bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis and Synthesis of Optical Images
Authors: Rhodes J. Elmer
Published: August 2005

The formation of an optical image by a lens is often treated so that the image appears as the double Fourier transform of the object, limited by the aperture of the lens and other stops. This treatment is here presented including details that are usually omitted in articles where an application of the treatment is the primary purpose.

Separate developments are presented that are most adaptable, respectively, to the configuration usually used with a microscope objective with a short object distance and a large image distance, and to the configuration normally used with a telescope objective.
An Experiment on Cosmic Rays
Authors: Guest P. G. , Simmons Wendell M.
Published: August 2005

An experiment suitable for an undergraduate laboratory course is described. A two-counter cosmic-ray telescope is employed in conjunction with a Rossi-type coincidence circuit. Details of the circuits are given. The methods of calculating the intensities of the cosmic rays are discussed, and a typical set of experimental results is shown. These results are used to illustrate the statistics of the rate of arrival of cosmic-ray particles.
Trend Analysis of Physical Data
Authors: Hudson G. E.
Published: August 2005

The problem of reduction of data, i.e., the derivation of the value of certain physically meaningful parameters which enter into the analytic description of the trend of the data, is solved by a generalization of the usual methods of fitting empirical curves. In taking a rather general point of view toward this method of trend analysis, the problem of “closeness of fit” is formulated in a new way and investigated briefly. Some applications of the method presented herein are to the problems of the analysis of radioactive samples, of the responses of electrical networks or electromechanical systems, of instrument records and vibrations including drift of the baseline of recording instruments, of variable illumination from stars, and of statistical distributions, and to the problem of differentiation of empirical data.
The Heritage of a Physics Teacher
Authors: Sutton Richard M.
Published: August 2005

This article is in response to the presentation of the Oersted Medal of the American Association of Physics Teachers, January 23, 1953. The opportunities and intellectual rewards to physics teachers are stressed.
Electronics in a Sophomore Physics Course
Authors: Williams E. Allan
Published: August 2005

The introduction of electronics in a sophomore physics course is discussed with special emphasis being given to the content of the half-year course in electronics, electricity, and magnetism. Experiments and equipment are listed and several are presented in some detail.
The Physics of the Organ Flue Pipe
Authors: Mercer Derwent M. A.
Published: August 2005

This is a review article in which the physical principles underlying the function of the organ flue pipe are considered. Many of the points are not understood, and attention is called to them as possible lines of investigation. A survey is made of the various theories of the action of the airstream at the mouth of the pipe; details are given of the variations in construction and their effect on the tone. Finally attention is paid to the tones of organ pipes in combination, and the conditions for a satisfactory musical effect are outlined.
Coulomb Friction with Several Blocks
Authors: Thomsen John S.
Published: August 2005

This paper considers the problem of finding the initial accelerations of a number of blocks piled on top of each other with a given set of applied forces. Coulomb friction is assumed at all surfaces. The first section solves a numerical example of the two-block problem. Next, a general solution for the case of two blocks is obtained and presented graphically somewhat like a phase diagram. Finally, a method for solving the general case is given.
A New Analogy in Transient Heat Conduction
Authors: Collins R. E.
Published: August 2005

An equation of transient heat conduction is derived that involves the velocity of an isotherm and the rate of heat flow across the isotherm. It is shown that this equation is analogous to the equation of wave theory which relates the group velocity and phase velocity of the wave. It is shown that the equation derived for heat flow serves as a criterion for the propagation of a temperature distribution without change of form in the same way that the analogous equation of wave theory serves a similar purpose. It is also shown that under certain conditions the moving isotherms can be treated as moving heat sources.
Electrical Equipment for Physics Lecture Demonstrations
Authors: Wadey Walter G.
Published: August 2005

A revision and rebuilding of the general-physics lecture apparatus used at Yale for electronic and electrical demonstrations has resulted in a set of pieces of apparatus designed to minimize the time wasted by the lecturer in wiring and arranging equipment. At the same time the students have a clearer view of the essentials. Improvements and modifications may be made economically. Brief descriptions of the use of the apparatus are included.
The Reflection Method of Surface Tension Measurement
Authors: Kolossvary Bela G.
Published: August 2005

Attention is called to a method of measuring surface tension of liquids, originally due to Eötvös, and suitable for advanced laboratory practice. The method is recommended when freedom from contamination is otherwise difficult to achieve, and when measurements are desired over a considerable range of temperature.
The Theory of Mechanical Electrometers
Authors: Munick Raymond J.
Published: August 2005

The theory of a generalized mechanical electrometer is developed in terms of the direct capacitances and potential differences between each pair of conductors comprising the electrometer, regardless of which is the movable conductor. A criterion is established for stable static equilibrium of the movable conductor. A distinction is made between voltage and charge measurements. General expressions are obtained for voltage and charge sensitivities, period, and the magnitude of random fluctuations in position of the movable conductor.
Rejection of Outlying Observations
Authors: Proschan Frank
Published: August 2005

