bluuebunny/crossref_metadata_2025 huggingface dataset:
Laboratory experiments with silicon solar cells
Authors: Kammer D. W. , Ludington M. A.
Published: March 2005

The uses of silicon solar cells as subjects of experiments in undergraduate teaching laboratories are discussed. The basic theory of these cells is presented, including equivalent circuits and characteristic equations. Fundamental experiments on the power output and efficiency, which are appropriate for non-science majors’ courses, are detailed, as well as more advanced experiments on cell parameters. Experimental results and agreement with theory are presented for a typical inexpensive cell.
Nonrelativistic quantum mechanics and the anomalous part of the electron g factor
Authors: Grotch H. , Kazes E.
Published: March 2005

The departure of the electron g factor from 2 is calculated using a nonrelativistic theory of the electron interacting with the quantized transverse electromagnetic field. Although the magnetic moment correction δμ, due to the radiation field, is antiparallel to the magnetic moment μ0 of the bare electron, it is shown that the g factor correction is positive for a reasonable cutoff. This is due to the fact that the g factor is defined as the magnetic moment in units of the ’’physical’’ Bohr magneton. The role of mass renormalization is emphasized in this approach, and it is shown that the experimental g factor emerges for a cutoff of 0.53 electron masses.
Variational method for two-electron atoms
Authors: Srivastava M. K. , Bhaduri R. K.
Published: March 2005

A simple two-parameter trial wave function for the helium atom and helium-like ions is proposed on physical grounds. A variational calculation for the ground-state energy yields a much better result than the usual one-parameter example given in textbooks.
PSI quantum mechanics with optional lectures on videocassettes
Authors: Roper L. David , Braden Roberts A. , Head J. Thomas
Published: March 2005

Optional videotaped lectures have been developed for use with a senior level PSI quantum mechanics course. Details of the course and the videocassette system are given. A summary of a comprehensive evaluation of the course and optional lectures is presented.
Experiment in the Bragg reflection of light for the undergraduate using cholesteric liquid crystals
Authors: Olah A. , Doane J. W.
Published: March 2005

Light scattering from a cholesteric liquid crystal behaves in a manner analogous to x-ray scattering from solid powder samples. A simple experimental setup is described in which the student can detect and record light spectra, study and test the concept of Bragg reflection, and measure the anisotropy of the index of refraction in a cholesteric liquid crystal.
A new addition to the homework assignment: Demonstration–problems
Authors: Prigo Robert
Published: March 2005

Introductory physics homework problems done in conjunction with student-performed demonstrations in the UC Santa Barbara Physics Learning Center are described and evaluated. These demonstration–problems presently supplement the standard textbook assignment for 370 students from our physics for engineers and scientists courses. Students find them more enjoyable than their textbook problems. We view them as valuable exercises within a process approach to instruction and consistent with the developmental theory of Jean Piaget. Arguments are given regarding their potential for promoting intellectual development. Other advantages are also cited.
Partons in antiquity
Authors: Gaisser Julia H. , Gaisser T. K.
Published: March 2005

We point out that the idea of confined quarks or partons as constituents of the elementary particles was already present in the Greek atomic theory. We describe some similarities and differences between ancient and modern confinement, and we suggest that in both cases the idea is in large part a response to an inherent conflict between the intuitive notion of infinite divisibility and the idea of discrete fundamental atoms of matter.
An elementary model for the radiometer
Authors: Paveri-Fontana S. L.
Published: March 2005

The radiometer is a commonly known toy that presents interesting features for scientific demonstrations in the field of the kinetic theory of rarefied gases. If a light beam is shined upon it, the radiometer starts moving in a manner that is, at first, quite unexpected. A simplified model is presented to illustrate its behavior in steady state operation. Some implications of the law of interaction between a rarefied gas and a solid surface are illustrated by the model.
An interactive curve-fitting program for science students
Authors: Farquhar R. M. , Pitre J. M. , Sutton M. , Wight L.
Published: March 2005

An interactive computer-assisted linear least-squares curve-fitting program is described. The program consists of two parts. The first is designed for first users and, although it allows students to generate basic tables, plots, and fits to their data, it is primarily a teaching introduction to the more sophisticated second part. Linear functions of one or more variables with or without errors may be fitted to data, and very general data transformations are permitted. The program has been tested by over 600 first-year physics students.
Systems approach for teaching electronics to scientists
Authors: Barclay J. A. , Hutton D. R.
Published: March 2005

We have used a systems analysis procedure to organize an electronics unit for presentation in the second year of a physics course. The method and details of the unit are described.
Cranking model calculation of the moment of inertia using the method of Dalgarno and Lewis
Authors: Harris Samuel M.
Published: March 2005

