bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and use of a computerized test generating program
Authors: Schaefer Edward , Marschall Laurence A.
Published: March 2005

An easy-to-use set of programs for the computerized generation of multiple-choice and essay examinations in an introductory astronomy course is described. The programs allow the user to establish files of test questions and to rapidly assemble printed copies of examinations suitable for photocopying. Written in ALGOL for a Burroughs B6700 computer, the programs can, in principle, be implemented on large mainframe computers or on microcomputers of a size increasingly available to physics departments. The advantages and costs of computerized test generation are discussed.
Cohesive energy of the alkali metals
Authors: Poole R. T.
Published: March 2005

The cohesive energies of the alkali metals are calculated, using a description based on the free electron model, to within to 0.1 eV of the experimental values. Also it is shown that for lithium metal the electron kinetic energy is comparable in magnitude to the energy associated with the repulsive interactions over a substantial range of lattice spacing. The method used is considered to be appropriate for presentation to undergraduate students in materials science and related courses.
Allowed values of J in j
j coupling of equivalent electrons
Authors: Tuttle E. R.
Published: March 2005

A simple method is given for finding the values of the total angular momentum J for configurations of equivalent electrons in jj coupling. It is also shown how a knowledge of both the LS and jj terms can contribute to the student’s understanding of the role of different representations in elementary quantum mechanics. Because the principles and the computations required are elementary, this material is particularly suitable for presentation to undergraduates and to graduate students taking a first course in quantum mechanics.
Dipole relaxation in an electric field
Authors: Neumann Richard M.
Published: March 2005

From Boltzmann’s equation, S=k lnΩ, an expression for the orientational entropy, S of a rigid rod (electric dipole) is derived. The free energy of the dipole in an electric field is then calculated as a function of both the dipole’s average orientation and the field strength. Application of the equilibrium criterion to the free energy yields the field dependence of the entropy of the dipole. Irreversible thermodynamics is used to derive the general form of the equation of motion of the dipole’s average orientation. Subsequent application of Newton’s second law of motion produces Debye’s classical expression for the relaxation of an electric dipole in a viscous medium.
Angular momentum of a system of particles in the center-of-mass frame
Authors: Faucher G.
Published: March 2005

It is shown that the angular momentum of a system of particles may be expressed in different equivalent ways in the center-of-mass system.
Physics 13: Teaching modern physics through science fiction
Authors: Freedman Roger A. , Little W. A.
Published: March 2005

We describe a one-quarter seminar course on ’’Modern Physics through Science Fiction.’’ This course is designed as a supplement to the conventional introductory series of physics courses taken by undergraduates in the biological sciences. We show how a course of this kind can serve both to teach new physics and to develop the imagination.
Measurement of time by quantum clocks
Authors: Peres Asher
Published: March 2005

A clock is a dynamical system which passes through a succession of states at constant time intervals. If coupled to another system, it can measure the duration of a physical process and even keep a permanent record of it, such as in a time-of-flight experiment or in observing the lifetime of an unstable atom. A clock can also be used to control the duration of a process, e.g., the precession of a spin in a magnetic field which is turned on and off at prescribed times. This article shows how to construct time-independent Hamiltonians describing these possible uses of a quantum clock. As expected, a good time resolution entails a large energy exchange between the clock and the other system, thereby modifying the evolution of the latter. This evolution may even be halted by using a clock which is too precise (this is the quantum analog of Zeno’s paradox).
Energy considerations concerning current loops and magnetic objects
Authors: Fluitman J.
Published: March 2005

In the thermodynamics of compound magnetic systems there is an ambiguity in defining the free energies connected to the constituent parts or subsystems. It is argued that the choice, usually made in defining the energy of a magnetized body, leads to an expression for the energy of a current loop or coil of the form U?(L−italic)=i2+iφa, where i and φa (an externally aplied flux, coupled to the loop) are considered as independent variables. With this expression a convention to decompose compound magnetic systems into subsystems can be given, which fits to the rules applied for nonmagnetic systems. Analogous to the case of a coil, an expression for the energy of a charged particle in a magnetic field can be derived which results in an expression for the Hamiltonian, which is generally applicable.
Pedagogical aspects of time-dependent rotation operators
Authors: Leubner C.
Published: March 2005

For tutorial purposes, the simple problem of a classical magnetic moment interacting with various magnetic field configuration is reformulated in terms of coordinate-free, time-dependent rotation operators. In this approach, the corresponding equation of motion assumes the form of an operator equation, identical with the Schrödinger equation of a spin-1 interacting with the same field configurations. It is solved utilizing deliberately the concepts of a Hermitian Hamiltonian and a unitary time evolution operator to familiarize students early in their curriculum with these important ingredients of the quantum-mechanical formalism. It turns out that besides furnishing useful exercises for the manipulation of three-dimensional rotation operators, being an end in itself, the approach also provides simple but nontrivial examples for a number of theorems for which the students will have frequent use in their quantum-mechanics course.
Electron optics cannot be taught through computation?
Authors: van der Merwe J. P.
Published: March 2005

