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

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2
votes
2answers
265 views

Has the speed of gravity been measured experimentally? How? [duplicate]

In Newtonian physics, changes in gravity propagate instantly. In general and special relativity, gravity propagates at the speed of light, $c$. From reading answers to questions about gravity on this ...
3
votes
2answers
378 views

Why do physicists always give “event rates”?

Many times I see plots for expected/measured "event rates", but what's the motivation for this? Why not generate/use plots for expected/measured event numbers/counts instead?
1
vote
0answers
162 views

3D Simulation Software

I need a software capable of simulating the physics of a car going off a ramp. This is a stunt that I will be attempting and looks like the following: A car, going off a curved ramp, doing a barrel ...
0
votes
0answers
22 views

Could diamagnetism be used to create an airbag for your internals?

Could a massively strong magnetic field be used to shield a human body from the effects of excessive +/- accelerations? My understanding is that say for a pilot suitably strapped in that the strain ...
2
votes
2answers
114 views

Appartus for Young's double slit?

I am wanting a full description of an apparatus used for Young's double slit (not necessarily the one that Young himself used though), which takes monochromatic light (though not laser light) and ...
1
vote
1answer
49 views

How many pairs of nuclei collide in heavy ion collisions?

As each bunch of heavy ions consist of a large number of nuclei it does not seem unlikely that multiple binary ion collisions will occur as it does in p-p collisions. However, should this be the case, ...
0
votes
0answers
60 views

Has string theory predicted any experimently verified results? [duplicate]

I'm just getting into string theory and I'm wondering if it has made any unique predictions that have been verified by experiment?
-1
votes
1answer
415 views

What is the freezing/melting point tap water?

Yes, I know purity is not a constant and depends on area etc. Does anyone have any experimental results on freezing/melting point of any tap water, as opposed to distilled, de-ionized, saline etc? I ...
2
votes
1answer
63 views

Do we regularly measure and update our physical constants (By using the LHC)?

This question is motivated by sheer curiosity. I certainly do not expect that the free parameters we use in the standard model have changed in value since we started measuring them with a "modern" ...
4
votes
2answers
117 views

Is circular masking a laser beam an acceptable way to get the beam diameter you require?

I am wondering what are the down sides to just masking a laser to get the beam diameter you require? For example if you have a collimated eliptical beam of say 2mm width and 4mm height, but you ...
1
vote
1answer
92 views

How was the neutron's spin measured?

In 2012 it was asked, How to measure the spin of a neutral particle. I'm not sure that the answer "Neutron spin can be measured in a Stern Gerlach setup." was really carried out. So what for ...
0
votes
1answer
55 views

What's the difference between two types of diaphragms?

What's the principal difference between aperture iris diaphragm and field iris diaphragm?
2
votes
0answers
34 views

Is there a resonance within the earth, separate from the Schuman resonance?

In a very recent biography of Nikola Tesla by Bernard Carlson, the author explains that Tesla measured the resonant frequency of the earth using his invention - the amplifying transmitter. Tesla came ...
0
votes
1answer
124 views

Is there a formula/relationship between $q$, $m$, $c$, $\Delta T$ and $t$ (time)?

I am currently doing an experiment where I am burning methanol to test for the heat of combustion. To test this, I am heating 100g of water and raising it by 20 degrees Celsius before extinguishing ...
1
vote
1answer
38 views

Recreating an image from a photometer or similar light-detecting device?

I'm thinking if it is possible to recreate an image from data from this kind of device. It is known analog signals theoretically have infinite resolution, but since we use them in discrete systems ...
4
votes
1answer
107 views

What causes this IR emission in UV 365nm LED?

I've just got access to spectrometer and measuring spectrum of everything. But when I took a look at 365nm UV led from chinese UV flashlight I got something really strange - it had some IR at exactly ...
2
votes
0answers
45 views

Estimate Uncertainties in Rietveld Refinement

I have the output of an x-ray diffraction experiment made on a thin film. Here I report the output of the experiment (I analyzed those data using powdercell and coloured regions have been excluded ...
-3
votes
3answers
250 views

Does Size affect Distance covered at constant speed? [closed]

How does size of an object affects its speed? Suppose if two objects of different sizes (very different indeed) moves at speed of say 100 mph for an hour, will the object greater in size covers the ...
2
votes
2answers
227 views

How many of the Standard Model free parameters are mutually independent: (all of them)?

