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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How did they explain the radiation from hot objects at different wavelengths before the concept of atom was widely accepted?
I was reading about blackbody radiation and came across the following quote.
Planck did not believe in atoms, nor did he think the second law of
thermodynamics should be statistical because ...
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Quote about the history of particle physics
I have a (very) vague remembrance of a quote about the history of particle physics, particularly (I think?) the development of the standard model. As I recall, it was about how it was a very exciting ...
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When was the geometric structure of a water molecule discovered?
How and when was water the structure of a water molecule (specifically the angles) discovered?
Was it discovered by using a specific type of spectroscopy?
I know you can derive these angles ...
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Why is thermodynamics called thermodynamics?
Thermodynamics is derived from two Greek words
Therme, which means heat
Dynamis, which means power
We know that 'thermodynamics' encapsulates many concepts like energy, temperature, entropy, exergy, ...
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Help in Understanding Emission theory of Empedocles
Empedocles state that the Eyes have fire in them surrounded by water, by this fire ray of the beam goes from eyes to object, then we see that thing, But Question arises to me, Than why not people able ...
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How did ancient Greeks explain that we don't fall off the Earth's sphere? [closed]
Ancient Greeks knew that Earth is not flat. How did they explain that people don't fall off the sphere when they're not located on the top of it?
Knowing how ancient Greeks explained gravity (i.e. ...
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Did Maxwell discuss charge quantization?
I once read in Wikipedia that James Clerk Maxwell included the possibility that charge could be both quantified and continuous. Since the electron hadn't been discovered in 1873, does Maxwell discuss ...
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In which work was Boltzmann's entropy originally introduced?
I get an impression from this enyclopedia entry
that the primary source of the Boltzmann entropy equation $S = k \log W$ might be
1866, Über die Mechanische Bedeutung des Zweiten Hauptsatzes der ...
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How did Niels Bohr arrive at the second postulate of his atomic model?
Niels Bohr's second postulate of the Atomic Model states that the electron revolves in specific orbits in which the electron's angular momentum is an integral multiple of $\large\frac{h}{2π}$. Since ...
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To what extent did d'Alembert want to avoid the newtonian concept of force?
The context of this question:
In everyday life we use push and pull all the time to get things moving, to move ourselves. To ride a bicycle: our feet push the pedals to get moving. To accelerate we ...
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The abstraction of mathematics from physics
When and how did mathematics come to be abstracted away from the physical world?
At first, mathematics would originate in its simplest form of counting and addition as to keep track of certain ...
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What concept did pre-modern people have about thermodynamic phenomena?
How did people before the advent of modern science in the 17th century conceive thermodynamic phenomena? I want to know how people in Ancient Mesopotamia, Egypt, Greece, Rome, China and in the Middle ...
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The housing of the Cavendish Experiment
[I posted this to History, but it was suggested that History of Science and Mathematics would be a better choice. So I'm posting it here too.]
I’m working to build the Cavendish experiment of 1798 ...
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How has the modelling of classical electrodynamics changed since Maxwell?
Maxwell published his Treatise on Electricity and Magnetism in 1873, 150 years ago; before the discovery of quantized charges, special relativity, quantum field theory etc. How has the mathematical ...
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Upon which incorrect equation of Euler did Sophie Germain rely in her work that won a prix extraordinaire from the Paris Academy of Sciences?
Wikipedia's Sophie Germain; Work in elasticity; Subsequent attempts for the Prize says:
Germain had derived the correct differential equation (a special case of the Kirchhoff–Love equation),31 but ...
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Context behind Planck's "A new scientific truth does not triumph by convincing its opponents...but rather because its opponents eventually die..."?
The open access paper Lehtola & Karttunen (2022) Free and open source software for computational chemistry education (found in this answer) contains the following paragraph:
2 FREE AND OPEN ...
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How was adiabatic expansion seen from the caloric theory perspective?
Nowadays we say that during the adiabatic expansion stage of the Carnot Cycle the internal energy due to the temperature of the gas gets transformed into work, but Carnot himself supported the caloric ...
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Are there anonymous contributions to physics with large impact?
Based on this question
Are there any anonymous contributions to mathematics that had a great impact? , I would like to ask the same question for physics. Physics is different from mathematics in the ...
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Bardeen's missing talk
Back in 1968, James M. Bardeen gave a talk at the GR5 (5th international conference on gravitation and the theory of relativity), in which he presented a slight modification of the Schwarzschild ...
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What data did Copernicus use to construct his heliocentric model?
I think Copernicus and his contemporaries were modeling based on some data.
What data was Copernicus using and who created it?
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Why is electric potential denoted by $\phi$?
I haven't found any explanation for it, and I'm curious.
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What were some 19th century objections to the existence of absolute zero?
William Thomson (Lord Kelvin) proposed the existence of an absolute zero in 1848(1) by linearly extrapolating the experimentally determined volume-temperature law for gases. I recently learned that ...
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Units in J.J. Thompson's m/e experiment
The original paper by J.J. Thompson, where he exposes his experiment to measure $m/e$ can be found here. (Note that Thompson actually measured $m/e$ whereas the modern discussion is in terms of $e/m$.)...
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How did Cross and Dot signs come in vector multiplication?
We use cross sign in vector multiplication that gives vector result and dot sign that gives scalar result.
But how did the dot sign come in scalar product and the cross sign in vector product? It ...
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Who described the weak interaction as a non-contact force?
It is known that Enrico Fermi described the weak interaction as a four-fermion contact interaction, and Steven Weinberg, Sheldon L. Glashow and Abdus Salam developed the electroweak theory, in which ...
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Are there any good books on the history of condensed matter?