This paper makes available to the physicist two of the modern statistical tests for possible rejection of outlying observations. These two methods have been selected because they apply in a majority of the actually occurring situations and because they are so easy to use.
Scattering Theory—A Second Note
Authors: Park David
Published: August 2005

In this note, a continuation of an earlier paper, is given a general symbolic solution of equations of the type of the Schrödinger equation with sources. From this it is easy to see the connection which exists between the solutions of two important special problems: that in which the function vanishes initially and is therefore entirely determined by the source, and that in which the source vanishes and the function is entirely determined by its value at some initial instant.
An Experiment in Mechanical Resonance Vibrations
Authors: McDaniel Boyce D.
Published: August 2005

An apparatus suitable for an elementary laboratory experiment on mechanical, forced, damped oscillations is described. Sample results with this apparatus show four ways of measuring Q and three ways of measuring the resonance frequency of the system with good agreement among the results.
Reproductions of Prints, Drawings, and Paintings of Interest in the History of Physics. 54. The Invention of Spectacles
Authors: Watson E. C.
Published: August 2005

The invention of spectacles can be dated very approximately by their appearance in early paintings. The history of this invention is here briefly sketched and some of the early paintings in which spectacles appear are reproduced.
Physics for Engineers
Authors: Hrones John A.
Published: August 2005

The role that courses play in modern engineering curricula is discussed in the light of a very rapid development in the so-called engineering sciences. The importance of basic training in modern physics for the engineer is discussed. It is strongly recommended engineering students be taught physics by a physics department which is actively contributing to knowledge in the field of physics rather than to follow what appears to be a trend of having physics taught to engineering students by engineers.
Some Generalizations in Geometrical Optics Derived by a Convergence Method
Authors: Irons Eric J.
Published: August 2005

A simple but general treatment of reflection and refraction at spherical surfaces is based on properties of nodal points and the specification of wave fronts by their convergences. Rules for the location and description of images are justified and extended to the images formed by thin lenses, the positions of whose nodal points make apparent an analogy with single refracting surfaces. The formula for the change in convergence of a wave front proceeding in a homogeneous and isotropic medium is applied to describe the images of axial objects, to derive Newton's relation in generalized form, and to consider refraction by separated refracting surfaces of unspecified powers. Solutions to five numerical problems, obtained by methods advocated in the paper, are appended.
Parameters Characterizing the Strength of a Shockwave
Authors: Hollyer R. N. , Laporte Otto
Published: August 2005

Inspection of the equations of compressible hydrodynamics in one dimension shows that the steady state may possess a discontinuity in the flow variables u, p, ρ. From this there arises the possibility of constructing a dimensionless parameter characterizing shock strengths. Its relations with other shock parameters are discussed.
Making the Laboratory a More Effective Scientific Experience
Authors: Pippert Glen , Roller Duane
Published: August 2005

Suggestions are made for restoring to elementary laboratory work the sense of adventure and intellectual excitement which has to a considerable extent been displaced by the notion that “efficient” and assembly-line speed of instruction is desirable.
Demonstration of Parabolic Velocity Distribution in Laminar Flow
Authors: Kolin Alexander
Published: August 2005

This paper describes a method for rendering visible the parabolic velocity distribution in laminar flow through a conduit. An opaque cloud having the shape of a thin line disposed along a pipe diameter is created by electrochemical means. This line is distorted into a parabola by the motion of the fluid.
Steady-State Shape of a Wire Cutting a Uniform Medium
Authors: Reid Walter P.
Published: August 2005

Equations are derived for the steady-state shape of a wire cutting a uniform medium, and some wire shapes are shown. The principal assumption is that any element of length of the wire moves into the medium at a rate proportional to the kth power of the normal force per unit length that the wire exerts on the medium.
Some Current Misinterpretations of N. L. Sadi Carnot's Memoir and Cycle
Authors: La Mer Victor K.
Published: August 2005

The indiscriminate translation of the words “feu,” “chaleur,” and “calorique,” uniformly as heat (or wärme) in the accepted translations of Carnot's memoir, without recognizing differences in meaning which Carnot consistently implied, has led to erroneous misinterpretations of his thesis, which are prevalent in present day texts.

Carnot had at least an intuitive conception of the modern interpretation of entropy in his consistent use of “chute de calorique” as analogous to “chute d'eau.” He never speaks of “chute de chaleur.”

