Questions tagged [physics]
For questions about the scientific discipline that concerns itself with analyzing the laws of nature in full generality. It is one of the largest branches of natural science. Before applying this tag to a question, please consider using the "theoretical-physics" or "experimental-physics" tags instead, as they are more descriptive.
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How transparency was explained by corpuscular theory and Young/Fresnel's wave theory
How did the light theories of Newton and Young/Fresnel explain the transparency of materials such as glass, or opacity of materials such as paper and wood?
Newton's theory of light was largely based ...
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1answer
96 views
Which conception of a “machine” allows to call “mechanical” the new physics of the 17th century?
My questions deal more properly with pre-Newtonian modern physics in its Cartesian or Hobbesian versions.
The word "mechanical" comes from a Greek word meaning "machine". However, the received ...
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28 views
Fresnel's partial aether drag hypothesis
In 1810, François Arago realised that variations in the refractive
index of a substance predicted by the corpuscular theory would provide
a useful method for measuring the velocity of light. These ...
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47 views
Where can I find Lagrange’s equilateral triangular solution for arbitrary masses?
This answer to What kind of triangle is formed by three unequal masses in a circular restricted three body orbit? explains that
In the Newtonian limit, an equilateral 3-body solution exists for any ...
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61 views
How has the degree of mathematisation in physics university education in the U.S. changed in the 20th century?
I'm mostly interested in the degree of mathematisation with which physics was taught. Intuitively, I believe to recall that Europe has had a long tradition of mathematical physics, while physics ...
4
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1answer
85 views
Quantum chromodynamics - an origin of the name
A theory of strong interaction is called quantum chromodynamics (QCD). Particles interacting strongly are supposed to have color charge, for example quarks appear in three "mutations" - red, green and ...
5
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0answers
101 views
Origin of Fourier Transform (1878)
I located Joseph Fourier's book, Analytial Theory of Heat (1878), but at first glance it looks like it is all about heat. What did Fourier call the Fourier transform? When did he first use it?
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1answer
58 views
How was a material independent temperature scale created?
Temperature measurements started with the developments of thermoscopes and thermometers. They were based on the fact that liquids in general expanded significantly on change in temperature (especially ...
4
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1answer
96 views
Was Joseph Priestley “isolated”
Joseph Priestley is often said to have discovered Oxygen, or not due to calling it Dephlogisticated air - depending on one's preference. However, regardless of this, it is often said in popular ...
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59 views
Did the mathematician Garrett Birkhoff ever work with or mention Feynman's path integrals?
Did Garrett Birkhoff ever work with Feynman's path integral? Did he ever work in his Many-Histories interpretation? Or at least, did he mention it in any of his articles?
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2answers
151 views
How did Newton prove his third law of motion?
I guess it is an experimental law, so what was the experiment?
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1answer
127 views
Natura non facit saltus (nature does not make jumps), who said that?
The sentence is Latin for nature doesn't make jumps. It refers to the fact that, in most physical processes, quantities vary continuously.
The principle was used by Leibniz, Kant and Darwin among ...
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44 views
Use of kT for energy of a wave?
The energy of $\frac12kT$ for each degree of freedom of a particle from statistical mechanics was derived from particles, and yet Rayleigh and Jeans just nonchalantly said let's borrow this and apply ...
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1answer
65 views
What did people understand heat and temperature to be in Clausius' time?
I just took a read of Clausius' original writing from 1867 on the second law. He refers to the "unit of heat" as "that amount of heat which is required to increase the temperature of unit-weight of ...
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0answers
110 views
Did Heisenberg ever accept Schrödinger's formulation of quantum mechanics, or at least did he relax his negative views about it?
Both Heisenberg and Schrödinger found each other's way of formulating Quantum Mechanics quite repellent.
My question is: Did any of the two change their views towards each other (specially Heisenberg)...
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1answer
94 views
Portrait of Stephen Butterworth
Does anybody know of a portrait of Stephen Butterworth (1885 - 1958), a British physicist?
2
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0answers
67 views
Historical accounts of a oft-cited quip by astronomer Walter Baade
I am looking for any documented, historical reference to an oft-cited humorous reply by German astronomer Walter Baade (1893 – 1960).
