bluuebunny/crossref_metadata_2025 huggingface dataset:
Subharmonic Oscillation in Melde's Experiment
Authors: Pong William
Published: August 2005

The characteristics of the subharmonic oscillation found in Melde's experiment are described by an approximate solution of a nonlinear differential equation of the second order with a periodic coefficient. The steady variation of the string's tension may be looked upon as an equivalent nonlinear effect.
More Effective Teaching of Physics through Television
Authors: White Harvey E.
Published: August 2005

The teaching of introductory physics courses to large groups of students has been conducted in the past by the use of large lecture halls. Problems that arise in such situations are numerous, some of the major ones being (1) making equipment large enough to be seen by everyone, (2) finding storage space for much large equipment, (3) keeping the lecture hall free of students for one whole period to provide ample time for setting up demonstrations, etc. Methods for solving these problems are presented here. By building three lecture room fronts on a single turntable, two complete lecture periods become available for setup time. Roll-in tables are not satisfactory. By using TV cameras with TV monitors suspended from the ceiling, demonstrations can be made clearly visible to everyone. An alternate solution, and in many respects the best one, is to develop several TV studio areas, use TV methods entirely, and by closed circuit transmission to monitors in small classrooms, reach students in groups of twenty-five or thirty. A teaching assistant in each of these rooms is then available for more intimate discussions.
Interrelationship of Physical Quantities
Authors: McNeill K. G.
Published: August 2005

An account is given of the derivation of the Young's modulus, melting point, coefficient of expansion, latent heat, and surface tension of copper and lead from relatively simple ideas of matter. The object is to provide for a student a simple demonstration of the interrelationship of these quantities and thus offset the separation of the various topics sometimes apparent in physics courses.
Elementary Diffraction Theory of Zone Plates
Authors: Sussman Milton
Published: August 2005

After a short introduction in which the notion of half-period zones is recalled, the axial intensity distribution of a zone plate, in the first-order approximation, is derived from diffraction theory. Its focal properties are then studied in some detail, including off-axis effects. Similarities in the axial distribution patterns for a zone plate and Fraunhofer patterns for a linear grating are discussed, and finally some possible applications and practical difficulties are presented.
Nonsecret Laboratory Examinations
Authors: Dewdney John W. , Christy Robert W.
Published: August 2005

Described here are two laboratory examinations of the performance test type whose novelty is that the exact problems have been revealed to students in advance. The results of these examinations are compared with one another and with an earlier examination of the traditional secret sort.
Apparatus Drawings Project. Report Number 6. Bragg Diffraction Apparatus
Authors: Marcley Robert G.
Published: August 2005

The apparatus described is a macroscopic crystal-lattice analog which may be used for a quantitative investigation of the Bragg law of diffraction. Three-cm microwaves are used rather than expensive and dangerous x-ray equipment. The data obtainable agree with the theory to within less than 10%.
Graphical Method for Comparing Galvanometer Sensitivities
Authors: Dewdney John W.
Published: August 2005

A method is described for making graphical comparisons of galvanometers of different resistances and periods. The effective sensitivities in a given circuit can also be easily compared.
Anniversaries in 1960 of Interest to Physicists
Authors: Barr E. Scott
Published: August 2005

During the year 1960 there will be major anniversaries of the birth or death of one woman and seven men who have figured importantly in the development of physics. Brief accounts of their lives and contributions are presented here.
Electron-Nucleus Hyperfine Interaction in Atoms
Authors: Ferrell Richard A.
Published: August 2005

It is pointed out that the so-called “hyperfine interaction” between the magnetic moment of a nucleus and the spins of the surrounding electrons is completely classical in origin. Quantum mechanics is irrelevant and not necessary to the understanding of this coupling. A simple derivation, based only on classical static magnetism, is given of Fermi's formula for the interaction energy.
Relativistic Reaction Systems and the Asymmetry of Time Scales
Authors: Kowalski K. L.
Published: August 2005

As a simple illustration of the asymmetry of time scales between inertial and noninertial reference frames, a specific accelerated trajectory of a reaction system is calculated. A time dilatation resulting from the asymmetry is found to exist and to arise from contributions of the accelerated and constant velocity portions of the trajectory.
Application of the Rayleigh-Schrödinger Perturbation Theory to the Delta Function Potential
Authors: Epstein Saul T.
Published: August 2005

E. P. Wigner has shown that although there are reasons why one might hope to succeed, one cannot in fact derive the binding energy of the hydrogen atom by second-order perturbation theory applied to a free particle in a box. To further clarify the reasons for this failure we here consider the one-dimensional attractive delta function potential.
Orbit to the Sun
Authors: Feenberg Eugene
Published: August 2005

The problem of dropping a projectile into the sun is considered from the point of view of minimizing the rocket capability required to convert from a nearly circular orbit (essentially the orbit of the earth) to a nearly radial obrit.
Hyperfine Interaction and the Knight Shift
Authors: Milford F. J.
Published: August 2005

