Interferometer Experiments in Acoustics and Gravitation (Classic Reprint)

Interferometer Experiments in Acoustics and Gravitation (Classic Reprint)

Author: Carl Barus

Publisher:

Published: 2015-08-05

Total Pages: 162

ISBN-13: 9781332300365

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Excerpt from Interferometer Experiments in Acoustics and Gravitation In Chapter V, on the direct interferometry measurements of the compression of a sound-wave, much of my work has been superfluous, as it was anticipated in an admirable paper by Raps, using the Jamin interferometer. I have therefore given only as much as is necessary for the coordination of the other chapters. My method, however, is, I think, superior, owing to its much greater flexibility and the ease with which fringes in any orientation may be produced and shortened to a string of silvery beads. The simple organ-pipe blower or adjustable embouchure much used in the chapter will, I think, be found serviceable for many purposes, both of research and instruction. As the telephone is an indispensable convenience throughout these chapters, it was thought necessary to begin an interferometer investigation on the vibrations of the plate of that remarkable instrument. What comes out definitely in the research, Chapter V, is the readiness of the plate to quiver in overtones. A small mirror at the center is not therefore displaced, as a rule, translationally, but rather rotationally, giving rise to very complicated wave-forms, difficult to analyze. In corroboration of this, it was found (in Chapters IV and V, for instance) that a telephone current may often be commutated. In the endeavor to place the Foucault mirror on the interferometer I have thus far, for incidental reasons, failed of achievement; but as different apparatus useful in experiments of the present kind were tried out in the course of the work, I have given a brief account of it in Chapter VII. In Chapters VIII and IX, in deference to the wishes of Dr. R.S. Woodward, I have begun a search for methods of measuring the acceleration of gravity other than those classically in use. Such an inquiry necessarily consists in referring gravitational forces to forces generated in other mechanisms. An interferometer torsion-balance is first tested, but the results are found to contain relatively large and uncontrollable temperature coefficients, both of rigidity and viscosity, even if the ordinary effects of viscosity can be allowed for. The other (pneumatic) method for g, in which gravitational pull is referred to the pressure of a gas, has at the outset much to recommend it, for it admits of rough handling in spite of the otherwise surprising precision of results. The two errors which offer a serious menace to the accurate hydraulic weighing of the Cartesian diver, viz, the diffusion and solution discrepancies, though at first approach apparently insuperable, may not remain so indefinitely. At least, in experiments on the diffusion and convection of gases in narrow tubes, made in the lapse of years, coefficients of a negligibly small order of value were obtained. Though the work is very laborious, I think it will be worth while to carry it further. The remainder of the volume is largely concerned with work (Chapters XI and Xii) bearing on the constant of gravitation. The object of these experiments was at the outset a mere endeavor to read the deflections of the gravitation needle by displacement interferometry. The plan succeeded at once, almost beyond my expectations; but on computing the Newtonian constant it came out actually several times too large. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com


Interferometer Experiments In Acoustics And Gravitation Part III

Interferometer Experiments In Acoustics And Gravitation Part III

Author: Carl Barus

Publisher: Hassell Street Press

Published: 2021-09-09

Total Pages: 186

ISBN-13: 9781013561658

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This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.


The Ten Most Beautiful Experiments

The Ten Most Beautiful Experiments

Author: George Johnson

Publisher: Vintage

Published: 2009-03-10

Total Pages: 210

ISBN-13: 140003423X

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A dazzling, irresistible collection of the ten most groundbreaking and beautiful experiments in scientific history. With the attention to detail of a historian and the storytelling ability of a novelist, New York Times science writer George Johnson celebrates these groundbreaking experiments and re-creates a time when the world seemed filled with mysterious forces and scientists were in awe of light, electricity, and the human body. Here, we see Galileo staring down gravity, Newton breaking apart light, and Pavlov studying his now famous dogs. This is science in its most creative, hands-on form, when ingenuity of the mind is the most useful tool in the lab and the rewards of a well-considered experiment are on exquisite display.


Molecular Beams in Physics and Chemistry

Molecular Beams in Physics and Chemistry

Author: Bretislav Friedrich

Publisher: Springer Nature

Published: 2021-06-19

Total Pages: 639

ISBN-13: 3030639630

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This Open Access book gives a comprehensive account of both the history and current achievements of molecular beam research. In 1919, Otto Stern launched the revolutionary molecular beam technique. This technique made it possible to send atoms and molecules with well-defined momentum through vacuum and to measure with high accuracy the deflections they underwent when acted upon by transversal forces. These measurements revealed unforeseen quantum properties of nuclei, atoms, and molecules that became the basis for our current understanding of quantum matter. This volume shows that many key areas of modern physics and chemistry owe their beginnings to the seminal molecular beam work of Otto Stern and his school. Written by internationally recognized experts, the contributions in this volume will help experienced researchers and incoming graduate students alike to keep abreast of current developments in molecular beam research as well as to appreciate the history and evolution of this powerful method and the knowledge it reveals.