We present a calculation of the moment of inertia of a system of noninteracting particles moving in a common deformed, harmonic-oscillator potential well. Our calculation employs the cranking model formula, but instead of performing the usual sum over intermediate states, we use the method of Dalgarno and Lewis to replace that sum by an expectation value of appropriately defined operators. It is suggested that this calculation may serve as a useful example in a quantum mechanics or nuclear theory course.
Bose particles in an external electromagnetic field as a one-particle problem
Authors: Avilez C. , Mello P. A.
Published: March 2005

The statement is often made that the second quantized Hamiltonian for a system of noninteracting particles in an external weak electromagnetic field gives rise essentially to a one-particle problem, to which there corresponds a dressed vacuum different from the bare one. In this paper we implement that statement by explicitly constructing the dressed vacuum, together with the quasiparticle creation and annihilation operators associated with the one-particle problem. The process of diagonalizing the Hamiltonian is illustrated step by step in a simple model.
Color centers: An example of a particle trapped in a finite-potential well
Authors: Hughes Gregory P.
Published: March 2005

The wavelengths for color-center absorption can be determined from a simple quantum-mechanical model consisting of an electron trapped in a square finite-potential well. By varying the depth and width of this well we are able to adjust this model so that it predicts Ivey’s relationship [λ (Å) =73a1.80] between the F-center wavelength λ and the nearest-neighbor lattice spacing a. A more complicated model based on a spherical finite-potential well is also used to obtain Ivey’s law. The depth and width of the well that fit this latter model to the F-center absorption data are then used to predict the wavelengths for the K, L, L2, and L3 centers to −6%, 4.5%, 1.5%, and −1.0% respectively.
Enskog and van der Waals play hockey
Authors: Cutchis Protagoras , van Beijeren H. , Dorfman J. R. , Mason E. A.
Published: March 2005

We consider the mean free path of a hockey puck in a system of other pucks on an air table, and show how the simple low-density kinetic-theory value for this mean free path can be extended to higher densities. This approach is connected both with the Enskog theory of the transport properties of dense gases and with the van der Waals theory of the equation of state of dense gases. We derive several simple approximations for the high-density mean free path, and compare the results with each other, with accurate computer-simulation results, and with experimental results obtained in the freshman physics laboratory of the University of Maryland. We present the arguments in both simplified and more elaborate forms.
Geometry factors for experiments in radioactivity
Authors: Wray E. M.
Published: March 2005

The problem of determining the number of radioactive particles entering a detector window of radius a from a parallel and coaxial disk source of radius b is discussed. A diagram is presented which gives the effective solid angle, or geometry factor, subtended by the detector at the source for various values of b and z, the source-detector spacing. The range of parameters covered is a=1, 0<b<8, 1<z<5.
Stiffness corrections for the vibration frequency of a stretched wire
Authors: Hornung H. G. , Durie M. J.
Published: March 2005

By introducing the corrections due to the wire stiffness, arising both from the directional constraint at the ends and from the distributed curvature of the wire axis, the instructional value of the first-year physics experiment on the monochord is considerably increased. Although these corrections have been derived and shown to be correct by Seebeck (1852), our method of applying them, unlike Seebeck’s, does not rely on any detailed assumptions about the end constraints.
The compound pendulum in intermediate laboratories and demonstrations
Authors: Pedersen N. F. , Soerensen O. Hoffmann
Published: March 2005

A student laboratory course on the motion of the compound pendulum is described. The course is suited for physics and engineering students in their first year and requires a background in mechanics and mathematics corresponding to a one-semester course in these disciplines. The purpose of this course is to present a system to the students which can be approached experimentally and to some extent theoretically using elementary methods, and hence allow the students to practice their newly acquired knowledge. All the experimental results presented here are obtained by the students using a simple and readily fabricated version of the compound pendulum.
Method for solving electrostatic problems having a simple dielectric boundary
Authors: Sometani Taro , Hasebe Kenroku
Published: March 2005

Electrostatic problems having a simple dielectric boundary are solved using the concept of polarization charge. Using elementary mathematics, it is shown that the electrostatic field due to the total polarization charge distributed on a boundary surface between two homogeneous and isotropic dielectrics, is equivalent to that due to the lumped image charge used conventionally in teaching these problems. The demonstration of the equivalence of the surface polarization charge to the image charge will help students to understand the physical base of the image charge. Two problems are treated: a plane dielectric boundary, and a dielectric sphere immersed in a uniform field.
Rejuvenation of helium–neon lasers
Authors: Oakes M. E. , Hudler S. B. , Michie R. B.
Published: March 2005

A simple method is described that has been used successfully to return a nonlasing He–Ne laser to operating condition.(AIP)
Hyperfine structure in the triplet states of cadmium
Authors: Lewis E. L.
Published: March 2005

An experiment is described which investigates the hyperfine structure of the 63S1 and 53P0,1,2 excited levels of cadmium. The nuclear spin of the odd isotopes and the hyperfine constants for the levels are derived.
Listening to the coefficient of restitution
Authors: Bernstein Alan D.
Published: March 2005

