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.

Filter by
Sorted by
Tagged with
1
vote
1answer
55 views

Did Galileo use an erroneous geometrical result in 'Two New Sciences'?

In Thm. 4, Prop. 4 of Galileo's 'Two New Sciences' (pg. 187, Crew Translation), Galileo says the following: "From a single point $B$ draw the planes $BA$ and $BC$, having the same length but ...
4
votes
1answer
115 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? ...
6
votes
1answer
77 views

Einstein: 'SR is a theory of invariants, not relativity' — source?

It is occasionally remarked that Einstein was unhappy that SR became referred to as a ‘theory of relativity’, when in his eyes it was, much more importantly, a theory of invariants (Invariantentheorie)...
3
votes
2answers
358 views

How did Lorentz transformations get their modern definition?

Historically, Special Relativity was motivated by apparent inconsistencies between Maxwell's Electrodynamics and Newtonian Mechanics. In Einstein's well known paper "On the electrodynamics of moving ...
10
votes
2answers
1k views

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 ...
2
votes
0answers
58 views

Why is it that so many early astronomers and cosmologists wanted to believe in a static/infinite/eternal Universe?

I've been doing some research for a cosmology series and I'm struck by how many physicists and philosophers, from Newton to Einstein, had a notion that the Universe should be static and eternal. Why ...
4
votes
1answer
79 views

Who studied kinematics before Galileo? Did Galileo base his kinematic research on the previous work of any other scientist?

Galileo is known to have studied kinematics through his work with projectiles. How did he first consider researching motion and velocity? Was he inspired by previous work done by earlier scientific ...
0
votes
0answers
71 views

Was Lagrange the first to have used generalized coordinates?

I was wondering if Lagrange was the first to use generalized coordinates as defined by their wikipedia article.
1
vote
0answers
40 views

When was the first analysis of the single-slit experiment done using wave theory?

I am a bit confused by the history here. We know that in early 1800's Thomas Young performed the double-slit experiment to demonstrate light interference. After wave theory of light became more ...
3
votes
2answers
561 views

Who introduced the partition function?

Is it by Gibbs? Or Boltzmann? I do not expect Maxwell. The point is, how was the textbook introduction of partition function today developed.
2
votes
1answer
750 views

Who really was the first inventor of the laser?

I am reading these articles and books about science and I find that there are debates on who was the real (and first) inventor of the laser. Who is the real inventor of the laser? Please include ...
7
votes
2answers
6k views

Who is the lady on the image? [closed]

I stumbled upon the following napkin (yes, a napkin) and was wondering who the lady on the picture is: She is surrounded by some basic mathematical functions, as well as physical equations which ...
2
votes
0answers
74 views

Where can I find Lagrange’s original 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 ...
3
votes
0answers
190 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 ...
14
votes
4answers
2k views

What was Einstein's motivation for relativity theory?

I'm a high school student who never studied any relativity before, but I'm just wondering what was the question that Einstein asked himself before going into this field. I knew he has done lots of ...
5
votes
1answer
181 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 ...
8
votes
11answers
13k views

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 ...
2
votes
0answers
150 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 ...
8
votes
3answers
467 views

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 $i \hbar \frac{{\rm d}}{{\rm d}x}$? ...
0
votes
0answers
61 views

How was the term speed treated in the 16th and 17th centuries?

What did people in the 16th and 17th centuries mean by the term speed? Did they have $$\text{speed} = \frac{ \text{distance} }{ \text{time} }$$ back then? Or did they have some other notion of speed ...
19
votes
2answers
788 views

How did scientists plot complicated graphs in the 19th century?

I am wondering how did Maxwell in the 19th century draw such figures as the one shown? What tools or procedures did he need? Is it all compass and ruler drawing?
5
votes
1answer
129 views

Was Captain Cook’s voyage to observe the transit of Venus going to enable better ship navigation at the time?

On a recent visit to the Royal Observatory at Greenwich I was struck by its proximity to the Naval Academy next door. The theme of the history of clocks and development of astronomy was driven by the ...
25
votes
2answers
1k views

What attracted Einstein to the anomalous precession of Mercury?

The story is usually told starting with Einstein's 1915 paper Explanation of the Perihelion Motion of Mercury from General Relativity Theory, or at least its drafts from 1913-14. It was the first ...
14
votes
4answers
1k views

Why isn't Feynman's path integral taught more widely and earlier in today's academic physics curricula?

Anyone who has studied Feynman's path integral will know that it makes quantum mechanics more like classical mechanics. A student who has learned about the Lagrangian will easily understand the ...
3
votes
3answers
2k views

When and by whom was the earliest definition of speed given?

Speed is defined to be distance divided by time; when and who by was this definition first put forward? The obvious guess would be Galileo in early modern physics; is this right, and can it be ...
4
votes
0answers
107 views

During the development of QFT was this theory actually used to build any invention like the MRI?

I have always wondered if the equations of quantum field theory were actually ever used in the production of some invention or device other than needed to make predictions about the Standard Model of ...
5
votes
2answers
1k views

Why is the thermoelectric figure of merit denoted by $ZT$?

Why is the thermoelectric figure of merit denoted by $Z T$? Does $Z T$ come from the abbreviation of words in some language? Update: So far, $T$ has been figured out — it is the temperature, to make ...
6
votes
1answer
59 views

What was the historical importance of the discovery of high-$T_c$ superconductors?