It is shown how certain concepts which are basic to electron optics may be introduced to undergraduate physics students by calculating trajectories of charged particles through electrostatic fields which can be evaluated on minicomputers with a minimum of programming effort. High precision ray tracing through central fields require only programmable pocket calculators, whereas Fourier–Bessel fields are easily accommodated on small desk top computers. Examples include coaxial, two-foil, one-foil, and open electron lenses.
A density of states-frequency theorem for general one-dimensional oscillator systems
Authors: McKelvey J. P.
Published: March 2005

A theorem relating the density of states function for a general one-dimensional oscillator to the energy-dependent oscillator frequency is derived and discussed. The use of the theorem in calculating the time-average kinetic and potential energy is also described. The theorem facilitates calculation of density of states functions and ensemble averages, and provides useful insight into the physical nature of the density of states function.
Master’s level graduate training in medical physics at the University of Colorado Health Sciences Center
Authors: Ibbott Geoffrey S. , Hendee William R.
Published: March 2005

Medical physics is an applied branch of physics which is concerned with the application of energy in various forms to the diagnosis and treatment of disease. It is allied closely with medical electronics, bioengineering, and health physics, but extends beyond the boundaries of these rather specific disciplines. The diversity of medical physics demands a broad background of both coursework and experience for persons working in this field. To provide such training, educational programs have been developed such as the Master’s degree program in medical physics of the University of Colorado Health Sciences Center. The program at the University of Colorado was established in 1971 and is noteworthy for its emphasis on the practical and clinical aspects of medical physics.
Vorticity and rotation
Authors: Lindgren E. Rune
Published: March 2005

It is shown that the vorticity vector may be expressed as the sum of a ’’microscopic’’ and a ’’macroscopic’’ rotation. This permits a rational interpretation of the fact that it equals twice the rigid body rotation vector, removing uncomfortable notions expressed in the literature on this subject.
Wave propagation in dispersive and attenuation media: A delay line simulation of plasma waves
Authors: Martin D. J.
Published: March 2005

Expressions are developed for the dispersion relationship and characteristic impedance of a general lumped element delay line. A delay line is described whose dispersion relationship is equivalent to that of a transverse electromagnetic wave in a plasma. The propagation of a sine wave burst, a square wave, and a pulse are described and analyzed illustrating the concept of group velocity and the techniques of Fourier analysis and Fourier transformation.
Thermodynamics of cooling a (live) human body
Authors: Weinstock Harold
Published: March 2005

Students in a junior-level thermodynamics course were presented a practical problem in which a human body must maintain its normal interior temperature of 37 °C while the surface is at 15 °C. Suggested solutions to this problem are offered along with details of heat flow in the body.
Derivation of Maxwell’s equations from the gauge invariance of classical mechanics
Authors: Kobe Donald H.
Published: March 2005

The Lagrangian for a single classical charged particle is made form invariant under the addition of a total time derivative by adding an interaction Lagrangian which involves compensating fields. The compensating fields are the vector and scalar potentials of the electromagnetic field which couple to the current and charge densities, respectively. To insure form invariance of the Lagrangian, the vector and scalar potentials must undergo the usual gauge transformations of electromagnetism. The electric and magnetic fields, which are gauge invariant, are obtained by examining the equation of motion for the charged particle. Faraday’s law and the condition that there are no magnetic monopoles are obtained from the expressions for the electric and magnetic fields in terms of the potentials. The simplest possible gauge-invariant Lagrangian which is quadratic in the electric and magnetic fields is constructed. From the principle of least action Gauss’ law and the Ampère–Maxwell law are obtained.
Easy displacement versus time graphs for a vibrating string: Tuning a guitar by television
Authors: Jones Gordon E. , Ferguson Joe L.
Published: March 2005

When a vertical, vibrating string is silhouetted against a television screen, a wavelike shape may be seen. The shape will appear distinct and stationary if the ratio of the string’s fundamental frequency to 60 Hz is the ratio of small integers. The vertical scan of the (horizontally sweeping) electron beam is responsible for this shape, which amounts to a displacement versus time graph for the string. The effect can be used to tune stringed musical instruments to absolute pitch.
Demonstrating Poisson statistics
Authors: Vetterling William T.
Published: March 2005

A pulsed x-ray tube is used to generate Poisson distributions. By varying the tube plate current, we produce distributions with different mean, and show the transition to Gaussian form as the mean increases. The relationship of these distributions to electronic ’’shot noise’’ is discussed.
Momentum flow as an alternative perspective in elementary mechanics
Authors: diSessa Andrea A.
Published: March 2005

Through a series of sample problems and solutions, the case is made that the notion of force as momentum flow can serve as the basis for vastly expanding the importance of Newton’s third law, ’’action and reaction,’’ as experienced by students in elementary mechanics courses. The reasons this potential has been neglected seem more ’’cultural’’ than pedagogical. The final section raises some particular issues concerning the advisability of actually teaching elementary mechanics from this alternative point of view.
Elastic and inelastic multiple scattering of a two-particle system with a fixed wall
Authors: Newby Neal D.
Published: March 2005