After having asked if other astronomers were familliar with the ...
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0answers
27 views
Who originally worked out the magnetic field produced by a solenoid and toroid?
Although, it seems very easy to find the magnetic field produced by a solenoid or a toroid, all we got to do is to make a suitable an Amperian Loop and take the $\mathbf B$ out of the integral and so ...
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1answer
43 views
Lawrence and Segre: Further information about relationship
There is a oft-repeated story (https://en.wikipedia.org/wiki/Emilio_Segr%C3%A8) about Lawrence, upon discovering that Segre was legally trapped in the USA, unable to return to Italy due to fascist ...
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3answers
112 views
What made Newton realize that the law of gravitation was 'universal'? [duplicate]
Newton's law of gravitation operative near the earth is the same law causes the earth and the other planets to go around the sun and other heavenly phenomena. Was it a giant leap of faith by Newton or ...
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33 views
Did pre-Galilean astronomy inspire Mach's principle?
Was Mach, in his formulation of "Mach's principle," influenced by pre-Galilean astronomy, such as that of Aristotle in On the Heavens, where heavenly bodies influence terrestrial ones?
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21 views
What experiment proved that electric current is charge transport? [duplicate]
To my knowledge, neither Volta nor Ampere nor Oersted, the founding fathers of electric current, knew that current is the transport of charge. Who, then, and by which experiment, proved the nature of ...
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1answer
741 views
Who first solved the classical harmonic oscillator?
There is a question Who solved the quantum harmonic oscillator?, but not one for the classical oscillator. Wikipedia's article Harmonic Oscillator does not have historical information either. So who ...
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1answer
197 views
How did 19th century physicists do their undergraduate/graduate studies?
I have read that
In 1847, he became aware of physicist James Prescott Joule’s argument for the mutual convertibility of heat and mechanical work and for their mechanical equivalence.
We study ...
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46 views
Can you suggest good resources for reading about history of science especially physics? [duplicate]
I'm looking for good resources of history of sciences (especially physics) which cover history from the time of Newton and Galileo (or before them) till the modern physics world (21st century).
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Advance of the perihelion of Mercury
When I did my MSc in astrophysics back in '95-'96, I was told that there had been an attempt around the early 20th century to account for the advance of the perihelion of Mercury by altering the ...
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1answer
287 views
Who introduced the “dagger”symbol as conjugate transpose in quantum mechanics?
The $\dagger$ symbol is often used in quantum mechanics,and also often in general mathematics to represent the conjugate transpose operation.For Hermitian matrices we can write $$A^\dagger=A$$Who ...
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79 views
What exactly was Lagrange's “grave mistake” with respect to rotating bodies under hydrostatic equilibrium?
A comment below What would be different about satellite orbits if Earth were prolate? Would we have Sun-synchronous and Molniya orbits? got me reading Wikipedia's Jacobi ellipsoid which begins:
...
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55 views
Dirac and proton-electron annihilation
Wikipedia says:
Robert Oppenheimer argued strongly against the proton being the negative-energy electron solution to Dirac's equation. He asserted that if it were, the hydrogen atom would rapidly ...
3
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1answer
92 views
What is the explanation of rope's strength in Galileo's Two New Sciences?
I'm reading Galileo's Two New Sciences. But as other Scientific Book it is hard. I am having trouble in First day, where SIMPLICO asks this question(Page 7):
"But how can one make a rope one ...
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88 views
What did Hans Bethe think of von Neumann's quantum logic?
Nobel laureate Hans Bethe was a friend of mathematician-physicist John von Neumann, and he once said:
"I have sometimes wondered whether a brain like von Neumann's does not indicate a species ...
6
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2answers
115 views
What is the history behind defining temperature as measure of hotness?
I know that when two bodies of different temperature are kept in contact "heat" flows from hotter body to colder. But how did anyone know that it is the "hotness" that flows, one could have said that ...
2
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1answer
54 views
When was spin of subatomic particles other than the electron discovered?
The idea of a spin angular momentum was first proposed in a 1925 publication by George Uhlenbeck and Samuel Goudsmit to explain hyperfine splitting in atomic spectra.
