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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What was the vis viva controversy, including its philosophical aspects?

Leibniz's concept of vis visa (literally translated as living force) was a precursor to our modern concept of kinetic energy. His formula for it was close to the modern non-relativistic one: $mv^2$, ...
Michael Weiss's user avatar
19 votes
2 answers
8k 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 ...
Quantum spaghettification's user avatar
11 votes
1 answer
2k views

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 ...
Quantum spaghettification's user avatar
13 votes
1 answer
4k 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 ...
John's user avatar
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8 votes
1 answer
780 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 ...
Hamid Enki's user avatar
8 votes
1 answer
2k views

What is the history of electric current and resistance?

Thomas Kuhn writes in The Structure of Scientific Revolutions Part of what the acceptance of Ohm’s Law demanded was a redefinition of both ‘current’ and ‘resistance’; if those terms had continued ...
Christian's user avatar
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40 votes
6 answers
7k views

Whose shoulders did Newton stand on?

In a letter to Robert Hooke in 1676, Newton wrote: If I have seen further it is by standing on the shoulders of giants. Do we know which giants Newton was referring to? And was he referring to a ...
TooTone's user avatar
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24 votes
1 answer
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How was Einstein led to make a contact with Differential Geometry for his theory of General Relativity?

General Relativity was developed with Differential Geometry as the tool. How was Einstein led to make a contact with Differential Geometry for his theory of General Relativity? Who suggested him to ...
Display Name's user avatar
21 votes
3 answers
2k views

How did Kepler "guess" his third law from data?

It is amazing that Kepler determined his three laws by looking at data, without a calculator and using only pen and paper. It is conceivable how he proved his laws described the data after he had ...
user avatar
18 votes
5 answers
2k views

Why don't we learn Buridan's laws of motion?

My question is why has Jean Buridan faded into obscurity while Newton is venerated as a God by scientists? Here is a description of Buridan's impetus theory: The concept of inertia was alien to the ...
Neil Meyer's user avatar
9 votes
2 answers
9k views

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. ...
Creepy Creature's user avatar
6 votes
1 answer
4k views

What are the major flaws of the “caloric” theory of heat?

I was reading about the history of thermodynamics and came across Lavoisier's idea of heat. He proposed that heat was a fluid. I am curious to know what are the major drawbacks of this theory. I know ...
Student's user avatar
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25 votes
3 answers
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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....
Shing's user avatar
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12 votes
1 answer
1k views

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?
J.Bates's user avatar
  • 191
9 votes
1 answer
565 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.
user2986288's user avatar
6 votes
4 answers
1k views

Galileo's Discussion of Uniform Motion

Can someone help me here? the language is archaic. This is (translation of) Galileo If two particles carried at a uniform rate, the ratio of their speeds will be the product of the ratio of the ...
john mangual's user avatar
15 votes
1 answer
2k views

When was the vector notation in physics and other sciences first introduced?

The vector notation in physics is a very compact and easy way to write things down, and according to Feynman it also saves print. When exactly did scientists realize that they were summarizing things ...
Gonenc's user avatar
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10 votes
3 answers
2k 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 ...
cspirou's user avatar
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8 votes
2 answers
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How did Newton come up with his formula for gravitational force?

In high school students are taught the formula that describes the universal gravitational force $F=G\frac{m_1 m_2}{r^2}$. However it is not taught how and why Newton came up with it. Does Newton give ...
PunkZebra's user avatar
  • 189
8 votes
1 answer
1k views

Where did Rayleigh derive the ultraviolet catastrophe?

Where can I find this paper: J.W. Strutt, Verh. d. deutsch. phys. Ges. 2, 65 (1900). It is presumably where Rayleigh derived the black-body radiation formula (the incorrect one that has ultraviolet ...
user avatar
8 votes
1 answer
1k views

When were the modern notions of work and energy created

Reading through Wikipedia says that Coriolis was the first to introduce the notion of work, described as "weight lifted through a height". Our modern conception of work is of a force that realizes a ...
Mark Fantini's user avatar
8 votes
3 answers
2k views

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 ...
SaitamaSensei's user avatar
7 votes
1 answer
4k 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 ...
wythagoras's user avatar
  • 3,042
5 votes
1 answer
611 views

Who first derived $a =v^2/r$

This is a basic formula in mechanics, which determines the acceleration of a particle performing uniform circular motion. By who first derived it? In Newton's Principa, what one can find is that $$...
poisson's user avatar
  • 407
4 votes
3 answers
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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 ...
Mozibur Ullah's user avatar
4 votes
1 answer
369 views

Was there any atomic model(s) that came between Bohr's and the actual beginning of Quantum Mechanics in early 20s?