One needs only to identify “calorique” as entropy and “chaleur” as heat to achieve simplicity and lucidity in understanding his memoir and at the same time imparting accordance with modern theory for pertinent passages that have been misconstrued.
Reproductions of Prints, Drawings, and Paintings of Interest in the History of Physics. 57. A Contemporary Portrait of Joseph Black
Authors: Watson E. C.
Published: August 2005

A photograph of a very fine contemporary portrait of Joseph Black sculptured in wax by the famous modeler, James Tassie, is here reproduced.
Films Selected for College Physics Courses
Authors: Weber Robert L.
Published: August 2005

Some 190 instructional films in physics are classified and listed as being well suited for college courses in physics, both at the introductory and advanced levels. Sources for purchase or loan of the films are included.
The Ionization in Air Maintained by a Uniform Plane Circular Distribution of α Radioactivity
Authors: Nicholls R. W.
Published: August 2005

The rate of ionization maintained in air in the region of a uniform plane circular distribution of α radioactivity has been computed numerically and is shown graphically. Such information is of interest as a lower limit upon the excitation rate maintained by the same source and is of use in the interpretation of spectroscopic observations in the excitation of radiation caused by the passage of positive ions (α particles in this case) through gases.
Some Characteristics of Military Research and Development
Authors: Wooldridge Dean E.
Published: August 2005

Military research and development possesses features of interest to physicists other than the employment opportunities provided by projects in this field. Military systems development work, in particular, affords technical problems of unusual variety, the solution of which frequently involves a degree of scientific teamwork not commonly encountered in other forms of industrial research and development.
Laboratory Teaching in General Education Courses
Authors: Henshaw Clement L.
Published: August 2005

The extent to which laboratory activities are used in general education science courses, and the nature of these activities, have been investigated in the course of visits to 16 institutions and by reference to catalogs of 13 additional liberal arts colleges. Laboratory was found to be fairly regularly used in about two-thirds of the physical science courses, and in a still larger fraction of the biological science courses. Probably less than ten percent of the students at these institutions earn the B.A. degree without a substantial laboratory experience of some kind. Significant attitudes, techniques and experiments in practice at a number of institutions are reported, and an appeal is made for many more to be published. As a result of the study, a set of ideals for “discovery-type” laboratory activities for general education courses is suggested.
Physics in Physiology
Authors: McLain Paul L.
Published: August 2005

The importance of physics to the physician is discussed. It is pointed out that the routine process of physical examination of a patient is, in essence, based on physical principles. A few applications of physics made during every medical student's education are interpreted from the point of view of man as a machine.
Physics of the Glassy State. II. The Transformation Range
Authors: Condon E. U.
Published: August 2005

The concept of fictive temperature as a means of describing nonequilibrium states of glass is described. Activation energies and the modern views of chemical rate processes are discussed in relation to the kinetics of the approach of these nonequilibrium states to equilibrium.
Rectangular Plate Pendulum
Authors: Freeman Ira M.
Published: August 2005

A uniform rectangular plate is arranged so that it oscillates in its own plane around either one of two axes, one at the center of each edge. The analysis shows that there is a particular ratio of the lengths of the two sides (in addition to unity) for which the two periods are equal, and still another ratio giving the minimum period. These computations check satisfactorily by experiment.
Premedical Courses in Physics—Advantages and Trends
Authors: Harrington E. L.
Published: August 2005

After a brief account of the development of special courses in physics for premedical and predental and for other nonengineering groups of students, and of the growing need for such courses, suggestions are made as to the types of students to be admitted, suitable textbooks, and sources of illustrative material. The relatively minor changes needed in the laboratory work are pointed out. Evidence that medical schools strongly endorse such courses is included.
Reproductions of Prints, Drawings, and Paintings of Interest in the History of Physics. 60. Heron's “Ball on a Jet” Experiment
Authors: Watson E. C.
Published: August 2005

An experimental arrangement for balancing a ball upon a jet of steam is described in the treatise on Pneumatics written by Heron of Alexandria probably in the first century A.D. It is here reproduced.
Employment of Women in Physics
Authors: Schwarz Guenter , Dilmore Betty Lou
Published: August 2005

A survey of 35 companies employing physicists shows that the majority is willing to employ women on equal terms with men. The major objection voiced is that their professional career is, in general, for a much shorter period than that of men in equivalent positions.
Oscilloscope Pictures of Intermodulation Distortion
Authors: Hitchcock Richard C.
Published: August 2005

One low- and one high-frequency sinusoidal signal are simultaneously applied to the input of an audio-amplifier. When the high-frequency component in the output is isolated and shown on an oscilloscope, it is usually seen to be modulated by the low-frequency component. This is intermodulation distortion, IMD.

As the input voltage is increased, at first the IMD increases at a faster rate, then tapers off. A multiline graph, in addition to the oscilloscope picture, is needed for a reliable indication when the IMD is greater than five percent.
Storm Location at Sea—An Illustration of Group Velocity
Authors: Mendoza Eric
Published: August 2005

When the waves from a storm at sea travel outwards, the long waves arrive first at any distant fixed point and are succeeded by shorter and shorter ones. Observation of the wavelength of the arriving train as a function of time determines the distance away of the storm center. A description of the phenomenon involves an account of the progress of an arbitrary disturbance in a dispersive medium, and it is suggested that this might prove an interesting illustration for teaching purposes of the concept of group velocity.
Physics of the Glassy State. III. Strength of Glass
Authors: Condon E. U.
Published: August 2005

