E. Scott
Published: August 2005

During the year 1962 there will be major anniversaries of the birth or death of ten men who have played important parts in the development of physics. Brief accounts of their achievements and lives are given here.
Experimental Study of the Motional Electromotive Force
Authors: Then John W.
Published: August 2005

Experiments are described that develop a pure motional electromotive force detected with a sensitive galvanometer. Old questions are re-examined by an original experimental approach as follows: What are the conditions of relative motion between magnetic field and conductor for developing a motional electromotive force? Unipolar induction is considered when a uniform or symmetrical magnetic field is concerned and special attention is given to the rotation of nonuniform magnetic fields. The results of the latter differ markedly from the former. Concepts of macrostructure and microstructure magnetic fields are considered briefly as applied to the experiments described. References are made to theoretical treatments to clarify the issues, but discussions are kept to the experimental approach with a qualitative rather than quantitative treatment.
Vector Representation of Rigid Body Rotation
Authors: Grubin Carl
Published: August 2005

In this note we examine the problem of determining the final orientation of a rigid body which undergoes a finite rotation around some axis fixed in space. It is shown here that the result of such a rotation can be found as the solution to a simple vector differential equation.
Student Experiment on the Measurement of Nuclear Excitation Functions
Authors: Bate George L.
Published: August 2005

Deuteron bombardment of stacked gold foil permits simultaneous determination of the cross sections for the competing (d,p) and (d,2n) reactions. The student laboratory work begins with the bombarded foils and consists primarily of analyzing the gamma radiation from Au198 and Hg197m by the use of a sodium iodide detector and single-channel analyzer. The experiment affords the student direct contact with nuclear reactions, and its successful completion requires the student to draw upon a variety of fundamental principles and experimental techniques in nuclear physics.
Apparatus Drawings Project. Report Number 28. Versatile X-Y Projector Plotter
Authors: Marcley Robert G.
Published: August 2005

The apparatus described is a simple X-Y plotter designed to fit the slide stage of a standard 10- ×10-in. overhead projector. Graphs are drawn with felt pens on the projector's normal writing medium, a disposable plastic foil strip. A magnified image of the graph, as it is being drawn, can be projected at any size suitable for the lecture room involved. The plotter consists of two servo-balanced slide-wire potentiometers set at 90° to each other, with simple, direct-coupled amplifiers controlling the motors. Each potentiometer has a carriage, fitted with a slide-wire contact and a slotted arm, coupled to its servo-motor by a cable system. The pen, passing through both arm slots at their intersection, records all carriage movements. Both axes have a sensitivity of ca 18 v/in. over a range of 180 v that can be traversed in about 4 sec. The low-cost electronic circuits are as simple as is consistent with stability and reliability. Full information regarding construction of both mechanical and electrical systems is given.
Apparatus Drawings Project. Report Number 29. Accessory Apparatus for Large Electromagnet
Authors: Marcley Robert G.
Published: August 2005

The four devices described are designed to fit the large electromagnet, described earlier in this series, thus greatly enhancing its usefulness. (1) A magnetic force on a current-carrying conductor apparatus is intended for undergraduate laboratory investigations. A current of 50 amp in a magnetic field of 0.8 weber/m2 will produce a force on the conductor of nearly 3.2 newtons. The conductor current is normally obtained from lead storage cells. (2) An eddy current pendulum, 1 meter long, is used for lecture demonstrations. (3) Truncated square pyramidal pole faces provide the intense magnetic fields (about 1.3 weber/m2) required for a practical sophomore laboratory experiment on the Zeeman splitting of spectral lines. (4) The last device described is a single pole face specially tapered to produce a highly inhomogeneous magnetic field for experiments and demonstrations dealing with para- and dia-magnetism. Detailed information regarding construction of the apparatus is given.
A Geometric Representation of Galilean and Lorentz Transformations
Authors: Brehme Robert W.
Published: August 2005

The kinematic concepts of special relativity seem best understood by the beginning student if they are presented in purely geometric form. The description of events in space-time is given geometrically as viewed from different coordinate systems in relative motion with one another, both from the classical and relativistic points of view. These geometric representations differ somewhat from those usually seen. Some justification is given the Lorentz transformation by requiring that the velocity of light be the same for all observers and that in the limit of small velocities, the Lorentz transformation reduce to the Galilean transformation. The relativistic contraction of lengths and the dilation of time intervals are deduced.
Subharmonic Oscillations in a Piecewise Linear System
Authors: Pong William , Marcaccio William
Published: August 2005

