ISSN:0002-9505    

DOI:10.1119/1.12516

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

Physics began about 600 B.C. with the Ionian Greeks and reached full development within three centuries. The creation of the concept of the atom is understandable within the context of Greek physical theory; so is the rejection of the atomic theory by the Greek physicists.

ISSN:0002-9505    

DOI:10.1119/1.12518

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

Newton’s achievements, both in thePrincipiaand theOpticks, were firmly rooted in an atomistic theory of matter, resembling aspects of modern nuclear physics in its emphasis on fundamental particles held in differing arrays by short and long‐range forces. Marred by premature sophistication, its parameters of particle size and shape and interparticulate forces could not be quantified. Although it inspired many scientists of the eighteenth century and was further developed into a qualitative theory which intrigued scientists into the twentieth century, Newtonian unitary corpuscular (or atomistic) matter theory was replaced for most investigators by a variety of substances for which the particulate nature was of less concern than the character of their gross behavior. It was on this basis that Dalton developed his new (chemical) atomism, reifying the multiplicity of substances with separate atoms for each, distinguished by operational differences in their chemical atomic weights.

ISSN:0002-9505    

DOI:10.1119/1.12519

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

In the middle of the 19th century, physicists abandoned the idea of heat as a special kind of matter in favor of the idea that heat was a ’’mode of motion’’ of ordinary matter. From this ’’dynamical’’ view of heat, they proceeded to a more precise ’’kinetic’’ theory and, along with it, the idea of the kinetic atom. This paper will survey the research of men like Joule, Kelvin, Maxwell, Clausius, and Boltzmann, as it comments on the basic conceptual issues involved in this area of the history of physics.

ISSN:0002-9505    

DOI:10.1119/1.12520

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

Bohr used to introduce his attempts to explain clearly the principles of the quantum theory of the atom with an historical sketch, beginning invariably with the nuclear model proposed by Rutherford. That was sound pedagogy but bad history. The Rutherford–Bohr atom stands in the middle of a line of work initiated by J.J. Thomson and concluded by the invention of quantum mechanics. Thompson’s program derived its inspiration from the peculiar emphasis on models characteristic of British physics of the 19th century. Rutherford’s atom was a late product of the goals and conceptions of Victorian science. Bohr’s modifications, although ultimately fatal to Thomson’s program, initially gave further impetus to it. In the early 1920s the most promising approach to an adequate theory of the atom appeared to be the literal and detailed elaboration of the classical mechanics of multiply periodic orbits. The approach succeeded, demonstrating in an unexpected way the force of an argument often advanced by Thomson: because a mechanical model is richer in implications than the considerations for which it was advanced, it can suggest new directions of research that may lead to important discoveries.

ISSN:0002-9505    

DOI:10.1119/1.12521

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

In obtaining the instantaneous angular velocity of a rotating rigid body, a large number of standard textbooks uses an incorrect argument by only considering the rate of change of the Euler angles but disregarding the simultaneous rate of change of the corresponding time‐dependent rotation axes. Therefore, a correct and concise derivation of this quantity for a rather general case is given, which also reveals that the usual simple formula does not at all arise as the erroneous textbook reasoning suggests, but as a consequence of certain generalized commutation relations satisfied by Euler rotations.

ISSN:0002-9505    

DOI:10.1119/1.12522

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

An experiment to illustrate mechanical resonance has been designed for use in lower division laboratories. The apparatus and procedure have deliberately been kept as simple as possible. The basic experiment yields measurements of amplitude versus driving frequency, but a fairly simple elaboration allows for measurements of the phase lag as well.

ISSN:0002-9505    

DOI:10.1119/1.12523

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

The structure of physics, which consists of physical concepts and their relationships, can be treated as an instructional variable by teachers who make the following choices: defined versus derived concepts, operational versus paraphrase (formal) definitions, theoretical versus empirical relationships. Different forms of the structure of physics will emerge from treatments that differ in these respects. For beginning students, reliance on operational definitions and empirical relationships is recommended. For advanced students, paraphrase definitions and theoretical relationships lead to more efficiency and elegance.

ISSN:0002-9505    

DOI:10.1119/1.12524

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

This paper describes a systematic investigation of the understanding of the concept of acceleration among students enrolled in a variety of introductory physics courses at the University of Washington. The criterion for assessing understanding of a kinematical concept is the ability to apply it successfully in interpreting simple motions of real objects. The main thrust of this study has been on the qualitative understanding of acceleration as the ratio Δv/Δt. The primary data source has been the individual demonstration interview in which students are asked specific questions about simple motions they observe. Results are reported for the success of different student populations in comparing accelerations for two simultaneous motions. Failure to make a proper comparison was due to various conceptual difficulties which are identified and described. Some implications for instruction are briefly discussed.

ISSN:0002-9505    

DOI:10.1119/1.12525

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP

摘要:

Sprinting is described by a simple physical model. The model is used to predict the differences between the recorded times for races on a straight track and on a curve. It is shown that the choice of the running lane makes a non‐negligible difference.

ISSN:0002-9505    

DOI:10.1119/1.12526

出版商:American Association of Physics Teachers    

年代:1981

数据来源: AIP