for questions about design, process, data, or analysis of experiments and observations.

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3
votes
2answers
202 views

Fiber optics with broadband, incoherent light

I wonder if someone could help clarify waveguiding with broadband, incoherent light please. If we take a telecomms fiber, which is single-moded above ~1.4 μm and couple a laser beam in, we assume ...
0
votes
4answers
80 views

How to measure the mass of Earth?

I was wondering how you can measure the mass of Earth. From what I find on the internet, people are using Newton's Laws. But how can you do that ? Newton's Laws are assumed to work because you know a ...
4
votes
1answer
45 views

How is $J^{PC}$ value experimentally determined for new types of particles?

How is $J^{PC}$ value experimentally determined for new types of particles? For example, this paper says ... Angular correlations in B+→X(3872)K+ decays, with X(3872)→ρ0J/ψ, ρ0→π+π− and J/ψ→μ+μ−, ...
3
votes
2answers
529 views

What experiment(s) have or can refute the existence of an electron-particle “system” over the separate existence of a neutron within itself?

This question actually came about from a discussion of another question posed here The neutron is known to be comprised of an electron and a proton, and there are observations that the neutron can be ...
2
votes
1answer
108 views

Where to download dynamics demonstration videos for motion analysis? [closed]

I'm looking for videos of demonstrations/experiments of dynamics for download. Also they should be clear and of good quality. I want to use them in a video analysis program ...
14
votes
7answers
3k views

Experimental evidence of a fourth spatial dimension?

As human beings, we observe the world in which we live in three dimensions. However, it is certainly theoretically possible that more dimensions exist. Is there any direct or indirect evidence ...
1
vote
1answer
88 views

Measuring depth or height from sea level

How is the depth or height relative to sea level measured? Well, if it's near the ocean, it can be easily measured manually, but what if it is 100 km away from the sea? What method is used?
0
votes
0answers
15 views

Propagation of incertitude - specific example [duplicate]

I am setting up an experiment, where I know the force and the incertitude (delta) of that force. However, I need to graph the logarithm of that force with the incertitude of the log. Can someone help ...
3
votes
5answers
319 views

Detecting absolute motion inside a box

This is not a contradiction and I know it is impossible but still consider a thought experiment by me and point out if something is wrong. See the following picture and then the explanation follows. ...
2
votes
0answers
32 views

Experimentally realizable states for bosonic quantum fields

I would like to know which type of quantum states of a bosonic field, that have an explicit analytical expression as vectors/density matrices in a symmetric Fock space, can be prepared in an ...
1
vote
1answer
121 views

Resolution in a Fourier transform spectroscopy setup

I am a bachelor physics student and as an assignment we had to perform measurements on an FT spectroscopy setup. Context. Our setup consisted of a Michelson interferometer through which the light ...
0
votes
0answers
11 views

What is the exact definition of Magneto-optical Polar Kerr angle?

As stated in the title. I would like to know the exact definition of the Magneto-optical Polar Kerr angle. Whether it is just the rotation angle of the polarized light or it is something else?
0
votes
1answer
23 views

A way to treat uncertainty in intensity measurement

I did an experiment to prove the inverse square law but don't know if my idea to calculate the error is correct. The relationship is $I=const*r^{n}$ with n=-2, we had a computer software to read the ...
0
votes
1answer
97 views

What is the general definition of signal acceptance?

Suppose I have a beyond Standard Model theory and want to test it. I want to test if some experiments, say conduced in LHC, show signals of the theory. In this case, what is "signal acceptance"?
1
vote
0answers
25 views

Are there computerized ontologies for Relativity and (Experimental) Physics? How to contribute?

As machines and automation can generally assist humanity in physical activities, and even exceed mere human capabilities, so, increasingly, also in tasks of reasoning. A basic component of the latter ...
2
votes
1answer
127 views

Problem on Einstein - de Haas experiment

I am a Physics student (4th year) and I'm trying to study the Einstein - de Haas effect in laboratory. That is what I got: a suspended Iron cylinder with about 5 cm height and a radius of 0.8 cm is ...
0
votes
0answers
26 views

what does the i-v curve in josephson junction mean?

according to the i-v curve for Josephson junction tunneling for S-I-S (superconductor-insulator-superconductor): do we have any tunneling current for 0< V<= Vc ? if yes, then why don't we show ...
5
votes
0answers
47 views

Why do flux qubits have to be micrometer-sized?

