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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Which physicists died very young or in a tragic way?
Inspired by Which mathematicians died very young or in a tragic way? , I wonder which physicists had similar fates.
A quick search lead me to Heinrich Hertz who died from a malignant bone condition at ...
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Who was the first to hypothesise that gravity from one mass causes the spacetime around another mass to curve?
Was it Einstein? Or was there someone before him to hypothesise this?
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Did Richard Feynman ever meet Stephen Hawking or comment on Hawking radiation?
I was just curious what Richard Feynman thought of Stephen Hawking's Hawking Radiation. Feynman was one of the developers of quantum field theory and Hawking's work would have been cutting edge on the ...
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How did Planck derive the black body radiation formula without using the Bose statistics?
It is so funny that science never develops as in the textbooks. Bose only introduced his statistics in 1924, so Planck could not possibly have used it to derive the radiation formula in 1900. So how ...
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Why did Einstein stop publishing so many papers in Annalen der Physik?
In his early years (actually, straight through the early 1910s), Albert Einstein published a lot of papers in Annalen der Phyisk, a very old and prominent German scientific journal. However, this ...
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Einstein's confusion about Stern-Gerlach
In a historical description of the Stern-Gerlach experiment, [Friedrich 2003] says:
Einstein and Paul Ehrenfest, among others, struggled to understand how the atomic magnets could take up definite, ...
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Why and when did some areas separate themselves from philosophy and some not?
When the Greeks invented science and mathematics in around 600 BC, it was considered as a part of philosophy. Thales of Miletus was a mathematician and philosopher. Aristotle was a philosopher, ...
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Why was Alain Aspect discouraged from doing his now Nobel-winning work?
In an interview following Aspect's winning of the Nobel Prize in Physics, he claims that John Stuart Bell discouraged him from pursuing his now-famous 1982 experiment on quantum entanglement. The ...
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How did gyromagnetic ratio come up before quantum mechanics, and who introduced it?
I am really curious about who was the first one to define the gyromagnetic ratio $\gamma$ of a body, i.e. the ratio of its magnetic dipole momento to its angular momentum. It is a very important ...
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What explanations are there for this strong spike in the use of 'angular momentum' in the 1960s?
A recent comment called my attention to the Google Ngram for 'angular momentum', which shows a very strong and rather sharp peak in the usage of the phrase shortly after 1960, followed by a steady ...
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Was there early opposition to Newton's mechanics?
Scientific theories are rarely accepted immediately. Even if the evidence for a theory is impeccable, there will be some stragglers who resist it for lack of understanding. More interesting is when a ...
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Why did Einstein develop General Relativity?
I know that ultimately GR was validated by experiment. I'd like to know however, if there was any experimental discrepancy at the time that pointed to a conclusive flaw in Newtonian gravity, and which ...
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How did Young perform his double slit experiment?
Thomas Young is famous for his double slit experiment, but I can't seem to find his experimental setup (such as how is prepared the light before it went through the apparatus. Does anyone know his ...
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When was it first discovered (or comprehended) that air has weight?
When was it first discovered (or comprehended) that air has weight?
Did the ancients know of this, or did they think that air is weightless?
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What new physics was discovered or needed as a result of the Manhattan Project?
I originally asked this question on the Physics StackExchange and was told to migrate it here. I've tightened up the question a bit.
I recently got into a discussion with colleagues regarding ...
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When did people notice the special shapes of snowflakes, and when did they start to study them?
What was the first written account about snowflake shapes and when did physicists start to study the reasons why the form appears and how snowflakes form in the air?
Is there any old book that ...
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Was Aristotle really wrong about gravity?
When I was in 9th grade, I learned that Aristotle was responsible for holding back physics for centuries because he said that heavier objects fall faster than lighter objects. Finally, in the 16th ...
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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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What is the historical basis for the length of a year?
It is currently accepted that a year is equal to the time it takes for the earth to revolve around the sun. However around Roman times, Ptolemy's geocentric model was the widely accepted view of ...
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Heisenberg's Obituary to Pauli
In an interview of Heisenberg by Thomas Kuhn:
When Pauli had died, I was asked to write this memorial volume. Weisskopf had asked me. Then, actually, originally I had written an article on Pauli's ...
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Who predicted the existence of the muon neutrino?
The Wikipedia article on the muon neutrino says:
The muon neutrino is a lepton, an elementary subatomic particle which has the symbol $\nu_\mu$ and no net electric charge. Together with the muon it ...
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Why didn't Lorentz conclude that no object can go faster than light?
Based on Lorentz factor $\gamma = \frac{1}{\sqrt {1-\frac{v^2}{c^2}}}$ it is easy to see $v < c$ since otherwise $\gamma$ would be either undefined or a complex number, which is non-physical. Also, ...