An air track experiment is described and analyzed. This experiment involves a massive particle incident on a fixed wall with a light particle trapped in between. The interaction of the massive particle with the wall is mediated by the multiple bouncing of the light particle between the two. Both elastic and inelastic bouncing are studied. It is shown that the motion of the system point in the velocity space of the two particles provides a convenient graphical representation of this process—a process in which the total momentum of the system is not conserved. A mathematical transformation in the velocity space results in simple formulas for the velocities of the two particles at any stage of the multiple-bounce interaction. The graphical method is supplemented in the inelastic case by a formalism which describes the interaction via two noncommuting scattering matrices which operate on a system state vector.
Operator formulation of classical mechanics
Authors: Cohn Jack
Published: March 2005

An operator formulation of classical mechanics is given. Rather than being concerned with Lie algebraic or abstract Hilbert space properties of classical mechanics, the present formulation is directly concerned with wave packets in configuration space and is thus more similar to that of conventional quantum theory than other extant operator formulations of classical mechanics. Among other things, the following items are discussed for classical systems: Ehrenfest’s theorem, the uncertainty principle, dissipative systems, and field theory.
Simple harmonic motion in harmonic plane waves
Authors: Benumof Reuben
Published: March 2005

The displacement of a particle in a medium in which there is a traveling or standing harmonic plane wave is a sinusoidal function of the time, and the particle may therefore be said to execute simple harmonic motion. An incorrect view of this motion is that it is identical to the free vibration of a mass attached to a massless spring. In general, the total energy of a particle in the medium varies from zero to a maximum. In the case of standing waves, the energy surges from the nodes, where it is entirely potential, to the antinodes, where it is entirely kinetic, and back again. The paradox of a transverse traveling wave on a string transmitting longitudinal momentum is resolved by noting that a differential length of string stretches as its slope increases. A point on the string has a small longitudinal motion in addition to its transverse motion.
Ultrahigh and audio frequencies in a laser beam
Authors: Casabella P. A. , Gonsiorowski T. , Leitner A.
Published: March 2005

The helium–neon lasers readily available in teaching laboratories usually operate in several photon modes simultaneously. The first-difference and second-difference beats lie in the uhf- and audio-frequency ranges, respectively, and can be detected as sinusoidal signals with photodiodes. These are instructive experiments which raise thought provoking questions about cavity resonance and negative dispersion.
Generalization of the principal plane concept in matrix optics
Authors: Arsenault H. H.
Published: March 2005

In the Gaussian approximation, the propagation between any two planes may be represented as the product of a lower triangular matrix times an upper triangular matrix. The matrices themselves, as well as their elements, have an immediate physical meaning. This representation contains the principal plane representation and the focal plane representation as particular cases.
Rutherford’s scattering formula via the Runge–Lenz vector
Authors: Basano L. , Bianchi A.
Published: March 2005

The Runge–Lenz vector provides a way to derive the relation between deflection angle and impact parameter for Coulomb and Kepler fields in a very simple and straightforward way. No solution of the orbit equation is required.
Spurious excitations in semiclassical scattering theory
Authors: Gross D. H. E. , Schmid G. Bruno , Taksar J.
Published: March 2005

It is shown through proper handling of the nonuniform motion of semiclassical coordinates that spurious excitation terms are eliminated.
Electromotive force: Volta’s forgotten concept
Authors: Varney Robert N. , Fisher Leon H.
Published: March 2005

The concept of electromotive force as first presented by Volta seems to be all but forgotten. Introduction of the term often occurs without any definition at all and is often confused with electrostatic potential difference. When a formal definition is given it is usually neither in accord with Volta’s original idea nor conceptually useful or comprehensible. We emphasize Volta’s use of the term to describe nonelectrostatic action on charges. The relationship of emf’s to electrostatic potential differences is presented through the introduction of electrostatic and nonelectrostatic fields (as was described by Abraham in 1904). A failure to note a distinction between these types of electric fields mars some highly important works including J. C. Maxwell’s.
Comment on ’’Fraunhofer diffraction patterns from apertures illuminated with nonparallel light’’
Authors: Crawford Frank S.
Published: March 2005

A general formula for the diffraction width of an optical system is given in terms of a generalized f-number. (AIP)
Ballistics calculations of R. W. Gurney
Authors: Jones Gordon E. , Kennedy James E. , Bertholf Larry D.
Published: March 2005

Gurney’s method of calculating speed imparted to driven metal by high explosives is described and applied to several geometrical configurations. The method permits derivation of a differential equation with a closed-form solution describing the acceleration of the metal. Because of its versatility, Gurney’s approach continues to find new applications. This article serves as an appendix to a recent article on Gurney and, in addition, provides instructive applications of classical mechanics.
Abbreviated instructive description of the resistive hose instability
Authors: Uhm Han S.
Published: March 2005