The difference between the magnetic field at which a specific nuclear magnetic resonance occurs in a metal and the field at which the same resonance occurs in a nonmetallic compound is known as the Knight shift. The prediction of this shift is a straightforward and sensitive test of electronic wave functions in metals. An elementary derivation of the relationship between the Knight shift and the electronic wave functions is presented here. The current experimental and theoretical situation is briefly reviewed. Also included is a derivation of the S state magnetic hyperfine interaction Hamiltonian.
Phase Production and Measurement from 0 to 2π
Authors: Hart J. B. , Haas F. X. , Hofmeyer G. M.
Published: August 2005

The Helmholtz coil phase generator produces a continuous phase change from 0 to 2π in a signal of any frequency over a range limited by the coils used. A method and two unique rules are presented for determining the phase difference between two signals by means of an oscilloscope.
Wesleyan Conference on Demonstration Lectures
Authors: Eaton V. E. , Overbeck C. J. , Winch Ralph P.
Published: August 2005

A working conference on Demonstration Lectures, sponsored by the American Association of Physics Teachers and supported by the National Science Foundation, was held at Wesleyan University June 22–24, 1959. A list of participants appears in a report of the activities of this conference, written by B. F. Wissler, which was published in Physics Today for November, 1959. The complete Proceedings of the Conference have been printed and copies sent to chairmen of all college departments of physics. A still wider distribution is desirable and anyone wishing a copy may secure it by writing to Professor V. E. Eaton, Scott Laboratory, Middletown, Connecticut. The Conference committee on Summary and Recommendations, composed of V. E. Bollman, Occidental College, T. E. Manning, Oberlin College, and M. W. Zemansky, City College of New York, prepared a document which was mailed to all conference members. This article is their report as revised by the Editorial Committee in the light of comments and suggestions received from the conference members and condensed somewhat for publication in the Journal.
Single-Domain Particles : New Uses of Old Theorems
Authors: Brown William Fuller
Published: August 2005

This article describes some applications of potential theory and classical dynamics to one field of current research, the theory of magnetization processes in “hard” magnetic materials. Many such materials owe their magnetic properties to the fact that they are composed of fine ferromagnetic particles separated by less magnetic regions. In very fine particles, the exchange forces responsible for the spontaneous magnetization keep it uniform in direction within any one particle; the magnetization curve is then determined by rotations of the particle magnetizations. The rotations are controlled by the interplay of external magnetic energy and of internal energy, also largely magnetic. A first step in the theory is therefore the derivation of a general formula for the internal magnetic energy. Simplifications can then be made because of the uniformity of magnetization of each particle; in particular, it can be shown that a particle of arbitrary shape is equivalent to an ellipsoid. Calculation of static hysteresis loops requires consideration of stability conditions ; analysis of magnetization reversals and of the behavior in microwave fields involves the dynamics of gyroscopic systems.
Space Science Symposium
Authors: Singer S. F.
Published: August 2005

A symposium on space science was held in connection with the Annual Meeting of the American Association of Physics Teachers at New York, on January 29, 1960. Part of the remarks made by the chairman in introducing the participants, Hannes Alfvén, Herbert Friedman, and Ernst J. Öpik are reproduced in this introduction.
Cosmical Electrodynamics
Authors: Alfvén H.
Published: August 2005

A review is given of the development in the field of cosmical electrodynamics. It is mentioned that the great interest in thermonuclear research has produced a considerable progress in plasma physics. This is of astrophysical interest because it is now possible to check the theories of a plasma by experiment.

As an example, a recent experiment in a “homopolar” machine is discussed, and its importance to the theory of the origin of the solar system is emphasized. Conclusions about the origin of the solar system are drawn. In particular, the mechanism by which Saturn's ring has been produced is discussed. It is further pointed out that the moon probably was born as a planet later captured by the earth.
Surface Conditions on the Nearest Planets
Authors: Öpik E. J.
Published: August 2005

From a critical study of the available evidence, the author has prepared a review, chiefly of the more controversial problems relating to the surface structure of our nearest neighbors in space—the moon, Mars, and Venus. The task is similar to that of solving a crossword puzzle; the answer must agree with, or at least not contradict, all the existing data. In many respects the conclusions differ from those conventionally accepted and quoted in standard textbooks.
Electromagnetic Field of a Ferromagnetic Transformer
Authors: Bevc Vladislav
Published: August 2005

It is pointed out that oversimplified pictures of ferromagnetic transformers are not satisfactory from the viewpoint of Maxwell's equations. A simple one-dimensional solution for the electromagnetic field of an ideal ferromagnetic core consistent with the field equations is presented. The author suggests that only such fields be used in introductory courses.
Self-Energy and Stability of the Classical Electron
Authors: Rohrlich F.
Published: August 2005

