Questions tagged [physics]
For questions about the scientific discipline that concerns itself with analysing the laws of nature in full generality
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In Geiger-Marsden experiments how was charge of alpha particle and charge of gold atom found?
Here: https://en.wikipedia.org/wiki/Geiger%E2%80%93Marsden_experiments
Some calculations were done to show how JJ Thomson's model predicts alpha particles will be mostly undeflected by the gold foil. ...
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Who was the first to say "Shut up and calculate!"?
The best thing I could find on the internet was this apparently forgotten article from 2004:
N. David Mermin, Could Feynman have said this?, Physics Today 57 (5), 2004.
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On the naming of quantum chromodynamics
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 ...
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On early US patriotism to choose quark color charge labels
Sean Carroll has a video about gauge theory (2020) in his series about Greatest Ideas of the Universe, where he claims that early in the development of quantum chromodynamics, some physicists tried to ...
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An English copy of One Hundred Authors Against Einstein?
I've been trying to find the famous article, "One hundred authors against Einstein" (100 Autoren gegen Einstein), of various objections to special relativity, which is quite often referenced, but ...
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Writing Mathematical Symbols in 20th century
As I was reading some papers written by Schrödinger and Heisenberg back in 1920s, I noticed that the symbols they use such as the integral or summation sign or calligraphic letters are as if printed ...
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What was different about Planck's quantization of light compared to Einstein's?
In describing black body radiation Planck assumed that the energy that can be absorbed or emitted by charges is quantized, i.e., they can only absorb or emit certain quantities of energy. But it was ...
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Who first noted the connection between Heisenberg's uncertainty principle and the Fourier transform?
Who first noted the connection between Heisenberg's uncertainty principle and the Fourier transform?
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How did Newton come up with his formula for gravitational force?
In high school students are taught the formula that describes the universal gravitational force $F=G\frac{m_1 m_2}{r^2}$. However it is not taught how and why Newton came up with it. Does Newton give ...
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In JJ Thomson's cathode ray experiment I need values for the electric field and magnetic field when net force on the cathode beam = 0
I asked here as well https://chemistry.stackexchange.com/questions/177889/in-jj-thomsons-cathode-ray-experiment-why-is-effects-of-gravity-on-electron-not
https://physics.stackexchange.com/questions/...
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Need a reference for Euler's velocity initial condition for the wave equation
In DOI: 10.4236/ahs.2020.94019 235 Advances in Historical Studies, p.234
D’Alembert and the Wave Equation: Its Disputes and Controversies, or https://www.scirp.org/pdf/ahs_2020112716312281.pdf p.6 of ...
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Who postulated the first Lagrangian for electrodynamics?
I am trying to find who first translated Maxwell's equations and Lorentz's force into the Lagrangian formalism. It seems a very straightforward thing to do if you know enough of electromagnetism and ...
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Did Newton know about non-inertial frames?
When answering a Physics.SE question, I made a claim that Newton realized that $F=ma$ worked in some frames, which are called "inertial frames." Nowadays, we know that there are non-...
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Book on the evolution of Quantum Theory
Can anyone recommend some good book(s) on the Evolution of Quantum Theory, focusing on history, not necessarily on explaining the technical/math part?
The books I have read so far,
"Quantum: ...
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What was the last "hole" in the electromagnetic spectrum where amplified, tunable, narrow-band power couldn't be produced artificially?
We had radio amplifiers that could transmit powerful signals and those were pushed to microwaves. We had lasers that were originally natural transitions in solids and gasses but now tunable lasers go ...
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Old square bracket notation for units
As discussed in this answer https://physics.stackexchange.com/a/77691/667 there are several common conventions for the notation $[q]$ of a physical quantity $q$.
However, I often see people to put ...
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1
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Why did systems theory never gain popularity?
Briefly from wikipedia,
Systems theory is the interdisciplinary study of systems, i.e. cohesive groups of interrelated, interdependent components that can be natural or human-made. Every system has ...
CommunityBot
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Did J. W. Gibbs “invent” Hilbert spaces before Hilbert formulated the notion of such spaces?
I was surprised to see a reply to a comment on his answer to a Quora question by a research mathematician claiming that Hilbert spaces were actually due to J. W. Gibbs rather than to D. Hilbert. The ...
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What is Heaviside's version of Maxwell's equations?
I have read, in many places, statements like this:
Heaviside was able to greatly simplify Maxwell's 20 equations in 20
variables, replacing them by four equations in two variables. Today we
...
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Onsager on phase transitions
Surely You're Joking Mr. Feynman has Feynman ascribing to Onsager the following quote (during the International Conference of Theoretical Physics in Kyoto, in 1953):
"We should tell Feynman ...
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Did Wheeler and Feynman said that vacuum zero point energy could boil the oceans?
Following on this Were Feynman diagrams motivated by the cosmological constant problem? and this Who was the first to estimate the vacuum energy discrepancy by 120 orders of magnitude? I found a ...
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1
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Why was the Greek letter psi (Ψ) chosen to represent the wave function?
When I was reading, the question just popped into my head after noticing that the Greek letter ψ looks kind of like a wave itself. Stylized, they look even more wavy:
$$\Huge \Psi\;\Huge\psi$$
This ...
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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 ...
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What's the difference between Galileo's "impeto" and "momento"?
In Galileo's Two New Sciences, he describes an experiment demonstrating pendulum motion and how the pendulum will rise to the same height from where it started its fall. This discussion can be found ...
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Do gravitational waves hold the record of longest delay between prediction and confirmation under the same theory?
This question is similar to What was the longest delay between prediction and confirmation of a theory? but I want to frame it in a different way. I am looking for long delays between prediction and ...