It is possible to generate subharmonic oscillations by means of an electromechanical analog which simulates a piecewise linear system similar to that of the middle ear structure. The subharmonic vibration observed was a steady-state oscillation having a large component of frequency one-half that of the periodic driving force. The occurrence of the subharmonic response is dependent on the amplitude of the periodic excitation and the range of frequency.
Air-Bearing Maxwell Top
Authors: Neher H. V.
Published: August 2005

The Maxwell top herein described is suitable for use in a student laboratory. With it, measurements may be made on angular acceleration and precessional motion. Over a wide range of angular speeds, friction is too small to affect the measurements. The precision attainable is limited primarily by the patience and skill of the experimenter.
Second-Order Electric Field Due to a Conduction Current
Authors: Rosser W. G. V.
Published: August 2005

It is shown that a conduction current can give rise to an electric field due to the different velocities of the positive and negative charges in the conductor. This electric field is in addition to the electric fields associated with the seat of emf and stray capacitances. Some typical examples are considered.
Experiments with an Electrically Operated Kundt Tube
Authors: Hastings R. B. , Shih Yung-Yao
Published: August 2005

An experimental investigation of the striations in a Kundt tube was carried out, using an electrically driven source of sound. Thus was produced by modern equipment, consisting of an audio frequency oscillator, amplifier, and reproducing unit, details concerning which follow in the paper. Spacing between striations was found to depend on particle size. Particles in striations were observed to be repelled from each other and did not touch. All striations tested showed electrostatic effects, with strong negative charges exhibited by cork dust and positive by powdered magnesium. Standing waves in the air in a tube are shown to produce a pattern on the surface of a ribbon of liquid located in a trough along the bottom. Photographs substantiating the above statements are included in the paper.
Entropy and Uncertainty
Authors: Castañs Manuel
Published: August 2005

Some properties to be fulfilled by any measure of uncertainty, leading to a logarithmic relation between entropy and uncertainty, are stated. A few simple examples (equation of state of an ideal gas, osmotic pressure, heat of vaporization, and free expansion in a vacuum) are included in order to show the fruitfulness and very general application of this relation. As an appendix the mathematical form of uncertainty is given, indicating its connection with statistical mechanics and information theory.
Exact Normal Modes of Oscillation of a Linear Chain of Identical Particles
Authors: Louck James D.
Published: August 2005

A simple matrix theorem is used to derive the exact normal modes of oscillation of a linear chain of N identical particles connected by identical springs, but with arbitrary springs connecting the end particles to rigid walls.
An Experimental Evaluation of the Use of Instructional Films in College Physics
Authors: Tendam D. J. , McLeod R. R. , Snow Richard E.
Published: August 2005

The substitution of motion picture films for some lecture demonstration experiments would facilitate the continuous use of lecture halls by eliminating the necessity of allowing time between lectures for setting up and adjusting apparatus. This article gives the results of an experiment to measure the effects of such substitution on student achievement. The first physics course for engineering and physics majors was taught by two methods: (1) with conventional presentation of lecture demonstrations, and (2) with films substituted for some of the demonstrations. Students were randomly assigned to two classes and, within each class, to groups of seats at different distances from the lecture table. The same quizzes and examinations were given to all students. Statistical analyses of student scores indicate that: (1) presentation of lecture-demonstration experiments by film is as effective instructionally as the conventional method of presentation, and (2) student achievement is independent of the distance (up to 60 ft) between the student and the lecture demonstrations, irrespective of the two methods of presentation. The results of an informal study of voluntary use of films outside of class are also reported.
Analog Display of Ptolemaic and Copernican Orbits
Authors: Hafner E. M. , Bilaniuk O. M.
Published: August 2005

An electronic analog computer, capable of displaying two circular motions and the epicycle derived from them, is described. It is inexpensive and easy to build. As a demonstration lecture apparatus it is useful in discussions of elementary astronomy, kinematics, and basic electronics. Construction and analysis of the system constitute a fruitful experiment for students in an elementary laboratory course.
Women and Physics
Authors: Clancy Edward P.
Published: August 2005

Relatively few American women are pursuing physics, either as a subject of study or as a profession. The question is increasingly being asked as to why this is so. The argument is here made that several important factors exist, some of which are not generally understood. The emancipation of woman—so far as her supposed freedom to pursue any intellectual activity she chooses is concerned—is shown to be illusory. Social pressures, from all directions, are heavy in this country. Furthermore, study leading to professional status in physics is harder for a woman simply because she is a woman and therefore a minority and an “outsider” in the community of physics graduate students. The matter of possible differences between the sexes in aptitude for physics is discussed. Finally, there is mention of employer attitude as a factor in the attractiveness of physics as a profession for women.
An Inelastic Neutron Scattering Experiment
Authors: Ortiz Eddie
Published: August 2005

