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

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0answers
22 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
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1answer
47 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. ...
2
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1answer
171 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 ...
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0answers
41 views

I want to test a tunable optical filter that can quickly change from being a red light filter to being a blue light filter [on hold]

I want to test a tunable optical filter that can quickly change from being a red light filter to being a blue light filter. For this purpose, I am wondering about photonic crystal tunable optical ...
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1answer
36 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 ...
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0answers
50 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
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2answers
41 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 ...
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1answer
13 views

The working of rheostat/ potentiometer [closed]

I can't grasp the concept of how a rheostat divides potential and acts as a variable resistance in a circuit.I have tried asking my teachers and fellows but their explanation hasn't been satisfactory. ...
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9answers
4k views

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

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 ...
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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?
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0answers
21 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 ...
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0answers
23 views

How do I determine the heat conductivity of a material? [closed]

I have a cup. I want to determine how much heat is transferred between the inside contents (boiling water) and the outside surroundings. What kind of information and how do I determine how to ...
1
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1answer
67 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 ...
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0answers
29 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
39 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?
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1answer
45 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
25 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
22 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 ...
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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
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1answer
35 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 ...
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0answers
19 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 ...
3
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1answer
36 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 ...
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0answers
20 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
38 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: ...
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2answers
77 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 ...
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 ...
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3answers
81 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 ...
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2answers
152 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 ...
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0answers
28 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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0answers
19 views

How can I precisely measure the intensity of the Hydrogen Alpha (Balmer) line at low intensities?

I assume that I will need some kind of very precise filtering, but how is that accomplished? After that, photon counting at worst, but I am expecting millions of photons per second. The background is ...
4
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4answers
104 views

Are there any planned experiments to intentionally create black holes in the lab for study?

And if they did what kind of machine would be making them? And what would they study?
3
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1answer
182 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
24 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 ?
0
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1answer
48 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 ...
6
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4answers
115 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 ...
1
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1answer
64 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 ...
2
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2answers
240 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
55 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 ...
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0answers
28 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
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1answer
67 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 ...
2
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1answer
42 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
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1answer
202 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 ...
0
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1answer
46 views

Michelson-Morley experiment

I have to do an experiment about light. I preferred to measure the speed of light by the experiment of Michelson and Morley. When you do the experiment, it will result in an interference pattern by ...
0
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1answer
39 views

Role of quark color with respect to exclusion principle

From Wikipedia's article on color charge: "Shortly after the existence of quarks was first proposed in 1964, Oscar W. Greenberg introduced the notion of color charge to explain how quarks could ...
4
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2answers
358 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 ...
1
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1answer
61 views

Quark-gluon plasma: status [closed]

Can we say that a QGP has been observed or is there only suggestive evidence? Is the idea that string theory, through the AdS/CFT correspondence, could help to understand this new state of matter ...
2
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0answers
34 views

Are Cosmic Microwave Background (CMB) photons entangled?

Suppose we'd like to know whether two cosmic microwave background photons emitted from different parts of the sky have any quantum correlation with each other. We could measure polarization of two ...
2
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1answer
372 views

Is there a significant possibility of the LHC missing “exotic” particles or events?

In his popsci book, "Particle at the end of the universe", Sean Carroll says that the LHC, due to it's sheer information gathering capability, necessarily needs to completely discard most of the data ...
2
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1answer
96 views

With the LHC about to restart as max energy, are there absolutely no hints or tantalizing signs of Supersymmetry in previous data?

Over the last couple of years I've seen several articles talk about hints or bumps in the data that might point to Supersymmetry. An article in NewScientist from Summer 2012 discussed the discovery of ...
2
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1answer
25 views

What is the value (order of magnitude) of electric charge density of the atom and the nucleus?

The mass density of the nucleus is constant. But what is the electric charge density of the nucleus and the atom (any order of magnitude)?