摘要:

Buoyant conduits of a water–syrup mixture were produced in syrup by injection from below. Low‐amplitude waves on the walls of these conduits have been theoretically shown to obey the Korteweg–de Vries (KdV) equation which has soliton solutions. However, qualitative soliton behavior persists even for very‐large‐amplitude waves. Collision properties of two waves are compared to KdV solitons using video images of 16 collisions. Wave amplitude is conserved upon collison to better than ±10%, but there is a slight enlargement of the large wave at the expense of the small wave. Position change in the trajectory of the waves due to wave–wave collison has the correct qualitative behavior when plotted against KdV theory. Wave packets that disperse into isolated solitary waves are also easy to observe.

ISSN:0002-9505    

DOI:10.1119/1.15283

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

The wavefunction and the Kronig–Penney dispersion relation of an electron moving in a one‐dimensional periodic array of delta potentials are found, in the relativistic as well as in the nonrelativistic case. The Green’s function method and Bloch’s theorem are used in a simple form.

ISSN:0002-9505    

DOI:10.1119/1.14922

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

A method for evaluation of chemical potential and energy of an ideal Fermi–Dirac gas is presented. Additional terms in the series expressions for chemical potential and energy are given.

ISSN:0002-9505    

DOI:10.1119/1.14923

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

Multipole moments for the harmonic oscillator as well as for other familiar quantum systems can be obtained without knowledge of the wavefunction by means of simple recursion relations. The third‐order differential equation satisfied by the probability density is first obtained and from it, the recursion relation for the moments is directly deduced. A general and presumably novel formula giving all the multipole moments is obtained by solving the finite difference equation generated by the recursion relation.

ISSN:0002-9505    

DOI:10.1119/1.14924

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

This article describes a mechanical system for viewing motion in a rotating reference frame and in particular under a pure Coriolis acceleration. It also discusses how this motion may be made visible to a large audience by using a TV camera in the rotating frame and projecting the motion in the rotating frame on a screen. In addition, the article discusses the theory involved in producing a pure Coriolis acceleration.

ISSN:0002-9505    

DOI:10.1119/1.14925

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

A holographic transmission grating is made using a 15‐mW He–Ne laser (Spectra Physics Model No. 124B). Two front‐surface mirrors are used to obtain two coherent beams by the method of division of wavefront. The interference pattern is recorded on a high‐resolution photographic plate. The value of ‘‘d’’ the grating constant is calculated using the relationship between the fringe spacing and the angle between the two interfering beams. This value is then compared with the one obtained by using the grating equation, a spectrometer, and a mercury lamp. From the results obtained and in view of the fact that He–Ne lasers are readily available in physics laboratories, this experiment is recommended as suitable for an advanced undergraduate optics and spectroscopy or quantum physics laboratory.

ISSN:0002-9505    

DOI:10.1119/1.14926

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

This is a discussion of the conceptual problems that have muddled the equation of motion for a radiating charged particle for a long time. An effort is made to pinpoint the weak parts of the usual arguments on this topic. The problems found range from doubts on the applicability of the classical electrodynamics of Maxwell and Lorentz to the problem at hand, to the inapplicability of certain perturbation techniques once the general theory has been tentatively accepted. Hopefully this will raise interest on these challenging problems, whose importance goes beyond the classical domain.

ISSN:0002-9505    

DOI:10.1119/1.14927

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

Much of the present article serves as an introduction to a set of ideas familiar in dynamical systems theory. No familiarity with these ideas is assumed on the part of the reader. The ideas are then combined in simple, geometric arguments to prove Sarkowskii’s theorem. This theorem is important in the study of one‐dimensional, deterministic, dissipative dynamical systems. It provides a unified framework for the occurrences of both orderly and chaotic motions. The relationship of the mathematical models discussed here to real physical and biological systems is discussed briefly and the reader is referred to the literature for descriptions of diverse, beautiful, relevant experiments.

ISSN:0002-9505    

DOI:10.1119/1.14928

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

摘要:

A physicist’s ‘‘toolkit’’ might include mathematical, diagrammatic, and modeling tools, including such models as a crystalline solid, a harmonic oscillator, or an inverse square law of interaction. The notion of a toolkit provides a meeting ground for scientists, philosophers, and teachers for appreciating what scientists do. For doing science may be thought of as a craft, skillfully employing a kit of tools.

ISSN:0002-9505    

DOI:10.1119/1.14929

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP

ISSN:0002-9505    

DOI:10.1119/1.14930

出版商:American Association of Physics Teachers    

年代:1987

数据来源: AIP