A pedagogical method is described for measurement of the coefficient of restitution for collisions between a bouncing ball and a horizontal surface. Indirect measurement using only the sound made by the bouncing ball facilitates the rapid collection of data, allowing introductory laboratory students more time to concentrate on theory, method, data reduction, analysis, and the physical implications of their results. The coefficient of restitution is found to decrease systematically with increasing relative approach speed.
Elementary calculation for the momentum correlation function of a particle in a one-dimensional box
Authors: Kim Sungwoon
Published: March 2005

An elementary method for the calculation of the momentum autocorrelation function of a particle in a one-dimensional box is presented.
Fourier analysis and synthesis with a pocket calculator
Authors: Schmidt Stanley A.
Published: March 2005

Recent advances in design of small programmable calculators have brought some important but previously impractical problems within range of such instruments. Procedures are described for doing Fourier analysis and synthesis with a Hewlett-Packard HP-25 calculator. Only one program is required for each operation. Both programs should be suitable for instructional use by physics, engineering, and mathematics students at a wide range of levels.
The tippe top revisited
Authors: Cohen Richard J.
Published: March 2005

The tippe top displays the unexpected behavior of inverting itself when it is spun upon a flat surface. In the process its center of mass rises. Several explanations of this behavior have been offered in the literature. Here, in the light of a historical perspective, physical arguments are presented which support the contention that the influence of sliding friction is the key to the understanding of the top’s behavior. Then, a rigorous analysis of the top’s mechanics is offered, together with computer-generated solutions of the equations of motion.
Einstein’s first paper on relativity
Authors: Schwartz H. M.
Published: March 2005

Because of its exceptional significance in the history of great ideas in science, Einstein’s first paper on relativity, especially its first part, deserves a more careful translation into English than presently exists. A new and annotated translation of this first part is presented here, together with a brief discussion of certain aspects of Einstein’s paper.
Operator functionals and path integrals
Authors: Kourkoumelis C. , Nettel S.
Published: March 2005

In a paper entitled ’’An Operator Calculus Having Applications in Quantum Electrodynamics’’ [Phys. Rev. 84, 108 (1951)], Feynman gives techniques and theorems for working with ordered operators. We believe that the entire development, because of its direct involvement in the transition from the Heisenberg–Schrödinger to Feynman’s path-integral formulation of quantum mechanics, is of general interest. We aim to make these less appreciated early techniques of Feynman more accessible to the general physicist.
Geophysics without geology
Authors: Rudin Robert A.
Published: March 2005

A one-semester course in geophysics for physics students with no background in geology is described. Several students of the course chose to pursue graduate study in that field after receipt of the B.S. degree in physics.
H. Richard Crane: Oersted Medalist for 1976
Authors: Guernsey Janet B.
Published: March 2005

Remarks by the Chairman of the Committee on Awards in presenting H. Richard Crane the award of the 1976 Oersted Medal in recognition of his notable contributions to the teaching of physics.
AAPT Distinguished Service Citations—February 1977
Authors: Guernsey Janet B.
Published: March 2005

The American Association of Physics Teachers conferred Distinguished Service Citations on seven outstanding contributors to physics education: Monica Bainter, University of Wisconsin; Alfred M. Bork, University of California, Irvine; Ernest Coleman, U. S. Energy Research and Development Administration, Walter C. Connolly, Appalachian State University; Homer L. Dodge; Haym Kruglak, Western Michigan University; Joe P. Meyer, Oak Park and River Forest High School. The presentations were made by Janet B. Guernsey, retiring Past President of the Association, at its annual business session on 10 February 1977 in Chicago.
Einstein’s comprehensive 1907 essay on relativity, part I
Authors: Schwartz H. M.
Published: March 2005

As an important sequel to his first paper on relativity, Einstein’s extensive discussion of the subject in the 1907 issue of Jahrbuch der Radioaktivit?t und Elektronik, including a first exposition of his embryonic ideas on gravitation, is of intrinsic as well as considerable historical interest. In this, the first of three parts dealing with Einstein’s essay, a translation is presented of the Introduction and of Part I, which is concerned with relativistic kinematics.
Textbook-integrated problem sets
Authors: Walker Jearl D. , Walters Virginia F. , Casper Karl J.
Published: March 2005

For both engineering physics and life science physics sequences, machine-graded problem sets derived from textbook problems drastically reduce the grading time while substantially increasing the student effort outside of class. With simple modifications, the problem sets can be reused each time a course is offered. Such problem set grading has some of the merits of computer-assisted instruction, but is considerably lower in cost and applicable to large classes and students who have little time on campus.
Quantum transitions without quantum jumps
Authors: Macomber James D.
Published: March 2005

It is now recognized that quantum systems undergoing an uninterrupted transition between two stationary states (due to the influence of a coherent perturbation) do so in a smooth, continuous process that does not involve a quantum jump. The theoretical reasons for this continuity are given, and an atomic beam experiment is described that might be used to illustrate the process.
Eighth velocity of light
Authors: Bloch S. C.
Published: March 2005