A recording spectrometer model 1820 manufactured by Nuclear Chicago with a NaI crystal scintillator, a neutron source, and an iron scatterer were used to measure the gamma ray at 0.84 MeV from Fe56 by inelastic scattering of fast neutrons.
A Review of Recent British Texts in Electricity and Magnetism
Authors: Worrell Francis T.
Published: August 2005

A group of contemporary British texts in electricity and magnetism at the intermediate level is surveyed. Of interest is their general approach, and how it differs from ours.
Production of Professional Physicists Decreasing
Authors: White Marsh W.
Published: August 2005

Data are presented to show the numbers of physicists-in-training graduating at various levels during the academic years from 1946–1947 to the present. Following World War II there has been a vast increase in the numbers of physics majors. The number of bachelor's degrees awarded by 525 institutions reached a maximum of 3770 in 1949–1950 and declined each year thereafter, with 3000 estimated for 1951–1952. The number of master's degrees awarded by 158 departments was highest at 1065 in 1949–1950 and has fallen off to an estimated 950 for the current year. At the doctorate level the production is continuing to increase, although at a reduced rate, with 475 estimated for 1951–1952. The total enrollment of undergraduate physics majors reached a maximum of 12,670 in 1949–1950 and has now declined to 10,200. The total number of physics graduate students has been nearly constant for the last two years at 5750.
Synchronization of Pendulum Clocks with the Help of Signals Taken from a Quartz-Crystal Clock
Authors: Ments M. v.
Published: August 2005

A great number of good pendulum clocks have an accuracy of between ±0.1 and ±0.5 sec/day. This figure does not compare very well with the accuracy of a fairly good quartz-crystal clock, which can be of the order of 0.01 sec/day and better. Besides, setting a pendulum clock in the case that the difference in time is a fraction of its period is rather tedious.

A method will be described by which a pendulum clock is locked into synchronization by energizing a pair of electromagnets (put at some critical places along the orbit of the pendulum) with special signals taken from a quartz-crystal clock.
Associated Legendre Functions
Authors: Scherr Charles W. , Ivash Eugene V.
Published: August 2005

It is shown in two different derivations that a discussion of the associated Legendre functions can be based on the well-known pure-recurrence relation between associated Legendre's functions, ulm(x), (l+1−m)ul+1m(x)−x(2l+l)ulm(x)+(l+m)ul−1m(x) = 0, provided the proper “boundary conditions” Pll(x) = [(2l)!/l!2l](1 − x2)12l, Qll(x) =thinsp;(1+x2)12l(dlQl(x)/dxl), are imposed.
Role of the Observer in Quantum Theory
Authors: Shimony Abner
Published: August 2005

In quantum theory as it is currently formulated the measurement of an observable quantity of a physical system is the occasion for a change of state of the system, except when the state prior to the measurement is an eigenstate of the observable. Two proposals for interpreting this kind of change are examined in detail, and several variant proposals are considered briefly. According to the interpretation proposed by von Neumann, and by London and Bauer the change of state is completed only when the result of the observation is registered in the observer's consciousness. Although this interpretation appears to be free from inconsistencies, it is not supported by psychological evidence and it is difficult to reconcile with the intersubjective agreement of several independent observers. According to the interpretation proposed by Bohr, the change of state is a consequence of the fundamental assumption that the description of any physical phenomenon requires reference to the experimental arrangement. Bohr's proposals are valuable as practical maxims in scientific activity, but they are shown to involve the renunciation of any ontological framework in which all types of events—physical and mental, microscopic and macroscopic—can be located. It is concluded that a satisfactory account of the observation of microphysical quantities is unlikely if the present formulation of quantum theory is rigorously maintained.
Physics Teaching: An Anthropological Angle
Authors: McNeil Edward B.
Published: August 2005

In the teaching of physics, behavior patterns are involved as well as factual material. Behavior patterns (even those on an unconscious level) are susceptible to analysis and, once analyzed, can be taught technically, if it seem desirable.
Maxwell's Equations as Properties of the Vortex Sponge
Authors: Kelly Edward M.
Published: August 2005