The main empirical facts about the strength of glass are reviewed, including statistical theories effects of adsorbed moisture and of acid treatments.
Reproductions of Prints, Drawings, and Paintings of Interest in the History of Physics. 61. Caricatures of Sir Isaac Newton by Two Famous Artists
Authors: Watson E. C.
Published: August 2005

Caricatures of famous scientists, particularly when done by competent artists, often have historical as well as entertainment value. Two amusing caricatures of Isaac Newton, one by John Leech, the other by George Cruikshank, are here reproduced primarily for the reader's entertainment.
The Effective Mass of Electrons in Crystals
Authors: Kittel C.
Published: August 2005

The transfer of momentum between a conduction electron and a crystal lattice is examined in detail. By physical considerations we are led to the expression (mm*)ij = δij+ ∑ GGiδδkj|aG(k)|2 for the reciprocal effective mass tensor, where G is 2π times a reciprocal lattice vector and aG(k) is a coefficient in the momentum representation of the Bloch eigenfunction: ψk =  ∑ GaG(k) exp[i(G+k)·r]. This expression for the effective mass tensor is shown to be completely equivalent to the usual definition.
A Note on the Study of Uniformly Accelerated Motion
Authors: Chen Henry S. C.
Published: August 2005

A method to analyze the experimental data is suggested, in which no assumption is made beforehand that the motion is uniformly accelerated. Instantaneous velocities are obtained from the limits approached by the average velocities, and the linearity of velocity vs time curve proves the constancy of the acceleration.
Displacement Current, A Useless Concept
Authors: Warburton F. W.
Published: August 2005

The Maxwell relation, curlB = (μk/c)δE/δt+4πμj, is obtained directly by differentiation without mention of displacement current. It is also deduced as a consequence of propagation with speed c, and the form of the expressions chosen for the fields E and H. These methods of examining retarded action of charge on charge have the advantage over emphasis on continuous fields that weaknesses of classical theory become evident, and closer correlation with symmetric propagation theories becomes possible.
On the Theory of the Van de Graaff Electrostatic Generator
Authors: Simon A. W.
Published: August 2005

The detailed quantitative theory of a two-carrier, constant potential, electrostatic generator is given. It is shown that if the inductor of such a machine is held at constant potential, the collector voltage also approaches a constant value, which is proportional to the potential of the inductor, the factor of proportionality depending only on the geometry of the machine. It is shown that a Van de Graaff machine can be considered as a generator of the same type except that the two separate carriers are replaced by a single continuous belt. Some erroneous conclusions commonly made with respect to the action of the Van de Graaff machine are discussed. It is pointed out that a possible advance in the application of belt-type generators is operation in series to attain higher voltages.
Elementary Derivation of Equations for Wave Speeds
Authors: O'Leary Austin J.
Published: August 2005

The equations for the speed of waves in the following cases are derived in an elementary way: transverse waves along a stretched wire and through an elastic solid; longitudinal waves through a fluid in a uniform tube, through a uniform rod, and along a stretched spring; long gravity waves through a shallow canal. Several errors in previously published derivations are pointed out.
Polarization and the Stokes Parameters
Authors: McMaster William H.
Published: August 2005

The Stokes parameters have been found to offer a very convenient method for the description of polarization of both electromagnetic radiation and elementary particles. Their development is presented along with some applications to physical problems.
Metaphysics of a Physics Teacher
Authors: Wall C. N.
Published: August 2005

Remarks by Professor C. N. Wall on the occasion of his receiving the Oersted Medal for notable contributions to the teaching of physics at the twenty-third annual meeting, New York, January 29, 1954.
Reproductions of Prints, Drawings, and Paintings of Interest in the History of Physics. 62. The Invention of the Siphon
Authors: Watson E. C.
Published: August 2005

Egyptian pictorial records dating from before 1100 B.C. exist which show siphons and drinking-tubes in use. Two of these are here reproduced, together with the explanation of the operation of siphons given by Heron of Alexandria in the first century A.D.
Responsibility of the Physics Teacher in Engineering Education
Authors: Frank N. H.
Published: August 2005

A panel discussion under the above title was presented at the twenty-third annual meeting of the Association in New York, January 28, 1954, under the chairmanship of Joseph H. Keenan, who is also chairman of the Committee on Engineering Education. Speakers at the session were: N. H. Frank, Massachusetts Institute of Technology; L. E. Grinter, University of Florida, President of the American Society for Engineering Education; Lloyd P. Smith, Cornell University; and Homer L. Dodge, Norwich University. Their addresses, revised in some cases, are published hereafter for the benefit of members unable to attend the session, who are concerned about this problem of great significance both to physics teachers and to engineering educators.
Theorems on Centers of Gravity
Authors: Gale Grant O.
Published: August 2005