In dispersive media the phase velocity, group velocity, energy velocity, signal velocity, relativistic velocity constant, and ratio-of-units velocity are usually not useful concepts for wave packets. The centrovelocity has been suggested as a measure which overcomes many of the objections to the first six. We describe yet another, based on the cross-correlation of the original and received wave packets, which is shown to be useful in time-of-flight measurements in weakly and strongly dispersive media; absorption and amplification are readily accommodated. Applications for specific examples of wave packets in magnetoplasmas are presented.
Stirring up a magnetic paradox
Authors: Fahnline Donald E.
Published: March 2005

A commerical magnetic stirrer provides a convenient rotating horseshoe magnet for several well-known demonstrations of induced eddy currents and Lenz’s law such as the spinning of a nonferromagnetic metal top or coin and the operation of a speedometer. A new demonstration is paradoxical: A steel ball rolls in a circle either in the same direction as the rotation of the stirrer magnet or in the opposite direction. That an aluminum cone or rivet also rolls in the opposite direction shows that the latter effect is due to induced currents, but this seems to violate Lenz’s law.
The physics of Einstein’s relativity paper of 1905 and the electromagnetic world picture of 1905
Authors: Miller Arthur I.
Published: March 2005

Einstein’s seminal paper on the special relativity theory of 1905 ’’On the Electrodynamics of Moving Bodies’’ is discussed in its historic context. It is shown how different was Einstein’s approach to the electrodynamics of moving bodies from that of a major research effort which attempted to deduce all of physics from H. A. Lorentz’s electromagnetic field theory—the electromagnetic world picture.
Procedure for the determination of orbits of astronomical bodies
Authors: Birnbaum David
Published: March 2005

A procedure is presented for finding the elements of the orbit of an astronomical object from three or more observations. From a set of assumed elements an ephemeris is calculated and compared to the observations. The assumed elements are then adjusted using standard nonlinear least-squares techniques.
The nature of physics and history: A cross-disciplinary inquiry
Authors: Leacock Robert A. , Sharlin Harold I.
Published: March 2005

We describe a cross-disciplinary course, called ’’Physics, History and Society,’’ which has as its theme: the nature of physics and history. The major goal of the course is to examine and compare physics and history in order to illuminate the implicit assumptions underlying the two disciplines. Specific historians such as the Americans Frederick Jackson Turner and Charles A. Beard, and specific physicists such as Tycho Brahe, Johannes Kepler, and Isaac Newton are studied as representative of historical and physical inquiry. In addition to describing the materials, techniques, and aims of the course, we also present insights into physics, history, and teaching that we have gained by offering the course. In particular, we consider Newton’s ’’rules of reasoning in philosophy,’’ discuss why physicists and historians of science often disagree about physics, examine a problem of cross-disciplinary teaching, and evaluate the impact of the course.
The particle in a box is not simple
Authors: Cummings F. E.
Published: March 2005

Naive use of the position representation wave functions for a particle in either a finite or infinite square well predicts properties of the momentum distribution in disagreement with those calculated in the momentum representation. The discrepancy is removed by explicit consideration of the effects of the discontinuity in the potential at the walls on position space calculations.
Visible spectroscopic studies with Fourier transform interferometry
Authors: Davis Jeffrey , Rynne Timothy M.
Published: March 2005

Use of a Michelson interferometer in studies of visible spectroscopy is presented. The experimental setup is discussed for obtaining reflectivity spectra of various semiconducting materials. The resulting interferograms are analyzed using a Tuckey–Cooley fast Fourier transform technique. Results include measurements of the absolute reflectivity of coated germanium, uncoated germanium, coated silicon, and the output spectra of both red and green light-emitting diodes.
Physicists and the elementary schools—seven years later
Authors: Jakhelln Judith , Paldy Lester G.
Published: March 2005

Seven years ago, the State University of New York at Stony Brook, with the support of the National Science Foundation, attempted to provide training and curriculum assistance to school systems in the Long Island region seeking to improve their elementary school science programs. A retrospective examination of the impact of that program has revealed that, although initial program objectives were achieved, pilot projects did not lead to school-wide adoptions in those school systems that participated. An analysis of the reasons for the failure of pilot projects to expand leads to some speculative conclusions with implications for institutions and individuals seeking to become involved in school curriculum development.
Bose’s second paper: A conflict with Einstein. A translation of ’’Thermal equilibrium in the radiation field in the presence of matter’’
Authors: Bose S. N. , Theimer O. , Ram Budh
Published: March 2005

The probability for an arbitrary state of a system consisting of radiation and molecules is calculated, and the conditions for statistical equilibrium are deduced therefrom. On this basis new expressions for the statistical probability of those elementary processes which correspond to the interaction between radiation and matter are suggested.
A van der Waals theory of the crystalline state
Authors: Clark A. , de Llano M.
Published: March 2005