Flux qubits are made using micrometer sized Josephson junctions. They exploit superconducting properties to create and interfere with the magnetic flux between them. My question is that I've seen ...
7
votes
1answer
246 views

What are the different ways to measure the spatial curvature of the universe?

Just what the question asks. Assuming the Friedmann-Rovertson-Walker (FRW) metric, what measurements can be performed to determine the spatial curvature of the universe.
1
vote
1answer
87 views

What has been observed as the “Hawking radiation” emitted by a black hole analog?

I've noticed this paper which explains that they have observed the "Hawking radiation" emitted by a black hole analog. In which sense the Bose-Einstein condensate described by the paper can be ...
0
votes
1answer
29 views

How to find the least count of a normal scale

Well suppose i have a normal measuring scale how do i find its least count?I have just been introduced to errors in measurement and our professor was giving us least counts of different instruments ...
2
votes
0answers
79 views

Where does an LED use energy other than emitting light?

I have a quantum formula describing what kind of photon should be emitted by an LED depending on its voltage. Of course the colour is depending on the material, but every type of LED also needs its ...
0
votes
0answers
36 views

Simple question relating to physics prac reports

I am writing a physics practical report relating to the elasticity of materials relating to their momentum in a collision. I have values for the elasticities that are all within 2% of each other but I ...
2
votes
1answer
84 views

Why can't a high intensity beam be injected into the LHC when the machine is empty

Watching this YouTube video about the LHC at around 3 minutes and 50 seconds into the video the narrator says... For machine protection reasons we are not allowed to inject a high intensity beam ...
2
votes
2answers
163 views

What exactly is meant by saying that two events had been “simultaneous in an inertial frame”?

In order to address my question based on a concrete example setup let the following two separate events be given: participants $A$ and $J$ encountering each other in passing (additional participants ...
4
votes
0answers
22 views

How can the effects of temperature be accounted for in-situ electrical resistance corrosion monitoring?

In reading the Berkeley Lab's article Rust Never Sleeps, where research is underway investigating the use of iron oxide rust as a photovoltaic, they state: Rust – iron oxide – is a poor conductor ...
3
votes
4answers
3k views

How many digits of Pi are required in physics? [closed]

In other words: which physics experiment requires to know Pi with the highest precision?
1
vote
5answers
228 views

Normal distribution of x, xdot [closed]

I have some real measurements from a process and I happened to look at the mutual distribution of (x(t), xdot(t)). I found that they seem to follow 2d normal distribution around (mu, 0). See image, ...
3
votes
3answers
367 views

What would happen to me if I was in the LHC while it was running? [duplicate]

This is possibly a stupid question, but one I have been always wondering. What would happen to me if I was in the center of the Large hadron Collider while it was running? Would the energy of the beam ...
2
votes
2answers
38 views

Is this a possible monopole setup, or will it cancel out? [duplicate]

Suppose you have a ball that is covered in magnets, in which the North Pole of every magnet faces outward. Is this a monopole? Or at least "functions" as a monopole? And what will happen if you placed ...
0
votes
0answers
34 views

Ratio between power of chaotic and regular airflow

Turbulent field is created as a result of an impact of an airjet on an edge (the flow velocity is high enough). The field of velocities have a regular and a chaotic component. What I need is to ...
7
votes
0answers
50 views

What's the smallest height difference over which gravitational time dilation has been experimentally observed?

In a famous experiment, reported in Optical Clocks and Relativity. CW Chou, DB Hume, T Rosenband and DJ Wineland. Science 329 no. 5999 pp. 1630-1633 (2010); NIST eprint. and nicely described in ...
1
vote
2answers
37 views

Experimental verification of bound state transition times

I am trying to reconcile, what to me at least, are two slightly different answers to what I think is the same question. The first answer below to an earlier OP implies to me that there is a definite ...
4
votes
2answers
644 views

Do the copper connectors we used in measuring the resistance of a wire contribute to the said measurement?

