for questions about design, process, data, or analysis of experiments and observations.
0
votes
1answer
130 views
What is the particle residence time for given flow rates of gas mixture components?
For two different chemical substances there are two open valves with flow rates $$Q_1=a\frac{m^3}{h}\ \text{ and }\ \ Q_2=b\frac{m^3}{h},$$ leading into seperate cables.
Next, the cables join, the ...
6
votes
3answers
412 views
How are the masses of unstable elementary particles measured?
I am interested in knowing how (Q1) the particle's masses are experimentally determined from accelerator observations.
What kind of particles? They must be as far as we know elementary and unstable ...
-1
votes
1answer
78 views
A question on the property of proton and neutron? [closed]
The NOVA show on the string theory have mention once that the proton and neutron will be disappear in finite amount of time, then reappearing on somewhere else. Is there any experiment have shown that ...
4
votes
5answers
584 views
Regarding string theory: how to refute the argument “if it cannot be tested experimentally then it is not science”? [duplicate]
Possible Duplicate:
What differs string theory from philosophy or religion?
I find a lot of people disbelieve in string theory, saying that since it cannot be tested experimentally then it ...
0
votes
0answers
44 views
Which subject matter for those experiment is on that help Bohr win over the Einstein-Bohr debate? [closed]
Which subject matter for those experiment is on that help Bohr win over the Einstein-Bohr debate?
List the name of those experiment and categorize them by subject please, if time is available please ...
3
votes
1answer
120 views
How do people get the proton number for each element from experiment?
How did people determine the proton number for each element from experiment in each decade of 20th century?
1
vote
0answers
93 views
How do I calculate the Radiation length of a Molecule
I want to calculate the Radiation length in a Molecule with the Formula given on wikipedia. How do I calculate Z and A for a molecule to put it into the Formula?
4
votes
2answers
214 views
What are the effects of cosmic rays on consumer electronics?
When electronics/computer companies design a new chip, processor/ memory card/ or a solar cell, do they study the effect of cosmic rays on such electronically sensitive materials? If not, why not?
3
votes
1answer
128 views
How could we experience multiverse through cosmic background radiation?
I'm reading a book about string theory, and it tells me in the future it could be possible to detect existence of other bubble universes through cosmic background radiation. Is this true? What could ...
3
votes
2answers
285 views
How is angular momentum measured in experiments/in practice? [duplicate]
Possible Duplicate:
How does one experimentally determine chirality, helicity and spin?
How do you find spin of a particle from experimental data?
We read about and study angular momentum ...
0
votes
1answer
104 views
Increase the signal-to-noise ratio of photomultiplier
It is a GRE physics problem.
A technique would most likely increase the
signal- to-noise ratio of a photomultiplier tube is to
operate the tube at a lower temperature
operate the tube at higher ...
4
votes
0answers
38 views
Experimental tests of Cluster Decmposition
How tight are experimental and astrophysical tests on whether Cluster Decomposition is satisfied at various space-like separations?
Is there a review paper or a standard reference on the question?
I ...
6
votes
2answers
286 views
Use of Monte-Carlo simulation in High-energy Physics
I've been doing some research into the analysis used in particle physics when determining the significance of a finding (e.g. the recent Higgs candidate was announced as a boson in the 125-126 ...
2
votes
1answer
67 views
random triggers
I understand that a small proportion of events at the LHC that would not trigger on any deterministic trigger are saved on what might be called a random trigger, so that, amongst other uses, proposed ...
1
vote
2answers
315 views
What Observations could undeniably support string theory?
What experiments could provide observable "stringy" effects.
All valid experiments are acceptable (also theoretical experiments).
4
votes
2answers
103 views
What equations govern the formation of droplets on a surface?
When some smooth surface (like that of a steel or glass plate) is brought in contact with steam (over e.g. boiling milk) then water is usually seen to condense on that surface not uniformly but as ...
2
votes
0answers
58 views
Remaining Potential Experimental Particle Physics Discoveries at the TeV Scale?
With the discovery of the Higgs Boson, some have been calling it the end of experimental particle physics for our generation, due to the fact that all of the particles predicted by the standard model ...
