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

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0answers
55 views

Weighted average whenever a variance is 0? [closed]

So I have data for the number of times a certain event happens. Each column is a different event and each row is one trial. A sample of data would look like \begin{bmatrix} 1& 4& 7& ...
0
votes
4answers
290 views

Can we create invisible things?

We are able to see this beautiful world because of light. When light gets reflected from the object, the reflected light enters our eye retina and thus we are able see that particular object from ...
2
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2answers
313 views

Measuring background radiation

We tried to measure background radiation using a geiger counter for a experiment at school. The meter showed $0.12$-$0.21$ microSv/h during the day averaging at about $0.14$ mcSv/h. As we tried to ...
0
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1answer
74 views

How magnets create electricity in conductors?

what are the reasons for current appearing in a wire when wire is in a changing magnetic field?
1
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0answers
89 views

Do I understand measurement of dispersion relation in a solid correctly?

I'm currently doing an introduction to solid state physics course and have a quick question about measurement of the dispersion relation of phonons in a solid: The way I understood it is the ...
0
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1answer
147 views

Is there a way of measuring the spin along an arbitrary direction of a spin 1 particle?

I am familiar with the expression for spin 1/2 but haven't seen one for spin 1.
1
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1answer
215 views

Questions about MTW's “thousand” tests of the Einstein principle

In Misner, Thorne, Wheeler (henceforth written as "MTW"), "Gravitation", Box 16.4, there's an experimental setup construction (or method) presented by which "Each geodesic clock is constructed and ...
2
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1answer
106 views

Quantum fluctuations in a classical domain?

"In the presence of chaos, even small fluctuations (including quantum fluctuations) can be amplified to produce large uncertainties in later behavior"(http://arxiv.org/pdf/gr-qc/9210010v2.pdf) Is there ...
3
votes
2answers
129 views

How do you measure proton's spin? [duplicate]

I've probably read it somewhere in Sakurai but I cannot recall it at the moment. So how does one really measure the proton's spin? I mean the proton's spin and not its constituents. Do you measure ...
0
votes
0answers
80 views

Elemental sensitivity factors for Auger electrons

Is there any open database of elemental sensitivity factors for Auger electrons? I'm trying to figure out graphite oxidation degree from AES spectra, so relative sensitivity of O to C is required. ...
6
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3answers
176 views

Are there any Meson colliders?

There are no stable mesons as far as I know. Are there any meson-colliders analogous to for example proton-proton colliders?
4
votes
1answer
143 views

How do I calculate the experimental uncertainty in a function of two measured quantities

I am performing an experiment where I'm measuring two variables, say $x$ and $y$, but I'm actually interested in a third variable which I calculate from those two, $$z=f(x,y).$$ In my experiment, of ...
2
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1answer
124 views

Evidences against Supersymmetry [closed]

Recently, some experiments show that the supersymmetry is not realised by Nature according to the simple models that we currently have. Nevertheless, it is far from saying that the "game is over" as ...
0
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3answers
161 views

Physically implementing quantum measurement of energy

If there were a particle in a box, how could one measure its energy? I understand the theory behind quantum measurements: the Hamiltonian operator represents the energy observable, so you perform an ...
0
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1answer
44 views

How can I determine a gas partial pressure knowing the flow?

I have a vacuum chamber with a pressure 10-8 Torr. Then I open an Oxygen valve with a set flow of 2 sccm from a tank with a pressure of 2 bars. The pressure in the chamber decreases to 10-2 Torr. What ...
1
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0answers
55 views

Exorbitant number of counts per sec. in the Rutherford Experiment

May someone kindly advise on the Rutherford experiment? I have created a Gaussian of dP$_0$/$\Delta$$\theta$($\theta$), where P$_0$ is the number of counts of alpha particles through a 1.05X19.86 mm ...
4
votes
2answers
138 views

Is Galilei's reasoning on free fall valid?

