摘要:

An equation of transient heat conduction is derived that involves the velocity of an isotherm and the rate of heat flow across the isotherm. It is shown that this equation is analogous to the equation of wave theory which relates the group velocity and phase velocity of the wave. It is shown that the equation derived for heat flow serves as a criterion for the propagation of a temperature distribution without change of form in the same way that the analogous equation of wave theory serves a similar purpose. It is also shown that under certain conditions the moving isotherms can be treated as moving heat sources.

ISSN:0002-9505    

DOI:10.1119/1.1933530

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

A revision and rebuilding of the general-physics lecture apparatus used at Yale for electronic and electrical demonstrations has resulted in a set of pieces of apparatus designed to minimize the time wasted by the lecturer in wiring and arranging equipment. At the same time the students have a clearer view of the essentials. Improvements and modifications may be made economically. Brief descriptions of the use of the apparatus are included.

ISSN:0002-9505    

DOI:10.1119/1.1933531

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

Attention is called to a method of measuring surface tension of liquids, originally due to Eötvös, and suitable for advanced laboratory practice. The method is recommended when freedom from contamination is otherwise difficult to achieve, and when measurements are desired over a considerable range of temperature.

ISSN:0002-9505    

DOI:10.1119/1.1933532

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

The theory of a generalized mechanical electrometer is developed in terms of the direct capacitances and potential differences between each pair of conductors comprising the electrometer, regardless of which is the movable conductor. A criterion is established for stable static equilibrium of the movable conductor. A distinction is made between voltage and charge measurements. General expressions are obtained for voltage and charge sensitivities, period, and the magnitude of random fluctuations in position of the movable conductor.

ISSN:0002-9505    

DOI:10.1119/1.1933533

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

It is shown that the forces on a nonplanar circuit with a steady current in a uniform magnetic field are the same as those on an equivalent plane circuit uniquely determined. The proof involves several remarks of mathematical interest.

ISSN:0002-9505    

DOI:10.1119/1.1933534

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

This paper makes available to the physicist two of the modern statistical tests for possible rejection of outlying observations. These two methods have been selected because they apply in a majority of the actually occurring situations and because they are so easy to use.

ISSN:0002-9505    

DOI:10.1119/1.1933535

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

The oscillations of a pair of classical oscillators which are synchronized because of anharmonic resonance can be calculated by the method of variation of constants. Two types of motion are studied: librational and nonlibrational—referring to oscillatory and progressive behavior, respectively, of the phase difference of the two oscillators. These motions are exemplified by the corresponding motion of a rod pendulum. Conditions for prolonged persistence of librational motion are discussed. This paper is essentially a review of some of E. W. Brown's papers on nonlinear resonance.

ISSN:0002-9505    

DOI:10.1119/1.1933536

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

This paper analyzes the educational process, using graphical methods wherever possible. In its simplest aspect education is represented by a growth curve. If restricted to a single subject the curve is a two-dimensional one and may include both learning and forgetting. The mechanism of learning appears to be quite different for accumulative subject matter such as mathematics or physics from that in nonaccumulative fields such as political theory or business management. Combining the learning curves for several subjects one obtains an educational pattern which may be directly related to particular job requirements or to college admission requirements.

ISSN:0002-9505    

DOI:10.1119/1.1933537

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

An analysis is made of existing textbooks in secondary school courses in physics. Particular attention is called to the illogical order, content, and over-popularization of material. These criticisms are supported by a detailed study of two important texts, and the question is raised whether these failings contribute to the shortage of young scientists.

ISSN:0002-9505    

DOI:10.1119/1.1933538

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP

摘要:

In this note, a continuation of an earlier paper, is given a general symbolic solution of equations of the type of the Schrödinger equation with sources. From this it is easy to see the connection which exists between the solutions of two important special problems: that in which the function vanishes initially and is therefore entirely determined by the source, and that in which the source vanishes and the function is entirely determined by its value at some initial instant.

ISSN:0002-9505    

DOI:10.1119/1.1933539

出版商:American Association of Physics Teachers    

年代:1953

数据来源: AIP