The vortex sponge, devised by John Bernoulli in 1736 in an attempt to explain light in mechanical terms, consists of an ideal fluid interlaced by fine vortex tubes oriented in all directions. When vortex tubes follow the fluid, the medium behaves like an elastic solid because of momentum transfer effects arising from the fine-grained vorticity. This character of the medium is altered by displacements which bend the tubes so that they move laterally. The motion of curved tubes relative to the fluid can result in macroscopic vorticity with accompanying rotation of the bulk medium. The mathematical expressions of these effects have the form of Maxwell's curl equations for free space.
A Demonstration Illustrating the Lorentz Transformation
Authors: Streib John F.
Published: August 2005

A teaching aid, used in introducing the theory of relativity, is described. It imitates at a slow and controlled rate the behavior of clocks and measuring rods in two reference frames in relative motion (β = 0.866), and shows their relation to a propagating light signal. Appropriate demonstrations are outlined. The construction is shown in diagrams.
Resource Letter FC-1 on the Evolution of the Electromagnetic Field Concept
Authors: Scott William T.
Published: August 2005

Prepared at the request of the AAPT Committee on Resource Letters; supported by a grant from the National Science Foundation.

This is one of a series of Resource Letters on different topics, intended to guide college physicists to some of the literature and other teaching aids that may help them improve course contents in specified fields of physics. 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 and suggestions concerning the content and arrangment of letters as well as suggestions for future topics will be welcomed. Please send such communications to Professor Arnold Arons, Chairman Resource Letter Committee, Department of Physics, Amherst College, Amherst, Massachusetts.

Notation: The letter E after an item number indicates elementary level, useful principally for freshman liberal arts through sophomore physics courses; the letter I indicates intermediate (junior, senior) level; and the letter A indicates advanced material principally suited for senior, graduate study. An asterisk (*) indicates items particularly recommended for introductory study.

Additional copies: Available from American Institute of Physics, 335 East 45 Street, New York 17, New York. When ordering, request Resource Letter FC-1, and enclose a stamped return envelope.
Remark on the Eigenvectors of Angular Momentum Operators
Authors: Buchdahl H. A.
Published: August 2005

Elementary treatments of a single angular momentum having components Jk (k =1, 2, 3) usually go as far as discussions of the spectra of these operators and the derivations of their standard, i.e., J2, J3-diagonal, representatives. On the other hand, the standard representatives of their eigenvectors are not usually obtained, leaving J3 aside, for which the problem is trivial. In fact, this part of the theory is most often dealt with only after a lengthy excursion into the theory of matrix representations. The representatives in question are obtained, in the first part of this paper, by means of essentially elementary arguments. Once these representatives are known, the standard representative of the unitary operator U which generates the state vector of a system after it has undergone a rotation R from the state vector prior to the rotation are deduced; this representative comprises just the familiar matrix representations of the rotation group. Finally, the relevance of harmonic oscillator theory to the present problem is briefly considered.
An Experiment Offering Varied Experience: Conductivity Changes of a Germanium Crystal under Tension and Illumination
Authors: Allen Mildred , Saxl Erwin J.
Published: August 2005

Using Bridgman's compensated potentiometer method an experiment is described in which the electrical resistance of a single germanium crystal may be shown to change when illuminated and when under tension, both well-known effects. The procedure sketched here differs from those usually employed in this field and gives experience in a number of different techniques and types of measurement. It is capable of showing that the effect of tension and the effect of illumination on the resistance are independent of each other and that the photoconductivity results from infrared, rather than visible, radiation.
Maxwell, Displacement Current, and Symmetry
Authors: Bork Alfred M.
Published: August 2005

Maxwell's reasons for introducing displacment current are considered. His published works disclose no arguments based upon symmetry, but emphasis on the symmetry of Maxwell's equations with regard to electric and magnetic fields is found in Oliver Heaviside's work on electromagnetic theory.
A Two-Dimensional Air Table
Authors: Daw Harold A.
Published: August 2005

The construction of a two-dimensional air table is described. This is an extention of the Neher-Leighton one-dimensional air trough to two dimension. The air cushion is provided by a perforated surface placed over an air-distribution manifold. The pucks consist of solid glass disks. A special wall keeps the energy loss from the system small. The conservation laws of linear and angular momentum can easily be studied, as can the general behavior of a two-dimensional gas.
Geometrical Model of Electromagnetic Fields
Authors: Lowry Edward S.
Published: August 2005

The electrostatic field, electromagnetic waves, electromagnetic induction, and the pure magnetic field are illustrated and explained in terms of a single pictorial representation of the general electromagnetic field of a classical charged particle. The field of a charged particle is described by the orientation and density of a family of surfaces radially distributed about the path of the particle in space-time. This description of the Maxwell field requires no reference to any coordinate system or field components.
Resource Letter F-1 on Friction
Authors: Rabinowicz Ernest
Published: August 2005

Prepared at the request of the AAPT Committee on Resource Letters; supported by a grant from the National Science Foundation.

