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

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1answer
97 views

Is the intuition of “absolute simultaneity” necessarily wrong?

I read about Einstein’s theories of relativity with all the interesting stuff like time dilation, mass increase and whatnot. And also about the relativity or conventionality of simultaneity. The ...
0
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1answer
37 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 ...
2
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2answers
42 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 ...
8
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1answer
72 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 ...
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0answers
13 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
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0answers
23 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 ...
1
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2answers
151 views

Use something that slower than light in Michelson–Morley experiment

Follow by the Michelson–Morley experiment, What happen if we use something that has a speed lower than light instead of light in Michelson–Morley experiment? How about the result?
5
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3answers
249 views

Has anyone tried Michelson-Morley in an accelerated frame?

After doing much more digging than I thought I had to do, I found out that the speed of light is NOT invariant in an accelerated reference frame. Has anyone done any experiments to confirm this? In ...
1
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1answer
69 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 ...
1
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1answer
139 views

Error calculation for experimental data

I have the list of experimental values: $$\{w_i \pm \Delta w_i\},$$ where $w_j$ is a mean value and $\Delta w_i$ is an error. I want to calculate the second list $\{a_i \pm \Delta a_i\}$ according to ...
9
votes
5answers
4k 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. ...
0
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0answers
30 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 ...
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1answer
40 views
1
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0answers
43 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 $0< V\leq V_c$? If yes, then why don't ...
11
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5answers
9k views

How do you determine power flow direction in a transmission line?

Below is a picture of a typical transmission line(about 200 kV). Is there a simple physics experiment which can be performed safely near the line, to determine the power flow direction. Or in other ...
0
votes
1answer
64 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
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1answer
35 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
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0answers
25 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 ...
4
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1answer
341 views

Why is the relationship between velocity and radius curved, in circular motion?

We are supposed to graph velocity squared against period. My instructor specifically said: The gradient of this graph is acceleration and We should observe a trend of decreasing orbital velocities ...
0
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0answers
23 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 ...
1
vote
1answer
38 views

What is “forward peaking”?

In "Research and Development for a Gadolinium Doped Water Cherenkov Detector" the phrase "forward peaking" is used to describe a signal. This comes up in lots of other contexts too, but I still can't ...
0
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0answers
25 views

How accurate is the Callendar-Van Dusen equation?

... over 0 degC to 100 degC? The equation itself can be found here I can do a very accurate one point calibration of a 1/10 DIN PT100 sensor at 0 degC. If I use the equation to correct for non-linear ...
1
vote
2answers
88 views

Linear momentum experiment

trying to design an experiment for linear momentum. Could someone tell me whether this would work. Get a wooden toy car and attach it to some string which is hung over a pulley on the end of the ...
9
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2answers
796 views

Mechanical Equivalent of Heat

Recently I have been looking up James Joule's experiment regarding the mechanical equivalent of heat. After viewing some drawings of the apparatus, I assumed that the lines holding the weights would ...
1
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1answer
116 views

Upper limit to electric charge confinement?

The following questions are not intended for conventional capacitors (which stores excess charge on the outside surface), rather a type of hypothetical capacitor which is designed to confine charge by ...
3
votes
1answer
37 views

Median filtering - cheating?

The concept is simple, and is used to remove non-typical data. A sample set is put in numerical order and the extremes discarded. For example, in an experiment I am doing I take batches of 10 ...
1
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0answers
23 views

Error propagation log2

I have a quick question to report some numbers on an experiment. I made measurements of fluorescence in a titration of a chemical. The titrations were 1:2 serial dilutions so I report each ...
3
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0answers
39 views

How “steady” are screw threads?

I have a setup whereby two stainless steel end caps screw into a similar tube about 100mm in length and 25mm internal diameter. Thread is fairly standard, and is finger tight. The question is: ...
4
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4answers
2k views

What are the effects of cosmic rays on consumer electronics? [closed]

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?
7
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2answers
162 views

Has a phonon, a formal quasi-particle, ever been observed as a point particle?

Phonons are a nice tool to simplify the quantum-mechanical description of lattice vibrations by identifying the ladder operator of normal modes as creation operators of a certain quasi-particle. In ...
0
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0answers
9 views

Corona discharge v pressure in air

Does anyone have any information on how a corona discharge between two electrodes changes as pressure is reduced from atmospheric to below 1mB? I am assuming current limited. Also, what I am looking ...
0
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3answers
85 views

How to measure the wave-function experimentally?