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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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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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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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How did Newton explain his interference rings without wave optics?
Nowadays we know it is a consequence of the wave property of light. But ironically it was discovered by Newton who held the particle point-of-view of light. So how did he explain his discovery?
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Cavendish Laboratories Photo, 1939
So this photo of the Cavendish Laboratory is from 1939, and I was wondering if anyone knew any more about who was in the photo. (Click to enlarge)
From notes I've been given, I believe the front row ...
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When and how was UV radiation found to be dangerous to human skin?
It is pretty common knowledge nowadays that prolonged exposure to solar ultraviolet radiation is dangerous to human skin, potentially resulting in cancers such as melanoma and photoaging.
A bit of ...
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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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In which units did Sir Isaac Newton define force at that time as SI system didn't exist then?
Sir Isaac Newton led the foundation of his famous laws of motion during the 17th Century but at that time SI system hadn't existed. So in which units did he define force? Did he define it in some ...
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What would have been the popular textbook to learn mechanics in the 19 th century?
If you were a student of physics of let's say between 14-20 years old, what textbook would you be using to learn physics from ?
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Have the results from Computational Physics disprove any physics theory?
We are familiar with the instances when experimental results disproved physics theories, such as the Michelson-Morley experiment.
What about computational physics results? To date, is there any ...
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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 did Henry Cavendish deduce the inverse square law in electrostatics from his experiment in 1772?
An elegant experiment in 1772 by Henry Cavendish. Cavendish charged a spherical conducting shell that contained within it, and temporarily connected to it, a smaller sphere. The outer shell was then ...
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Was Thomson's model of Plum Pudding widely accepted as a model of atom?
Was this model widely accepted in the time as a model for the atom? or was it just a model between many alternatives?
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What actually led Feynman to the path integral formulation of quantum mechanics?
It is commonly known that Feynman's path integral was inspired by Dirac's observation that the kernel is proportional to $\exp{iS/\hbar}$. It was Feynman, however, who had the idea of expressing the ...
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How was difference in water pressure perceived in ancient cultures or the middle ages?
I recently wondered: Even when diving to just 2-3 meters without any modern equipment one can feel the change in pressure. Do we have any evidence how this was perceived and explained back in ancient ...
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Were there serious attempts to model the photoelectric effect classically?
Today we see the photoelectric effect as one of the simplest pieces of empirical evidence that leads to quantum physics. The historical development of the subject, however, seems to have involved much ...
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When and by whom was the term 'momentum' introduced?
We know that up to 1726, when the third edition of the Principia was published, the name for $m\vec v$ was: quantitas motus.
Do you know who substituted that with another Latin word: 'momentum'?
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Did Galileo bet money on the ship experiment?
Galileo's writings describe two experiments involving ships. These are summarized in the Wikipedia article Galileo's ship. (A lot of the text in the article is mine, and if there are things I'm ...
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Interpretation of $W$ in Boltzmann's entropy formula
Background
In the famous Boltzmann's entropy formula, carved in the physicist's tombstone, a mysterious quantity $W$ appears (a):
$$S=k_B \log W\label{1}\tag{1}$$
We often hear that $W$ represents "...
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Is Coulomb's law the earliest mathematical formula describing electricity?
Is Coulomb's law the earliest formal equation of electricity?
Before Coulomb, many scientists and engineers conducted experiments of electricity.
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Landau doubting conservation of energy---and what followed
When the original beta decay experiments seemed to suggest that energy was not a conserved quantity, Landau (among others) proposed that energy conservation was a statistical law rather then a ...
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Remarkable numerical calculations before electronic computers
I know the story that Cole found the factoring of the big number $2^{67}-1$.
Is there any other remarkable achievement of hand calculation?
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When did the use of complex numbers become widespread in physics?
Complex number are extremely useful in every branch of physics dealing with ondulatory phenomena. In electromagnetism, for example, they allow to write the solution of Maxwell's equations in a form ...
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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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What is the history of the energy concept and its measurement?
Could someone please explain how the concept of energy was originally conceived and how it evolved over time to our current understanding of it? Also how did people come about various ways of ...
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Origin of operators in quantum mechanics
Historically, where did the concept of operators in quantum mechanics come from?
How did people first understand that momentum operator should be of the form of $i \hbar \frac{{\rm d}}{{\rm d}x}$?
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Which book gives a thorough understanding on the scientific environment of antiquity?
I have started reading Rene Dugas' History of Mechanics book. I want to understand physics from the spectacle of seeing its intellectual evolution instead of directly jumping into its general theories/...
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Why did Einstein oppose quantum uncertainity?
Einstein always believed that everything is certain, and we can calculate everything. That's why he rejected quantum mechanics, due to its factor of uncertainty. But still quantum physics was right. ...
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