摘要:

The infinite universe, uniformly populated with stars, was popularized in the 16th century. Early in the 17th century Kepler argued that within such a universe the sky everywhere would be as bright as the Sun. Since that time astronomers have sought in various ways to resolve the ’’dark night sky paradox’’ that is nowadays widely known as ’’Olbers’ paradox.’’ It is shown that the paradox has a simple resolution which has nothing to do with absorption of starlight, clustering of stars into galaxies, or expansion of the universe. The resolution is that stars do not shine long enough to fill space with sufficient radiation to create the bright sky visualized by Kepler.

ISSN:0002-9505    

DOI:10.1119/1.10974

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

Observational astronomy was carried out in detail by members of the cultures which flourished in western Europe in the third and second millenniab.c. Understanding the methods and goals of these observers necessitates consideration of the Sun and Moon and their motions in some detail. The methods by which eclipses may be predicted is also examined. Finally, the case to be made for Stonehenge as an observatory is reconsidered.

ISSN:0002-9505    

DOI:10.1119/1.10975

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

A method is presented for determining the approximate radius vector of a planet or asteroid from two closely separated observations of position. Much of the tedious computation of traditional methods is eliminated, and the mathematical ability required is not beyond freshman or sophomore students.

ISSN:0002-9505    

DOI:10.1119/1.10976

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

A procedure is presented for finding the elements of the orbit of an astronomical object from three or more observations. From a set of assumed elements an ephemeris is calculated and compared to the observations. The assumed elements are then adjusted using standard nonlinear least‐squares techniques.

ISSN:0002-9505    

DOI:10.1119/1.10977

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

We discuss some general guidelines and practical suggestions for systematically allocating limited resources so as to improve instruction, lower its costs, or both. Our main guideline consists of separating goals and assigning to each those resources which serve it best. We apply this procedure to selecting instructional goals, to dividing labor between human instructors and instructional materials (e.g., printed booklets, audio tapes), and to assessing student achievement. Our own experience with both PSI and conventional physics courses provides illustrations for these comments, which are generally applicable to both innovative and traditional course formats.

ISSN:0002-9505    

DOI:10.1119/1.10978

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

A description of a science study tour that included visits to eight European cities is given. Visits to science museums, research centers, and educational institutions are listed, as are special lectures.

ISSN:0002-9505    

DOI:10.1119/1.10979

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

We describe a cross‐disciplinary course, called ’’Physics, History and Society,’’ which has as its theme: the nature of physics and history. The major goal of the course is to examine and compare physics and history in order to illuminate the implicit assumptions underlying the two disciplines. Specific historians such as the Americans Frederick Jackson Turner and Charles A. Beard, and specific physicists such as Tycho Brahe, Johannes Kepler, and Isaac Newton are studied as representative of historical and physical inquiry. In addition to describing the materials, techniques, and aims of the course, we also present insights into physics, history, and teaching that we have gained by offering the course. In particular, we consider Newton’s ’’rules of reasoning in philosophy,’’ discuss why physicists and historians of science often disagree about physics, examine a problem of cross‐disciplinary teaching, and evaluate the impact of the course.

ISSN:0002-9505    

DOI:10.1119/1.10980

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

A flexibly designed set of units used to present a laboratory‐centered, inquiry‐oriented physical science course to education students is described. The activities in these units place the students into situations in which they must make sense out of their experiences, and provides the instructor with the opportunity to guide, evaluate and prescribe, according to the individual student’s interests, intellectual capabilities, and knowledge of science.

ISSN:0002-9505    

DOI:10.1119/1.10647

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

Naive use of the position representation wave functions for a particle in either a finite or infinite square well predicts properties of the momentum distribution in disagreement with those calculated in the momentum representation. The discrepancy is removed by explicit consideration of the effects of the discontinuity in the potential at the walls on position space calculations.

ISSN:0002-9505    

DOI:10.1119/1.10981

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP

摘要:

The dissipative forces of classical mechanics can be included in quantum mechanics by the use of non‐Hermitian Hamiltonians. The Ehrenfest theorem for such Hamiltonians is derived, and simple examples which show the classical correspondences are given. The viscosity coefficient for a nuclear collision is estimated.

ISSN:0002-9505    

DOI:10.1119/1.10982

出版商:American Association of Physics Teachers    

年代:1977

数据来源: AIP