Elementary concepts from classical statistical mechanics and solid-state physics are employed in extending the van der Waals ’’mean-field’’ picture to a spatially periodic one, based solely on microscopic principles. A simple calculation and comparison of the Helmholtz free energies involved, as well as of the associated ’’Maxwell constructions,’’ allows for the qualitatively correct inclusion of the crystalline phase into the usual P-V-T diagram of a simple substance.
Fast least-squares algorithms
Authors: Davidon William C.
Published: March 2005

New least-squares algorithms are introduced. Instead of waiting for all data to be in before making a fit, these algorithms update a fit after each point is entered so trends can be detected promptly as an experiment proceeds. Coupled linear equations are not solved numerically, reducing rounding errors, calculation time, and memory requirements. When used for fitting degree-N polynomials to equally weighted data points whose abscissas are equally spaced, these algorithms need just one multiplication by an integer constant and one division to update each of the N+1 polynomial coefficients. Pocket calculator programs are available for polynomial fits to data points whose abscissas are equally spaced; one of these gives equal weight to all points while another gives more weight to recent points.
Treatment of optical propagation in crystals using projection dyadics
Authors: Kunz Kaiser S.
Published: March 2005

The propagation of light in crystals has many features that suggest an eigenvalue problem involving a real symmetric dyadic, such as the occurrence of two distinct phase velocities vo and ve for the ordinary and the extraordinary waves and the orthogonality of their polarizations. The usual treatment by the use of Fresnel’s formulas, however, does not reveal an eigenvalue problem. It is shown in this paper that there is indeed an eigenvalue problem but that it relates, not directly to the permittivity dyadic ?, but to the dyadic P↘⋅?−1⋅P↘, where P↘ is the projection dyadic onto a plane orthogonal to the propagation vector k↘. The displacement vectors ?o and ?e for the ordinary and extraordinary waves act as eigenvectors of this dyadic with eigenvalues 1/εo and 1/εe. These effective permittivities εo and εe determine the phase velocities vo= (μεo)−1/2 and ve= (μεe)−1/2 of the ordinary and extraordinary waves, respectively.
On the motion of a charged particle in a dipole field
Authors: Chen C. H.
Published: March 2005

The relativistic Lagrangian function of a charged particle in an axially symmetric electromagnetic field is used to deduce the canonical momentum integral conjugate to φ, where φ is the azimuth angle in the plane perpendicular to the axis of symmetry. The integral has the same form as that deduced from the nonrelativistic Lagrangian function. Sto/rmer’s integral is used as an example to illustrate the need for a relativistic treatment of the motion of a charged cosmic-ray particle in the Earth’s magnetic field.
Simple classical approach to spin resonance phenomena
Authors: Gordon R. A.
Published: March 2005

A simple classical method of describing spin resonance in terms of the average power absorbed by a spin system is discussed. The method has several advantages over more conventional treatments, and a number of important spin resonance phenomena, not normally considered at the introductory level, are calculated in simple quantitative fashion.
Pedagogical trick for general relativity
Authors: French John D.
Published: March 2005

A simple method is given to device the equations of motion of a test particle in General Relativity theory.
Using the Doppler effect in the microwave region to study motion on a linear air track
Authors: Bates Harry E.
Published: March 2005

Two parallel explanations of homodyne Doppler velocimetry are discussed as well as its application in an undergraduate experiment. This phenomenon is applied in the measurement of the constant acceleration of coupled masses utilizing the microwave region of the electromagnetic spectrum. One mass is an air car with radar reflector and is coupled by a pulley system to the other, a drop weight. AJP
Strong interaction effects in hadronic atoms
Authors: Kaufmann W. B.
Published: March 2005

The WKB method is applied to the calculation of strong interaction-induced level widths and shifts of hadronic atoms. The calculation, while elementary enough for undergraduate quantum mechanics students, gives a good account of kaonic and antiprotonic atom data.
Conservative discrete models with computer examples of nonlinear phenomena in solids and fluids
Authors: Greenspan Donald
Published: March 2005

This paper describes a completely arithmetic development of Newtonian dynamics in which all the classical conservation laws are valid. The equations are already in a form amenable to high-speed digital computation. Related particle-type models are then described for highly nonlinear dynamical phenomena, and computer examples are given to illustrate the ease with which they can be analyzed.
Einstein’s comprehensive 1907 essay on relativity, part II
Authors: Schwartz H. M.
Published: March 2005