This is one of a series of Resource Letters on different topics, intended to guide college physicists to some of the literature and other teaching aids that may help them improve course contents in specified fields of physics. 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 and suggestions concerning the content and arrangement of letters as well as suggestions for future topics will be welcomed. Please send such communications to Professor Arnold Arons, Chairman Resource Letter Committee, Department of Physics, Amherst College, Amherst, Massachusetts.

Notation: The letter E after an item number indicates elementary level, useful principally for freshman liberal arts through sophomore physics courses; the letter I indicates intermediate (junior, senior) level; and the letter A indicates advanced material principally suited for senior graduate study. An asterisk (*) indicates items particularly recommended for introductory study.

Additional copies: Available from American Institute of Physics, 335 East 45 Street, New York 17, New York. When ordering, request Resource Letter F-1 and enclose a stamped return envelope.
A Laboratory Linear Analog for Lattice Dynamics
Authors: Runk R. B. , Stull J. L. , Anderson O. L.
Published: August 2005

The application of the linear air track, a laboratory demonstration apparatus, is extended to demonstrate theorems in lattice dynamics. As a one-dimensional model it, visually and quantitatively, reveals details of the frequency versus wavenumber diagram, in particular the various modes of vibration, dispersion, phase velocity, the separation between the acoustic and optic branches, and the frequency spectrum.
A Laboratory Experiment on the Kinetic Theory of Gases
Authors: Weichman Frank L.
Published: August 2005

An apparatus is described which can be used to demonstrate that the heat conductivity of a gas is independent of gas pressure over wide limits as predicted by kinetic theory. The role played by the mass of the molecules and the mean free path can also be demonstrated.
Resource Letter ME-1 on the Mössbauer Effect
Authors: Wertheim G. K.
Published: August 2005

Prepared at the request of the AAPT Committee on Resource Letters.

This is one of a series of Resource Letters on different topics, intended to guide college physicists to some of the literature and other teaching aids that may help them improve course contents in specified fields of physics. 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 and suggestions concerning the content and arrangement of letters as well as suggestions for future topics will be welcomed. Please send such communications to Professor Arnold Arons, Chairman Resource Letter Committee, Department of Physics, Amherst College,Amherst, Massachusetts.

Notation: The letter E after an item number indicates elementary level, useful principally for freshman liberal arts through sophomore physics courses; the letter I indicates intermediate(junior, senior) level; and the letter A indicates advanced material principally suited for senior,graduate study. An asterisk (*) indicates items particularly recommended for introductory study.

Additional copies: Available from American Institute of Physics, 335 East 45 Street, New York 17, New York. When ordering, request Resource Letter ME-1, and enclose a stamped return envelope.
The Problem of Measurement
Authors: Wigner Eugene P.
Published: August 2005

The standard theory of measurements in quantum mechanics is reviewed with special emphasis on the conceptual and epistemological implications. It is concluded that the standard theory remains the only one which is compatible with present quantum mechanics. Hence, if one wants to avoid the conclusion that quantum mechanics only gives probability connections between subsequent observations, the quantum-mechanical equations would have to be modified. Particular attention is paid to the case that the measuring apparatus is macroscopic and its state vector not accurately known before the measurement.
Measurement of the Velocity of Light Through μ0, ε0
Authors: Stephens William E.
Published: August 2005

An instructional laboratory experiment is described in which the velocity of light is determined using resonance in a series circuit of a standard inductance and a standard capacitance by measuring the geometric dimensions of the reactors and the frequency of resonance. With appropriate corrections to the simple formulas, an accuracy of about 1% can be achieved. This method is intended to clarify the physical basis of the measurements and the assumptions.
An Experiment on Angular Momentum for the Introductory Laboratory
Authors: Palmieri J. N. , Strauch Karl
Published: August 2005

An experiment for studying the principle of conservation of angular momentum is described. A steel ball, with linear momentum p, moving at a distance r from a fixed shaft, is involved in a completely inelastic collision with a rigid body which is free to rotate about that shaft. The angular momentum r×p of the ball before the collision is compared with that of the rotating system afterwards; agreement within 2% is obtained. The experiment is designed for the introductory course for students majoring in the physical sciences.
Guidelines to Antigravity
Authors: Forward Robert L.
Published: August 2005

