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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1answer
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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 ...
0
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1answer
64 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 ...
22
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2answers
2k 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.
3
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0answers
89 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 ...
0
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0answers
65 views
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 ...
5
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3answers
353 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 ...
0
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0answers
67 views
Does Einstein's original derivation of E=MC^2 exist and what is it?
I read an article published by Scientific American stating Einstein did not prove the equation within the context of Special Relativity but I am skeptical. I was hoping someone could point me in the ...
4
votes
1answer
211 views
Why are 'speed' and 'velocity' not given the same name?
Position is a vector. Distance/length is a name of its magnitude.
Velocity is a vector. Speed is a name of its magnitude.
Acceleration is a name of a vector and its magnitude.
Force is a name of a ...
4
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0answers
94 views
Did Paul Dirac believe in multiple universes?
Prominent physicist Paul Dirac proposed a hypothesis that said that constants and laws of physics would evolve with time into different constants and laws of nature.
This hypothesis was used by ...
2
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0answers
92 views
Feynman's statement about the importance of basic science
I remember reading in the line that Feynman saying if the best technicians were tasked to build a radio they would make longer and thicker cables and transfer message but it took a physicist to ...
1
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0answers
31 views
Did Werner Heisenberg ever agree or propose the existence of some kind of multiverse?
I was watching a video (https://www.youtube.com/watch?v=muJYTeQlvC4) where the director of a videogame company speaks about one of its most successful games. This game is set in a floating city which ...
4
votes
4answers
157 views
Where did the false “equal transit-time” explanation of lift originate from?
It's supposedly a "widely circulated" false claim that wings generate lift because of their asymmetric shape, forcing air above to travel faster so that they meet up on the trailing edge at the same ...
0
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1answer
73 views
Reference for history of physics with description of mathematical models
I am interested in some reference text, for example, textbook that would describe going from old times (say, Greece) till modern times:
1) definitions of units and measurements
2) describing ...
1
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0answers
85 views
What did people mean by the term Force in earlier times?
Initially I used to believe that before Newton gave his Laws of Motion, people thought that Force was something that caused motion. It was Newton who first said that Force is something that causes ...
2
votes
0answers
57 views
Did Wheeler ever propose the existence of a multiverse containing parallel simultaneous universes?
It is known that the physicist John Archibald Wheeler proposed the existence of a multiverse in the form of a set of cycles of Big Bangs and Big Crunches (Cyclic/Oscillatory Multiverse Model).
But I ...
1
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1answer
103 views
Did physicist David Bohm ever propose the existence of a multiverse?
Did physicist David Bohm ever propose the existence of any kind of multiverse?
0
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3answers
86 views
Does Heliocentrism predate Copernicus?
I have seen this mentioned on the interwebs a few times. people have mentioned that some Greek thinkers and Islamic astronomers came up with heliocentrism before Copernicus and that Copernicus copied ...
1
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0answers
42 views
How did Gibbs discover Gibbs entropy?
I have read and I think that I agree with the idea that if we have to choose probability distribution for an unknown system then it is a good idea to choose a distribution that has the least bias.
I ...
2
votes
1answer
100 views
What was this experiment tainted by the observer effect?
I once heard a cautionary tale about the dangers of the observer-expectancy effect. It was at least presented as a true example from the history of science, but I'm having trouble identifying the ...
2
votes
0answers
112 views
Who discovered Maxwell-Faraday equation, $\nabla\times E=-\frac{\partial B}{\partial t}$? Was it Maxwell or Neumann?
I have been trying to find out who discovered Maxwell-Faraday equation, $\nabla\times E=-\frac{\partial B}{\partial t}$. Was it Maxwell himself, or was it Franz Ernst Neumann who derived it?
The ...
0
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0answers
41 views
Did Ludwig Boltzmann ever go to Copenhagen or any other part of Denmark?
Did Ludwig Boltzmann ever go to Copenhagen or any other part of Denmark?
I also read that he was appointed "Honorary Doctor" by the university of Oslo. Does this mean that he went to Norway?
https://...
2
votes
1answer
83 views
Are Wheeler's It from Bit/Participatory Universe and the Multiverse related?
Could I ask you for the relation between Wheeler's ideas and the multiverse? Do you know if these are related?
I ask you this because I found this very interesting article written by Kip Thorne with ...
6
votes
1answer
207 views
When and how did the notion/idea of physical constant emerge?
Physical constants (e.g. c, h, G, alpha and so on) play a central role in our scientific theories and they have yet drawn much of controversial flavor into questions concerning the foundational status ...
5
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1answer
226 views
How were negative numbers first used in physics?
The use of negative numbers in most of today's calculations is natural. But how did the use of negative numbers began in physics? What physical quantity required the introduction of negative numbers ...
1
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1answer
87 views
Did John von Neumann ever go to any Nordic Country? Did Eugene Paul Wigner ever go to any other Nordic Country apart from Sweden?
I'm researching about the presence of important scientists in Nordic Countries (Iceland, Norway, Denmark, Sweden and Finland).
I was hoping that someone could help me since I've not been able to find ...
8
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2answers
2k views
Which physicist is this quote attributed to?
There is a quote from a 19-20th century scientist that goes (and I am paraphrasing):
New scientific theories are never accepted until old scientist die.
