The historical development of physics concepts: who did what and when.

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Why did Kepler thought that the Earth was hollow? [on hold]

I was researching a little about the theory of the hollow earth, since I am a mathematician I don't understand well about physics some famous scientific thought this namely Euler, Edmond Halley and ...
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2answers
133 views

On Newton's discovery of the universal law of gravitation

I'm reading Peter Collier's book on relativity and was on the chapter where he describes how Newton figured out the law for universal gravitation. This is the cannonball referred to in the following ...
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35 views

How was light used to detect targets in pre-radar times? [closed]

I read that light (optical systems) was used to detect targets in the air and sea before radar was used. I saw photos of light being focused in the skies etc. But I want to know more about this - How ...
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1answer
37 views

What are the tools used by Newton to measure motion?

I was wondering how did Sir Newton measured motion of objects (non celestial ones). What was his toolskit at the time?
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45 views

Why isn't mass conservation counted among the laws of thermodynamics? [closed]

Is this purely a historical artifact, a consequence of how the original formulators of the three laws were thinking and experimenting at the time? Or is there a compelling scientific/logical reason ...
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3answers
13k views

Electric field of a negative charge

How was it discovered that the electric field of a negative charge points towards the charge itself? Is it true? (Courtesy of wikipedia)
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1answer
172 views

Why does math work for describing and solving physics problems? [closed]

The clarified version As far as I understand, Wigner considers a "miracle" the fact that it is even possible to find a mathematical equation that describes a natural phenomenon. It is not exactly ...
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4answers
106 views

Was there physics science before invention of calculus?

Is there a part of physics that there is no calculus in it?
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1answer
398 views

Electrostatics-Coulomb's Law

Coulomb's Law is an experimental result. The furmula that Coulomb found to describe electrostatic interactions is: $$F=k_e\frac{q_1 q_2}{d^2}.$$ How did or What did Coulomb do to verify this law as ...
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1answer
33 views

Why are Bose-Einstein Condensates (BECs) named after Bose and Einstein?

Why are Bose-Einstein Condensates (BECs) named after Bose and Einstein? What did Einstein contribute to BECs? What were the relevant papers by Bose and Einstein?
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946 views

How did physicists know that only negative charges move?

I have phrased similarly another question about how physicists knew that two charges exist, positive and negative. The purpose of the question is not necessarily to educate me historically. It's just ...
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2answers
97 views

Why did Einstein retain the hypothesis of length contraction?

Why did Einstein retain the hypothesis of length contraction, which Lorentz introduced to save his æther theory, yet Einstein had no need to accept length contraction because he rejected the æther?
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50 views

Was Einstein familiar with the Michelson-Gale experiment?

Was Einstein familiar with the Michelson-Gale experiment (related to Sagnac's experiment)? If so, did Einstein explain the results of the Michelson-Gale experiment with his relativity theory? If so, ...
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37 views

What exactly were the “asymmetries which do not appear to be inherent in the phenomena” in Einstein's 1905 SR paper?

The first ¶ of Einstein's "On the Electrodynamics of Moving Bodies" says (my emphases): It is known that Maxwell's electrodynamics—as usually understood at the present time—when applied to moving ...
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5answers
5k views

How did physicists know that there are two kind of charges?

Problems The question I am about to make is either too stupid or hasn't bothered anyone because its obvious because I can't really find the answer anywhere. I am currently studying electricity and ...
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2answers
268 views

Doppler effect of matter waves

We all know that the relativistic mass of a moving object in Special relativity increases for an observer who is measuring it for a moving object. We also know the the concept of particle-wave ...
5
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1answer
128 views

How did Heisenberg come up with matrix mechanics?

I have learnt that matrix mechanics came before Schroedinger's wave mechanics, however introductory quantum mechanics textbooks introduce you to wave mechanics first. The way in which the transition ...
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2answers
48 views

Reference request: history of models and equations? [closed]

I am looking for an in-depth self-contained text for the layman which covers the historic development of major questions in physics and the models and equations considered to answer them, and their ...
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1answer
110 views

Why didn't Newton study electricity and magnetism?

This is a soft question about the history of physics. In Newton's time, electrical and magnetic phenomena (such as amber attracting things or the alignment of compass needles) were well known. Yet I ...
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1answer
174 views

Recent missed opportunities à la Freeman Dyson

There is an excellent paper by Freeman Dyson from 1972 (here) and therein the author cites old talks by Hilbert (here) and Minkowski (chapter 2 here) speaking about similar topics, namely how ...
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2answers
2k views

How is the number of electrons in an atom found?

I was wondering, what type of experiments were held to identify the number of electrons in an atom? (For example, how do we say that carbon has 6 electrons and magnesium 12.) I would like someone to ...
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55 views

Potential Energy = mgh. What is the name of this principle and did Newton discover it?

Somebody I know keeps trying to convince me that Potential Energy $PE=mgh$ is one of Newton's Laws (as well as the closely related idea, Work Done = force x distance moved). I am fairly certain that ...
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3answers
2k views

Did Einstein know about Michelson-Morley experiment?

The second postulate of special relativity deals with constancy of light in inertial reference frames. But, how did Einstein came to this conclusion? Did he knew about the Michelson-Morley experiment?
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1answer
36 views

How did Fizeau control the cog's rotations per second?

In Fizeau's cog experiment to determine the speed of light, how would he have had a way to accurately determine the number of rotations per second of the cog, given the experiment was conducted in ...
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2answers
942 views

History of the names “Feynman-gauge” & “Landau-gauge”. How arised & how settled?

Edit: Use this PO.org question instead. Warning: Students, stay away from antiquities. The aim to learn is to survive. Hi. Today the nomenclatures Feynman gauge and Landau gauge seem established, ...
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3answers
132 views

How did steady-state universe deal with entropy?