This paper emphasizes certain little known aspects of Einstein's general theory of relativity. Although these features are of minor theoretical importance, their understanding and use can lead to the generation and control of gravitational forces. Three distinctly different non-Newtonian gravitational forces are described. The research areas which might lead to methods for the control of gravitation are pointed out and guidelines for initial investigation into these areas are given.
Multipole Expansion of Coulomb Energy
Authors: Carlson B. C. , Morley G. L.
Published: August 2005

The electrostatic self-energy of a given charge distribution is expanded in an infinite series, each term of which corresponds to a single term in the multipole expansion of the potential. Several new forms of the energy expansion are derived. As an illustrative example, the Coulomb energy of a hemisphere uniformly filled with charge is calculated.
Resource Letter SO-1 on the Kinematics and Dynamics of Satellite Orbits
Authors: Blitzer Leon
Published: August 2005

Prepared at the request of the AAPT Committee on Resource Letters.

This is one of a series of Resource Letters on different topics, intended to guide college physicists to some of the literature and other teaching aids that may help them improve course contents in specified fields of physics. 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 and suggestions concerning the content and arrangement of letters as well as suggestions for future topics will be welcomed. Please send such communications to Professor Arnold Arons, Chairman Resource Letter Committee, Department of Physics, Amherst College, Amherst, Massachusetts.

Notation: The letter E after an item number indicates elementary level, useful principally for freshman liberal arts through sophomore physics courses; the letter I indicates intermediate (junior, senior) level; and the letter A indicates advanced material principally suited for senior, graduate study. An asterisk (*) indicates items particularly recommended for introductory study.

Additional copies: Available from American Institute of Physics, 335 East 45 Street, New York 17, New York. When ordering, request Resource Letter SO-1, and enclose a stamped return envelope.
Linear Air Trough
Authors: Neher H. V. , Leighton R. B.
Published: August 2005

The construction and operation of a linear air trough, a device for floating small rectangular blocks (called gliders) on an air film, is described. The apparatus is useful for demonstrations and laboratory study of one-dimensional particle mechanics. The very small friction that is present is due to the viscosity of the air film, and causes the speed of a glider to decay with a time constant of the order of a few hundred seconds. A type of bumper has been designed which yields a coefficient of restitution greater than 0.99. Ten of these air troughs have been used in a student laboratory for a year, and have proved quite successful in experiments involving Newton's laws, collisions, damped harmonic motion, and motion on an incline.
Some Applications of the Brehme Diagram
Authors: Sears Francis W.
Published: August 2005

The Lewis-Tolman collision, the Feynman clock, the relativistic Doppler effect, and the “twin paradox” are analyzed by means of a Brehme diagram.
Geometrical Method for Relativistic Particle Kinematics
Authors: Cha Moon H. , Simons Donald G.
Published: August 2005

A geometrical method for solving relativistic particle kinematics is presented. The method is especially useful for obtaining the energy and momentum distributions in a two-particle system, and the threshold energy for particle production. Energy and momentum distributions in a many-particle, system are also discussed.
Self-Stress, Covariance and the Classical Electron
Authors: Tangherlini Frank R.
Published: August 2005

It is shown that the covariance problem of the classical electron cannot be divorced from the self-stress problem as claimed recently by Rohrlich. The basic invariance principle of a relativistic field theory (i.e., the formalism should be independent of the choice of the family of space-like hypersurfaces) is used to give another derivation of von Laue's theorem. This new derivation makes it quite clear that the energy-momentum expressions calculated from the Maxwell energy-stress tensor are surface dependent because of the nonvanishing of the self-stress. The fact that the early workers obtained the well-known factor of 43 in the momentum expressions for one choice of surface, and Rohrlich and others find a factor of unity for another choice of surface, merely serves to confirm the violation of the basic invariance principle. Some additional remarks are made about the covariance problem of classical electrodynamics. The advantages and implications of the alternative proposal of Poincaré are elucidated.
TEM Modes and Circular Polarization
Authors: Kunz Kaiser S.
Published: August 2005

In this treatment of transverse electromagnetic waves circularly polarized waves of opposite senses are associated with a given positive frequency and the corresponding negative frequency. Linear polarization is thus obtained only as a superposition of circularly polarized waves. The development also leads naturally to the anticonformal properties of the field with respect to the transverse coordinates.
Internal Energy and Specific Heats of a Boyle's-Law Gas
Authors: Weinstock Robert
Published: August 2005