The classical theory of the electron, as proposed by Abraham and Lorentz, is usually presented as beset by the difficulty that the momentum and velocity of its Coulomb field are incorrectly related kinematically: p = 43msv, where ms is the electromagnetic mass defined by the electromagnetic self-energy. This problem also persists in the relativistic theory. It is shown here that the difficulty is eliminated from the relativistic theory by treating the integrals over the electromagnetic field in a relativistic fashion, i.e., taking note of their dependence on the motion of the electron. The surface dependence of the integrals representing the electromagnetic momentum and energy of the particle is essential and occurs whenever the matter tensor is not introduced. The nonrelativistic limit of this formulation then also leads to the correct relationship p = msv. The corrected Abraham-Lorentz theory still contains the stability problem, but this problem is no longer related to the transformation properties. It can be removed by renormalization.
Rubber Model for Demonstrations and Laboratory Experiments
Authors: Cooper C. Burleigh
Published: August 2005

Use of the rubber membrane model as a teaching aid is discussed, both for elementary lecture demonstrations and for intermediate laboratory experiments. The model can be used to demonstrate directly and vividly by analogy two-dimensional potential fields, and trajectories of particles moving in these fields.
Lecture Demonstration of Optical Properties of Thin Films of Dielectrics and Metals
Authors: Anderson Scott
Published: August 2005

Apparatus for demonstrating some optical properties of thin films to large audiences is described. In addition to all the thin film interference effects, one can demonstrate (a) the phase shift experienced by the electric vector parallel to the plane of incidence when passing through the Brewsterian angle and (b) the phase shift at a metal-dielectric reflection. The apparatus depends for its success upon the high brilliance and saturation of the reflected interference colors from a composite metal-dielectric film. Its construction and properties are described.
Massless Particles
Authors: Good R. H.
Published: August 2005

This paper gives a discussion of massless particles, especially the two-component neutrino and the photon, in the light of modern ideas about space reflection. The emphasis is on the physical arguments and mathematical details are omitted.
Apparatus Drawings Project. Report Number 10. Air-Suspended Pucks for Momentum Experiments
Authors: Marcley Robert G.
Published: August 2005

This article is a description of air-suspended “pucks” for investigating the conservation of momentum between two colliding bodies. The film of air separating the pucks from their supporting surface provides an extremely small coefficient of friction. The experiment confirms that momentum is conserved with errors of less than 5%. The operating principles of these devices are easily applicable to other experiments requiring motion with negligible friction.
Fun in Space
Authors: DuBridge Lee A.
Published: August 2005

This after-dinner address attempts to point up in a simplified way the amusing, as well as some of the more serious, problems which arise in connection with flight into space. Figures are given to challenge some of the more fanciful claims about the value of the moon as a military base, noting the very large amounts of fuel required to take weapons up to the moon and then to return them to the earth. Some of the important research problems in physics and astronomy which can be carried out by the use of space vehicles are enumerated. As examples of a space science enterprise, the results of the magnetic field measurements by the Pioneer V package are summarized. The impractibility of using the moon and other planets as colonies for the earth's excess population is also demonstrated.
Problems in Electrostatics
Authors: Ainslie D. S.
Published: August 2005

Despite the fact that the study of electrostatics has been carried on for centuries, the problems as to why there is a transfer of electricity when dissimilar substances are rubbed together and how this transfer is facilitated by the rubbing process have not been answered satisfactorily. In this paper some experimental work in electrostatics which gives results in contradiction to the treatment of this topic, given in many elementary text books of physics, is described.
Speed of Light in Flowing Dispersive Liquids
Authors: Evett A. A. , Fried D. C.
Published: August 2005

A general, rigorous method is presented for obtaining the equation for the speed of light in a flowing liquid. The derivation leads to an expression correct to all orders in the ratio of the speed of the liquid to the speed of light in a vacuum. The procedure used is based on establishing a differential equation which relates the light frequency to the speed of the liquid. Comparison is made between this general approach and the more usual approach. Limitations of the usual approach are discussed.
Half-Life of a Water Column as a Laboratory Exercise in Exponential Decay
Authors: Smithson J. R. , Pinkston E. R.
Published: August 2005

A sophomore laboratory exercise is described which uses the flow of water from a vertical column through a long horizontal capillary tube as an example of exponential decay. The theory involved is within the comprehension of the students and excellent numerical results are obtained.
Equivalence Principle and Red-Shift Measurements
Authors: Schild Alfred
Published: August 2005

Two questions are discussed. The first asks whether experiments on accelerated systems (e.g., red-shifts produced in rotating disks) can serve to verify the general theory of relativity. The answer is “no.” The second asks to what extent the special theory of relativity and the principle of equivalence determine the well-known effects of the general theory of relativity. It is important to formulate this question very carefully because special relativity and the equivalence principle do not form a consistent theoretical system. If this is done, then the answer is that the equivalence principle leads to the same gravitational red-shift as general relativity but does not lead to specific values for the bending of light rays by a star or for the perihelion rotation of a planetary orbit.
Current Teaching Practices and Problems in the General Physics Laboratory
Authors: Kruglak Haym
Published: August 2005