Several useful relationships regarding centers of gravity of plane figures are presented. The most useful are the fourth theorem, which shows a regularity existing among the degree of the equation, the area, and the centroidal distance, and the last theorem, which shows that the X-centroidal distances of the two parts of a rectangular lamina are in the ratio of 2 to 1.
Reproductions of Prints, Drawings, and Paintings of Interest in the History of Physics. 63. Conservation of Momentum in Ancient Greece
Authors: Watson E. C.
Published: August 2005

Although it was not until the seventeenth century A. D. that the principle of the conservation of momentum was formally enunciated by Newton, interesting applications of it were made as early as the sixth century B. C. Two such early applications are here illustrated and described.
Studies of Intermediate and Heavy Nuclei with Neutrons
Authors: Barschall H. H.
Published: August 2005

Experimental results on the interaction of neutrons with intermediate and heavy nuclei are summarized. Until recently the interaction of nucleons with nuclei has usually been described in terms of the compound nucleus theory. The data presented, however, can not be accounted for by the compound nucleus theory. It appears to be necessary to assume instead that a neutron can traverse a nucleus rather easily with only a small chance of being absorbed into a compound system. Feshbach, Porter, and Weisskopf have proposed an optical potential consisting of a complex square well to account for the experimental data. While this model gives better agreement with the experiments than the compound nucleus theory, it leads to some inconsistencies. In order to be consistent with the results of measurements on neutrons and with the shell model the potential needs to be modified to be deeper than that used by Feshbach et al., and it should contain a spin-orbit coupling term.
Reproductions of Prints, Drawings, and Paintings of Interest in the History of Physics. 64. The First Appearance of Concave Eyeglasses
Authors: Watson E. C.
Published: August 2005

Although spectacles were invented near the end of the thirteenth century, there is little evidence that concave lenses were generally used to aid the nearsighted before the middle of the sixteenth century. However, Lucas Cranach's “Adulteress before Christ,” painted about 1500, shows a pair of spectacles with lenses which apparently were concave.
Distribution Functions and Isotropic Gases
Authors: Benson G. C. , Flood E. A.
Published: August 2005

The concept of the isotropy of a perfect gas is examined from the point of view of the distribution functions for molecular speed and velocity components. It is shown that to be compatible with the assumption of isotropy, any velocity component distribution function must satisfy several general relations. These relations are often presented as a consequence of the Maxwellian distribution but are shown to be independent of the form of the distribution of molecular speeds.
The Fellowship Program of the National Science Foundation
Authors: Dees Bowen C.
Published: August 2005

The purposes and some of the results of the fellowship program of the National Science Foundation are described by the program director.
Topology of Steady Current Magnetic Fields
Authors: McDonald Keith Leon
Published: August 2005

Textbooks often hold erroneously that the condition ∇·H = 0 implies that lines and tubes of force are closed. Examples are given in which the lines of force are not only unclosed, but also, the density of lines may be made infinite in a region where the field intensity is finite. If the steady electric current density is everywhere finite, the magnetic field has singularities only at discrete points, lines, or surfaces, where H = 0. In general, an infinity of lines of force may terminate on these points. Lines of force may have finite length, going from one singularity to another. A systematic analysis is made of the allowed distribution of singular points, and the linear fields in the neighborhoods of these points are classified. Certain types of singularities may appear in regions of finite current density, but cannot occur in regions free of current. Lines of force may form limit cycles.
Note on Perturbation Theory
Authors: Epstein Saul T.
Published: August 2005

Perturbation theory is derived in such a way that the wave function renormalization terms appear automatically. The derivation is based on the Feynman theorem for the rate of change of an eigenvalue with respect to a parameter, and a corresponding theorem for the rate of change of an eigenfunction.
Teaching Transistor Physics
Authors: Leivo William J.
Published: August 2005

In June, 1952, the Bell Telephone Laboratories, Murray Hill, New Jersey, sponsored a summer school for teachers of transistor physics. During the sessions the basic ideas of semiconductors were studied, and a series of fundamental experiments was performed. At Carnegie Institute of Technology the student interest in these experiments has been very high and the results were so gratifying that we felt it would be most welcome if the Bell Telephone Laboratories made these experiments available to colleges which were not represented at the transistor sessions. This they have kindly agreed to do. A brief discussion of the experiments developed by the Bell Telephone Laboratories is given in this article.
Biophysics in the Premedical Curriculum
Authors: Riess Karlem
Published: August 2005

A brief survey of the need for additional physics in present-day premedical curricula is given. Since the routine courses in physics and biology usually follow the standard classical approach it is suggested that appropriate border field illustrations of the basic principles of physics in biology and medicine be introduced as a separate undergraduate course in biophysics. An outline of a successful course for junior and senior premedical students is presented.
A Stabilized Power Supply for the Elementary Electronics Laboratory
Authors: Williamson Charles
Published: August 2005