Until the 1960's the general consensus was that the universe is infinite years old (steady-state). The second law of thermodynamics says that entropy always increases, so we'd expect that within a ...
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29 views

Galileo's pendulum and any references

In some texts about the simple pendulum we use to see references about some "experiments" Galileo Galilei did realize and whereby he found some important results, including that the period of the ...
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1answer
36 views

History of Turbulence suggestions

I am looking for extensive historical accounts of turbulence that ideally is strong in math and physics (at least giving references). Any suggestions? The only book I found is "A Voyage Through ...
38
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1answer
2k views

Why was the first discovered neutrino an anti-neutrino?

In the search for neutrinos, Cowan and Reines discovered the electron anti-neutrino and named it as such. Why is the particle they discovered the anti-variety? The reason we call electrons 'electrons'...
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1answer
383 views

What was Feynman's famous formula?

In Welton(1983), Memories of Feynman, Welton mentions two formulas which he denotes as Feynman's Famous Formula (FFF) and FFF #2. Which famous formulas is he talking about? Is he maybe talking about ...
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1answer
2k views

The possibility of free electrical energy?

Please excuse my lack of knowledge/understanding. Question: Why Nikola Tesla's Free Energy concept was never worked upon? Even today. Context: Now that we know Nikola Tesla was a genius and did ...
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1answer
115 views

Who determined the half-life of Uranium 235 and how?

By Wiki, the half-life of Uranium 235 is as long as 703,800,000 years. This is huge. Therefore, on an human time scale, the decay is very small. This should pose difficulty for determining the half-...
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3answers
9k views

Why is a second equal to the duration of exactly 9,192,631,770 periods of radiations?

Why is a second equal to the duration of 9,192,631,770 periods of radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium-133 atom? Why is the number ...
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2answers
3k views

Were the Michelson-Morley results a surprise?

How unexpected were the Michelson-Morley experiment results? Did physicists have theoretical reasons to predict that the speed of light would result to be invariant?
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137 views

Schrödinger's interpretation of his wave function before Born

The below shows some excerpt from Feynman's lecture notes. 21–4 The meaning of the wave function When Schrödinger first discovered his equation he discovered the conservation law of Eq. (21....
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38 views

Which experiments of harmonic generation at low frequencies preceded Franken's SHG?

In The Principles of Nonlinear Optics by Shen, he says that the generation of harmonics at low frequencies were long-known before Franken did SHG in the optical range. Franken's idea was simple. ...
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2answers
146 views

What is the inconsistency between Maxwell's electrodynamics and newtonian mechanics?

As far as I understand, when a modification of a theory is made it is because some observation required this modifcation. Quantum Mechanics is a nice example of that: observations of microscopic ...
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3answers
2k views

Planck's distribution and Bose-Einstein distribution?

If the application of the Bose-Einstein distribution is in blackbody radiation, then what is Planck's distribution? Are they same? How did Planck know that he should use a Bose-Einstein distribution ...
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2answers
205 views

Why did Albert Einstein receive a nobel prize? [closed]

We all know that he received the prize due to his explanation of photoelectric effect. But the photoelectric effect, it’s a mere 3-4 page topic and uses a simple equation that typically anyone can ...
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147 views

Did Newton conduct any experiments to find something called momentum, or was he such a great genius that he was able to spot it intuitively?

I wanted to go to the depth of the discovery of classical mechanics, instead of just reading, accepting and learning things. Now my question is not a single question, but it can answer many of my ...
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2answers
97 views

Is electromotive force really a force? [duplicate]

As far the definition goes emf of electromotive force is basically potential difference. It even has dimensions of potential. Then why is it called a force?
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20 views

Classification of experimentally-determined physics laws? [duplicate]

Has anyone classified (or attempted to classify) all the experimentally-determined laws of physics, such as with a simple diagram or even in a full-length book?
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1answer
2k views

Historic derivation of Wien's law

Every book I've read, including a lot of websites, Wikipedia, etc, say that Wien derived this: $$\rho_\nu(T)=\rho(\nu,T)=\nu^3f\left(\frac{\nu}{T}\right)$$ Being $\rho_v(T)$ the spectral enegy ...
4
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4answers
586 views

Why is an electron negatively charged, and what is the difference between negative and positive charges?

Nobody has yet defined the actual meaning of a charge, or why a negative charge is different from a positive charge. Everybody knows that positive charge is due to protons and negative charge is due ...
5
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3answers
130 views

What are the original papers on the hydrogen spectral lines?

I am trying to find original sources for experiments that had observed spectral lines from hydrogen or other gases. I am looking into experiments that motivated Niels Bohr to write his ideas on the ...
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2answers
487 views

Why was the Stark effect discovered much later than the Zeeman effect?

This is strange. The Zeeman effect involves the magnetic field. The Stark effect involves the electric field. In the course of classical electrodynamics, we get the impression that for many physical ...
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1answer
83 views

What is really sought when we purpose Einstein's postulates in Special Relativity?

Special Relativity can be motivated by looking at Maxwell's Electrodynamics and noticing that there is some kind of inconsistency between it and Newtonian Mechanics. Indeed, as Einstein pointed out on ...
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7answers
3k views

Good book on the history of Quantum Mechanics?

Can anyone recommend a good book on the history of Quantum Mechanics, preferably one that is technical and not afraid to explain the maths (I did a degree in Physics many years ago) and also that ...
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1answer
432 views

Velocity distribution in ion source (electron bombardment) for Bainbridge mass spectrometer

Consider the following schematics of a Bainbridge mass spectrometer (Source: http://www.schoolphysics.co.uk/age16-19/Atomic%20physics/Atomic%20structure%20and%20ions/text/Mass_spectrometer/images/...