The First and Second Laws of Thermodynamics are used directly to investigate the internal energy and specific heats of a gas for which only Boyle's law is assumed to hold. The behavior of these quantities is found to be intimately linked with the relation between the absolute thermodynamic temperature scale and a temperature scale defined in terms of the pressure-volume product for one mole of the gas. It is deduced that the difference Cp − Cv of specific heats can be at most a function of temperature alone.
Measurement of the Relativistic Time Dilation Using μ-Mesons
Authors: Frisch David H. , Smith James H.
Published: August 2005

An experiment has been performed to demonstrate the relativistic time dilation as a large effect, using only comparatively simple equipment. μ-mesons incident on top of Mt. Washington, New Hampshire, were selected to have speeds in the range between 0.9950 c and 0.9954 c. The number of these which survived to reach sea level was measured in Cambridge, Massachusetts. The number expected without time dilation was calculated from the distribution of decay times of these μ-mesons (i.e., the mean life as measured in both this experiment and others) and from the known distance of descent. The observed time dilation factor is 8.8±0.8 to be compared with the effective time dilation factor calculated for mesons of these speeds in our detection geometry 1/(1 − v2/c2)12 = 8.4 ± 2.
Discussion of Quadrupole Precession
Authors: Raich J. C. , Good R. H.
Published: August 2005

In this paper the motion of a nucleus with an intrinsic quadrupole moment in an external electrostatic field gradient is discussed from a classical point of view. It is shown that in the classical approximation the angular momentum may precess about the direction of strongest field gradient or about the direction of intermediate field gradient, but not about the direction of weakest field gradient. The classical precession frequencies are found to be related to the quantum mechanical dipole transition frequencies.
A Physics Independent Study Course With Computer
Authors: Bork Alfred M.
Published: August 2005

An independent study course for sophomore physics majors is described. A digital computer was used extensively in the course which covered mechanics, circuit theory, relativity, and quantum mechanics.
Contemporary Electricity for Elementary Physics
Authors: Stahl Frieda A.
Published: August 2005

For the first year nonmajors' course, fundamental topics in E & M not usually included are shown to be capable of treatment in simple algebra, and are therefore proposed for inclusion in view of their timeliness. General revision is necessary, of course, to make room in the syllabus. The topics discussed are conductivity theory, Hall effect, and Poynting's theorem. Their inclusion paves the way for additional topics in Modern Physics, such as solid state and energy conversion. Appropriate laboratory experiments are cited wherever feasible. The underlying philosophy considered is a shift in approach from macroscopic to microscopic physics, and an emphasis on principles rather than applications.
Quantum Dynamical Description of Atoms and Radiative Processes
Authors: Fowles Grant R.
Published: August 2005

Within the framework of ordinary quantum mechanics a very graphic description of atoms and of radiative processes can be made. Upon examination of the probability current-density distribution, the atom is seen to be a dynamic entity. Selection rules can be made understandable by studying the temporal behavior of the charge distribution during the transition from one stationary state to another.
A Physics Building for the University of California, Riverside
Authors: Russell A. M. , Hewitt R. R.
Published: August 2005

A physics building planned for occupancy in the academic year 1964–65 has been designed for the Riverside campus of the University of California. The basis on which the planning proceeded is discussed, including the development of the graduate and undergraduate teaching facilities. The building has been designed to accommodate twenty staff members, ninety-one graduate students and an expanded undergraduate program. The floor plans and laboratory layouts are shown and include a 300-seat physical science lecture hall.
Faraday's Law and Ampere's Law
Authors: Sears Francis W.
Published: August 2005

It is suggested that the origin of the induced electromotive force in a stationary circuit, given by Faraday's law of induction, could be made clearer to a beginning student if emphasis were placed in introductory courses on the geometry of the induced electric field set up by a time-varying magnetic field instead of on the line integral of this field around a closed path, or the emf in the path. If the Faraday law is written as o∫E·ds = −Φ̇, instead of ε = −Φ̇, it has the same form as Ampere's law, o∫B·ds = μ0I, and both laws are simply the integral forms of the Maxwell equations, curl E = −Ḃ, curl H = J + Ḋ.
Lorentz Transformation in the Undergraduate Curriculum
Authors: Sokoloff Jeffrey
Published: August 2005

The paper criticizes a two-dimensional derivation of the Lorentz transformation commonly utilized in teaching special relativity on the undergraduate level. It is then shown that the assumptions involved in the two-dimensional proof are more stringent than those required in the four-dimensional case. A simple and rigorous two-dimensional proof employing “yard-stick-and-clock” methods is then outlined.
A Magnetic Resonance Demonstration Model
Authors: Hill John J.
Published: August 2005