The resistive hose instability of a self-pinched, relativistic electron beam in a collision-dominated background plasma is investigated. Previously known results are recovered in a simple instructive way, without going through a lengthy mathematical derivation.
Compact solar camera
Authors: Juergens Albert
Published: March 2005

A compact solar camera built as a one semester student project is described. The overall length of the camera is 112 cm, and the effective focal length is 70 to 600 cm. The adjustable focal length means that an image of the sum with a diameter of 0.7 to 6.0 cm can be formed for viewing or recording. Lenses used in this camera were ’’borrowed’’ from a microscope and a photographic enlarger, and as such, there was no expenditure for constructing the camera.
An analogue model for teaching reflection and refraction of waves
Authors: Bates Harry E.
Published: March 2005

A concrete model for teaching the concepts of reflection and refraction is described. This model is based on the use of wave strips which can be utilized by application of the principle of wave-front continuity to demonstrate the concept of reflection and Snell’s law. A single and split field projection method is described for use in the classroom to demonstrate wave-front matching at a boundary.
A final year physics undergraduate experiment on ultrasound propagation in liquids
Authors: van der Sluijs M. J. , van der Sluijs J. C. A.
Published: March 2005

We describe an advanced undergraduate physics experiment which permits the measurement of ultrasound velocity and absorption in liquid systems at frequencies between 10 and 30 MHz and temperatures between 25° and 60 °C.
Dispersion relation for de Broglie waves
Authors: Paul Derek
Published: March 2005

The dispersion relation for de Broglie waves is examined sufficiently to remove a possible ambiguity in the de Broglie frequency. The motion of a heavy (guided) photon, which obeys the same dispersion relation, is then studied in a gravitational field, leading to the Einsteinian relation frequency shift in a gravitational field.
An exactly soluble Schrödinger equation with a bistable potential
Authors: Razavy M.
Published: March 2005

For a bistable potential which is the sum of two hyperbolic cosine functions, the Schrödinger equation for the low-lying states of a homonuclear diatomic molecule can be solved analytically. In this model the potential and the energy eigenvalues depend on three parameters, and the resulting wave functions are continuous and have continuous derivatives everywhere. This last property of the wave functions enables one to generate a family of soluble bistable potentials by applying the theorem of Darboux to the discrete eigenfunctions of the Schrödinger equation.
Motion of damped oscillators: Expansion in normal modes
Authors: Goebel C. J. , Epstein S. T.
Published: March 2005

The expansion of the small oscillation motion of a damped system in terms of normal modes is given.
Turning point approximation and application to nonlinear oscillators
Authors: Chen T. W.
Published: March 2005

A nonperturbnative method is developed and is applied to solving for the period of a nonlinear oscillator given by (1/2)kx2+(1/n)bxn. A general solution valid for wide ranges of k and b values is obtained. It agrees well with the exact solution for n =4. Comparisons with perturbative solutions are also made.
Lateral magnification–angular magnification relationship for a simple magnifier
Authors: Keating Michael P.
Published: March 2005

In discussions of a simple magnifying lens, lateral magnification and angular magnification are usually treated as separate, unrelated entities, perhaps because the lateral magnification for a collimating magnifier goes to infinity, while the angular magnification remains finite. However, the angular magnification is equal to a ratio of the total lateral magnification for the combined magnifying lens–observation system to the initial lateral magnification for the observation system. The total lateral magnification for the combined magnifying lens–observation system remains finite for a collimating magnifier because the lateral magnification for the observation system goes to zero, while the lateral magnification for the magnifying lens goes to infinity. The resulting indeterminate form can be evaluated by limit techniques and is finite. Ways to avoid the indeterminate form are also discussed.
Parametric instability: An elementary demonstration and discussion
Authors: Case William
Published: March 2005

A simple, easy to construct, system which exhibits parametric instability is presented. The two lowest-order resonances are described and analyzed in detail. The analysis stresses the physical and intuitive aspects of the problem. The purpose of the paper is to give the reader some familiarity with parametric oscillators and parametric instability.
Maxwellian distribution derived from N-body disintegration theory
Authors: Livesey D. L.
Published: March 2005

The distribution of classical kinetic energies has been calculated in the center-of-mass frame for one particle type among N particles emitted from a point with total kinetic energy E. The distribution goes over into the Maxwellian form when N is large. Applications to nuclear disintegration problems are briefly introduced.
Supernovae in binary systems: An application of classical mechanics
Authors: Mitalas R.
Published: March 2005

A supernova explosion in a binary system is presented as an application of classical mechanics. The realistic assumptions that the original binary system was circular, the mass loss instantaneous, and the companion unaffected by ejected matter, permit a simple, analytic determination of the post-explosion binary. The period, semimajor axis and mass function of the original circular binary are related to the period, semimajor axis and mass function of the present binary. The space velocities of the post-explosion components are derived. The results are of current interest in connection with O,B runaway stars, collapsed stars in binary x-ray sources and with the discovery of a pulsar in a binary system.
Analysis of blackbody radiation with derivative spectroscopy
Authors: Dusek J. , Kearney R. J. , Baldini G.
Published: March 2005