Galileo Galilei discovered by experiments that all bodies tend to fall with the same rapidity (I use it in an intuitive sense, you can replace it by 'acceleration' used in today's physics language), ...
0
votes
1answer
82 views

Can we make rigid floating helium spheres?

Is there any material that we can make rigid floating helium spheres out of without it collapsing? I have been playing with surface area and volume formulas and with a bit of trial and error have ...
0
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0answers
35 views

References on the LHC experiments

I'm looking for a references / short book which discusses what is going on LHC collider - specific experiments, collision processes, analysis of data, how exactly the facility is operating (not ...
2
votes
1answer
184 views

Rutherford Experiment - practical and theoretical questions

I performed the Rutherford experiment the other day, using Au thin foil of $2\,\mathrm{\mu{}m}$, a source/gun of α particles (241Am) and a detector/counter. α particles were shot from the source ...
1
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2answers
68 views

Can a broken light filter shift the wavelength of light exiting it?

I've measured the wavelength of light emitted from a red Helium–Neon laser passing through a red intensity filter (indirectly, by fitting a function to a single slit diffraction pattern, then forcing ...
-1
votes
1answer
346 views

Measure mass difference of an object without a scale

For a project i need to separate items based on their mass in real time. I like to explore measuring weight of an object (round metal ball) by taking photographs (several) during free fall and ...
4
votes
3answers
4k views

Is the Earth negatively or positively charged?

The Earth carries a negative electric charge of roughly 500 thousand Coulombs. Does that mean the Earth is negatively charged?
1
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1answer
79 views

Conductive glue

I would like to use some conductive glue to contact a silicon chip's back gate. Any suggestions on what to use? Can I use thermal silver paste? I would be operating at cryogenic temperatures below 4K. ...
3
votes
1answer
104 views

Motion in a Paul trap: $2n$th harmonic with larger amplitude than $n$th harmonic

Using a Paul trap, we captured the motion of a light charged particle (based on a rotating potential applied by AC current). Our rotational frequency was 50 Hz, and so when used FFT on the data, we ...
3
votes
1answer
124 views

Is it possible to use the parabolic shape of a rotating fluid to measure the angular frequency of the rotation of the Earth?

A fluid in a rotating bucket will take on a parabolic shape (for example of some simple derivations of this result see http://en.wikipedia.org/wiki/Bucket_argument). The assumptions that play into the ...
1
vote
2answers
686 views

Observations in the cathode ray tube experiement

1.One of the observations I learned was that the glass tube begins to glow with a brilliant green light. Many websites I read through refer to a fluorescent material. However, as shown in the above ...
1
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1answer
164 views

LHC Experiments for finding parallel universes?

I watched this video featuring Michio Kaku explaining parallel universes. In the last two minutes he said that experiments in the LHC could reveal that there might be parallel universes and then he ...
15
votes
1answer
217 views

If time isn't continuous, what is the best-known upper bound on the length of time intervals?

There have been several questions about whether time is continuous or not and it seems like the answer isn't currently known. I know quantum mechanics treats time as continuous and any mathematics ...
3
votes
2answers
312 views

How to determine what an object is composed of?

Heads up: This question has never been asked (here) before the way I will ask it here, so let's shed some light on it a bit. Prelude and anecdote(can be skipped): The other day I was walking home, ...
0
votes
1answer
125 views

How long does it take to scan a typical scanning electron microscope image?

I suppose the answer depends on resolution and imaging area, but can you provide some ball park measures of imaging times with an SEM?
5
votes
3answers
1k views

Why are roofs blown away by wind?

Whenever there are high winds, such as in storms, thin metal roofs on sheds as well as concave roofs on huts are sometimes blown away. One explanation provided to me said that the higher velocity of ...
0
votes
2answers
494 views

Difference between Vernier constant and least count

What is the difference between the Vernier constant and least count of a Vernier caliper?
11
votes
3answers
1k views

Interpretation of “transition rate” in Fermi's golden rule

This is a question I asked myself a couple of years back, and which a student recently reminded me of. My off-the-cuff answer is wrong, and whilst I can make some hand-waving responses I'd like a ...
2
votes
0answers
25 views

What were the immediate consequences Yang-Lee work on Weak Interaction?