Questionnaires on laboratory instruction were mailed to 1000 colleges in the U. S. A. Frequency distributions of the 500 returns are given for length of laboratory period, instructional methods, evaluation techniques, enrollments, and pressing teaching problems. Separate analyses are made for schools offering a physics major and those not offering it.
Definition of the Perfect Gas and Its Relation to the Second Law of Thermodynamics
Authors: Miller Donald G. , Dennis Warren
Published: August 2005

It is shown that a perfect gas must be defined by two independent statements. Besides PV = nRT, either (δE/δV)T = 0 or T = θ may be used. The proof shows that the second law will not yield (δE/δV)T = 0 from PV = nRT alone, and is given for both the Carnot cycle and Carathéodory formulations of the second law.
Temporal Reversal of Events in Restricted Relativity
Authors: Berenda Carlton W.
Published: August 2005

A simple “scissorlike” effect is mathematically examined as a measurable process that can produce over-light speeds of the intersectional point. This process is studied under the conditions of restricted relativity theory, and it is shown that when the intersectional point exceeds light speed c in one inertial system S, it can undergo “temporal reversal” relative to some other inertial system S′.
Experimental Self-Plotting of Trajectories
Authors: Sutton Richard M.
Published: August 2005

A ball is rolled repeatedly down an incline and launched in free flight in a vertical plane. It strikes a vertical drawing board set perpendicular to the plane of flight and records each point of striking by means of carbon paper on white. The board is moved farther and farther from point of launching of ball and at same time laterally by equal amounts. Thus a curve which lies in xy plane is made to record points in yz plane. In a short time, good curve of trajectory is obtained and then compared with theoretical curve fitted to origin, highest point, and range. Unexpectedly, the experimental is not sensitive to g, so would lead to exactly the same curve on moon or Mars!
Elementary Analysis of the Gyroscope
Authors: Barker Ernest F.
Published: August 2005

The simple gyroscope is an excellent subject for a lecture table demonstration to classes in elementary physics. The only observable force acting upon the precessing top is a downward pull due to gravity, yet, instead of falling, it moves with a continuous horizontal displacement. An adequate and convincing explanation of this curious behavior is essential, and it must be stated in language familiar to the student. One possible approach to the problem, using a very simple model, is given here. The internal reactions are described and their values are computed. Because of some difficulty in visualizing motion in three dimensions, it is recommended that a model be constructed. It may be very crude and yet quite adequate.
Experiments in X-Ray Physics Using a Commercial X-Ray Spectrometer
Authors: Muldawer Leonard
Published: August 2005

Commercial x-ray spectrometers are useful in chemical analysis; they operate on the principle of the spectrum analysis of the fluorescent radiation from the sample. Such instruments can be used in simple analysis experiments but can also be used for additional experiments in x-ray physics. The tungsten L spectrum and the general shape of the continuous spectrum can be observed by scattering from elements of low atomic number. Absorption edges can readily be shown and the quantum limit of the continuous spectrum can be seen to vary with tube voltage. Planck's constant can be determined. Monochromatic x-ray beams can be obtained and utilized in the measurement of absorption coefficients.
Physics Summer Institute in Pakistan
Authors: Rogers Eric M.
Published: August 2005

The writer went to Pakistan, at short notice, last summer to teach in a Summer Institute for college physics teachers there. This article gives an account of the Institute, its 40 “participants” and their needs, and answers one or two questions that a reader would ask.
On Nature Study in Physics Teaching
Authors: Seeger Raymond J.
Published: August 2005

This paper recommends direct observation and understanding of optical phenomena in nature as a means of stimulating interest of young students in physics. In particular, it urges the collection and utilization of actual photographs. Unsolved problems of meteorological optics are recommended for master's theses not only for their own intrinsic worth, but also as a means of encouraging the modernized field of atmospheric sciences.
Primary Aberrations of Mirrors
Authors: Filler A. S.
Published: August 2005

The first approximation to the wave aberrations of a mirror is found in a simple manner by comparing the figure of the mirror with the figure of the surface which would give perfect imaging for the same conjugate foci. In order to introduce the various primary aberrations, the following cases are considered: (a) object and image on the axis of the mirror, (b) object and image equidistant from the mirror vertex, and (c) object at infinity. Three examples are worked out, discussing (1) the effect of a change of focus on spherical aberration, (2) the Newtonian telescope, and (3) the Schmidt camera.
A Useful Thermodynamic Diagram
Authors: Schenck Hilbert
Published: August 2005

Using the equations for the efficiency of a heat engine and the coefficient of performance of a refrigerator, it is shown that a diagram constructed of straight lines can express the heat flows, efficiencies, COP's, and work terms of such devices. The diagram may also be used for Carnot-type machines when temperatures of the heat sources and sinks are given. A hypothetical system is shown in schematic and plotted on the diagram.
Magnetostatic Fields at an Iron-Air Boundary
Authors: Van Bladel J.
Published: August 2005