At what time was it measured ...
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1answer
119 views
Einstein praising Sophus Lie
p. 153 of
Raúl M. Falcón Ganfornina and Juan Núñez Valdés, “Mathematical Foundations of Santilli Isotopies,” trans. Alan Aversa, Algebras, Groups, and Geometries 32 (2015): 135–308.
quotes (but does ...
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65 views
How does the concept of centre of mass came to existence?
I am wondering as how does the concept of centre of mass came into being. Considering the usefulness of the concept how were the physicist able to define such a quantity. I mean was it just trial and ...
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0answers
55 views
How did the terms stress and strain come to describe two different things?
In physics, stress essentially captures forces in a body, where as strain captures displacements. Two dimensionally very different concepts. If you look it up in a thesaurus, stress and strain are ...
3
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1answer
205 views
What is the origin of the concept of reduced mass?
I am looking for the origin of the concept of reduced mass as used in vibrational spectroscopy e.g. vibration of a diatomic molecule. Most of the texts simply define reduced mass as the sum of the ...
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3answers
183 views
Did anyone mention the possibility of antimatter before 1928?
In 1932 positron and annihilation were discovered, but in 1928 Dirac had provided a formula allowing for the positron
Did anyone between that date and the discovery of electron ever imagine or ...
2
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1answer
58 views
What is Leroy Grumman Medal won by theoretical physicist Kenneth G. Wilson?
I happened to find that one of the most important inventors of the renormalization group, Kenneth G. Wilson, won the Leroy Randle Grumman Award Medal in 1986, 4 years after his Nobel prize. Details in ...
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1answer
142 views
How did $SU(2)$ came into physics?
It is natural for physicists to consider the group $SO(3)$. Presumably, $SU(2)$ came into physics because of quantum mechanics. How did people realize that when studying rotation of a physical system, ...
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1answer
138 views
What is the ancient cosmic canon of proportion and its role in the history of science?
Who had direct inside knowledge of the canon through the alleged secret oral tradition? Some possible examples that have been alluded to include Pythagoras, Plato, Euclid, Copernicus, Galileo, Kepler, ...
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1answer
78 views
How was (non-instantaneous) electric current first discovered?
How was (non-instantaneous) electric current first discovered and what were some of the main first thoughts on it?
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What happened to the undergrad students who attended the Feynman Lecture Series in 1961-63?
Note: This question was originally asked here, but I was wondering if I could get further clarification as this has truly intrigued me.
In the academic years of 1962-2 and 1962-3, Richard Feynman ...
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1answer
1k views
Why do many names of technical and scientific subjects end with “ics”?
The names of many technical and scientific subjects, like mathematics, physics, statistics, etc., etc., end with letters "ics". What is meant by this, if anything? Was there any logic behind it or is ...
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1answer
92 views
When did the use of Sine and Cosine as functions become mainstream?
In the work of early physicists like Newton, everything is explained in terms of cumbersome (in today's standards) geometry. They don't talk about "cosines" of certain angle, but about proportions ...
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1answer
93 views
Are these Newton's quotes apocryphal?
I have stumbled upon the following alleged Newton's quotes, but I could not find them in any of their works.
No great discovery was ever made without a bold guess.
No sciences are better ...
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2answers
3k views
Who discovered the covering homomorphism between SU(2) and SO(3)?
Who discovered this? It is quite nontrivial and very important in quantum mechanics.
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182 views
Identification of scientists in de Gennes book
Petit Point: A Candid Portrait on the Aberrations of Science is a charming book written by the French physicist Pierre-Gilles de Gennes containing short essays on some of the prominent scientists that ...
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Theory criteria from Misner-Thorne-Wheeler
In chapter 39.1 of Gravitation, by Misner, Thorne and Wheeler, it is asserted, quite reasonably, that a theory of gravitation (and, I assume, quite generally) must satisfy the three following criteria ...
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940 views
What is the origin of the $\hbar$ symbol?
Equations involving Planck's constant, $h ,$ are often simplified by instead writing them in terms of the reduced Planck's constant, $\hbar \equiv \frac{h}{2 \pi}.$ But where did the symbol for the ...