This continuation of the English rendition of Einstein’s 1907 essay on relativity, of which the first part appeared in the June 1977 issue of this Journal, is devote to Parts II-IV of the essay, dealing with the relativistic treatments of electrodynamics, optics, mechanics, and thermodynamics. The original text of these parts covers 27 printed pages. However, owing to the nature of the subject matter and the character of the original exposition, it was possible to reproduce here the essential content of the original text intact in terms of a free rendition, using modern notation, and retaining all the original formulas with their numbering, and also including direct translations of all passages of possible historical interest. Mathematical amplifications of a few of the key derivations in the original text are presented in added footnotes.
Historical development of the Bhabha first-order relativistic wave equations for arbitrary spin
Authors: Krajcik R. A. , Nieto Michael Martin
Published: March 2005

From letters, personal reminiscences, and the published works of the authors involved, we describe the historical development of the Bhabha system of first-order relativistic wave equations for arbitrary spin. The simplest special cases of these equations reduce to the Dirac and DKP (Duffin–Kemmer–Petiau) equations for spin-1/2 and spins 0 and 1, respectively.
Gravitational fields whose brachistochrones and isochrones are identical curves
Authors: Chander Ramesh
Published: March 2005

Among the radial gravitational fields the property that the brachistochrones and the isochrones of a field are identical curves is possessed by only those fields whose potentials vary directly as the squares of distances from the centers of the fields. The gravitational field obtaining inside a sphere of constant density is of this type. The relevant curve for such fields is the hypocycloid.
New elementary experiments in plasma physics
Authors: Alexeff I. , Pytlinski J. T. , Oleson N. L.
Published: March 2005

Several plasma physics experiments especially suitable for an undergraduate physics laboratory are described. The experiments can be set up using commercially available gas tubes and standard electronic equipment available in most university or college laboratories. The simplicity of the equipment involved and its low cost are features of these experiments. An introductory plasma physics course or a modern physics course gives adequate theoretical background to perform the experiments.
An introduction to phase-sensitive amplifiers: An inexpensive student instrument
Authors: Temple Paul A.
Published: March 2005

The principle of operation of phase-sensitive amplifiers is discussed. Three examples of the use of the phase-sensitive amplifier, or ’’lock-in,’’ are given. The examples have been chosen to be suitable for undergraduate laboratory use. The paper is concluded with the description of an inexpensive ’’student’’ lock-in amplifier which has an overall voltage gain of 1000.
Extraordinary shadow disappearance due to a fast-moving light source
Authors: Lai Hon-Ming
Published: March 2005

As a horizontally moving light source is approaching and passing over a wall, it is shown that the shadow on the ground at a nearer position to the wall may disappear at an earlier time. In fact, the light rays first illuminate a point on the ground and the neighboring shadow around this point will disappear subsequently in the shape of illuminated ellipses of increasing area. Such an extraordinary phenomenon occurs whenever u/c≳1−hW/hS, where c and u are the speeds of light and the source, and hW and hS are the heights of the wall and the source, respectively.
Spin and photon echoes
Authors: Haueisen D. C. , Bonifield Thomas D.
Published: March 2005

The classical interpretation of the spin echo is reviewed, followed by a simple quantum-mechanical derivation of the general echo phenomenon for a two-state system. The photon echo is then examined, and graphs of hydrogenic wave functions for eigenstates and transitional states are shown as examples. As many as possible of the classical notions associated with the spin echo are applied to the case of photon echoes.
Vergence, vision, and geometric optics
Authors: Keating Michael P.
Published: March 2005

The vergence treatment of geometric optics provides both conceptual and algebraic advantages over the traditional object distance–image distance–focal length formalism. These advantages are particularly useful for the life science student. In this paper vergence is defined in terms of the curvature of the wave fronts, and some examples are given to illustrate the advantages of this approach.
Project Boomerang
Authors: King Allen L.
Published: March 2005

The returning-type boomerang illustrates many of the principles of rigid body dynamics and some aerodynamic principles as well. Here is described an experimental project on boomerangs by members of an undergraduate course in classical mechanics. The students designed and made their own boomerangs, devised their own procedures, and carried out suitable measurements. Some of their data and a simple analysis for the two-bladed boomerang are presented in this article.
Least action principle on an air table
Authors: Provost J. P.
Published: March 2005

In most standard texts, the illustration of the least action principle proceeds through Lagrange’s equations. This approach is severely limited by the mathematical knowledge of the students. We prefer to adopt the experimental approach to mechanics, using air tables; that is, we first study conservation laws, with interactions at a distance as the second stage. We want to show that the least action principle enables both the trajectories and the conservation laws (of energy, momentum, and angular momentum) to be obtained without using Lagrange’s equations.
Solutions to boundary value problems of the potential type by random walk method
Authors: Gibbs R. L. , Beason Charles W. , Beason James D.
Published: March 2005

The random walk method of solving Laplace’s and Poisson’s equations is illustrated. Electrostatic boundary value problems are treated explicitly on a square plate with Dirichlet boundary conditions.
One-dimensional models for two-electron systems
Authors: Lapidus I. Richard
Published: March 2005