It is often stated that the magnetic field in the vicinity of a body of infinite permeability (hereafter called iron) is perpendicular to the boundary surface. This property is not always true. The present analysis presents a criterion which allows one to predict whether the perpendicularity condition is valid or not. The boundary-value problem for the magnetic field is then formulated for the iron and air regions.
Elementary Derivation of the Electron-Electron Interaction via the Phonon Field
Authors: Hill Robert Nyden
Published: August 2005

The electron-electron interaction via the phonon field is calculated from classical physics. A transition to quantum mechanics via the correspondence principle then yields the matrix element which is the starting point of the Bardeen-Cooper-Schrieffer theory of superconductivity.
A Simple Mechanical Analogy for Isothermal Compression of Liquids and Solids
Authors: Mills Blake D.
Published: August 2005

When a liquid or solid is compressed isothermally, the heat energy given off is greater than the work done in compressing the material, unless the pressure is very high. This some-what paradoxical behavior is shown to be characteristic of a simple and rather analogous mechanical system whose performance is readily calculated.
An Optical Analog to the Motion of Magnetically Trapped Particles
Authors: Stern D.
Published: August 2005

It is shown that the motion of a beam of light confined in a diamond-shaped mirror geometry has many properties in common with the motion of magnetically confined particles. The significance and reasons of this are discussed; the long term behavior of the beam's motion is also investigated, by means of a simplified model. In this model it is shown that the solution's behavior depends on a certain numerical initial condition and fluctuates according to the terms of its continued fraction development. If this is infinite, the fluctuations will go on indefinitely, on a small though not intrinsically limited scale; if on the other hand the numerical value is rational and its expansion finite, the fluctuations will exhibit a recurring pattern which may or may not be superimposed on a monotonous drift.
Early Work in Electron Diffraction
Authors: Thomson George
Published: August 2005

Both the work of de Broglie and a number of scattering experiments were forerunners of the two pieces of work that established the existence of electron refraction. The history of the experiments is discussed, as are some of the difficulties, both experimental and conceptual, which had to be overcome before de Broglie's hypothesis could be verified.
Early Work on the Positron and Muon
Authors: Anderson C. D.
Published: August 2005

Early work on the positron and muon is described in an informal way, with emphasis on those aspects of the work which normally would not find their way into the literature.
Cognitive Development in Children and Readiness for High School Physics
Authors: Stendler Celia B.
Published: August 2005

The student of superior intelligence is not always the superior performer in both the linguistic and the scientific fields. The able English major may have difficulty in learning physics, while his counterpart, the physics major, may find rhetoric his bête noire. This paper offers a possible explanation of how readiness for learning physics is developed. It explores the hypothesis that certain kinds of childhood experiences structure an individual's perceptions of the physical world; that these perceptions are stored as information in cell-assemblies in the cortex; and that this neural reservoir facilitates the learning of concepts in the physical sciences. The nature of experiences that might contribute to the building of such a neural reservoir is discussed.
Definitions of Resonance and Exact Conditions for Resonance in Some Electrical Circuits. I. Definitions of Resonance for Series and Parallel LCR Circuits
Authors: Burge Edward J.
Published: August 2005

Six definitions of resonance are distinguished and considered for the series LCR circuit. The corresponding exact conditions are derived for each of the four variables and their practical significance discussed. Some of the results for the parallel LCR circuit are briefly considered.
Note on Gauge Transformations in Quantum Mechanics
Authors: Barut A. O. , Leiser M.
Published: August 2005

Gauge transformations are treated from the point of view of unitary transformations in ordinary quantum mechanics. Gauge-independent form of the constants of the motion is discussed. It is shown that the orbital angular momentum in an arbitrary gauge is given by r×[(p−eA)+12e(B×r)].
Apparatus Drawings Project. Report Number 11. Classen's Method e/m of Electrons Apparatus
Authors: Marcley Robert G.
Published: August 2005

A simple apparatus for an undergraduate laboratory measurement of the ratio e/m of electrons by Classen's method is described. A flanged metal vacuum chamber contains the electrode system, a filament, two adjustable slits, and a collector. Helmholtz coils supplying the magnetic field are mounted externally. Accelerating potentials of 750 to 1500 v and fields of 60 to 70 gauss are required. The electrode system can be conveniently removed from the chamber for inspection and measurement. When properly adjusted, the apparatus will permit the determination of the ratio e/m to a precision of ±2%.
Screening Effect of a Circular Disk
Authors: Thomas T. S. E.
Published: August 2005

A theory of the effect of a circular metal disk in screening the electric field of a pole and the magnetic field of a radio-frequency dipole (eddy current screening) on the axis is developed in terms of spheroidal functions. The screening effectiveness is defined as the ratio of the screened to the unscreened field and curves are given showing its variation along the disk axis. In the electrical case the field is zero at a certain distance along the axis.
Comments on Buchdahl's Treatment of Thermodynamics
Authors: Turner Louis A.
Published: August 2005