1
vote
1answer
170 views
Why not accurate masses of elementary particles?
In the standard model of particle accuracy in calculating mass is very low.
And you can not predict the upper limit of Higgs particle mass accurately. Why not accurate masses of elementary particles?
3
votes
4answers
804 views
What is meant by “Nothing” in Physics/Quantum Mechanics(QM)?
I am not a phycisist, so please forgive my ignorance. This is related to my posts and this.
I am trying to undertand what is meant by the term "Nothing" in physics or Quantum Mechanics since it seems ...
1
vote
1answer
2k views
Negative and positive energy and Hawking [closed]
I don't have any physics background (except the material we did in high school-long time ago).
I was watching a documentary with Stephen Hawking about whether God created the Universe and I could not ...
2
votes
1answer
219 views
Has the Higgs really been discovered at CERN?
Many news media round the world such as this http://www.scientificamerican.com/article.cfm?id=higgs-lhc have reported the possible discovery of the Higgs at CERN, to be announced at a conference on ...
3
votes
2answers
140 views
Pressures Necessary for Carbon Detonation
Carbon detonation is a characteristic event of Type 1a Supernova (EDIT: where an accreting white dwarf near the Chandrashankar limit of 1.4 solar masses explodes), an extremely important standard ...
1
vote
3answers
172 views
Quantum experiments in the pre-industrial era
Could an 18th century or earlier scientist have come across phenomena which require quantum theories to explain them, given the apparatus available at the time?
I'll choose 1805 as the cut-off date, ...
4
votes
5answers
1k views
What differs string theory from philosophy or religion? [duplicate]
Possible Duplicate:
What experiment would disprove string theory?
A hypothesis without hard evidence sounds very much like philosophy or religion to me. All of them tries to establish a ...
5
votes
0answers
167 views
Quasi 1D insulators with strong spin-orbital interaction
We know that the spin-1 chain realizes the Haldane phase which is an example of
symmetry protected topological (SPT) phases (ie short-range entangled phases with symmetry). The Haldane phase is ...
1
vote
1answer
65 views
What is the reason behind the shape of the absorption curve of electron paramagnetic resonance
In our EPR experiment, the signal looks like the "first derivative" part of the above picture. Why is this? What does the "first derivative" mean and why is it the quantity our instruments detect in ...
1
vote
0answers
53 views
What is the standard way to find averages of measurement values that contain statistic and systematic uncertainties?
How to find the average value of several measurement results if we know their statistical and systematics uncertainties?
There might be that there is no such thing as best way to do it, but it would ...
4
votes
2answers
79 views
How would you figure some of the methods (in order of importance) to take a picture of the supersonic bullet with the wave it produce in 1888?
It would still be almost impossible for me in 21th century to take this picture:
(image courtesy of wikipedia)
How would you figure some of the methods (in order of importance) to take a picture ...
1
vote
1answer
81 views
Variance of Nested Experimental Uncertainty
I have to find the uncertainty of a quantity $Q$ doing two mean values. For example for a set of parameters I measure ten times $Q$, I obtain a mean value $Q_1$ and variance ${\rm Var}(Q_1)$. Then for ...
4
votes
2answers
186 views
How does one get the value of acceleration of gravitation on earth accurately by experiment without electronic device?
How does one get the value of acceleration of gravitation on earth accurately to 5 significant digits by experiment without electronic device?
-1
votes
2answers
119 views
Bolometer calibration - voltage and intensity
I am interested in possible hazards due to high intensy infrared light sources. Therefore I want to use the "PASCO TD-8553 radiation sensor" (website) to measure the intensity of the radiation of an ...
1
vote
2answers
215 views
Explain these graphs of rotation and velocity of pucks on air hockey board
I've been tasked to do a simple experiment on the elasticity of collisions. For this experiment I used two "pucks" (very light circular metal pieces of certain height but hollow) and a table that ...
0
votes
2answers
629 views
Why the pressure of atmosphere doesn't crush you when you e.g. walk outside?
Why the pressure of atmosphere doesn't crush you when you e.g. walk outside? I mean the density of air is $1.26 kg/m^3$, so with $100 km$ above us, it exerts much pressure on you when you walk ...
