Questions tagged [soft-question]

Questions that ask about some aspect of physics research or study which doesn't involve the actual physics. In general, soft questions can be answered without using physical reasoning.

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36
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4answers
8k views

What was the 'quantum mechanics' before quantum mechanics?

Quantum mechanics is near-universally considered one of the most difficult concepts to grasp, but what were the persistently unintuitive, conceptually challenging fields physicists had to grasp before ...
1
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2answers
277 views

How did Isaac Newton derive the laws of gravity?

I would like to know how do people come to derive physical laws out of experiments alone, for example how did Newton came up with the laws of gravity? Did he just set those as axioms or did he ...
0
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0answers
36 views

Why a so strange shape on DES?

Why the selected area for the Dark Energy Survey was chosen to have such a shape? Are there any reasons? In the paper I found this The target footprint of the DES wide-area and supernova surveys ...
0
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3answers
157 views

Is it possible to know the efficiency of a particle detector without assuming the truth of Theory (e.g.,, Quantum Theory)

I reorganized the question to clarify exactly what it is that I'm asking. Suppose an experiment is performed where a particle detector records 50 particles per second, on average. Absent any other ...
0
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0answers
33 views

Physical Theories and Statistics (operationalism?)

I am under the impression that there must be a duality between physical theories and statistical models that have no reference to physical theories. For instance, given an apparatus, a researcher can ...
1
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0answers
94 views

What is the physical intuition for the definition of elliptic PDE's?

Consider the Laplace equation $$\Delta u=0.$$ I am aware of the relation of this equation to electrostatics, and that one can "guess" many of its mathematical properties from this physical framework. ...
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0answers
66 views

Mathematically equivalent physical systems

This seems a bit different than the typical question here, but I'm not sure where to ask. Is there a name or field of studying mathematically equivalent systems? The simplest example I can think of ...
1
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1answer
122 views

Meaning of a remark by Heisenberg: Die “Bahn” entsteht erst dadurch, dass wir sie beobachten

In a paper by Joos and Zeh, Z Phys B 59 (1985) 223, they say: This 'coming into being of classical properties' appears related to what Heisenberg may have meant by his famous remark [7]: 'Die "Bahn"...
3
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2answers
138 views

How much of the standard model could have been discovered in a world without computers?

Computers were not needed for the discovery of quantum mechanics (1920s) or general relativity (1910s), and the standard model was proposed when computers were much less powerful than today (1970s). ...
0
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3answers
241 views

If mass is indeed invariant in Special Relativity, why do we still say things still have a “rest mass”?

My lecturer reaffirmed to us a classical misnomer that mass is relativistic, by pointing out that when considering relativistic momentum the Lorentz Factor is due to time dilation and thus a change in ...
1
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0answers
92 views

Is there a good way to get feedback on a potentially crackpot physics idea? [closed]

I have a set of physics ideas that are probably false (they amount to a theory of everything, for a given value of theory), but at this point they are beyond my ability to evaluate. I think there is ...
1
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1answer
121 views

Theory of Everything and the initial conditions

From what I've understood, the basic motivation behind the idea of "the Theory of Everything" (its modern attempt being M theory) is to find a simple rule which unifies all phenomena observed in ...
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0answers
78 views

What does it mean when something is called “fundamental”?

Most of the books on science tell that quantum theory and general relativity are the fundamental theories in science. This has always sparked a question in my mind. What does it mean to be "...
0
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2answers
64 views

Transmural pressure

Transmural pressure I want to ask about transmural pressure. For example, if the pressure outside a balloon increases, the volume decreases, and if the pressure decreases, the volume goes up. But ...
15
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5answers
706 views

Could you please give an intuitive definition of chemical potential?