Condensed matter is probably as modern as quantum mechanics but has less coverage than other branches like particle physics. Is there are any good book on the history of solid state/condensed matter? ...
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What motivated formulation of the Hamilton-Jacobi equation?
I'm late to the Hamilton-Jacobi equation party and would like to know more about the historical context of its origin. What motivated its construction/discovery? What were its affordances over other ...
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Separation between Physics and Mathematics
When and under which circumstances did Physics and Mathematics take separate routes?
Even though connections between Mathematics and Physics have been strong and prosperous at all times the methods, ...
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Physical theories and Mathematics [closed]
I study pure mathematics. In pure mathematics, we begin from some axioms and obtain theorems. I am also interested in studying physics. I have some questions about the relationship between physical ...
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Einstein's overdetermination theory
In 1923 [1], Einstein proposed an idea for a classical theory that would explain some features of quantum mechanics, via the overdetermination of the EoM, so that only certain configurations would be ...
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On implications of Schrodingers Cat regarding macroscopic quantum states and decoherence
How exactly did Schrodingers Cat lead to development regarding macroscopic quantum states and decoherence? One often hears that the thought experiment was the initiator to the question, whether ...
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Scientific Collaborations during World War
Nowadays, scientific progress is often based on very big collaborations, like the discovery of gravitational waves by the Ligo and Virgo collaborations. But also in many other branches of science, ...
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What did Schroedinger try to say with the cat thought experiment?
In many books one finds different explanations. Specifically popular seems to be that he "argued against the Copenhagen interpretation". But what did he really intend to communicate?
I for ...
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What were the biggest physics challenges that Einstein personally faced in his attempt to geometrize electromagnetism?
From the Wikipedia's introduction to Einstein's entry:
However, for much of the later part of his career, he worked on two ultimately unsuccessful endeavors. [...] Second, he attempted to devise a ...
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Is there any theorem/physical law with different names in more than two different languages/regions?
Mathematical statements and physics equations often are named after a person (like Pythagoras theorem or Newton's second law). Reading from different authors with different origins one may sometimes ...
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Did a Chinese astronomical text conduct the "Galileo's Ship" thought experiment around the 2nd century BCE?
A math and physics magazine I was browsing through contains the quotation
The Earth is moving constantly, but people do not know it; like the
crew in an enclosed ship, they do not notice it.
The ...
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Source documents for Bronstein's Cube of Physics
The "cube of physics" is a quite useful summary of physics, for historical$^1$ and teaching$^2$ purposes, that is best explained (as far as I know) in "Physics On A Cube" by Jeremy ...
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Notation of Poynting vector
I know that the Poynting vector is defined as the cross-product $\vec{E}\times\vec{H}$ and that is "usually" denoted by $\vec{S}$ or $\vec{N}$.
I wonder if there is a particular reason for ...
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How did Rutherford detect the deflected alpha particles?
All I know is that detecting the deflecting alpha particles was a very tedious process, so much so that that was probably one reason why he asked Hans Geiger and Ernest Marsden to do the experiment. ...
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Who coined and popularized the term "photonics"?
Wikipedia mentions that the term "photonics" was first used in Bell Labs, but later got popularized by IEEE after introducing the "Photonics Technology Letters" journal.
But both ...
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What is the "legendary Chicago machine" Rosenfeld refers to in his 1963 paper *On quantization of fields*?
There's a famous paper by L. Rosenfeld (On quantization of fields. Nuclear Physics 40, 353–356 (1963). doi:10.1016/0029-5582(63)90279-7) in which he criticizes the theoretical arguments leading to the ...
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Had Albert Einstein tried to use the Galilean transformation on Maxwell's equations before AE's Special Theory?
I am looking for what motivated Albert Einstein in the direction of his Special Theory. I have read that it is unclear if he was set on that path by the Michelson-Morley experiments. Was AE aware ...
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Are there any direct comments by Isaac Newton on Leibniz's living force / vis-viva?
The living force or the vis-viva is a quantity usually attributed to Leibniz (although there were a few other people who identified it as a conserved quantity in certain collisions earlier). Many ...
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Have there been instances in physics where different scientists have interpreted the same data differently? [closed]
Have there been instances in physics where different scientists have interpreted the same data differently? If yes, can you please give me specific examples and explain why one interpretation was ...
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Who first measured the increase of mass with speed?
Wiki (https://en.wikipedia.org/wiki/Electromagnetic_mass) says that:
Thomson (1893) noticed that electromagnetic momentum and energy of charged bodies, and therefore their masses, depend on the speed ...
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How did the US get enough U235 for "Little Boy"
The answer to a different question (Where did Fermi get the U235 for the first nuclear pile) about U235, was that Fermi used natural uranium for his reactor. This explains, in particular, the origin ...
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Is there a source for a footnote in *A Canticle for Leibowitz* about the definition of the electron, "Negative Twist of Nothingness"
In a French edition of Fiat Homo (first part of A Canticle for Leibowitz) I found the following footnote about the definition of the electron given by Brother Francis to another monk, namely “Torsion ...
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Who was the first scientist to give a formula for the probability density function of the position of a photon in the double slit experiment?
The double-slit experiment shows the fundamentally probabilistic nature of quantum mechanical phenomena. On Wikipedia one can read:
This type of experiment was first performed, using light, by Thomas ...
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Why is the magnetic force on a current-carrying wire sometimes called the Laplace force?
Educated in the UK, I've been used to calling the force on a current-carrying wire in a magnetic field 'the motor effect force'. But I'm increasingly aware of another (less clumsy?) name for it: 'the ...
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Who introduced velocity potential?
Wikipedia cites John Anderson’s A History of Aerodynamics and says that velocity potential was introduced by Lagrange in 1788. However, I could trace it at least to Euler 1752, where he published his ...
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