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Technical papers or monographs without a single mathematical equation
Recently, I stumbled upon a historically important monograph on a technical subject, which explained complex physical phenomena without a single mathematical equation. I forgot the name of the author, ...
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"Nuclear fusion is 30 years away" since when?
It's a well-known, running joke (or criticism) in the fusion community that
Fusion is always 30 years away.
refering to the considerable difficulties that harnessing nuclear fusion as an energy ...
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Where did the popular idea of spacetime come from?
[This question is about popular conceptions and therefore goes into strange directions, don't get too shocked]
The notion of spacetime can be traced back to roughly the 18th century where some people ...
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Why didn't Einstein propose any metric solution to his equations?
I've read about general relativity (GR) recently and something stroke me: Einstein came up with his equations in 1915, linking the metric of spacetime to the distribution of energy (more exactly, to ...
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What were Newton's six laws of motion?
In The Norton History of the Mathematical sciences, Ivor Grattan-Guinness writes of Newton's Principia,
Indeed, in working drafts for the book Newton considered up to six laws, and this trio are ...
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1
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Reconstruction of Newton's axioms
Hilbert reconstructed Euclid's axioms. Is there an equivalent restructuring of Newton's axioms, or are they considered consistent?
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When were arrows first used to visualise vectors?
I guess the use of arrows to visualise vectors came before the general notion of vectors, so a more precise question is: when where arrows first used to visualise physical (or mathematical) quantities ...
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How does Legendre transformation in classical mechanics relate to Adrien-Marie Legendre?
I tried to look for the history of Legendre transformation, which transformed Lagrangian mechanics to Hamiltonian mechanics, usually formulated as
$$
\begin{cases}
p_i = \frac{\partial L}{\partial v_i}...
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0
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Who found the formula for sequential Stern-Gerlach experiments and when?
Today we know that if you make sequential Stern-Gerlach experiments, where the magnetic fields are at an angle $\alpha$, then the formula for the ratio how the beam splits is
$$p_{1}=\cos^2 \bigg(\...
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1
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How was light polarization interpreted when first discovered?
Malus first discovered light polarization just before 1810, but Maxwell's equation stuff came around 1860s. How was polarization interpreted before the EM theory?
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What were the initial physical applications of vector calculus such as curl, div, circulation, and flux?
In what context where vector calculus concepts, such as:
Circulation
Flux
Curl
Divergence
first developed? I had assumed they were developed first in fluid dynamics, since the flow of water is ...
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Who is the philosopher Feynman cites as saying that existence of science requires the same conditions to produce the same results?
In part 6 of his lecture series "Character of Physical Law", Richard Feynman remarks:
A philosopher once said, "It is necessary for the very existence of science that the same conditions always ...
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What became of the Boltzmann-Zermelo debate about the second law of thermodynamics?
At the end of 19th century there was a lively discussion about the nature of the second law of thermodynamics, and its relation to Hamiltonian dynamics. Boltzmann developed a position that the second ...
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1
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When was Galileo's De Motu (Antiquiora) Made Available to the Public?
This question is in regard to Galileo's early writings on motion titled De Motu (On Motion) or De Motu Antiquiora (Older Writings On Motion).
It is understood that Galileo never published this ...
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1
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What is the history of the use of the word daughter for a decay product in nuclear physics?
I was browsing the book Isotopes: Principles and Applications by Faure and Mensing and I would like to know what is the history of the use of the word daughter for a decay product. It seems to me that ...
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Did Maxwell originally write his equations using quaternions?
I read somewhere, some time ago that Maxwell originally wrote his eponymous equations using the formalism of quaternions and it was only the later intervention of Gibbs and Heaviside that put them ...
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1
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Were Feynman diagrams motivated by the cosmological constant problem?
Sean Carroll, while speaking about the history of quantum field theory, has said a couple of times (without being completely sure of its factuality) that Richard Feynman was motivated by his trying to ...
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Who was the first to estimate the vacuum energy discrepancy by 120 orders of magnitude?
Apparently, this discrepancy is one of the "worst predictions" in the history of science. Clearly the vacuum energy calculation depends on many approximations and it is not clear how it ...
- 2,688
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1
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What is the origin of the "red, green, yellow" quark color convention?
In physics, quarks come in one of three color states, usually chosen to be called, "red", "green", and "blue". However, because these are just labels, there are other ...
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What was the decisive argument against Le Sage's theory of gravity?
Le Sage's theory described gravity by means of corpuscules, small particles pervading space that hit masses all around. Between two masses a shadow comes about. None of them are present there. Masses ...
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Who determined the temperature of the Sun first?
It is commonplace that it is about 6000 Kelvin.
But who came to this value first?
And with what method? Based on the black body radiation theory?
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What values of Avogadro's Number did Jean Perrin come up with?
I am currently plundering the contents of the $1969$ reprint of the 2nd edition of Data and Formulae for Engineering Students published by Pergamon International (authors J.C. Anderson, D.M. Hum, B.G. ...
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How the concept of Momentum was discovered?
As we already know that the concept of Momentum was discovered before Newton discovered his laws of motion, but my question is $\rightarrow$ How they discovered the relationship p=mv without knowing ...
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134
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Did Heisenberg say free will could arise from quantum probabilistic mechanics?
I see this view attributed to him a lot during Twitter debates but I never found the source for it
does anyone know if Heisenberg actually held this view/suggested it?
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Early sources for surface and bound charges in polarization
I am looking for early sources (references) to the analysis in electrostatics where the polarization vector is rewritten in terms of bound charges and a surface polarization charge.
In terms of what I ...
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