An undergraduate experiment which uses derivative spectroscopy to investigate the validity of the Planck function [exp(hc/λkT)−1]−1 appearing in the blackbody radiation law is described. These measurements allow a critical examination of this function and also serve as an introduction to derivative spectroscopy techniques.
Brewster angle in a semi-infinite dielectric moving perpendicularly to the interface
Authors: Saca Mario
Published: March 2005

A particularly useful method of obtaining the Brewster angle and the polarization of the fields of an incident electromagnetic wave in moving isotropic dielectrics is discussed for the case of a vacuum-dielectric interface. In particular, it is applied to the case of a semi-infinite dielectric moving in a direction perpendicular to the interface. The dielectric is assumed nondispersive.
Solutions of the Schrödinger equation using approximate nucleon–nucleon and Λ–nucleon potentials
Authors: Banerjee S. N. , Chakraborty S. N.
Published: March 2005

An approach related to the teaching of the chapter on bound and scattering states in a short-range potential, which forms a standard part of quantum-mechanics course, is outlined with an example. The proposed interaction closely approximates the realistic Yukawa potential. It also represents the Coulomb potential in a limiting case. Investigation of the Schrödinger equation with the potential may serve as an excellent demonstration to be incorporated in the undergraduate quantum-mechanics or nuclear physics course.
Anomalous fine structure in sodium Rydberg states
Authors: Silverman Mark P.
Published: March 2005

The nd (2D5/2,3/2) fine structure levels of excited sodium provide an interesting example of Rydberg states with nonhydrogenic properties. A simple model employing perturbation theory and well-known relations drawn from the old quantum theory is described which accounts in part for this apparently anomalous behavior.
Spatially varying index of refraction: An open ended undergraduate topic
Authors: Krueger David A.
Published: March 2005

There are many commonplace examples of waves moving along a curved path in an inhomogeneous media. There are reports of a simple lecture demonstration of light bending in a sugar solution being used to motivate students in physics, geophysics, and acoustics courses. For those students who wish to pursue this topic we discuss many avenues of additional research. With relatively simple equipment one can measure the index of refraction n (y,t) and its first and second spatial derivatives as well as the time dependence. The analysis can be approached from a generalization of Snell’s law, the equations for the eikonal, Fermat’s principle, and the classical approximation and analogies with trajectories of particles.
Zero energy gaps for deep one-dimensional periodic potentials
Authors: Lin Shi-Tron , Smit Jan
Published: March 2005

Analysis of the Kronig–Penney model and of computer results for more general one-dimensional periodic potentials shows that, for certain depths of the potential wells, zero band gaps occur under conditions similar to those existing in real ’’free-electron’’ metals.
Simple measurement of the band gap in silicon and germanium
Authors: Collings Peter J.
Published: March 2005

A simple experiment which measures the forbidden energy gap in silicon and germanium is described. The procedure utilizes a p-n junction, and thus illustrates much of the physics connected with semiconductors and this basic electronic device. The results are accurate to within 2% and are consistent with more precise determinations of the band gap.
Breaking of gauge symmetry: A geometrical view
Authors: Moriyasu K.
Published: March 2005

We present a simple introduction to the basic physical ideas involved in the breaking of local gauge symmetry. By utilizing the geometrical approach to gauge invariance, we see that symmetry breaking corresponds to a phase adjustment in the interaction between a gauge field and a special class of ’’self-coherent’’ systems. As examples, we discuss superconductivity and spontaneous symmetry breaking in elementary particle physics.
Simple and inexpensive apparatus for Young’s modulus measurement
Authors: Tyagi Somdev , Lord Arthur E.
Published: March 2005

A simple and very inexpensive apparatus to dynamically determine Young’s modulus for thin reeds and wire samples is described. It uses a readily available audio generator, amplifier, and speaker.
Geometrical analogy for the formal definition of entropy
Authors: Basano L.
Published: March 2005

We present a simple geometrical problem lending to an integral which has many features in common with the Clausius’ integral. This example may be preliminarly discussed as a useful introduction to the entropy concept.
Electromagnetic radiation fields: A simple approach via field lines
Authors: Ohanian Hans C.
Published: March 2005

The electric radiation field of an accelerated charge is calculated by considering a kink in the electric field. (AIP)
Simple geometrical construction for finding the eigenvector of a general rotation
Authors: Blewett P.
Published: March 2005

A method is presented of calculating the eigenvector on the unit sphere, given the three Eulerian rotations. (AIP)
Physics and modern warfare: The awkward silence
Authors: Woollett E. L.
Published: March 2005

General education students enrolled in courses in physics or physical science are ill-served by an almost total lack of discussion of the intimate links between progress in science and ’’progress’’ in weapon systems. We discuss in detail the great dependence of the present arms race on a healthy physics enterprise and the pervasive connections between pure and applied science and military needs.
Science and society test V: Nuclear nonproliferation
Authors: Hafemeister David W.
Published: March 2005