This small and compact power supply is set up to furnish the voltages and currents usually required in elementary experiments with electronic circuits. It is stabilized with the aid of two voltage regulator tubes. Input fuses and an output indicator lamp are installed. Wire-wound three-terminal rheostats of ample overload capacity are used to adjust output voltages. The direct-current output from any one tap is limited to about 20 milliamperes, but two or more separate currents of this magnitude may be taken simultaneously from different taps. All parts of the circuit are insulated from the chassis and cabinet; therefore any one point in the circuit may safely be grounded. Also included is an unstabilized filament supply.
Composite Piezoelectric Resonator
Authors: Cady Walter G.
Published: August 2005

Various types of composite resonators and their uses are summarized. The general equations are given for the transducer for plane ultrasonic waves, consisting of a crystal assembly with back and front plates. Applications are made to several simple cases, and expressions are tabulated for the amplitude of vibration for various combinations of half- and quarter-wave components. Consideration is given to the effect of the acoustic load on the frequency for maximal amplitude. Theoretical formulas are compared with experimental results for rods of aluminum and fused quartz excited in vibration by piezoelectric crystals.
Advanced Undergraduate Experiments in Physics
Authors: Brown Thomas B.
Published: August 2005

A progress report of the work of the Taylor Memorial Manual Committee of the AAPT is presented by the Chairman.
Simplification of a Proof of Carathéodory's Theorem
Authors: Buchdahl H. A.
Published: August 2005

A previous proof of Carathéodory's theorem is simplified by considering the passage along arbitrary solution curves of a total linear differential equation instead of the passage along definitely prescribed solution curves.
MKS Units in Electricity and Magnetism
Authors: Merritt Thomas P.
Published: August 2005

The need for a strict definition of fundamental units of measurement is pointed out. The fact that the ampere is defined by an equation in terms of other previously defined quantities requires that it be defined in terms of those quantities. This would give the ampere the unit of newton12, and would make the permeability unitless. The instructional value of this analysis is pointed out by showing the ease with which the undergraduate student may balance, dimensionally, equations involving electrical quantities.
Some Current Misinterpretations of N. L. Sadi Carnot's Memoir and Cycle. II
Authors: Mer Victor K. La
Published: August 2005

New evidence is presented from Carnot's memoir to show that he defined “calorique” (entropy) differently from “chaleur” (heat in the general sense). Calorique is the thermal quantity conserved in reversible cycles; the unit of calorique melts one kilogram of ice; the unit of chaleur raises the temperature of a kilogram of water one degree centigrade, an irreversible process.

Although Carnot used these terms interchangeably for constant temperature (reversible) processes, which is justified when the temperature scale is not specified, he distinguished between chaleur and calorique for work producing reversible processes operating over a finite temperature range, where the distinction becomes necessary.

Carnot's major conclusions on heat engines are deduced on general principles and are not dependent upon any caloric or mechanical theory of heat. Carnot believed in the mechanical theory of heat, but in the last parts of the memoir he introduced, as axioms, conservation theorems for calorique (correctly) and for chaleur (incorrectly) which have tenets in common with the now-discredited caloric theory. These theorems do not require that these quantities be substantive in nature.
A Model Showing Current Conduction in an n-Type Semiconductor
Authors: Rood Paul
Published: August 2005

The two distinct ways in which a current may be carried by an n-type semiconductor—by electrons and by “holes”—are illustrated by means of a model. It is the control of one type of current by the other which makes possible various forms of transistor action.
A Beta-Ray Spectrograph Experiment
Authors: Fowler C. M. , Dragsdorf R. Dean
Published: August 2005

An experiment at the undergraduate level to study various nuclear radiations by utilizing a beta-ray spectrograph is outlined. A relativistic treatment of the data obtained allows a straightforward interpretation, while a classical analysis fails. This proves to be a simple way to demonstrate the use of relativistic energy and momentum equations to the student.
The Hydrostatic Paradox: Phases I and II
Authors: Dodd Laurence E.
Published: August 2005

The term hydrostatic paradox is likely to suggest the classical experiment of “Pascal's vases.” In a demonstration with this apparatus the observer's attention is centered upon the vertical direction, specifically the common vertical depth of liquid in the different branches of the container, with their varying cross sections and volumes. But the term properly has a broader connotation. Fully as striking is the hydrostatic paradox seen in the fact that the horizontal thrust of the water against a dam is independent of the volume of water impounded, and dependent only on its depth at the barrier. To differentiate sharply between these two aspects of hydrostatic paradox, the terms “Phase I” and “Phase II” are proffered. The two aspects are discussed in the paper. A simple projection cell is described for demonstrating Phase II in a direct manner, corresponding to the demonstration of Phase I with Pascal's vases. Considered also is the involvement of hydrostatic paradox with Archimedes' principle, and in capillary tubes.
Reproduction of Prints, Drawings, and Paintings of Interest in the History of Physics. 67. Other Fifteenth-Century Paintings in Which Spectacles Appear
Authors: Watson E. C.
Published: August 2005

Two additional fifteenth-century paintings of note in which spectacles are clearly portrayed are here reproduced and commented upon.
Flow and Convection Demonstration
Authors: Muller John Hubert
Published: August 2005