Well, the question arose in the physics chat when slereah mentioned about it. So, was there any prominent model that came to light after Bohr and before the actual beginning of Quantum Mechanics in ...
user avatar
1 vote
3 answers
5k views

How the law of inertia got discovered?

In the Feynman lectures, it is mentioned that [Vol 1; Gravitation]: Galileo discovered a very remarkable fact about motion, which was essential for understanding these laws. That is the principle ...
user avatar
27 votes
2 answers
2k 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 ...
Conifold's user avatar
  • 76k
26 votes
2 answers
2k 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?
hat's user avatar
  • 363
25 votes
2 answers
3k 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.
John's user avatar
  • 909
19 votes
2 answers
545 views

What data did Kepler work out his laws from?

It's well known that Kepler worked out his laws by fitting curves to Tycho Brahe's data on the trajectories of planets through the sky. What was this data? How does one record the trajectory of a ...
Jack M's user avatar
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17 votes
1 answer
1k views

How did the publication feat of Einstein's four 1905 Annus Mirabilis papers get through peer review?

Einstein's early career is well-known for the lack of success he had applying for assistant lecturer positions with universities; he could not get a position, and he ended up working in a Bern patent ...
DBS's user avatar
  • 273
16 votes
1 answer
954 views

Hidden agenda of the Galileo trial?

Redondi argued that Galileo's trial on heliocentrism was merely a show trial concealing the real objection against Galileo among the catholic establishment, which was his atomism thought to be at ...
Mikhail Katz's user avatar
  • 5,772
14 votes
4 answers
3k 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 ...
user avatar
12 votes
5 answers
4k 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 ...
Nat's user avatar
  • 459
10 votes
3 answers
2k views

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 ...
Bhagwad Jal Park's user avatar
10 votes
1 answer
994 views

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 "...
valerio's user avatar
  • 365
9 votes
3 answers
910 views

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 ...
INFOTECH  GAMING's user avatar
8 votes
5 answers
356 views

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/...
Sensebe's user avatar
  • 675
7 votes
2 answers
392 views

Who was the first scientist to suggest that objects can keep moving without applied force?

In the old days Aristotels argued that object needs a force to keep going in 'space'. Some philosophers, Philoponus and Buridanus (?), later argued that there was a need for some kind of 'impetus'. ...
Marijn 's user avatar
  • 383
6 votes
3 answers
2k 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 ...
Gonenc's user avatar
  • 785
6 votes
3 answers
785 views

Did Kepler arrive at his planetary laws based on Mars's orbit alone?

Kepler apparently arrived at his first two laws based on the Tycho's data for Mars. But Mars has the largest eccentricity except for Mercury, so it is easier to tell the difference between a circle ...
wdlang's user avatar
  • 915
5 votes
1 answer
313 views

On the naming of quantum chromodynamics

A theory of strong interaction is called quantum chromodynamics (QCD). Particles interacting strongly are supposed to have color charge, for example quarks appear in three "mutations" - red, green and ...
Martin Vesely's user avatar
5 votes
1 answer
411 views

Who originally derived the general force law equation of force between current elements?

Wikipedia credits this to Maxwell. This derivation can be found in Maxwell's Treatise on Electricity and Magnetism vol. 2, part 4, ch. 2 (§§502-527). I went through the derivation and found two self ...
Joe's user avatar
  • 181
5 votes
2 answers
464 views

What made Einstein believe (or know) that time was affected by speed and gravity?

How did he come up with this idea before there was any experimental data to prove this?
Curious Layman's user avatar
5 votes
1 answer
1k 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 ...
wythagoras's user avatar
  • 3,042
5 votes
1 answer
937 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 ...
Cicero's user avatar
  • 551
4 votes
1 answer
475 views

How did people figure out the formula for mechanical work, and related it to energy?

What developments led to the definition of Work as the dot product of Force and Displacement vectors? I did some searching but couldn't find a satisfying answer. According to what I have read, the ...
user194517's user avatar
4 votes
1 answer
285 views

How was the first parabolic telescope mirror made, and how was it used, and for what kind of telescope was this work done?

This answer to When was the first true Gregorian telescope built? explains: Newtonian uses one concave and one flat mirror (or just one concave). Gregorian uses two concave mirrors, and Cassegrain ...
uhoh's user avatar
  • 2,163
4 votes
3 answers
3k views

"Cycles" to "Hertz": Why the shift circa 1970?

Before circa 1970, it was more common to say "kilocycles" than "kilohertz" (and analogously for "mega-," "giga-," etc.). What contributed to "Hertz" becoming more common than "cycles"? cf. the Google ...
Geremia's user avatar
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