Epistemology of Experimental Gravity - Scientific Rationality

Epistemology of Experimental Gravity - Scientific Rationality

Author: Nicolae Sfetcu

Publisher: MultiMedia Publishing

Published:

Total Pages: 216

ISBN-13: 6060333214

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The evolution of gravitational tests from an epistemological perspective framed in the concept of rational reconstruction of Imre Lakatos, based on his methodology of research programmes. Unlike other works on the same subject, the evaluated period is very extensive, starting with Newton's natural philosophy and up to the quantum gravity theories of today. In order to explain in a more rational way the complex evolution of the gravity concept of the last century, I propose a natural extension of the methodology of the research programmes of Lakatos that I then use during the paper. I believe that this approach offers a new perspective on how evolved over time the concept of gravity and the methods of testing each theory of gravity, through observations and experiments. I argue, based on the methodology of the research programmes and the studies of scientists and philosophers, that the current theories of quantum gravity are degenerative, due to the lack of experimental evidence over a long period of time and of self-immunization against the possibility of falsification. Moreover, a methodological current is being developed that assigns a secondary, unimportant role to verification through observations and/or experiments. For this reason, it will not be possible to have a complete theory of quantum gravity in its current form, which to include to the limit the general relativity, since physical theories have always been adjusted, during their evolution, based on observational or experimental tests, and verified by the predictions made. Also, contrary to a widespread opinion and current active programs regarding the unification of all the fundamental forces of physics in a single final theory, based on string theory, I argue that this unification is generally unlikely, and it is not possible anyway for a unification to be developed based on current theories of quantum gravity, including string theory. In addition, I support the views of some scientists and philosophers that currently too much resources are being consumed on the idea of developing quantum gravity theories, and in particular string theory, to include general relativity and to unify gravity with other forces, as long as science does not impose such research programs. CONTENTS: Introduction Gravity Gravitational tests Methodology of Lakatos - Scientific rationality The natural extension of the Lakatos methodology Bifurcated programs Unifying programs 1. Newtonian gravity 1.1 Heuristics of Newtonian gravity 1.2 Proliferation of post-Newtonian theories 1.3 Tests of post-Newtonian theories 1.3.1 Newton's proposed tests 1.3.2 Tests of post-Newtonian theories 1.4 Newtonian gravity anomalies 1.5 Saturation point in Newtonian gravity 2. General relativity 2.1 Heuristics of the general relativity 2.2 Proliferation of post-Einsteinian gravitational theories 2.3 Post-Newtonian parameterized formalism (PPN) 2.4 Tests of general relativity and post-Einsteinian theories 2.4.1 Tests proposed by Einstein 2.4.2 Tests of post-Einsteinian theories 2.4.3 Classic tests 2.4.3.1 Precision of Mercury's perihelion 2.4.3.2 Light deflection 2.4.3.3 Gravitational redshift 2.4.4 Modern tests 2.4.4.1 Shapiro Delay 2.4.4.2 Gravitational dilation of time 2.4.4.3 Frame dragging and geodetic effect 2.4.4.4 Testing of the principle of equivalence 2.4.4.5 Solar system tests 2.4.5 Strong field gravitational tests 2.4.5.1 Gravitational lenses 2.4.5.2 Gravitational waves 2.4.5.3 Synchronization binary pulsars 2.4.5.4 Extreme environments 2.4.6 Cosmological tests 2.4.6.1 The expanding universe 2.4.6.2 Cosmological observations 2.4.6.3 Monitoring of weak gravitational lenses 2.5 Anomalies of general relativity 2.6 The saturation point of general relativity 3. Quantum gravity 3.1 Heuristics of quantum gravity 3.2 The tests of quantum gravity 3.3 Canonical quantum gravity 3.3.1 Tests proposed for the CQG 3.3.2. Loop quantum gravity 3.4 String theory 3.4.1 Heuristics of string theory 3.4.2. Anomalies of string theory 3.5 Other theories of quantum gravity 3.6 Unification (The Final Theory) 4. Cosmology Conclusions Notes Bibliography DOI: 10.13140/RG.2.2.35350.70724