Large convection currents in some laboratory liquids are made easily visible by a fine suspension of aluminum flakes. Ample contrast is available for photography. Acetone is the most practical of those liquids tested. A heat source such as a finger and a heat sink due to evaporation of the liquid are sufficient to set a small beakerful into motion at speeds around one cm/sec. A two-dimensional flow table was constructed without pumps or plumbing. Such flow is continous and long-lasting. Only a small occasional replenishment of liquid, to make up for that lost by evaporation, is necessary.
One Aspect of Ohm's Law and Its Application to Circuit Study
Authors: Wallace Thomas H.
Published: August 2005

Attention is drawn to the application of Ohm's law to a portion of a direct-current series circuit containing both sources of emf and resistance elements. Circuits are presented wherein for a portion of the series circuit the difference in potential, V, and the current, I, satisfy separately the three following situations:—(1) V ≠ 0 and I = 0, (2) V = 0 and I = 0, (3) V = 0 and I ≠ 0.
Physics Lectures for Young People: Variations on a Theme by Faraday
Authors: Kelly W. C.
Published: August 2005

Demonstration lectures for high school pupils are effective in stimulating some to choose careers in physics and in giving many an increased appreciation of physics. This institution has sponsored a diversified program of physics lectures for large groups during the past five years. The results of this experience are described, and an evaluation of the program is presented.
Maximum Range of a Projectile in a Vacuum
Authors: Baker Clyde D. , Hart Judson J.
Published: August 2005

A formula for the angle which produces maximum range of a projectile in vacuum on a spherical, nonrotating earth is derived. Initial velocities and altitudes are assumed to be such that the projectile returns to the earth.
Academic Origins of Fellows of the American Physical Society
Authors: Hirsh F. R.
Published: August 2005

Academic origins of 1137 Fellows of the American Physical Society are studied and academic eminence is investigated.
Laboratory Achievement in Relation to the Number of Partners
Authors: Kruglak Haym , Goodwin Ralph A.
Published: August 2005

This paper describes an experiment which investigated laboratory achievement of Naval Academy midshipmen, working singly, in pairs, and in quartets. No significant differences in the means of the three groups were found on two laboratory tests. The quartet groups had significantly higher laboratory grades, based on reports written in the laboratory.
Statistico-Mechanical Theory of Deformation, Involving the Activated State
Authors: Lyons W. James
Published: August 2005

The theory of deformation in matter which has been constructed by Eyring, his co-workers, and former pupils as an adaptation of the chemical reaction-rate theory is, in the present article, reviewed on the basis of concepts falling in the domain of physics in the more restricted sense. The theory of the physical phenomena of deformation, elasticity and flow is developed directly from statistico-mechanical fundamentals, without the introduction of concepts of chemical kinetics. Application of the basic theory to deformation in crystalline solids, as well as polymeric materials, is treated in some detail, and finally the work of numerous investigators who have contributed to the theory is briefly recounted.
Quantitative Kinetic Theory Model
Authors: Benade A. H.
Published: August 2005

A number of small glass balls are electrically agitated in a Lucite cylinder containing a piston. Consequences of the ideal gas law are demonstrated, as is the law of variation of molecular concentration with height in an isothermal gas. Effects equivalent to thermionic emission or evaporation are shown, and the temperature dependence of the Brownian motion is verified experimentally.
Student Experiment on the Observation of a Cosmic-Ray Shower Transition Curve
Authors: Bartlett A. A.
Published: August 2005

An experiment is described in which students observe the well-known Rossi shower (or transition) curve. A simple theory is presented which is appropriate only to the knowledge gained from this single experiment. Students are able to interpret their experimental results in terms of this theory in a way that indicates the existence in the cosmic radiation of a hard and a soft component, and they are able to calculate values of several of the parameters which are introduced in the theory.
Note on the Comparison of Weston Cells
Authors: Worrell Francis T.
Published: August 2005

The method of comparing two cells by measuring the difference voltage of two cells in opposition is reviewed, with particular emphasis on its use in the instructional laboratory to demonstrate a technique of measurement. Problems arising in the use of this method, and its precision, are discussed.
Verification of Bragg's Law by the Use of Microwaves
Authors: Allen Roland A.
Published: August 2005

An experiment which demonstrates the Bragg method of x-ray spectrometry using 12-cm microwaves and a model crystal.
Some Suggestions for a Laboratory Practical in Electrical Measurements
Authors: Worrell Francis T.
Published: August 2005

A laboratory test is described which consists of an experimental problem. The course in electrical measurements in which this test is given emphasizes the general rather than the specific aspects of electrical measuring techniques; the test is designed to test the student's ability to meet a new experimental problem. Examples of some of the questions are given.
Presentation of the Oersted Award to Professor Vernet Eller Eaton
Authors: Klopsteg Paul E.
Published: August 2005

Remarks made on the occasion of the presentation of the Oersted Award to Professor Vernet E. Eaton.
On the Use of Grand Ensembles in Statistical Mechanics: A New Derivation of Saha's Formula
Authors: ter Haar D.
Published: August 2005