One-dimensional models for two-electron systems resembling the helium atom and hydrogen molecule are studied using δ-function potentials between all particles. It is noted that the essential features of the helium atom and hydrogen molecule ground states are exhibited by these models. The calculations are simple and useful pedagogical tools for illustrating the techniques used in more complicated and realistic calculations of energy eigenvalues and eigenfunctions.
Charged particle motions in a magnetic field that reduce to motions in a potential
Authors: Stern David P.
Published: March 2005

If the Hamiltonian for the motion of a charged particle in a magnetic field has one or more cyclic coordinates, it may often be viewed as representing the motion of a particle subject to a potential V. The use of V provides qualitative insight about the motion even in some cases where a solution of the motion cannot be obtained. Several examples using this concept are reviewed and discussed.
Astrophysics: An integrative course
Authors: Gutsche Graham D.
Published: March 2005

A one-semester course in introductory stellar astrophysics at the advanced undergraduate level is described. The course aims to integrate all previously learned physics by applying it to the study of stars. After a brief introductory section on basic astronomical measurements, the main topics covered are stellar atmospheres, stellar structure, and stellar evolution. Problem assignments are designed to encourage the use of the computer and of current astronomical literature.
Environmental physics revisited
Authors: Inhaber H.
Published: March 2005

Environmental physics is a subfield which is rapidly coming into its own in conjunction with society’s greater emphasis on solving environmental problems. A number of courses, articles, and books have been produced dealing with this new subfield, and these are analyzed. An outline of a course approaching the subject from the point of view of fitting it in with other physics courses is described. This course uses relatively recent examples from the environmental literature.
Surface plasmons in silver films—a novel undergraduate experiment
Authors: Simon H. J. , Mitchell D. E. , Watson J. G.
Published: March 2005

Surface plasmon phenomena are a topic of considerable current interest. We describe a simple experiment and theory for a senior level undergraduate investigation of surface plasmons in silver films. An ∠500-Å-thick silver film is evaporated on the hypotenuse face of a right glass prism. Light (p-polarized) from a He–Ne laser is incident through the prism on the metal film. At an angle of incidence a few degrees greater than the critical angle for total reflection, a sharp minimum in the reflected light is observed, corresponding to the excitation of the surface plasmon. The minimum in the reflectivity results from the absorption of the resonantly enhanced surface plasmon mode in the silver film. The dispersion relation for the surface plasmon and the reflectivity due to the excitation of this normal mode are calculated. Only a modest vacuum of ∠10−3 Torr is necessary to produce the required thin silver films.
An inexpensive rotating-room apparatus
Authors: Calvert J. B. , Hofman E. V. , Westdal H. C.
Published: March 2005

The construction and use of an inexpensive rotating-room apparatus is described. The device has a 48-in.-diam platform, seats four at a table, and rotates at four possible speeds. The two lowest, 0.4 and 0.6 rad/sec, are the most useful. It is easily transported and erected without special arrangements.
Quantum mechanics in momentum space: An illustration
Authors: Lieber M.
Published: March 2005

The formulation of quantum-mechanical problems in momentum space, which is largely ignored in traditional courses but is used in research, is discussed. In particular, the formulation of scattering problems, for which the momentum representation is quite natural, is neither generally well known nor obvious. This is illustrated by solving a simple problem, the one-dimensional delta function potential, through which the bound state and continuum wave function are found.
WKB connection rules from the harmonic oscillator
Authors: Kroemer Herbert
Published: March 2005

The WKB connection rules are obtained from the asymptotic properties of the harmonic oscillator wave functions.
Resource letter MENP-1: Medium energy nuclear physics
Authors: Sternheim Morton M. , Koch Justus H.
Published: March 2005

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

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

Reprints: When ordering, request Resource Letter MENP-1. Enclose 50 cents per copy (not in stamps) together with a stamped and self-addressed envelope and send to Arnold A. Strassenburg, Executive Officer, American Association of Physics Teachers, Graduate Physics Building, SUNY at Stony Brook, Stony Brook, New York 11794. Brook, Stony Brook, New York 11794.
Classical covalent bond
Authors: Piela Robert , Huggins Elisha
Published: March 2005

In an introductory physics course one of the student computer projects provided a clear demonstration of how the covalent bond, the fundamental bond of organic chemistry and biology, arises directly from Coulomb’s law. Since the project was carried out by a student whose study of physics consisted of only one semester of Newtonian mechanics, the project shows that a background in quantum mechanics need not be a prerequisite for a basic understanding of molecular forces. In fact, this work suggests that we can reorganize our presentation of material in introductory physics courses, using the covalent bond as one of the basic applications of Coulomb’s law, just as we use planetary motion as a basic application of Newton’s law of gravity.
AAPT Distinguished Service Citations—January 1975
Authors: Jossem E. Leonard
Published: March 2005