Who is this cynical quote attributed to, ...
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2answers
125 views
What are the great works of Richard Phillips Feynman? [closed]
What are the prerequisites to read his book? Why Richard Phillips Feynman is so famous? What are great works of Richard Phillips Feynman?
5
votes
2answers
137 views
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 ...
3
votes
2answers
165 views
What animals or plants were used to illustrate ideas of physics?
This crossed my mind today...
There is Schrödinger's cat and Newton's apple.
Are there any other famous animals/plants featured in physics in a similar way?
2
votes
1answer
68 views
What was Isaac Newton's contribution to optics?
What was Isaac Newton's contribution to optics? I know that he believed in the corpuscular theory of light. Did he know about the laws of reflection ad refraction?
5
votes
1answer
110 views
Refraction in Newton's Corpuscular Theory of Light [duplicate]
Newton's theory of light stated that a light travelled in a straight line as small particles. When these particles travelled in a medium, they experienced an attractive force with the particles of the ...
2
votes
0answers
86 views
Were notable physicists great at math or computing? [closed]
Were famous or popular physicists like Galileo, Newton, Einstein, Feynman predominantly mathematicians or scientists (computing, experimenting, engineering, etc.)?
I am curious if people like the ...
3
votes
1answer
141 views
How did philosophers and scientists in the 18th century view mathematical explanation?
The 18th century saw a rise in the use of mathematical formalisms to account for natural phenomena. Works of Lagrange, Euler, d'Alembert, etc., were groundbreaking in the history of mechanics and ...
5
votes
1answer
107 views
Equivalence principle before Einstein [duplicate]
In a German interview some physicists were asked, what they would ask Einstein, if he were alive today. One of them wanted to know how Einstein came up with the idea of the equivalence principle, that ...
7
votes
2answers
201 views
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 ...
1
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0answers
40 views
Does anyone know articles or books about what the notion of difficulty in science, especially physics?
In physics, many problems were known at their time to be very challenging, for example the notion of heat, or how to understand the ideal gaz law, or the phase transition criticial behaviors, etc. And ...
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votes
1answer
128 views
Is Newton going to be the new Aristotle? [closed]
As general relativity and quantum mechanics become more accessible, is Newton going to become the new Aristotle, as the example of being wrong and misleading humanity for centuries? (as opposed to the ...
5
votes
6answers
246 views
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?
3
votes
1answer
79 views
Did old Crookes Radiometers ever have a pair of terminals?
This is a question about old physics lab equipment.
This and this question led to the question in SciFi SE Crookes Radiometer at the end of a telescope in old movie scene, something about a comet? ...
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votes
2answers
97 views
Can anybody identify an appropriate radio for this game?
This is quite a specific question about radio, but it has been rejected on the Amateur Radio and History Stack Exchanges, so I will ask it here...
I'm a complete radio ignoramous, but I've been ...
3
votes
1answer
80 views
How was the notion of the metacenter of a floating body discovered?
Does anybody knows how this important notion of hydrostatics was discovered?
I have read that it is about someone walking up and down the mountains of Latin America trying to disprove Cartesian ...
3
votes
0answers
35 views
Looking for references to an experiment on the evaporation rate of water in sunlight
I remember reading a long time ago about some experiments measuring evaporation rate of water in large open containers (tubs) sitting on open ground. It was a simple experiment, each day the water ...
10
votes
1answer
511 views
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, ...
3
votes
2answers
231 views
Did the Idea of Universal Gravitation predate Newton?
"Baba wrote over 60 books, almost everyone on a different topic, writing on issues from astronomy, identified stars that European scientists technology could not discover until the late 1800s, ...
0
votes
2answers
115 views
What experiments led to the sign of the electron's charge?
The famous Millikan's oil drop experiment in 1908 determined the magnitude of charge of the electron to be 1.59*10^(-19) C. However, it was well known that electron has a negative charge. Although ...
2
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0answers
93 views
Is it a historical coincidence that relative atomic weights by chemical methods and mass spectrometry are very close?
The concept of relative atomic weight originated from measuring the combining weight of hydrogen with a certain element. In the simplification process H was taken as unity (18th, 19th and 20th century)...
0
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1answer
166 views
Why is electric dipole moment represented by “p”?
"I recently came across a text where the electric dipole moment was represented as "d" instead of the more commonly used "p". The reason behind using "d" here is probably that "dipole moment" begins ...
0
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1answer
77 views
What's the relationship between Aristotle's theory of elements and motion and geometry?
I'm having a hard time gathering my thoughts about this.
I'm trying to find a connection or some sort of relation between the first 3 axioms (postulates) of Euclidean geometry (though around Aristotle'...
4
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1answer
92 views
High voltage / current sources in 19th century cathode ray experiments
In modern chemistry textbooks, a DC source (battery symbol) is usually shown for cathode ray tube experiments by Thomson and others. Certainly, no battery can provide very high voltages needed for gas ...
3
votes
1answer
239 views
Who associated the sharp, principal, diffuse, fundamental spectral terms with electron's momentum?
It is well documented that the notation for the electronic configuration (s,p,d,f) of atoms as used today originates from the words sharp, principal, diffuse, fundamental from alkali metal spectra (...