The advantages of using the method of the grand ensembles are discussed. As a special case Saha's formula for dissociation equilibria is derived using the method of the quantum-mechanical canonical grand ensembles. One of the advantages in this case is that it is possible at each step to take stock of the simplifying assumptions made during the derivation.
Role of Science in the Secondary School
Authors: Watson Fletcher G.
Published: August 2005

The differences between secondary schools and colleges are clarified. In schools the population of students range widely in abilities and interests. Because most high schools are small, teachers usually are responsible for three subjects—not all necessarily being in science. Teachers are viewed as stimulators and guides who develop enthusiasm for science through their instruction. Ways for collegiate instructors to assist and encourage high school teachers are sketched.
History and the Physicist
Authors: Kondo Herbert
Published: August 2005

There are five major reasons why the physicist should know and be interested in the history of physics: (1) the great physicists have left us in their writings a treasure containing valuable suggestions for future laws, principles, theories, and experiments; (2) it is necessary to know why theories are now, or have been, discarded and are in disrepute: frequently a hostile scientific atmosphere may have been the sole reason why an important theory was rejected in the past; (3) in physics, many historical theories have been revived and applied anew; (4) the original historical arguments given in support of a theory may be invalid; and (5) physicists can often obtain inspiration by studying the lives of great men.
Two Notes on the Physics of Walking
Authors: Sutton Richard M.
Published: August 2005

(1) Walking is related closely to a succession of motions approximating half-cycles of a simple harmonic motion. The large velocities and accelerations involved are computed. (2) The support of the body on the ball of one foot, as in walking, introduces large forces in bones and muscles which are analyzed. (3) A simple experiment related to standing on tiptoe is described.
Two-Fluid Barometer as a Student Project
Authors: Williamson Charles
Published: August 2005

The two-fluid barometer, invented by Descartes and constructed by Huygens, has been undeservedly neglected. It combines almost the compactness of the mercury barometer with almost the sensitiveness of the water barometer. Two patterns, the straight-tube and the J-tube, are described in this paper. Reasons for preferring the J-tube pattern are given. Neither pattern requires more than routine glassblowing skill. The two fluids may be mercury and butyl phthalate. Instructions for filling the barometer are included. The finished instrument is a good teaching piece and is interesting to the general public, but it is not recommended as a replacement for the standard mercury barometer when highly accurate readings are needed.
An Experiment in Electrical Measurements Which Teaches Several Valuable Lessons
Authors: Worrell Francis T.
Published: August 2005

An experiment is described wherein the resistance of a galvanometer is measured by several different methods. A number of difficulties arise in this experiment, which are analyzed. It is shown how these difficulties can be used to give the student important lessons about good experimentation.
Blackbody Radiation and Lambert's Law
Authors: Melvin M. A.
Published: August 2005

It is demonstrated by a general argument, using the property of isotropic intensity characteristic of cavity radiation, that the emissive radiance from the surface of a blackbody is Lambertian.
Lorentz Transformation and the Thomas Precession
Authors: Furry W. H.
Published: August 2005

The various kinematic effects of special relativity are here treated by considering iterations of the infinitesimal Lorentz transformation. There is only one relativistic effect that appears as a difference between an infinitesimal Lorentz transformation and the corresponding infinitesimal Galilei transformation; this effect is the relative character of simultaneity. When this has been introduced by a physical argument (following Einstein), finite transformations and the other effects are obtained by iteration. Special attention is given to an iteration procedure that reveals the existence of the Thomas precession.
Obstacles to Increased Physics Enrollment
Authors: Brandwein Paul F.
Published: August 2005

There is a continuing national need for trained physicists and citizens who understand the ways of the physicist and the nature of his contribution. This need can be met if physics teachers undertake to change teaching and curricular practice. One direction of the change which might be made is indicated.
Vibrational Dynamics with Lenses, Mirrors, and Prisms
Authors: Satterly John
Published: August 2005

In previous papers I have described experiments on the rocking of bodies. The rocking bodies have bearing surfaces which are plane, circular, or elliptical and they may rock on circular, elliptical, or plane surfaces.

Lenses also furnish interesting examples of rocking bodies. Their surfaces may be spherical, cylindrical, or plane and these have the advantage that they are smooth and of good geometrical form. Their curvatures may be measured accurately with calipers and spherometer. To lenses may be added prisms and mirrors. Odd lenses, prisms, and mirrors usually abound in a well-stocked laboratory so that examples are not far to seek. The larger the specimens the more easily do they lend themselves to experimentation. The calculations of the period of rocking furnish, as in earlier papers, interesting examples of the applications of mechanics to vibrational problems, and the calculation of positions of centers of gravity and values of moments of inertia provide additional exercises. The experiments are eminently suitable for senior classes in the physical laboratory, giving interest to the student by their novelty and little trouble to the demonstrators in the matter of putting out the apparatus for the use of the class. Their number illustrates the variations possible with very little apparatus.