Do experimental physicists really measure the wave function of a system? How do they do it? Do they make many identically-prepared systems and measure the position of the particle(s) over and over ...
6
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4answers
119 views

Explanation of Michelson Interferometer Fringe Shift

I have been working on an experiment where 2 glass microscope slides are pinched together at one end (so that there is a "wedge" of air between them) and placed in the path of a laser in one leg of a ...
4
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4answers
105 views
0
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0answers
30 views

Evaporation of black holes

What is the current scientific consensus about the evaporation of black holes? Is there any experimental evidence that support it? (I distinguish between Hawking radiation and black hole evaporation)
3
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1answer
189 views

Determine water level difference in two ponds

I live near two ponds whose water levels appear to differ by a few feet. The ground is hard clay, so I don't think there's any underground water exchange between the ponds. The ponds are separated by ...
0
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0answers
28 views

How much harder an aluminum bat will hit a ball as compared to a wooden bat?

I was thinking like what's the major difference between using aluminum bat and wooden bat means how much harder will an aluminum bat will hit a ball as compared to wooden bat ?
1
vote
1answer
66 views

Decay channels of the Higgs Boson in Large Hadron Collider particle production

I attach a diagram of 4 of the (many) possible decay channels produced by the Higgs boson, and I have read that 57 % of the time, we find a bottom quark, antibottom quark pair resulting from this ...
420
votes
22answers
161k views

Cooling a cup of coffee with help of a spoon

During the breakfast with my colleagues, a question popped into my head: What is the fastest method to cool a cup of coffee, if your only available instrument is a spoon? A qualitative answer would ...
13
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2answers
4k views

How do we know that some radioactive materials have a half life of millions or even billions of years?

If a radioactive material takes a very long time to decay, how is its half life measured or calculated? Do we have to actually observe the radioactive material for a very long time to extrapolate its ...
2
votes
1answer
46 views

How many different experimental configurations does the Large Hadron Collider have?

I understand that the LHC can collide protons with protons, heavy ions with heavy ions, or protons with heavy ions, giving three main configurations. But, I'm wondering: is that the only property that ...
0
votes
1answer
50 views

Probability of Vacuum Fluctuations near Charges

A short, simple enough question, if you know about field theory, which unfortunately I don't. Are vacuum fluctuations more probable near a charge, for example an electron with negative charge? I ...
2
votes
2answers
252 views

What is the essential difference between a resonance and a particle?

Let me start by explaining my particle physics background is very patchy, so this question may not be as coherent as I would like it to be. In general terms, what is the difference between a ...
3
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0answers
56 views

Large Hadron Collider 2015 upgrade, what can it show us?

I realise that the initial answer to my question that may come to mind is, "we don't know yet, duh!!" But my question is hopefully not opinion based. To be specific, have we now a greater chance of ...
1
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0answers
30 views

the torsion balance of the Cavendish experiment

I need to perform the Cavendish experiment and build a torsion balance but I can't find metallic spheres with enought mass so I was thinking about using a pair of dumbbells instead. My question is if ...
2
votes
1answer
85 views

Signs of supersymmetry and thus dark matter at CERN

The Large Hadron Collider at CERN has just re-started after a two year pause and is now running at unprecedented levels of 6.5 TeV, with collisions that will release up to 13.5 TeV. With this increase ...
21
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3answers
972 views

Has the gravitational interaction of antimatter ever been examined experimentally?

I know that the gravitational interaction of antimatter is expected to be the same as normal matter. But my question is, has it ever been experimentally validated? I think it would not be a trivial ...
1
vote
1answer
108 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
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1answer
214 views

About a recent experiment which claims reality doesn't exist until we measure it?

Reality doesn't exist until we measure it, Quantum Experiment confirms. Is this one more experiment which is the victim of how news generally hypes stuff like this? This is a section from the ...
4
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2answers
359 views

Physical experiments - False positives

How is it made sure that something has been discovered, and not just noise? Is one discovery of something that is predicted considered to be enough (Higgs-particle)? What are the probabilities of a ...