I remember very well from my (only) class in solid state physics how enthusiastically the professor recounted the discovery of high-$T_c$ superconductors. In one particularly vivid anecdote, he ...
4
votes
0answers
70 views

Who introduced the comma notation for partial derivatives?

In general relativity, it is common to use the comma notation for partial derivatives $$\frac{\partial g_{\mu\nu}}{\partial x_\rho} = g_{\mu\nu_,\rho}$$ Where did this notation first appear? Was it ...
4
votes
1answer
207 views

Did Einstein ever refer to the coordinate speed/velocity of light?

In modern parlance we talk about two different speeds of light in general relativity. We distinguish between the local speed of light, which is always $c$, and the coordinate speed of light, which can ...
3
votes
0answers
71 views

Did the concept of the Dirac Sea influence the development of semiconductors like the transistor?

Dirac (1928), (http://rspa.royalsocietypublishing.org/content/royprsa/126/801/360.full.pdf) explained the negative-energy solutions of his equations as holes in a sea of electrons. The concept seems ...
4
votes
1answer
329 views

Who first proposed the “colour” charge?

Does anybody know a paper or sorts in which the term "colour" charge in QCD was introduced first? Or any other source in which this label was proposed?
8
votes
2answers
1k views

Who is the father (if there is one) of string theory?

I have read a variety of articles and books about string theory that relate the various initial discoveries that ultimately lead to a theory we know now as "string theory" (and its descendants such as ...
5
votes
1answer
127 views

Who was the first person to describe turbulence in mathematical terms?

Here I found that: Sixty years later, Russian mathematician Andrey Kolmogorov furthered our mathematical understanding of turbulence when he proposed that energy in a turbulent fluid at length $R$ ...
5
votes
0answers
98 views

Physics Curricula of 19th Century French Universities?

What were the physics curricula for 19th century French universities? I am looking for something akin to this distribution of courses at the École Polytechnique, but for other French universities, ...
5
votes
4answers
363 views

What are some good references elucidating the discovery/creation of Fourier Series?

I've always grappled with anything related to Fourier since my undergrad days. Recently, when revisiting why I learned what I did, I discovered how Fourier's desire to understand the flow of heat ...
17
votes
2answers
5k views

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 ...
3
votes
1answer
45 views

When is considered the birth of nonlinear optics?

When in our recorded history did first nonlinear optics appear? I am more interested in the first recorded use of nonlinear crystals.
0
votes
0answers
70 views

Max Planck and energy quantization idea

Did Planck have an intuition behind the idea of energy quantization of atomic oscillators and radiation, or was it just a mathematical trick to derive his distribution law?
1
vote
3answers
295 views

Biographies on 20th Century physicists

I've recently finished reading Helge Kragh's Quantum Generations and am looking forward to something to read next. I am hoping to find biographies or more information about certain physicists such as ...
2
votes
0answers
48 views

Did Rydberg ever learn of Bohr's quantum-mechanical explanation of his formula?

The Rydberg formula on the wavelengths of a spectral line in chemical elements was first stated empirically in 1888 by Johannes Rydberg. A theoretical explanation of the formula wouldn't arive until ...
0
votes
0answers
48 views

How did percolation theory come to be established in network science, and who first studied it?

According to the textbook "Network Science" by Albert-László Barabási, percolation theory is a specialized branch of both mathematics and physics [1]. It involves node clustering in a ...
1
vote
0answers
65 views

What is the original source of the problem of finding equivalent resistance between two nodes in an infinite grid of resistors?

A famous problem in electronics or physics course,is the following--- Consider an infinite 2d grid of resistors having resistance of equal value.Find the resistance between any two nodes in the grid. ...
14
votes
3answers
17k views

Why is kg the standard unit for mass and not g in SI?

Why is $\mathrm{kg}$ the standard unit for mass and not $\mathrm{g}$? I know that there is the kilogramme des Archives which is a kilogram and not a gram. But originally on April 7, 1795 the gram was ...
6
votes
2answers
120 views

Is there an etymological dictionary of terms in physics?

There are of course many physics dictionaries and glossaries and some words can be found in general etymological dictionaries and even English dictionaries; but is there a Physics Etymological ...
0
votes
0answers
385 views

Are Gauss' electrodynamics laws for charge-charge interaction correct at all?

My question refers to a fragment on electrodynamics written by Gauss at around 1835. In this short note (see Gauss' Werke, volume V, p.617) Gauss wrote down a fundamental equation which describes the ...
7
votes
1answer
411 views

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 ...
2
votes
1answer
88 views

Did James Clerk Maxwell derive the permittivity of free space from his “Maxwell's” equations or was the parameter already known by him?

My problem is my lack of knowledge on the historical development of the constant used for the permittivity of free space. I know instead of asking the question I should read Wiki on the history of "...
9
votes
1answer
1k views

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 ...
6
votes
1answer
1k views

How did Planck calculate the Planck constant?

Having started to learn about quantum behavior, this formula came up: $$E = hf $$ Where $E$ is energy, $h$ is the Planck constant and $f$ is the frequency. My physics teacher suggested an ...

1
2 3 4 5
10