Numerical estimates are carried out on questions affecting the nation’s nonproliferation policy. We have considered some aspects of thermal recycle, improved efficiency of light water reactors, advanced converters, light-water reactor–fast breeder reactor economic tradeoffs, symbiotic systems, research reactors, laser isotope separation, and the thorium cycle.
Brecht’s G
a
l
i
l
e
o: A revisionist view
Authors: Schroeer Dietrich
Published: March 2005

Galileo is often claimed by scientists to be the first modern physicist, and because of his conflict with the Catholic Church is seen as a heroic figure fighting for the independence of pure science. Brecht, in his play Galileo, has presented a revisionist view of Galileo. This view developed over several versions of the play, and finally used him as a symbol for all scientists who reject social responsibility for their work. Is this revisionist view of Galileo any more distorted than the portrayal of him as the patron saint of modern science?
Newtons laws of motion: Some interpretations of the formalism
Authors: O’Sullivan Colm T.
Published: March 2005

Four distinct conceptual approaches to the treatment of Newton’s laws of motion are identified and discussed.
Titius–Bode law: An astronomy project for a cloudy night
Authors: Sapp Richard C.
Published: March 2005

A study unit on the Titius–Bode Law of planetary distances is described. Its format is based on a Piagetian learning cycle of exploration, conceptualization, and applications. More than enough material is provided, including options, for a variety of flexible, open-ended student activities in an astronomy observatory section faced with a cloudy night. Portions of the unit guide and related ideas may serve as starting points for independent study projects and term papers. The unit is quantitative, employing both arithmetic and algebra; it emphasizes graphical analysis to induce empirical relations.
Einstein and ΔtΔE
Authors: Cook L. F.
Published: March 2005

The two famous counterexamples of Einstein associated with the Solvay conferences of 1927 and 1930 are examined in the context of the present understanding of the time-energy uncertainty relations.
Motion of the sprung pendulum
Authors: Rusbridge M. G.
Published: March 2005

We extend the analysis of the motion of the sprung pendulum to show the full effects of the nonlinear coupling between horizontal and vertical oscillations. We show that even at modest amplitudes a theory involving second-order terms only is inadequate to explain experimental results, and suggest that the discrepancy is due to nonlinear detuning from the exact resonance condition, an effect which appears only in higher order. Finally, we investigate the effect of damping on the patterns of motion.
Geometrical optics derivation of the Fourier transform property of a lens
Authors: Jaffe Bernard M.
Published: March 2005

Geometrical optics and the concepts of optical path length and coherence are used to derive the Fourier transform properties of a lens. For a parallel bundle of coherent light, the Fourier transform appears in the back focal plane of the lens; for light originating in a coherent point source at a finite distance, the Fourier transform appears in the plane conjugate to the light source.
Fibonacci numbers revisited: A combinatorics function point of view
Authors: Phares Alain J. , Simmons Kim H.
Published: March 2005

The solution of the recurrence relation Fn=aFn−1+bFn−2 is shown to be very simply connected to the number of distinct partitions of a segment of length n into p parts of length 2 and (n−2p) parts of length 1. A sum rule is obtained and known results concerning Fibonacci numbers (for which a=b=1) are recovered.
Some experiments with thin prisms
Authors: Fernando P. C. B.
Published: March 2005

In most attempts at modernizing the college physics curriculum one of the first branches of physics to be eliminated is geometrical optics. However, in developing countries where the curriculum must give emphasis to applied areas (if physics is to survive at all!), geometrical optics has a role to play, especially in its relationship to the professional course ’’Optometry.’’ The author presents a few experiments in geometrical optics with an ophthalmic opitics bias, which could be introduced into the college physics laboratory.
Mu in silicon: An interesting example in quantum mechanics
Authors: Hintermann A. , Meier P. F. , Patterson B. D.
Published: March 2005

A quantum-mechanical example is presented which arose from experimental research with positive muons in solids. The anomalous muonium center in silicon apparently finds a necessary and sufficient description in terms of a spin Hamiltonian with interesting analytical solutions in various limits.
How incorrect is the classical partition function for the ideal gas?
Authors: Kroemer Herbert
Published: March 2005

The classical partition function for the ideal gas, by incorrectly counting orbitals with multiple occupancy, differs from the exact value for bosons or fermions in the classical regime. A quantitative estimate of the error is derived, and it is shown that the error may correspond to a large factor, even when the gas is well inside the classical regime. For 1 cm3 of He at 300K and atmospheric pressure this factor exceeds 1013. However, all observables of the gas involve the logarithm of the partition function, rather than the partition function itself. The fractional error in the logarithm is negligible, hence the classical treatment leads in the end to correct answers for all observables.
Use of operator wave functions to construct a refined correspondence principle via the quantum mechanics of Wigner and Moyal
Authors: Snygg John
Published: March 2005

