摘要:

An elementary classification of crystals according to their binding forces shows that an ideal crystal, defined as a perfect lattice of spherical atoms held together with two-body, central forces, should be found among the inert gas solids. The calculation of a lattice energy from an interatomic potential of the Mie-Lennard-Jones form is discussed, and the results for the hexagonal and cubic close-packed lattices compared. For argon, it is shown that a (12,6) interatomic potential, whose constants have been calculated from the crystal parameters at 0°K, can be used to predict both the specific heat of the crystal and the second virial co-efficient of the gas over suitable ranges of temperature. A comparison of this interatomic potential with existing calculations of the interaction of two argon atoms shows that the macroscopic properties of argon can be calculated at present from a pair potential, but not directly from the properties of an argon atom.

ISSN:0002-9505    

DOI:10.1119/1.1935108

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

摘要:

The basic idea of paramagnetic resonance is presented in terms of a simple classical mechanical model. The model is then elaborated to show how paramagnetic resonance may be used to obtain information about atomic nuclei and the structure of crystals. A typical apparatus with which it may be observed is briefly sketched.

ISSN:0002-9505    

DOI:10.1119/1.1935109

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

摘要:

Motivated by the common knowledge that earth satellites move in elliptic paths, a graphical demonstration is presented which shows that if a small mass moves in an elliptic orbit about a large mass at one focus and obeys Kepler's law of areas, the force of attraction on it must vary inversely as the square of the distance between the two masses. The demonstration differs from the usual elementary proofs of the inverse-square law in that it assumes elliptic rather than circular orbits, uses the law of areas instead of the dependence of period on semimajor axis, and requires a minimum of formal mathematics. By using a similar construction it may be shown that if the large mass is at the center of the ellipse, the force varies linearly with distance.

ISSN:0002-9505    

DOI:10.1119/1.1935110

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

摘要:

The equipment to be described is a sailboat model designed for use in an undergraduate student laboratory for the quantitative investigation of the resolution of forces The “sailboat” floats on a cushion of air to reduce friction to a minimum. The force to be resolved, which may be applied from any horizontal direction, is the “wind,” supplied by a high-velocity blower. The experimental error is less than 5%.

ISSN:0002-9505    

DOI:10.1119/1.1935111

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

摘要:

This article comprises a set of three independent reviews of the 1958–1959 television presentation of a course in modern physics at about the college freshman level. There is a short introduction to the reviews by Robert H. Randall, Chairman of the Visual Aids Committee of the AAPT, pointing out the part played in the production by Dr. Harvey White, the chief lecturer, and also noting the occasional appearance of a number of prominent guest speakers. The joint sponsorship of the program is also described.The three appraisals are supplied by Myron C. McCay of the University of Chattanooga, Truly C. Hardy of the City College, New York City, and Alan T. Wager of Arizona State University. In general, all three reviews pay tribute to the careful and effective handling of the subject matter by Dr. White and to the stimulation afforded by the presence of guest speakers. The lack of opportunity for discussion, inevitable with a television presentation, is stressed. A number of the guest speakers, in the view of the reviewers, spoke at too high a level. The course has apparently appealed to a large group of viewers well outside academic walls. In general, the venture is considered well worth the effort.

ISSN:0002-9505    

DOI:10.1119/1.1935112

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

摘要:

Students are influenced strongly by tests, because the tests are to them the basis of rewards for their efforts. Because of this, it is essential that attempts to emphasize methods, as well as subject matter coverage, in physics courses must include the construction of tests that require the student to demonstrate his knowledge of process or method as well as knowledge. Examples of the way in which this has been done in connection with the tests that accompany the Physical Science Study Committee Course are included.

ISSN:0002-9505    

DOI:10.1119/1.1935113

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

摘要:

The background and growth of the Advanced Placement Program are discussed. Construction, form, and grading of the examination are described. Some indications of the validity of the examination and acceptance by the colleges are presented. A number of problems still to be solved are posed.

ISSN:0002-9505    

DOI:10.1119/1.1935114

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

摘要:

The program of the National Science Foundation for the support of academic-year, summer, and in-service institutes is summarized and the place of physics in the various institutes is analyzed. Details are given as to dates at which proposals must be received, what type of financial help is available to institutions and to participating teachers, and as to the factors that all institutes have in common.

ISSN:0002-9505    

DOI:10.1119/1.1935115

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

摘要:

The physics course developed by the Physical Science Study Committee is outlined in some detail. Examples of the laboratory work and of the instructional films that accompany the course are included to show how these parts of the course are integrated with the text on the one hand and supplementary to it on the other.

ISSN:0002-9505    

DOI:10.1119/1.1935116

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.1935119

出版商:American Association of Physics Teachers    

年代:1960

数据来源: AIP