Volume 36, Issue 4, April 1968
Index of content:
36(1968); http://dx.doi.org/10.1119/1.1974514View Description Hide Description
Prepared at the request of the AAPT Committee on Resource Letters; supported by a grant from the National Science Foundation.
This is one of a series of Resource Letters on different topics, intended to guide college physicists to some of the literature and other teaching aids that may help them to improve course contents in specified fields of physics. No Resource Letter is meant to be exhaustive and complete; in time there may be more than one letter on some of the main subjects of interest. Comments and suggestions concerning the content and arrangement of letters as well as suggestions for future topics will be welcomed. Please send such communications to Professor Joel E. Gordon, Resource Letter Committee, Department of Physics, Amherst College, Amherst, Massachusetts 01002.
Notation: The letter E after an item number indicates elementary level, useful principally for high school and introductory college use; the letter I indicates intermediate (junior, senior) level; and the letter A indicates advanced material, principally suited for senior, graduate study. An asterisk (*) indicates items particularly recommended for introductory study.
Additional copies: Available from American Institute of Physics, 335 East 45 Street, New York, New York 10017. When ordering, request Resource Letter OE-1 and enclose a stamped return envelope.
36(1968); http://dx.doi.org/10.1119/1.1974515View Description Hide Description
Some 1020 films useful for instruction in physics, mostly at the college level, are listed by field. Addresses of distributors are given. This listing, which includes some foreign films, is intended to be helpful to instructors seeking suitable films for classroom use in school and college, and to those planning future films. Some comments are made on the availability and suitability of 8 mm films.
36(1968); http://dx.doi.org/10.1119/1.1974516View Description Hide Description
The concept of perturbations is introduced to the general physics student using a forced anharmonic oscillator constructed on a linear air track. The interaction between a bar magnet mounted atop the glider and two Umagnets supplies the perturbation. The general characteristics of the system are described, and plots of the amplitude versus driving frequency showing a “jump” effect are presented. The advantage of the system described is that all components of the system are open to study by the student.
36(1968); http://dx.doi.org/10.1119/1.1974517View Description Hide Description
An integral-differential equation was derived for the temperature-dependent spatialdistribution function of quantum statistical thermodynamics and analytical solutions for several quantum systems were given. It was shown that the classical and quantum-mechanical equations for the temperature-dependent spatialdistribution function for a separable potential differ by one term proportional to Planck's constant squared. In several limiting cases it was found that solutions obtained from the integral-differential equation agreed with those obtained by Uhlenbeck using other methods.
36(1968); http://dx.doi.org/10.1119/1.1974518View Description Hide Description
This paper presents a coherent approach to the theory of spherical sound-wave propagation in fluids and elastic solids. The formulation unifies the treatment of boundary conditions, prescribed displacement or stress at an interior surface, and brings together various results scattered throughout the literature. To illustrate application of the theory, square pulses in velocity and stress are specified at an interior surface and the flow variables in the resulting disturbances are calculated. The method of analysis and results are presented in a manner useful to research workers in this field as well as to physics students less familiar with the area of wave propagation.
36(1968); http://dx.doi.org/10.1119/1.1974519View Description Hide Description
A falling-ball type of viscometer has been developed employing remote sensing of the ball position. It has been utilized in measurements of the effect of pressure on the viscosity of liquids in the range up to 2 kbar. The experiment is well suited to use in the undergraduate physics laboratory.
36(1968); http://dx.doi.org/10.1119/1.1974520View Description Hide Description
The Green function method is applied to a system consisting of two spins which are coupled by exchange. The magnetization, the correlation function, the zero-field magnetic susceptibility, and the magnetic specific heat are evaluated. Since the two-spin system gives Green function results easily, and since exact results are calculated for comparison, the two-spin system is a particularly effective teaching tool for the Green function method. The calculations in this paper assume that the exchange coupling of the spins is as described by the Heisenberg Hamiltonian, and we treat only the case of positive exchange integral J. Only the case of spin and Tyablikov decoupling (or the random phase approximation) is considered in this paper. As might be expected the Tyablikov decoupling approximation gives poor results, but this is compensated by the ease with which the Green function results are obtained. However, in many cases one can simply generalize to larger spins and other decoupling approximations, if desired. Generalizations are also possible for larger “clusters” of spins with constant J for each pairwise interaction.
36(1968); http://dx.doi.org/10.1119/1.1974521View Description Hide Description
The optimum design of student experiments on Rutherford scattering is investigated in terms of both minimum counting times and range of useful experience of scattering techniques. The geometrical corrections for an annular target, source, and detector of finite sizes are presented; and the multiple-scattering and energy-variation corrections for a target of finite thickness are considered in detail. Apparatus is described and results presented for measurements over the range 15°–90°, using an α source of activity about 100 μCi, with the differential cross sections at 12 angles measured to an accuracy of ± 5% in about 6 h of laboratory time.
36(1968); http://dx.doi.org/10.1119/1.1974522View Description Hide Description
A one-semester experimental physics course has been divided into two parts to enable students to plan and execute their own experiments. The first part of the course introduces some of the instruments and techniques of experimental physics through a set of programmed laboratories. The second part provides the opportunity to do a complete experiment from design to analysis without lab notes and with very little supervision.