We represent the momentum operator p by p+(h//2i)(∂/∂p) and the position operator q by q−(h//2i)(∂/∂p). We then apply each resulting operator that appears in the nonrelativistic quantum mechanics of Schrödinger and Heisenberg to the constant 1. What results is a Wigner–Moyal theory which is as complete as the usual Schrödinger–Heisenberg theory. Replacing Planck’s constant h/ by zero in the Wigner–Moyal theory results in the classical physics of Newton. We thereby obtain a refined correspondence principle.
The Cyclotron Group at the Metallurgical Laboratory, Chicago, 1940–44
Authors: Snell Arthur H. , Bradner H. , Brolley J. E. , Camac M. , Kern B. D. , Levinger J. S. , Meiners E. P. , Mitchell A. C. G. , Nedzel V. A. , Rall W. , Sampson M. B. , Wilkinson R. G.
Published: March 2005

A small supplement to the official history of the Manhattan Project is offered in that some of the activities of the Cyclotron Group in the Metallurgical Laboratory are described. In particular, the work on the delayed neutron activities was essential to the decision to try for the first nuclear chain reaction in the middle of Chicago, and fast-neutron measurements in a 5-ton pile of solid uranium metal led to the assessment of the practicability of a controlled fast-neutron reactor, and also (through necessary and important subsequent developments by others) to the light-water-cooled, thermal-neutron reactors of today.
Resource letter CCV-1: Color and color vision
Authors: Pease Paul L.
Published: March 2005

The author has selected resource material that focusses on color vision and the measurement and specification of the stimulus for vision, that is, photometry and colorimetry. References are marked E (elementary), I (intermediate), and A (advanced). Those references to be included in a Reprint Book are marked with an ().
Special relativity with 2×2 matrices
Authors: Baylis W. E.
Published: March 2005

The elegance and efficiency of a two-component spinor representation of the restricted Lorentz group is enhanced by expressing the 2×2 transformation matrices in exponential form. Various advantages suggest its use in undergraduate courses in place of the usual Minkowski-space formulation. One starts with 2×2 Hermitian matrices to represent real Lorentz four vectors. Matrix products quickly give other physical quantities, both of four-vector type and ’’six-vector’’ (complex three-vector) type, such as the complex electromagnetic field E+iB or a generalized angular momentum. All are easily transformed without explicit reference to Cartesian components by multiplication with 2×2 unimodular matrices. Numerous examples are presented.
Degeneracy in one-dimensional quantum mechanics
Authors: Kwong Waikwok , Rosner Jonathan L. , Schonfeld Jonathan F. , Quigg C. , Thacker H. B.
Published: March 2005

The degeneracy of quantum-mechanical energy levels is discussed from the novel perspective of the inverse scattering problem. The coalescence of energy levels is illustrated for a class of potentials which are completely characterized by their bound-state spectra. Other applications of this style of analysis are suggested.
Zeno paradox in quantum theory
Authors: Peres Asher
Published: March 2005

The coupling of an unstable quantum system with a measuring apparatus alters the dynamical properties of the former, in particular, its decay law. The decay is usually slowed down and can even be completely halted by a very tight monitoring.
Applications of microcomputers in the teaching of physics—6502 software
Authors: Marsh David P.
Published: March 2005

Microcomputer systems are becoming widely available to both academic departments and individuals. Extensive software is available for systems using the 6502 microprocessor. A graphical program dealing with a coupled harmonic oscillator is used as an illustration of the capability of a compact and user adaptable high level language available for the 6502.
Computer-generated microwave holograms
Authors: Leming Charles W. , Hastings Orestes Patterson
Published: March 2005

Using the phasor method of superposition of waves, the intensity pattern from a system of microwave sources is calculated point by point on a plane corresponding to a film emulsion. The pattern is printed and directly converted to a hologram for 3-cm microwaves. A microwave source is used as a reference beam and the original system of sources is reconstructed.
Superconductivity demonstration
Authors: Smith A. D. , Tinkham M.
Published: March 2005

A simple lecture demonstration is described which illustrates the vanishing of resistance in superconducting wire and dramatizes its potential usefulness for electrical power transmission. The voltage drop across the wire is observed on a standard voltmeter, while the power transmission efficiency is monitored qualitatively with a light bulb. The demonstration is designed for elementary physics courses or similarly nonspecialized audiences.
Crystal video detection of stimulated emission and oscillation in a molecular beam maser
Authors: Lainé D. C. , Truman M. J. , Hope S.
Published: March 2005

A molecular beam maser is described that operates with a rotationally cooled beam of ammonia (14NH3) produced by nozzle expansion which permits oscillation as well as stimulated emission on the J=K=1 inversion transition at 23.694 GHz. In particular, it is shown that both stimulated emission and oscillation may be monitored by means of a simple crystal video detection scheme rather than by the more sensitive, although more complex superheterodyne detection method. The sensitivity obtained with crystal video detection is shown to be sufficient to permit the observation of maser action on the main and three out of the four quadrupole line groupings. For the main and inner high-frequency quadrupole lines only, doublet structures have been resolved. In the case of oscillation, it is shown that video detection via the observation of beats with the monitoring signal is hampered by phase-locking effects. However, it is shown that this difficulty vanishes when the self-oscillation is detected by the same basic method, but via the oscillation forced in a second cavity placed downstream from the first, by the oscillating polarization carried by the beam. The simplified maser scheme discussed in this paper is proposed for advanced undergraduate laboratory use.
Simplified channeling and the rule of reversibility
Authors: Patterson B. D.
Published: March 2005