My knowledge of the standard model is very limited so please let me spell out my assumptions first (and please let me know when I have mangled concepts, terminology or I am plainly just out of my ...
4
votes
1answer
166 views

What empirical evidence is there for displacement current?

I wonder what more or less direct measurements of the displacement current exist. I know that the existence of em waves demonstrates its existence, though somewhat indirectly. I also know that there ...
1
vote
0answers
34 views

Are there any experimental data for light bending angle? [duplicate]

The gravitational lensing formula is given by equation $a=4M/r$. Is there any experimental data for this equation. I am trying to plot a curve for this equation and the real experimental data and ...
0
votes
0answers
18 views

How is the influence of the ambient nitrogen gas in pulsed laser ablation calculated?

I've been using the Nd:YAG(1064nm) laser for laser ablation in the atmospheric condition for a year and this year I'm trying to conduct it in the chamber, where the chamber is filled with nitrogen ...
1
vote
1answer
53 views

How was hydrogen gas (H) obtained by spectroscopists? Why is there more H than H2 in space?

Introductory quantum mechanics lessons talk about emission and absorption spectra for the hydrogen gas, and then give you an explanation as if this gas were pure $H$ atoms, and not the $H_2$ molecule ...
0
votes
1answer
25 views

Would an electroscope work if it were not in a glass container?

I'm reading about the gold-leaf electroscope and all the sources I've read show that the gold leaves are placed in a glass container. Is there something special about the glass, or would any container ...
4
votes
1answer
91 views

Are there any attempts to directly detect dark energy?

Instead of relying on distant supernovas for tell tale sign that most galaxies are receding at faster rates away from each other, are there any experiments in the past decades or near future that can ...
6
votes
2answers
333 views

What experiment would disprove loop quantum gravity?

Loop Quantum Gravity (LQG) is a theory of quantum space-time that attempts to describe the interconnection between general relativity and quantum mechanics. It's main postulate is the granularity of ...
4
votes
1answer
65 views

What energy will the LHC use for pA collisions in Run 2?

Part of the LHC's Run 2 (which just recently started) will be dedicated to proton-ion collisions, but I haven't been able to find any firm information about what energy those collisions will run at. ...
9
votes
5answers
828 views

Is double-slit experiment dependent on rate at which electrons are fired at slit?

I am a mathematician and I am studying string theory. For this purpose I studied quantum theory. After reading Feynman's book in which he described the double-slit experiment (Young's experiment) I ...
1
vote
0answers
126 views

What are the longest half-lives we can detect experimentally? What stops us going further? Are we trying to?

Xenon 136, apparently, has a half-life of 2.11×1021 years. This strikes me as a humongously long time to run an experiment, clocking in at about 11 orders of magnitude longer than the age of the ...
0
votes
3answers
45 views

Ozone elimination

I have a potential problem with airflow through a high voltage capacitively coupled RF discharge (in a tube) producing ozone. How can I remove ozone from the airflow? The use of liquids is not ...
0
votes
1answer
31 views

Partitioning a single vacuum chamber to isolate out-gassing components?

Planning a DIY vacuume chamber that would contain motors and electronics for manipulating in random experiments My thought is to section the chamber into two parts: clean and dirty - the dirty part ...
16
votes
6answers
616 views

Has a double slit experiment ever been done using a track chamber or even contemplated?

I tried searches and the question has been posed in other fora, but no experiment came up. Track chambers (cloud chambers, bubble chambers , time projection chambers, solid state detectors like the ...
0
votes
1answer
39 views

What granular/colored material suspends itself in an enclosed container filled with water regardless of pressure, gravity and buoyancy?

i've been looking around for an answer but it turns out that google dsn't think it's an obvious question. Would really appreciate the help. Basically i'm wondering if there is any known material that ...
1
vote
0answers
70 views

Smallest measurable time increment

What is the smallest increment of time which can be measured using modern methods, and is not theoretical?
1
vote
0answers
47 views

What factors are influencing a woosh rocket?