It is shown that Buchdahl's treatment involves a tacit extension of Carathéodory's second axiom, that if such extension be made the zeroth law becomes a consequence of the other basic assumptions, and that Buchdahl's parameter s, the empirical entropy for a system, is the same as x0, the nondeformation coordinate of a simple system related to the system in question.
Wave Propagation in a Moving Plasma
Authors: Scarf F. L.
Published: August 2005

The electromagnetic properties of a moving plasma are examined in terms of the index of refraction and the Fresnel drag. Simple models are used to illustrate the basic mechanism of electromagnetic propagation and the dependence of the drag coefficient on the parameters of the plasma.
Research Programs in Non-Ph.D. Granting Institutions
Authors: McMillen J. Howard
Published: August 2005

Research in non-Ph.D. granting institutions has been growing. Up to now, the National Science Foundation has made grants to physicists in 60 different institutions of this type. An analysis of these grants shows that physicists in quite small colleges, even those with only two-man departments, engage in research. With research participation becoming more universal, some changes in the concept of the college teaching position can be anticipated. It is believed that because of this changing concept and increased research support for small colleges, more of each year's crop of Ph.D.'s will seek teaching positions in these institutions. Increased research activity in non-Ph.D. granting institutions is expected to help them continue their role as an important supplier of well-trained and well-motivated students to our graduate school system. The research conducted in the small undergraduate schools may not be as competitive as that in the large universities, but the research which survives will necessarily be of the challenging type. It is hoped that research programs in small colleges will not be forced in any way, and that research will not become falsely identified as a cure for bad teaching.
Zeroth Law of Thermodynamics
Authors: Turner Louis A.
Published: August 2005

The following is shown with respect to the zeroth law of thermodynamics. (1) Planck's argument that it follows from a general theorem concerning establishment of thermal equilibrium among numerous bodies does not appear to be conclusive. (2) The zeroth law is a consequence of the first and second laws in classical thermodynamics and need not, therefore, be considered as a separate assumption or law. (3) The zeroth law must be assumed as supplementary to the second axiom in Carathéodory's theory, as Carathéodory did, if one wishes to adhere to that axiom precisely as he gave it. If, however, the axiom be amplified slightly in a natural way, the zeroth law can be derived as a consequence.
Phase-Shift Method for One-Dimensional Scattering
Authors: Kahn A. H.
Published: August 2005

The phase-shift method is developed for the problem of the scattering of a one-dimensional wave by a symmetric potential. Reflection and transmission coefficients are expressed in terms of the phase shifts of odd and even solutions of the Schrödinger equation in the asymptotic range. Integral equations are established for the phase shifts and some approximate methods investigated.
Derivation of the Fermi-Thomas Equation
Authors: Broyles A. A.
Published: August 2005

A derivation of the Fermi-Thomas equation for a neutral atom is presented to show it as an approximation to the usual Hartree and WKB approximations.
Undergraduate College Physics Research and Its Sponsorship
Authors: Kruschwitz Walter H.
Published: August 2005

Results of a study of more than 100 physics departments in U. S. colleges that offer a major on the baccalaureate level only are reported. One hundred and eight institutions carrying on physics research were located, and a questionnaire was directed to the chairman of each department. Another questionnaire was sent to the chairmen of the physics departments of a selected group of colleges reporting no research being done. It was found that significant research is being done in undergraduate colleges and that it is often designed to allow some participation by the better students in the department. It was further found that more than one-third of the researching departments have part of the work sponsored by an agency outside the school.
Diffusion Cloud Chamber with a Vacuum Jacket
Authors: Silvidi Anthony A. , Marn Donald
Published: August 2005

A diffusion cloud chamber with a vacuum jacket is experimentally tested for its effectiveness in increasing the sensitive area of the chamber. Evidence is presented which indicates that such a jacket can increase the effective area for observing tracks.
Use of High-Frequency Sound Waves in the Investigation of Some Electronic Properties of Metals
Authors: Myers A.
Published: August 2005

Some basic ideas are presented from an historical aspect, having regard to the behavior of electrons in solids, particular reference being made to electrical conduction in both normal and superconducting metals. These ideas are used in the explanation of the mechanism causing electrons to attenuate high-frequency sound waves in metals, and the dependence of the attenuation on temperature and magnetic field is discussed. Tin and mercury are used as examples showing two extreme types of behavior of the temperature dependence in superconductors, while the magnetic field dependence is described using gold as an example, details being given of how the shape of the Fermi surface can be obtained from the magnetic measurements.
International Conference on Physics Education
Authors: Sears Francis W.
Published: August 2005

The papers and discussions at the First International Conference on Physics Education, held in Paris from July 28 to August 4, 1960 are summarized. The Conference, attended by 86 persons from 28 countries, showed that the same concerns about the improvement of physics teaching exist throughout the world, in spite of a variety of historical and practical conditions that result in great divergences in the possible solutions of the common problems. As the appended resolutions of the conference indicate, there are many common actions that can be taken within all nations to accomplish the desired ends.
Parity
Authors: McCauley Graham P.
Published: August 2005