I am studying the history of Modern Physics and Yang-Lee earned their Nobel the next year after the Cobalt experiments. I am familiar with the chronology, but am not clear what those findings meant to ...
1
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0answers
27 views

Is there a difference in binding energy between a regular material and a doped one?

Say Silicon and boron doped silicon. Would the doping affect the binding energy? Could I see this in an XPS spectra?
5
votes
0answers
98 views

Textbook about the handiwork of a HEP analysis?

I'm wondering if there is a textbook that describes the handiwork of a particle physics analysis. There are a bunch of books about theory, about the experimental aspects like detectors, and about ...
2
votes
0answers
54 views

What is the requirements from an optical lab in terms of darkness

I am characterizing an optical lab and would like to know therefore what are the requirement from a standard optical lab in terms of ambient luminescence. In other words how dark should an optical lab ...
1
vote
0answers
104 views

Buoyancy Correction for a Kater Pendulum

Question: Consider a Kater pendulum: that is, a rod with two cylindrical masses at both ends, with a knife edge between the two masses and another between one ...
1
vote
1answer
262 views

How can one explain the Kelvin Water drop experiment without assuming the container to already possess a positive charge?

Kelvin Water Dropper experiment refers to the electrostatic generator invented by Lord Kelvin, which uses falling water to generate a voltage by electrostatic induction occurring between ...
-4
votes
1answer
77 views

Free 'fall' on an Inclined Plane

I guess we can say that two identical balls on the same inclined plane with different heigths reach the ground at the same time. So, who was the first one to observe it? ...
4
votes
1answer
270 views

Can force be transferred through objects in a chain to the last object without any displacement of objects in the middle?

sorry for terrible graphical representation, I did an experiment, i took 6 coins fixed 4 of them in one place by placing some real heavy objects on them , then i took a 5th coin placed it in the ...
5
votes
1answer
90 views

Determining source of neutrinos

An article in Science, Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector, claims to have detected 28 neutrinos from an unidentified extra-solar location that has yet to be ...
4
votes
2answers
73 views

How to realize long-range interaction of colds atom in an optical lattice?

In the Bose-Hubbard model of cold atoms in an optical lattice, we consider only the short-range interaction or on-site interaction. Is it possible to realize long-range interaction similar to Coulomb ...
1
vote
2answers
184 views

Are there moments in particle collision experiments where the particle beam is in open air?

I keep encountering the story of Anatoli Bugorski, who apparently got hit in the head by a proton beam at the U-70 PS in Protvino, Russia. I find it difficult to believe that this is actually ...
3
votes
4answers
336 views

how long do large hadron collider experiments take?

This travel stackexchange answer has kinda got me wondering... how long do experiments involving the large hadron collider usually take? I'd expect you run it for a few seconds and bam - higgs boson ...
2
votes
0answers
158 views

Problem with (grad school) physics education? [closed]

(Just to anticipate, having looked at other closed threads about physics education, I don't think this question should be too opinion based or broad.) Since being in a lab now for a couple years, ...
2
votes
3answers
273 views

The cooling curve of tin during solidification

I'm going to measure the freezing point of tin by recording the cooling curve. It sounds like a dull experiment because all I have to do is to heat up the tin, wait for it to cool, and the computer ...
8
votes
4answers
440 views

Doesn't the use of a thermometer alter the temperature of the system?

If I place a mercury thermometer in hot water, heat energy will transfer from the water to the mercury inside the thermometer. Will this continue until thermal equilibrium is reached and thus the ...
2
votes
4answers
130 views

what could generate a high-pitched whine in electronics where the frequency depends on the current?

So I was operating a Laue machine recently which generates x-rays and fires them at a sample, and I noticed that there was a high-pitched whine coming from the instrument (nothing abnormal, just ...