Could you please give an intuitive definition of chemical potential? It seems that it is an extremely important notion of physics but definitions are really vague.
-1
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1answer
51 views

Why do physicists comes up with special names for change in quantities? [closed]

I only have a basic understanding of physics, so this may be a naive question. I've noticed in my self-study that when referring to the change in some quantity $Q$, instead of just calling it change ...
0
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1answer
78 views

Classical random walk equation - confusion

I have always thought that a (classical) on a straight line is governed by the binomial distribution: $$ {{n}\choose{k}} p^{k}(1-p)^{n-k},$$ $n$ being the number of tries and $k$ the number of ...
0
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1answer
40 views

How large would a laser interferometer have to be to detect the flapping of a mosquito's wings?

I understand the most general principle behind LIGO, but I am no physicist so I have no idea how to calculate the amplitude of gravitational waves, much less the length of the lasers required to ...
19
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2answers
2k views

“QFT is simple harmonic motion taken to increasing levels of abstraction”

"QFT is simple harmonic motion taken to increasing levels of abstraction." This is my memory of a quote from Sidney Coleman, which is probably in many textbooks. What does it refer to, if he meant ...
0
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1answer
119 views

Pressure variation during resonance?

Consider a hypothetical pipe of length $L$ with both end closed. The pipe is filled with a some fluid. Let there be a ultrasound source of frequency $f=v/2L$ at one end of the pipe and a sensor to ...
-2
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5answers
2k views

Why is the rate of change of velocity taken using time and not distance? [closed]

Why is the change in velocity taken with respect to time, why not distance? I am confused, because it makes sense - as the velocity increases, the distance increases or as the velocity decreases, ...
7
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2answers
2k views

Does breathing on your glasses help with cleaning?

I noticed people who wear glasses clean the lenses by first breathing on them and then wiping it with something like a tissue or cloth etc. Does this actually help?
2
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1answer
168 views

What is the etymology of the term “amplitude” as used in quantum mechanics?

Some people claim that the single most important conceptual point in all of quantum mechanics is that "probability amplitudes" (inner products) can be complex, as opposed to strictly positive. But in ...
1
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1answer
85 views

The relation between decay of particle in different reference frames?

I am reading the Wikipedia link: https://en.wikipedia.org/wiki/Particle_decay Is all the mathematical relation mentioned in the link is valid for any reference fame? What I mean by reference frame is ...
1
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1answer
149 views

Unruh effect and string theory?

My sincere apology if this question is not appropriate for this forum. Recently, I came across the Unruh radiation or Unruh effect. From the Wikipedia page https://en.wikipedia.org/wiki/Unruh_effect ...
1
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0answers
48 views

Is it the case that vector quantities always have to do with location?

We know that vector quantities follow vector law of addition and vector addition only makes sense in a plane/space (we can treat vector addition in a line as scalar addition). It is also worth noting ...
2
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0answers
210 views

Where is the method of Contour integration used in physics? [closed]

Complex numbers have a wide variety of application in physics and so must be contour integration but where do we exactly apply the principles of contour integration, residues and poles in the field of ...
-1
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1answer
849 views

Can an object be perfectly flat? [duplicate]

I ask myself this question from a microscopic point. I assume that at our scale it's pretty easy to say that an object is flat or not. You need to imagine that we are at the top layer of a material....
4
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1answer
138 views

Can our emitted infrared light turn on the TV?

We know that TV can be turned on with infrared light and we know that our body emits infrared to. Does the frequency of our emitted infrared corresponds to the frequency of the device that turns on ...
1
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0answers
249 views

Undergraduate Physics Journals [closed]

I'm currently an undergraduate physics student and I've recently completed a research project with one of my professors this past half-year or so. I'm interested in submitting what I have right now to ...
1
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1answer
117 views

Quote from Genius

In Genius Season 1 Episode 1 at 9:00, Young Albert Einstein defies his teacher by solving the equation on board and states Natural log of constant multiplied by x equals natural log of one plus v ...
2
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1answer
663 views

Is Energy real? [closed]

This is a question that has bothered me for a long time Is energy real or is it just a very useful mathematical construct? I personally think its just a mathematical construct, its designed so that ...
3
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0answers
114 views

Sanity tests on quantum mechanics

If I've learned one thing in my graduation so far is that I must assume when I finish my calculations that I am probably wrong and start doing "sanity" tests. I am very good at doing foolish mistakes. ...
0
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1answer
211 views

Programs trying unifying QM and GR instead of QFT and GR?

