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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4
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1answer
66 views

When and how was water first detected outside of Earth?

When and how was water (in ice or any other state) first observed outside of Earth? What is the high-level chronology of this discovery, and how did the scientific community first reach reasonable ...
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561 views

How did quantum mechanics operators come into being?

Now I am starting to learn Quantum Mechanics. In the class I am taught about operators, postulates and all other basic stuff. I understand operators to be +, -, /, etc; but quantum mechanical ...
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1answer
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What are Archimedes's contributions to the principle of the screw pump?

I read that the famous screw pumps were used before Archimedes (in the hanging gardens of Babylon for example), and that the Archimedean screw is named after him because he "developed a rigorous ...
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1answer
205 views

Was Einstein the first person to think of the equivalence of a ball drop in an accelerated elevator and a ball drop on Earth?

Consider the following figure taken from Wikipedia. Was Einstein the first person to think of the equivalence of a ball drop in an elevator with acceleration of $g$ and a ball drop on Earth? To be ...
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0answers
144 views

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 ...
7
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1answer
486 views

Nobel Prize work derived from Manhattan Project research?

There are quite a few Nobel Prize winners (e.g. Physics) who worked on the Manhattan project in the development of the atomic bomb. But, did any Nobel Prize result from direct research performed on ...
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2answers
220 views

Why did Greek Olympic games take place every fourth year?

I was wondering why Greeks chose to have Olympic games every four years. Now, since we usually every fourth year is a leap one, it makes sense; but the reform of the calendar which stated this is due ...
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Is Millikan's famous oil drop experiment a fraud?

I read in my mechanics textbook written by Goodstein that Robert Millikan cherry-picked his data in his famous oil drop experiment, and now I'm left wondering about the scientific value of his results....
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1answer
88 views

How did each base quantity get its name? [closed]

I've tried searching everywhere, but I can't seem to find anything related to how the quantities got named! Base quantities: Mass Distance Time Temperature Electric current Quantity of a substance ...
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0answers
55 views

Were Lagrangian coordinates or Eulerian coordinates used first in continuum mechanics?

In these lecture notes, I read about two different ways of looking at the position of a particle $\mathcal{X}$ in some body $\mathcal{B}$, Lagrangian and Eulerian coordinates. In Lagrangian ...
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How did Ising pronounce his name? [closed]

The surname of Ernst Ising, of Ising model fame, is often pronounced as EYE-zing by non-German speakers, but as EE-zing by German speakers. It is frequently claimed that EE-zing is the correct ...
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1answer
593 views

History of the study of indeterminism in classical mechanics

The classic Norton's dome problem, space invaders and other examples, show that Classical Mechanics, held as the paragon of determinism for ages having inspired Laplace's statements on determinism, is ...
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Conflict between physics and philosophy

In the old days. stars of physicists like Einstein$^{[1]}$, Poincare, Heisenberg, Pauli, $^{[2]}$ Bohr and so on are quite philosophical mind, and like philosophy. $^{[3]}$ But now, it seems to me a ...
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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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1answer
133 views

Looking for a Book Which Discusses the Rigor in Newton's Principia Mathematica

About an year ago, I had seen an article somewhere on the internet which discussed Newton's Principia Mathematica and the rigor (or lack thereof) of the arguments presented. I have forgotten who the ...
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Are Brillouin's papers translated into English?

I mean the Brillouin in the WKB method. I want to read his original paper. But it is in French. Is it translated into English? It should be.
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1answer
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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 ...
12
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3answers
834 views

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, ...
14
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3answers
18k 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 ...
4
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1answer
638 views

Where did $P=VI$ come from?

Where did the basic physics law $P=VI$ come from? Here, $P$ is power, $V$ is voltage and $I$ is current. It doesn't have a name like Ohm's law, as far as I could find. So where did it originally come ...
8
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1answer
408 views

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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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, ...
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2answers
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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 ...
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234 views

What are Carl Friedrich Gauss's contributions to acoustics?

