摘要:

A balance of special design demonstrates the principle of the siphon, and incidentally, if desired, that of Archimedes at the same time. A vertical rod, ending at the top in a hook that hangs from a knife-edge, supports a horizontal platform at its center. Placed symmetrically on the platform near its ends, are two equal beakers containing water in equal amounts. If the beakers are connected by a siphon tube, when water is added to or taken from either of them, the system will rebalance itself automatically. After rebalance, the volumes of water in the beakers are again equal. Putting a floating object into either beaker causes the same deflection that the same weight of water would (Archimedes' principle), and again the pointer returns automatically to zero. If the floating object is now removed, the balance behaves as if the same weight of water had been removed. But laying a weight on the platform outside a beaker causes the siphon to increase the deflection to a new equilibrium value.

ISSN:0002-9505    

DOI:10.1119/1.1933998

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

A laboratory test is described which consists of an experimental problem. The course in electrical measurements in which this test is given emphasizes the general rather than the specific aspects of electrical measuring techniques; the test is designed to test the student's ability to meet a new experimental problem. Examples of some of the questions are given.

ISSN:0002-9505    

DOI:10.1119/1.1933999

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

Remarks made on the occasion of the presentation of the Oersted Award to Professor Vernet E. Eaton.

ISSN:0002-9505    

DOI:10.1119/1.1934000

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

Remarks by Professor V. E. Eaton on the occasion of his receiving the nineteenth Oersted Medal for notable contributions to the teaching of physics, at the twenty-fourth annual meeting, New York, January 28, 1955.

ISSN:0002-9505    

DOI:10.1119/1.1934001

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

The advantages of using the method of the grand ensembles are discussed. As a special case Saha's formula for dissociation equilibria is derived using the method of the quantum-mechanical canonical grand ensembles. One of the advantages in this case is that it is possible at each step to take stock of the simplifying assumptions made during the derivation.

ISSN:0002-9505    

DOI:10.1119/1.1934002

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

The general objectives of a course in general physics for engineers are discussed. To ascertain whether these objectives are being met, the author has reviewed several leading physics textbooks and several basic engineering textbooks in equivalent areas. He is discouraged by the multiplicity of applied topics apparently discussed in the physics courses, without apparent major emphasis on concepts. He concludes that it might be better to ask the physics department to teach a course in atomic and nuclear physics, possibly at the junior or senior level, and allow Engineering to teach the fundamentals of the classical area as they are already doing to a large extent.

ISSN:0002-9505    

DOI:10.1119/1.1934003

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

The contentions are raised that a thoroughly integrated presentation of fundamentals is highly essential to engineering students and must be given regardless of the title or department of the professor doing it, that physics departments and texts are doing it today, not perfectly perhaps, but under considerable difficulties, and finally that physicists still have an approach and a point of view that is decidedly more basic than that of the engineer and is decidedly healthy for the engineering student to learn. A suggestion is offered for expanding the crowded four-year curriculum by bringing students from high schools a year earlier.

ISSN:0002-9505    

DOI:10.1119/1.1934004

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

The idea of a primitive system in Kron's theory is shown to involve two distinct concepts and to be not well defined. An attempt is made to give a sharper definition. The discussion is confined to electrical networks. The anomaly is stressed that though Kron's primitive network and the given network are physically different, the transformation laws imply that their instantaneous power inputs are equal. Ways proposed by various authors of avoiding this anomaly are briefly discussed. Some ignore the primitive network; others make the primitive network physically equivalent to the given network, either by changing the primitive network or by changing the given network. Since this does not accord with the method by which Kron forms his primitive network, the view is put forward that the primitive networkisphysically different from the given network. A new network, the “connected primitive network,” is introduced which, among other things, clarifies the physical significance of a singularC-transformation. The given network and primitive network are considered to stand for infinite families of networks; the singularC-transformation then selects from the family of primitive networks a subfamily that coincides with the family of given networks.

ISSN:0002-9505    

DOI:10.1119/1.1934005

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

The Néel theory of ferrimagnetism is a molecular-field theory of magnetic ordering in systems which contain nonequivalent substructures of magnetic ions. The two principal results of the theory are (a) the curve of reciprocal susceptibilityvstemperature above the Curie temperature is an hyperbola, and (b) the curve of spontaneous magnetizationvstemperature below the Curie temperature may have any one of a number of unusual forms. The exact form depends on the distribution of magnetic ions between the substructures and on the relative values of the molecular field coefficients.The agreement between the predictions of the Néel theory and some experimental observations on ferrites is discussed briefly.

ISSN:0002-9505    

DOI:10.1119/1.1934006

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP

摘要:

The cross sections of certain nuclear reactions, as functions of energy, show sharp maxima and low values between the maxima, thus exhibiting a great similarity to line spectra. The compound nucleus theory was originally designed to explain this structure and to describe the corresponding nuclear reactions. After a brief description of the picture which the compound nucleus theory presents for these reactions, the story of the extension of the theory to describe a wide variety of reactions is presented. This includes an outline of the mathematical concepts which the extended theory uses. The last part of the article deals with the connection between the so-called principle of causality, which expresses the fact that the scattered particle wave cannot leave the nucleus before the incident particle wave has reached it, and the formulas of the generalized compound nucleus theory.

ISSN:0002-9505    

DOI:10.1119/1.1934007

出版商:American Association of Physics Teachers    

年代:1955

数据来源: AIP