The channeling effect of a crystal lattice on the trajectory of a moving positive ion is investigated using harmonic approximations for the crystalline potential. Analytical expressions for planar flux peaks and blocking dips are derived for emission from and incidence on an impurity which is situated either between atomic planes or in a plane, and the validity of the ’’rule of reversibility’’ is discussed.
The other record of the first nuclear reactor start-up
Authors: Wollan E. O.
Published: March 2005

The author recounts his radiation monitoring work with the Manhattan Project. (AIP)
Magdeburg 1979
Authors: Higbie J.
Published: March 2005

The author offers a recreation of von Guericke’s demonstration with some slight modification to the public to make them aware of the kind of force the atmosphere is acting upon.(AIP)
Solid-state modification for the Cenco spark timer
Authors: Anderson Gerald A.
Published: March 2005

Inexpensive solid-state modifications for the spark timers is offered, the authors have chosen ’’C−MDS’’ and TTL families of integrated circuits.(AIP)
Integrating microcomputers and microelectronics into the physics curriculum
Authors: Gale Douglas S.
Published: March 2005

This paper describes a highly successful interdisciplinary microcomputer and microelectronics program offered jointly by the Physics and Computer Science Departments of East Texas State University. The program operates on both the graduate and undergraduate level. The content as well as the structure of the program are discussed.
Confirming the Planck–Einstein equation h
v=(1/2)mv2
Authors: Kirkpatrick Paul
Published: March 2005

Note is taken of the implausibility of Planck’s early views and papers on the quantum theory, of the interaction, though not collaboration, of Planck and Einstein in the nascent period of the theory, and of the essential roles played by two crucial experiments—schematically simple but technically formidable in their time—in bringing about the general acceptance of a theory of quanta. In particular, David Webster’s hitherto unreported work in this connection is put on record.
Graphical introduction to the special theory of relativity
Authors: Staunton L. P. , van Dam H.
Published: March 2005

An approach to special relativity employing space-time diagrams and elapsed time intervals recorded by a pair of stationary observers is presented. The conceptual simplicity of the approach does not preclude its use to obtain all of the usual results. The clock paradox as well as a length paradox are discussed as an illustration of the pedagogical technique.
Experimental study of Brownian motion in the limit of small time intervals by means of an ideal gas simulator
Authors: Unruh Henry
Published: March 2005

A simulator of an ideal gas and its use for the study of Brownian displacements in the limit of small time intervals is described. The study was carried out to identify either the Einstein or Ornstein formula as best describing Brownian motion. The results are consistent with the Ornstein formula rather than the familiar Einstein formula.
Minimum and absolute minimum spherical aberration of a simple, thin lens
Authors: Klingsporn Paul E.
Published: March 2005

Traditional treatments of third-order spherical aberration of a thin lens express the results in terms of a function Ls, involving a lens shape factor q and an object-image position factor p. The function Ls is defined in terms of the difference of the reciprocal paraxial and zonal image distances instead of the difference in distances, which is actually the longitudinal spherical aberration. The treatments show that a lens will have minimum spherical aberration for a shape q determined by minimizing Ls relative to q for a given p. In the present work it is shown that the same lens will actually exhibit smaller spherical aberration for values of p<0 determined by minimizing Ls relative to p. An equation is derived for minimizing the aberration itself, instead of the function Ls, and on the basis of the equation the object-image distances can be found for which a given lens will exhibit an absolute minimum spherical aberration. The results of the analyses are in good agreement with the results of mathematical ray tracing. also, some interesting graphical properties of the function Ls related to the refractive index of the lens are investigated.
Integral equations and the bound-state problem
Authors: Bagchi B. , Seyler R. G.
Published: March 2005

An integral equation for the s-wave bound-state solution is derived and then solved for a square-well potential. It is shown that the scattering solutions continue to exist at negative energies, and when evaluated at the energy of a bound state these solutions do reduce to the bound-state solution. The bound-state energies of a square-well potential are deduced also from orthogonality considerations. Finally, the existence of bound states for an arbitrary short-range potential is related to the occurrence of zeros of the Jost function or poles of the S matrix for that potential.
Bandwidth and spectrum analysis
Authors: Anderson J. Gerard
Published: March 2005

When complex waveforms are analyzed in undergraduate laboratory courses by examining oscillograms from simple resonant circuits, interpretation problems often occur. It is suggested that these problematic oscillograms are explainable by recognizing that typical resonant filters pass significant amounts of several harmonics adjacent to the one intended. The effect of such adjacent harmonics is computed, and the resulting Fourier partial sum compares favorably with oscillographic observation.