We measured the resistance of a wire by setting the multimeter to ohmmeter mode and connected the ends of the ohmmeter to the ends of the wire; and we also calculated the theoretical value using a ...
3
votes
1answer
69 views

Why do electrons in a superconductor lack energy to produce “massive” photons

My two questions are based around looking for a good, simple (if possible) explanation of the Cooper pair effect in superconductors. I follow the idea that, in intuitive terms, "a Cooper Pair" ...
0
votes
0answers
12 views

How to understand the uncertainty of quoted value of cosmic black body radiation?

Geiner's Quantum Mechanics - An Introduction quotes a alue of cosmic black body radiation, "$2.65 \pm 0.09 K$". How to understand this uncertainty? I have undergraduate mathematics degree and are ...
1
vote
1answer
136 views

Truck driven from a small motor that can carry a heavy load, yet can travel fast. [closed]

I am building a truck from trash as materials. I have one small motor and a a few small gears, but no other engineered materials are allowed. The truck must carry a load for a distance of 3m. The ...
3
votes
1answer
68 views

The actual space curvature

What is the curvature of our physical space, according to the latest experimental data? I've found it somewhat difficult to find a definitive answer to the question, because the spacetime curvature ...
5
votes
1answer
67 views

Charge of a moving particle [duplicate]

Is there an experiment that measures the electric charge of a moving particle, therefore proving "experimentally" that it is indeed the same as a static particle?
5
votes
2answers
137 views

Determining the refractive index of a foil

(59th Polish Olympiad in Physics, final stage, experimental part, 2010) You have at your disposal: a sample of blue foil of a homogeneous material, placed between two glass panes in a ...
1
vote
2answers
66 views

What happens when both of Polarizing filter in LCD screen are Horizontal

What would be the result if we replace the vertical polarizing filter in LCD device (screen) with a horizontal filter, what could we see exactly? Would we see the same if we use only one horizontal ...
0
votes
2answers
32 views

How to measure the range of a horizontal projectile?

For an experiment, I'm launching a projectile horizontally to determine the relationship between height and range. Pretty basic stuff. But I'm having trouble coming up with an effective way to measure ...
1
vote
2answers
41 views

Does the gravitational force of one object interfere with that of another?

Assume we have two iron spheres, Sphere A and Sphere B, with identical masses floating in the vacuum of interstellar space separated by some distance from each other. The gravitational force of each ...
6
votes
4answers
3k views

What experimental proof has been found of Einstein's theory?

As a casual science reader, I've always found the implications of relativity (inconsistent clocks after near-light-speed travel and various space-time paradoxes) to be confusing and magical-sounding. ...
10
votes
2answers
821 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 ...
1
vote
2answers
75 views

How do we know that the Law of Cooling is true?

According to James Stewart's Calculus book (exercise 14, page 609), Newton’s Law of Cooling states that the rate of cooling of an object is proportional to the temperature difference between the ...
1
vote
0answers
35 views

Kirchoff's voltage law doesn't seem to hold in an experiment conducted with series resistor, diode and signal generator

I've conducted an experiment to look at the electronic characteristics of a diode. This was done using a series diode, resistor ($R$) and signal generator. The signal generator was made to supply a ...
0
votes
1answer
58 views

Does it take more effort to move against earth's rotation?

I know that if we stand still, we are traveling at 0 m/s relative to the Earth. But if we move against the rotation of the Earth we lower our speed, so, wouldn't we have to fight against the ...
0
votes
0answers
30 views

What have we built? A resonant loop antenna? Rhombic?

Some background, my partner and I have built an antenna we are supposed to characterize for an assignment, and compare it to physical predictions. However, we don't know what type of antenna we have ...
5
votes
2answers
376 views

5 sigma result proof for particle discovery

Source: Carrolls : "Particle at The End of The Universe" P. 177 I am just checking my understanding of Carroll's point about "a 5 sigma result being the gold standard" of experimental proof. ...