The two-dimensional demonstration model consists of a single, small bar magnet in a static magnetic field with an applied oscillating magnetic field at right angles to the static field. It can be used to display the general principles of magnetic resonance such as the dependence of resonant frequency upon the static field, a zero field resonance, and the dependence of linewidth and resonant frequency upon relaxation processes. The model may also be used in the college laboratory for very simple and instructive experiments, and for the actual measurement of magnetic fields with an accuracy of a few percent, using no additional equipment otner than an audio oscillator.
Stability of a Conducting Droplet under the Influence of Surface Tension and Electrostatic Forces
Authors: Hendricks C. D. , Schneider J. M.
Published: August 2005

The Lagrange Equations of Motion are written in generalized coordinates which describe small departures from the spherical equilibrium configuration of a conducting liquid droplet. It is initially assumed that the actual shape differs only very slightly from the equilibrium sphere. The equation representing the surface is, then, written as a series of surface zonal harmonics in which the coefficients are shown to be the normal coordinates of the droplet. The frequency of oscillation of the normal coordinates is shown to depend on the total charge on the droplet in such a manner that for all values of charge below a certain limit, the frequency is real. For all values of charge above a certain limit, the frequency is imaginary; and, thus, the droplet is unstable. This paper presents a detailed derivation of a result communicated by Rayleigh in 1882. The results of this communication have been widely quoted but, until now, this particular derivation has not appeared in the literature.
1963 Citations for Distinguished Service
Authors: Verbrugge Frank
Published: August 2005

The American Association of Physics Teachers annually cites some of its members for distinguished service to the teaching of physics. Four citations were presented at the Annual Meeting of the Association on 26 January 1963. These citations are quoted below.
Classes of Carnot Cycles
Authors: Lufburrow Robert A.
Published: August 2005

The heat Q2 exchanged with the high-temperature reservoir and the heat Q1 exchanged with the low-temperature reservoir identify each Carnot cycle with a single point on the heat exchange plane, the Q2−Q1 plane. The axes and the zero work line divide this plane into half-planes whose physical interpretation is described with the aid of the laws of thermodynamics.
Special Relativity in Anisotropic Space
Authors: Edwards W. F.
Published: August 2005

An investigation of the propagation of light, assuming absolute spacial distances, the veracity of the principle of causality, and that the average speed of light measured over a closed path is a constant C, shows that the speed of light may have values between C/2 and is a function of direction. Generalized Lorentz transformations are found which are shown to be equivalent to those conventionally adopted. That an absolute simultaneity cannot be established electromagnetically is shown to follow. The arbitrary nature of indirect observables such as time dilation is discussed.
Response of Anisotropic Defects in Solids to Stress
Authors: Corbett J. W.
Published: August 2005

The stress-induced alignment of anisotropic defects in solids is considered. The treatment is pedagogical, dealing with simplified models rather than specific defect systems. Defects describable as classical systems and as quantum systems are considered, as well as the relationships between the two descriptions. Particular emphasis is placed on the experimental features of each. The process of measurement on the quantum system is considered in detail. In particular, it is concluded that, under appropriate circumstances, a linear combination of eigenstates of different energies can collectively and coherently participate in transitions, and that the experimental study of the time evolution of a system (e.g., tunneling) requires transitions to the nonstationary states described by such linear combinations of states. This discussion gives us extended insight into the roles of measurements and of superposition of states in quantum mechanics, and the model used in the discussion provides a ready vehicle for the classroom treatment of these problems.
Identification of Molecular Symmetry Groups
Authors: Calvert James B.
Published: August 2005

An easily remembered scheme for the assignment of a molecule to its point symmetry group is presented. The method rests on the identification of independent generators of the symmetry groups.
Spark Chamber for Cosmic-Ray Demonstrations
Authors: Earl James A.
Published: August 2005

A simple, flexible, and easily constructed design for small spark chambers is given. An inexpensive electronic circuit used to trigger the spark chamber is also described.
A Geometrical Approach to Relativistic Paradoxes
Authors: Romain J. E.
Published: August 2005

A geometrical method is proposed to clarify misconceptions regarding the so-called “stress effects due to Lorentz contraction” that have recently raised discussions in this Journal. The method is also applied to other related problems that shed additional light on the matter. It is shown that the same method provides a complete understanding of a paradox proposed by Dewan, and that it is applicable to two-dimensional problems. The two-dimensional system analyzed consists of a ring-shaped swarm of independent particles rotating with the same angular velocity.