The concept of parity conservation is the quantum mechanical expression of the intuitively reasonable hypothesis that the laws of physics do not distinguish between a system and its mirror image. This article attempts to provide a nonmathematical account of the importance of conservation laws in elementary-particle physics and the way in which this hypothesis was built into our thinking in this field. The steps by which it was first called into question in the case of certain weak interactions are outlined, and a brief account is given of the beautiful experiments which demonstrated that the concept was not universally valid.
Paramagnetism: A Key to the Knowledge of Chemical Bonding
Authors: McMillan Juan A.
Published: August 2005

The phenomenological classification of substances on the basis of their magnetic behavior is given. Together with the explanation of paramagnetism, cases are discussed in which this property changes with coordination. Simple qualitative experiments are described.
Undergraduate Curricula for Physics Majors in a Select Sample of Institutions
Authors: Clark Clifton Bob
Published: August 2005

The course requirements in physics and mathematics for undergraduate physics majors at 50 institutions in the United States have been tabulated. The information was obtained by an inspection of the official publications of the institutions. Other pieces of miscellaneous information concerning the curricula are reported.
Domino Rule. A Way of Handling Relative Velocities
Authors: Dewdney John W.
Published: August 2005

Relative velocities can be combined in a way similar to the positioning of dominoes in the parlor game. The advantage of this method over the more usual one involving addition or subtraction of vectors is that it is more intuitive. It is particularly useful in the transition between laboratory and center of mass coordinate systems.
Definitions of Resonance and Exact Conditions for Resonance in Some Electrical Circuits. II. Tuned Coupled Circuits
Authors: Burge Edward J.
Published: August 2005

The theory for simple tuned coupled circuits is given and exact conditions for some definitions of resonance are found and discussed. Approximations for high Q circuits are also compared.
Doppler Effect in Neutron Absorption Resonances
Authors: Solbrig A. W.
Published: August 2005

Although it was discussed almost 120 years ago by Doppler, the Doppler effect is of importance today in theoretical physics and reactor technology. The theory of Doppler broadening of spectral lines by thermal atomic motion is well known. This theory can be applied to nuclear neutron resonances because of similarity in shape of spectral and nuclear lines. Since such application is not completely satisfactory, different derivations have been worked out for the nuclear case. The more direct of these derivations is reviewed, and the technological importance of the nuclear Doppler effect is discussed.
Apparent Shape of Large Objects at Relativistic Speeds
Authors: Boas Mary L.
Published: August 2005

It has been recently recognized that there is a difference between the measured Lorentz contracted shape of an object moving at relativistic speed and the shape as seen by a single observer. The case of an object which subtends a small solid angle at the observer has been discussed by several authors. This paper discusses objects so large or so near that the subtended solid angle cannot be considered small, and gives simple proofs that spheres always present a circular outline and that straight lines may appear curved. These results are applied to revise Gamow's well-known picture of the bicyclist seen by Mr. Tompkins.
Characteristics Tracer
Authors: Guest P. G.
Published: August 2005

Details are given of a circuit which may be used in lecture demonstrations and undergraduate laboratory classes to display on an oscillograph the characteristic curves of both valves and transistors.
Correspondence Principle Approach to Radiation Theory
Authors: Low F. E.
Published: August 2005

The classical law for the spontaneous radiation by a charged particle is expressed in such a way that its interpretation in terms of probabilities for transitions between stationary states is straightforward.
Operational Formulation of the Second Law of Thermodynamics
Authors: Thomsen John S.
Published: August 2005

Various forms of the second law are discussed from the viewpoint of what is necessary to provide a direct experimental proof of the postulates. A new formulation is presented in the form of three axioms, not involving the usual notions of quasi-static processes and cyclic engines on the one hand or adiabatic inaccessibility on the other. Definitions of absolute temperature and entropy are given, and necessary theorems proved in order to derive the usual thermodynamic results. The method is shown to be substantially equivalent to the usual ones; the advantages of the various formulations are discussed. It is noted that the concept of absolute temperature may be derived from a weaker postulate than the second law.
Decade Scaler for College Laboratory Use
Authors: East Larry V. , Roys Paul A.
Published: August 2005

A relatively simple and inexpensive scaler is described which uses two decade counter stages followed by a mechanical register. This instrument is designed for use in radiation counting experiments utilizing Geiger-Müller detectors. The scaler has an input sensitivity of 0.3 v for negative pulses. The input resolving time is approximately 250 μsec, which is adequate for the use intended.
Student Experiment on the Attenuation of Gamma Radiation
Authors: Taylor H. W. , Whyte G. N.
Published: August 2005