2
votes
2answers
1k views
How does Newton's 2-prism experiment help to explain why light does not get dispersed into 7-colors in a parallel glass slab?
In a real parallel glass slide(with two prisms imagined to be touching each other to form a parallel glass slide),
The ray of light should pass through the Z in between without any dispersion or ...
2
votes
1answer
117 views
Good algorithm for in-experiment 1-D optimization?
I'm running an experiment -- for the question, it doesn't matter which one, but I'm measuring an optical intensity $I$ as a function of two parameters: reflection angle $\theta$ and wavelength ...
2
votes
0answers
58 views
How can one activate the decay of the quark b with PYTHIA event generator?
This is my problem and I hope finding a solution.
_In the simplest alternative, MSTJ(22) = 2, the comparison is based on the average lifetime, or rather (c*tau "time life") , measured in mm. Thus ...
3
votes
1answer
104 views
Experiment to find structure of water
Who first determined the structure of water (two hydrogen atoms stuck to an oxygen atom at approx 105 degrees), and, more importantly, how was this done?
1
vote
0answers
88 views
Is there analysis library for stress-strain data?
I have three column data that has time-displacement-force from 1D tensile/compression test. Now I would like to get the standard mechanical properties of the material, like Young modulus, yield ...
1
vote
1answer
110 views
Reference request for the terminology and usage of different types of plasmas
I'm looking into discharge models, specifically for combustion prcesses, and I'm swamped by the number of different types of plasmas and their respective treatments (thermal plasmas, non-thermal ...
1
vote
1answer
171 views
How does the Double Slit Experiment work in detail?
What is the best detailed description/visualisation of the experiment available?
Describing what is actually measured, how the data is analysed, correlated and interpreted when for example large ...
0
votes
1answer
67 views
Are a measured object always part of the theory?
Is there a notion of measurement, which doesn't correspond to a yes/no question or with the idea of the comparison of two real world objects, which produces a real number?
And does at least one of ...
1
vote
1answer
145 views
What is 'tilt locking' of a laser cavity?
In another question, jasonh mentions a scheme for locking a laser to a resonant cavity called 'tilt locking':
The signal is used for locking the frequency of a laser to a high finesse cavity. The ...
4
votes
2answers
933 views
Strategies against 50 Hz mains hum on detector signals?
I'm having problems with a strong 50 Hz mains hum on signals created by photodetectors. I assume that they are due to ground loops and I realize that the best option would be to remove those. What are ...
3
votes
4answers
1k views
Why the shape of rainbow is semicircular after rain why not the whole atmosphere is colorful?
I have a very simple question.
Everyone must have seen the rainbow after rain. According to the theory the rainbow is created due to the passing of sunlight from small drops of water in the ...
3
votes
2answers
662 views
Efficiencies of Coupling Light into a Fiber
I am in AMO Physics and work a lot with optics. I just wanted to get an idea of what coupling efficiencies one "should" get in a "reasonable time"* by coupling light into a fiber using different ...
1
vote
1answer
57 views
How to properly read a measurement result if it is a number?
If the result of a measurement is i.e. $3.2 \pm 0.7$, what is 0.7? At which confidence level we know that the real result is inside of this interval?
2
votes
1answer
155 views
Can Mirror box simulate long light travel?
Imagine that there is a cube box that has mirrors all 6 faces in . If we use a strong laser and enter in the box from a small hole on the box. The laser light travels in the box long time that we can ...
2
votes
2answers
138 views
How the nucleon structure has been identified experimentally?
It is known that nucleons (proton, neutron) are composed of partons (quarks, etc.). How was this identified experimentally? In particular, how it has been identified that nucleons comprise of more ...
1
vote
1answer
262 views
Enlightening experimental physics books/resources
Most book recommendations I've seen are usually geared toward theoretical understanding. It would be nice to know at least one or two classic experimental physics books.
e.g. from Carl Brannen's ...
10
votes
5answers
937 views
The square in the Newton's law of universal gravitation is really a square?
When I was in the university (in the late 90s, circa 1995) I was told there had been research investigating the $2$ (the square of distance) in the Newton's law of universal gravitation.
...
