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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21
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2answers
3k views

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: $mv^2$, ...
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1answer
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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 ...
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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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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 ...
7
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1answer
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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 ...
7
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1answer
478 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 ...
33
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4answers
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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 ...
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3answers
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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 ...
8
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1answer
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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. ...
20
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1answer
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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 ...
15
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5answers
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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 ...
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4answers
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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 ...
6
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1answer
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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 ...
8
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1answer
414 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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1answer
898 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 ...
13
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1answer
965 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 ...
6
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2answers
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How did Newton come up with his formula?

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 ...
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3answers
4k 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 ...
6
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1answer
660 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?
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2answers
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What were the criticisms against the introduction of “vector analysis”?

Frequently, 19th century physicists—e.g., Helmholtz or Maxwell—did not use modern-day vector notation, which Gibbs contributed in large part to. For example, Helmholtz in his famous paper on the ...
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2answers
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Who discovered the covering homomorphism between SU(2) and SO(3)?

Who discovered this? It is quite nontrivial and very important in quantum mechanics.
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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 ...
15
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1answer
674 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 ...
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3answers
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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 ...
5
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4answers
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Electromagnetics and vector calculus

A friend of mine claims that vector calculus was invented to do electrodynamics. I'm dubious. I know that Maxwell first wrote down the so-called Maxwell's equations in scalar form and only later ...
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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....
8
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5answers
323 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/...
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1answer
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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 ...
15
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1answer
685 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 ...
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3answers
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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 ...
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4answers
795 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 ...
4
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3answers
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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 ...
5
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2answers
312 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?
5
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1answer
254 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 ...
4
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1answer
201 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 ...
3
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2answers
503 views

Why is Maxwell and not Ampère credited for unifying electricity and magnetism?

Ampère, a half century before Maxwell, theorized that magnetism was caused by electrical currents. So, why is Maxwell and not Ampère credited for unifying electricity and magnetism? (cf. the question ...
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3answers
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“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 ...
41
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3answers
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When exactly (and why) did matrices become a part of the undergraduate curriculum?

Let me tell what I know about this. It is well-known that Heisenberg invented matrix multiplication himself, in his great paper that is considered part of the foundation of quantum mechanics. This was ...
23
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7answers
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In ancient times, how did people conclude that the shape of Earth is a sphere?

This is more of a philosophical question, but I want a mathematical explanation. During ancient times, it was well accepted that the surface of Earth was spherical. People first observed this when ...
18
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4answers
1k views

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 ...
8
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11answers
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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 ...
19
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2answers
835 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?
19
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1answer
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What cipher(s) did Isaac Newton use?

A number of sources including this one assert that Isaac Newton used encrypted messages to communicate some of his scientific discoveries, and as a way of establishing priority. What cipher(s) did he ...
4
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1answer
305 views

History of Energy

Can anyone suggest me some book/article explaining how and why the quantity named 'Energy' made its way into physics? I have gone through "Lectures on Physics" (Vol. 1) by R.P. Feynman and have been ...
23
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4answers
996 views

Did ancient/medieval non-European cultures have a concept of energy? If so, what are the similarities and differences to the modern concept?

For example, do we find something related to the modern energy concept in Ancient China, Ancient India, or the Islamic Golden Age? Among "similarities and differences", conservation is obviously ...
21
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2answers
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Why is there no named unit for momentum but there is one for energy?

Momentum and energy play very similar roles in mechanics, each being changed by the application of force over a interval. For energy the interval is in space and for momentum it is in time. Both have ...
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2answers
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Was Dirac really trying to take the square root of the Klein-Gordon operator?

As a student of physics one will, on several occasions, indubitably hear professors or other physicists (here is an example, from Physics.SE's highest-rep user John Rennie) tell the famous story that ...
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1answer
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Who invented the concepts of potential and kinetic energy? [duplicate]

Who invented potential and kinetic energy ? Was it Newton ? Or someone else ? I have the impression Newton used those ideas but they already existed.
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3answers
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Did light bulb companies commission Planck to study black body radiation?

Background When introducing Planck's switch to looking at black-body radiation, a number of sources -- like MinutePhysics, the Economist, random online encyclopaedias and even here on HSM.SE (plus ...
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2answers
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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 ...