An experiment employing only simple apparatus reveals aspects of the attenuation of gamma radiation in matter that are frequently ignored. The student is introduced to the exponential attenuation of gamma rays under narrow-beam conditions, the importance of scattered radiation in the more commonly encountered broad-beam conditions, and the concept of buildup factor.
Light-Optical Analogs of X-Ray Diffraction Patterns
Authors: Meyer-Arendt Jurgen R. , Wood John K.
Published: August 2005

Masks containing repeating arrays of holes were prepared to simulate the molecular structure of arbitrary crystals. These masks, after photographic reduction, were used for Fraunhofer-type light diffraction and the resulting diffraction patterns compared with x-ray diagrams. This procedure was evaluated from two points of view: (1) it facilitates the teaching of fundamental processes of x-ray diffraction, and (2) it shows that terms like “regularity” or “randomness” of the arrangement of crystallites apply to at least two different levels of organization: The structure of individual crystallites and the distribution and/or orientation of different crystallites relative to each other.
Jerrold Reinach Zacharias: Oersted Medalist for 1960
Authors: Sears Francis W.
Published: August 2005

Remarks made by the Chairman of the Committee on Awards for 1960 during the presentation ceremony of the Oersted Medal to Jerrold Reinach Zacharias in recognition of his notable contributions to the teaching of physics.
Low-Energy Predictions of Modified Yukawa Potentials between Two Nucleons
Authors: Lichtenberg D. B.
Published: August 2005

Predictions of the Yukawa potential are reviewed. It is pointed out that the potential leads to qualitative, but not quantitative, agreement with two-nucleon experiments at low energy. The agreement can be made quantitative by making modifications of the Yukawa potential at internucleon separations smaller than 12 the Compton wavelength of the π meson. This result is illustrated with specific examples of modified potentials. The significance of these potentials is discussed.
Length Contraction Paradox
Authors: Rindler W.
Published: August 2005

A certain man walks very fast—so fast that the relativistic length contraction makes him very thin. In the street he has to pass over a grid. A man standing at the grid fully expects the fast thin man to fall into the grid. Yet to the fast man the grid is much narrower even than to the stationary man, and he certainly does not expect to fall in. Which is correct? The answer hinges on the relativity of rigidity.
Busch Tube for Determining e/m for the Electron
Authors: Neher H. V.
Published: August 2005

A tube is described which is fabricated from parts readily available to most departments of physics. With the proper auxiliary equipment, it is possible to determine the ratio of charge to mass of the electron to 0.2–0.3% in a reasonable time. It is of additional interest that from the data giving the magnetic field of the solenoid, a value for the earth's magnetic field may be obtained.
Graphical Representation for Unit Systems
Authors: Condon E. U.
Published: August 2005

This paper presents some ideas concerning physical systems of units, and a graphical representation of them, which has been found useful in teaching the subject.
Apparatus Drawings Project. Report Number 19. Apparatus for Electron Paramagnetic Resonance at Low Fields
Authors: Marcley Robert G.
Published: August 2005

A simple apparatus for investigating electron paramagnetic resonance (EPR) in a magnetic field of 100 gauss is described. A one-tube oscillating detector with a shorted, quarter-wave coaxial line resonant circuit, operating at 315 Mc, is used. The 100-gauss field is obtained from small Helmholtz coils. The auxiliary electronic equipment required to operate this apparatus is conventional.
Apparatus Drawings Project. Report Number 20. Versatile Electric Stop Clock Control System
Authors: Marcley Robert G.
Published: August 2005

A flexible system for controlling a 10-in. diameter 0.01-sec electric stop clock by means of a photoconductive cell and/or electric contacts is described. A moving element of the lecture demonstration to be timed is utilized to operate the photocell and the nonperturbing electrical contacts in various combinations. Under optimum conditions, the absolute accuracy of the system is better than ±0.05 sec with a reproducibility of about ±0.01 sec. Manual control of the clock is retained. The components used are conventional and low in cost.
Concerning the Naming of the “Practical” Electrical Units
Authors: Barr E. Scott
Published: August 2005

One hundred years ago the first steps toward the establishment and naming of the units of the familiar “practical” electrical units system were taken. The present paper is concerned with tracing the devious development of the complete system, with special emphasis on the circumstances attendant to the assigning of the unit names.
Quantum Theory of Interference Effects in the Mixing of Light from Phase-Independent Sources
Authors: Fano U.
Published: August 2005

Correlations in space and time of the light intensity from extended sources, observed by Brown and Twiss and by Forrester, were analyzed by these authors primarily in terms of field oscillations. This paper discusses an atomic process which brings out the intensity correlations, namely, the photoionization of a pair of atoms following photon emission by another pair of independently excited atoms. The calculated probability of this process depends sinusoidally on the relative positions of the four atoms and also, when the source atoms emit different frequencies, on the time interval between the photoionizations, in agreement with the macroscopic treatment. The oscillations arise from an interference of probability amplitudes which is not affected by the random phases of the source atoms. The calculation follows a standard approach but involves some novel detail.