The American Association of Physics Teachers conferred Distinguished Service Citations on six outstanding contributors to physics education: Bill G. Aldridge, Florissant Valley Community College; Stanley S. Ballard, University of Florida; Phillip R. Brieske, University of Wisconsin, Superior; Wilbur V. Johnson, Central Washington State College; Walter E. Massey, Brown University; Lester G. Paldy, State University of New York, Stony Brook. The presentations were made by E. Leonard Jossem, retiring past President of the Association, at its annual business session on 31 January 1975 in Anaheim.
Development of concepts in the history of quantum theory
Authors: Heisenberg Werner
Published: March 2005

Editor’s note: The Editor heard Professor Heisenberg deliver the substance of this article as a lecture at Harvard University. We are grateful that permission has been granted to reprint this presentation from its original source.
Instructional innovations in physics at Stony Brook
Authors: Kahn Peter B. , Strassenburg A. A.
Published: March 2005

The authors describe four instructional innovations recently put into effect at the State University of New York at Stony Brook. The first is an inquiry-oriented physical science course which serves primarily prospective elementary school teachers. The second is a large, self-paced introductory course taken largely by biological science majors and premeds. In a more ambitious effort, a liberal arts physics major program has been designed. The outstanding features are that the course topics emphasize the historical and social side of physics, the choice and sequencing of courses is flexible, and students learn to use physics in a variety of contexts other than physics research. Finally, undergraduates and graduate physics students at Stony Brook have opportunities to produce instructional materials under supervision as part of their education in physics.
A look at the small-angle end of the Rutherford scattering formula
Authors: Kruse Olan E.
Published: March 2005

The lowest possible angle of validity of the Rutherford scattering formula is determined on the basis of a simple hypothesis. The corresponding impact parameter is then obtained and related to the distance between scattering nuclei that would exist if the scattering foil could be compressed into a single layer of atoms arranged in a square array.
Student attitudes toward science and society
Authors: Spears Jacqueline D. , Hathaway C. E.
Published: March 2005

The Schwirian Science Support Scale has been utilized to study the attitude toward science and its interrelationship to society of a broad cross section of nonscience students. In spite of the development of a counterculture antagonistic toward science, this study indicates that these students appear to accept those societal values important for the support of science.
An attempt at a personalized course in thermodynamics
Authors: Mullen J. G.
Published: March 2005

A personalized course in thermodynamics is described which organizes learning about moderately difficult projects designed to bring a sense of continuity and relevance to student studies. The approach minimizes formal lecturing and tries to encourage discovery and enjoyment in learning. Student lecturing, laboratory visits, and demonstrations, along with class discussions of projects, are used as a replacement for most, but not all, formal classroom lecturing. Student comments are used as a basis for evaluating the approach.
Mechanical analog of the synchrotron, illustrating phase stability and two-dimensional focusing
Authors: Alvarez Luis W. , Smits Robert , Senecal Gerard
Published: March 2005

A steel ball bounces in synchronism with a vertically oscillating piston. The piston surface is a hardened steel disk on which the ball bounces; two−dimensional horizontal focusing is provided by the concavity of the surface. The period of oscillation can be varied over a 3:1 range with the amplitude kept constant. As the period is increased, the ball bounces higher. As the period is decreased, the ball bounces lower, contrary to the intuition of most observers. The model illustrates the important properties of synchrotron accelerators.
Recording 360° holograms in the undergraduate laboratory
Authors: Stirn Bradley A.
Published: March 2005

A simple experimental configuation is described for recording good quality 360° holograms with a minimum of effort and expense. The reconstructed images allow one to observe in three dimensions how an original object appears from all sides save top and bottom.
Experiences with a multimedia course and a nonscience majors course
Authors: Coulter Byron L. , Adler Carl G. , Byrd J. William
Published: March 2005

The Physics Department at East Carolina recently instituted two separate programs at the freshman level in an attempt to attract more students into its classes and to improve the students’ attitude toward physics. One program involved a multimedia format in a course for science majors, and the other involved a new sequence of courses for nonscience majors. Due mainly to faculty resistance, the multimedia format was discontinued in the fall quarter of 1973. However, the enrollment in the nonscience major sequence has been increasing rapidly, and a noticeable change in the students’ attitude toward physicists has been effected.
Newton and the American political tradition
Authors: Arons A. B.
Published: March 2005

Students of intellectual history establish a clear line of connection from Newton and Locke through the philosophy of the Enlightenment and the evolution of deism to the American political tradition reflected in the Constitution and the Declaration of Independence. This paper briefly traces the historical sequence and indicates readily available sources (mostly in paperback) in which students and lecturers can find deeper background and additional detail.
Digital techniques for laboratory measurements
Authors: Dart S. Leonard
Published: March 2005

The development of measuring equipment in modular form with digital readout is described. This equipment is adapted to the measurement of many physical quantities such as velocity, frequency, temperature, resistance, capacitance, etc. It is easier to use, faster, and more precise than conventional equipment and forms a firm basis for more advanced work.