Not sure if this is too much chemistry, but I'll try: If I fill a plastic bottle with a small amount of rubbing alcohol, shake it around and hold a match to the bottle neck, I'll get a flame wooshing ...
0
votes
1answer
121 views

Wavelength of light too long to measure electron position in double-slit experiment?

I'm a mathematician, so I am not familiar with experimental physics. I am watching MIT course on Quantum Mechanics, and they describe the two-slit experiment with electrons passing through the slits. ...
3
votes
1answer
288 views

Is there any evidence against the Cosmological Principle?

I have been slowly getting more into math, but haven't gone into differential geometry or anything like that yet, so this question might be basic. Trying to get a deeper understanding of the ...
0
votes
1answer
49 views

What is supposed to be used as $m$ in $m\lambda = d\sin \theta $

I know that $m$ is the "order number", but I don't understand how this applies to the lab we did. We looked at Hydrogen gas through a diffraction grating (500 lines/cm or something like that) and saw ...
5
votes
1answer
129 views

Do metric theories with torsion contradict solar system observations?

Obviously, the answer to this question can be "maybe, if you make the torsion tensor small enough", but my question is, given some "typical" size to the torsion tensor, do the spin-orbit couplings ...
2
votes
2answers
73 views

How are determined experimentally the energy levels of the atoms ? How is the calibration done to several decimal points?

I see discrepancy for the absorption edges for the atoms in the X-ray ? For example K-absorption edge of carbon can be anywhere between 282 to 284eV according to different sources. My question is ...
14
votes
9answers
4k views

How to emulate 40ft (12 m) of water? [closed]

I am part of an underwater robotics team, and our next year's challenge requires us to compete at a depth of 40ft. We don't have any pools nearby to test in, so I want to emulate this 40ft of pressure ...
1
vote
0answers
18 views

why is clear electron saturation not obtained in a Langmuir probe experiment?

I recently conducted an experiment to study the I-V characteristics of a Debye sheath, but I can't obtain electron saturation. Why does it happen?
0
votes
0answers
35 views

Estimation of source irradiance given the spectral sensitivity of the instrument and spectrum of the source

I am trying to measure the irradiance of a UV source, but the available instrument has a different sensitivity. Suppose the black line corresponds to the spectral sensitivity of the instrument ...
0
votes
1answer
128 views

Hafele-Keating revisited with a gravity clock

Most modern clocks use electromagnetic phenomena to measure time. There are perhaps some older clocks that involve gravity to some degree (hour glass, pendulum), but I believe they still have a ...
0
votes
0answers
45 views

About Michelson-Morley experiment

Can you please explain it to me. As far as I know, we have a monochromatic and coherent em source and we getting an interference picture (because we clearly couldn't make the splitted beams travel ...
0
votes
1answer
57 views

How to experimentally create an atom in a superposition of ground and excited states? [closed]

For Quantum Computing we use atoms in superposed states, but how do we physically create them?
0
votes
1answer
1k views

Terminal velocity of a steel ball in water [closed]

I am investigating on the terminal velocity of steel balls moving in water. I used the balls with different diameters, such as 3.17mm, 6.02mm, etc. And I used a full-filled 1L graduated cylinder. I ...
1
vote
1answer
410 views

Dependence of Hall coefficient on temperature in copper

As part of a project on the Hall Effect in metals, we would like to find out whether the Hall Coefficient of copper depends on its temperature, and if so how. We passed a current I through a copper ...
0
votes
0answers
33 views

What is a “cut” in the Hanbury-Brown and Twiss (HBT) method?

I am currently working on p-p collisions simulations using PYTHIA 6. I am using a Monte Carlo approach, but I have done mass reconstructions in the past using something very similar to the ...
0
votes
0answers
30 views

Laser beam receiver

Problem: I have an object that can move in the $x,\,y,\,z$ direction. The goal is to measure the $x,y$ variation as the object travels along the $z$ axis. Typically the distance traveled is less than ...