Is there any program which attempts at unifying quantum mechanics and gravity rather than unifying quantum field theory and gravity? Motivation We use the heisenberg picture to define velocity $\hat ...
-2
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1answer
59 views

Why do we randomly get static shocks

Recently, I've been getting random static shocks from touching objects that don't seem to have any electrical current going through them, I was just wondering what causes these shocks as it happens ...
0
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2answers
105 views

Question about Lorentz invariant theory of gravitation

A generalization of Newton's law of gravitation to a Lorentz invariant version by using an analogy with electromagnetism is possible. Several slightly different ways to do it are described in ...
0
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1answer
64 views

How to find a reference that is 'to be published'? [closed]

How to find the references in the papers looks like e.g. that: P.Moller, J.R.Nix and W.J.Swiatecki, Proc. Winter Workshop on nuclear dynamics V, SunValley, Idaho, 1988, to be published. When I ...
0
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0answers
61 views

Time- the stubborn illusion? [duplicate]

BACKGROUND: As I was happily watching "Genius" tele-drama's teaser Genuis, I came across this very popular and subtle comment: The past,present and the future all exist simultaneously. Time is ...
-1
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1answer
71 views

What is Large about the LHC? [closed]

Does the Large in Large Hadron Collider describe the collider or the hadrons? I looked into it a bit and am posting this to share my answer with the community. I'm also required to write so much in ...
1
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0answers
59 views

Is topological insulators are quantum meta-material?

I am trying to understand the definitions of meta-material, quantum meta-material and topological insulators. Individually each definitions is explained in wikipedia pages. https://en.wikipedia.org/...
0
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2answers
144 views

what does it mean that theories are not true but assumed to be true? [closed]

I have read it in most of the article and heard in videos created to explain scientific method but i am not being able to understand it .please explain to me what does it mean? give some examples.
3
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0answers
292 views

Representation Theory of $SL(2, \mathbb{C})$

I'm a PhD. in mathematics (working mainly in complex algebraic geometry), but I'm looking for a "convincing" answer concerning the various applications of representation theory of the group $SL(2, \...
1
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0answers
47 views

History of thought experiments [closed]

I am writing a little article about thought experiments through the history of physics (university level); more specifically, from the times of Thales of Miletus (~ ancient Greeks) to our day. I want ...
-1
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1answer
271 views

Books aimed at clearing misconceptions for Olympiad Physics?

We are often confronted with the loopholes in our understanding of concepts of Physics when solving problems, especially if they are of high standard like the ones asked in Olympiads. In such cases ...
1
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1answer
140 views

Is it just a coincidence that one cubic foot of water weighs 1000 ounces?

Is it just a coincidence that one cubic foot of water weighs 1000 ounces (to within 0.1 percent accuracy)?
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0answers
44 views

Important physical models other than the harmonic oscillator? [closed]

Are there any other models used in physics that are as intuitive and mathematically accessible as the harmonic oscillator that can be used to describe a wide range of phenomena?
1
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3answers
184 views

Why do we invent non-physical concepts (like e.g. point particles) to study physical phenomenons?

There is nothing exist like point particles in reality then why did we invented the notion of point particles and how does it relate to real world?
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1answer
1k views

Is there any relation between focal length and aperture of a spherical mirror?

I was wondering whether there is a relation between the focal length and aperture of a spherical mirror (concave or convex). I drew a circle on a piece of paper to represent a sphere of which the ...
1
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0answers
57 views

measure thickness of multiple layers using ultrasound

I am trying to build an ultrasound thickness measurement device using either Arduino or raspberry pi (haven't decided on which yet), before i start i have a doubt and am hoping someone can clarify the ...
2
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1answer
119 views

Magnetic behaviour of magnet

A very direct question regarding behaviour of a magnet- When a magnet is heated such that it melts, why does it lose its magnetism? This is what I was wondering - When a solid magnet is heated, ...