I read in many sites that Gauss worked in theoretical physics in the areas of mechanics, crystallography, acoustics, capillarity, electromagnetism and optics, but I couldn't find any place in his ...
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2answers
702 views

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 ...
6
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1answer
3k views

Why is Einstein's mass-energy relation usually written as $E=mc^2$, and not $\Delta E=\Delta m c^2$?

Why is Einstein's mass-energy relation usually written as $E=mc^2$, and not $\Delta E=\Delta m c^2$? When you calculate the energy $\Delta E$ released during nuclear fission, you take the difference ...
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2answers
707 views

Who came up with the laws of conservation of momentum?

Who came up with the laws of conservation of momentum? I'm more specifically interested in the conservation of angular momentum.
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3answers
6k views

Are there any famous physicists that never went to university?

With the restriction of physicists after the year 1900, were there any self-taught physicists that achieved fame without having gone to university?
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Why did Aristotle make mistakes in his laws of motion?

I was studying Aristotle's laws of motion and comparing them to Newton's. He states that heavier bodies fall faster than lighter ones. I really can't understand how he could have committed such a ...
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1answer
646 views

How did we come to the conclusion that light moves as fast as it does?

Scientist predict that light moves 3x108 m/s in a vacuum. Then, when light hits a medium like air, it goes into a medium with a different index and travels slower (I believe it indexes at 1.007 in air)...
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2k views

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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196 views

Reading material suggestion for history of Newton's laws of motion

I intend to review the different concepts related to laws of motion floating around the publication of Principia and hopefully would like to comment on these (It's an essay project). I've gathered ...
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1answer
466 views

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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204 views

In which paper did the typical textbook diagrams of the Millikan experiment appear the first time?

There are two typical visualizations for one of the results of the Millikan oil-drop experiment to illustrate that only integer multiples of some elementary charge occur in nature. The first one is ...
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2answers
3k views

Who was the first to postulate that space was a vacuum?

The fact that space is a vacuum and that the Earth's atmosphere only extends a short way above the surface is accepted as obvious. However, there is nothing a priori obvious about it: you first have ...
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1answer
471 views

What 19th century developments contributed to the General theory of Relativity?

Regarding General Theory of Relativity, I'm interested to find out whether there are some contributors to this theory in 19th century or not. In fact I want to know whether there are some physicists ...
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3answers
997 views

Books on the History of Physics

I've just finished reading Quantum: Einstein, Bohr, and the Great Debate About the Nature of Reality by Manjit Kumar, which deals with the history of QM from Plank's quantisation for black body ...
3
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1answer
112 views

How did Aristotle define life using his elemental system?

How did Aristotle define life using his elemental system? Because it seems that Earth, Fire, Air, and Water, only defined non-living matter, and Quintessence was solely used as the element of the ...
5
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2answers
328 views

On the development of Newtonian Mechanics

Having borrowed from the library an English translation of Newton's Principia (Motte's), I read the begining sections, Part 1 and the Systems of the world, and noticed that Newton did physics ...
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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 ...
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2answers
233 views

Mathematical interpretation of Aristotelian mechanics

I am looking for books which include a mathematical interpretation of Aristotle's hypotheses about mechanics. I heard that there are a few books which interpret his mechanical ideas mathematically, ...
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1answer
428 views

Why was the reduced Planck constant introduced and when?

When was the reduced planck constant $\hbar= h/2\pi$ first introduced and what was the reason behind introducing such a constant? I know that $E=\hbar \omega$ and $p=\hbar k$ and writing again and ...
6
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1answer
149 views

Did classical physicists feel ill-at-ease about point charges?

The point charge concept is clearly a very useful mathematical fiction, but it is also problematic from the point of view of "physical intuition". Even a layperson would feel that an explanation is ...
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3answers
5k views

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 ...
9
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1answer
346 views

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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1answer
374 views

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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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 ...
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3answers
3k 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 ...
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1answer
163 views

Why did the “old quantum theory” start off considering circular electron orbits?

It seems that both Bohr and Rutherford assumed circular orbits of electrons around the atom. But why did they do so, instead of assuming e.g. elliptical orbits?
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1answer
284 views

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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