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

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25
votes
0answers
871 views

Are the fast axes on Thorlabs quarter-waveplates mislabeled?

Some members of my lab are performing a polarization-sensitive experiment where they need to use a quarter-waveplate (QWP) with the fast axis in a specific direction. In the process of carefully ...
6
votes
2answers
698 views

What's wrong with this experiment showing that either FTL communication is possible or complementarity doesn't hold?

The assumptions are: Alice and Bob have perfectly synchronized clocks Alice and Bob have successfully exchanged a pair of entangled photons The idea is simply to have Alice and Bob perform the ...
2
votes
0answers
79 views

Is there a cheap way I can do a Bell inequality experiment?

My work is almost completely theoretical/computational. But I'd really like to do a Bell inequality experiment just so I can personally see this (the best way to learn something is hands-on, right?) ...
1
vote
1answer
122 views

Is this a photograph of Surface Plasmon Resonance?

Does this photograph depict surface plasmon resonance? PHOTO 1 - Ellipsometric style photograph produces blue-green and purple resonance waves from nanogold-like tubule. PHOTO 1 was cropped from ...
9
votes
1answer
249 views

Current known *lower* bounds to the neutrino masses?

I started a little bit of Googling around the topic, and found very few information. There are mainly upper limits. I found lower limits only to the rest mass differences of the different neutrino ...
3
votes
1answer
140 views

EXAFS (Extended X-Ray Absorption Fine Structure) question?

EXAFS (Extended X-Ray Absorption Fine Structure), core electron is excited to the conduction band. The oscillations in the absorption coefficient persist for 100s of eV after the edge. Taking ...
2
votes
0answers
46 views

What to work on? [closed]

(I am not exactly sure if this question is supposed to go here, but it seems like the appropriate place for it.) Hello Scientific Community, I am soon graduating from high school and, as everyone ...
1
vote
0answers
31 views

How to isolate and verify the source of optical absorption/effects?

This is similar to my other question, but not the same -- that one was about the energy ranges of various absorption mechanisms, and this one is more about experimental techniques to find them. Let's ...
1
vote
0answers
65 views

What is the most effective dielectric material known to man?

What is the most effective dielectric medium/material (highest breakdown voltage) known to man? Is it the vacuum? or are there any materials which could be more effective than the vacuum?
0
votes
4answers
419 views

Equations of graphs

I am doing a practical write up of an experiment I did. Here is a graph using the raw data I got. What is the general formula of this graph, and what do I need to do in order to make that into a ...
1
vote
1answer
170 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 ...
4
votes
1answer
253 views

Is this a photograph of an electron-positron annihilation? [closed]

With degrees in Mechanical and Electrical engineering but no advanced education in physics, I submit a query based on ellipsometric macro photography of TEMS supplied by FDA/NIH. In one TEM a ...
4
votes
2answers
673 views

Why my simple electromagnetic experiment does not work?

I make a setup (see attached picture). ONE coil (1" diameter x ~120 turns), which is separated with a gap, is mount on two sides. Each side has an iron rod (1" diameter x 6" long) to increase the ...
3
votes
1answer
187 views

Interpretation of the WIMP annihilation cross section graph

I have some trouble in the interpretation of the WIMP cross-section annihilation versus their mass. I understand that the lines represent a upper bound on the cross section from the observation. ...
0
votes
3answers
237 views

What will happen after escaping earth's gravitational field?

Suppose that I escaped the gravitational field of earth. Then: am I going to be pulled by Sun's gravity?
9
votes
2answers
660 views

How do we measure meson decay constants?

I'm trying to understand how people actually measure decay constants that are discussed in meson decays. As a concrete example lets consider the pion decay constant. The amplitude for $\pi ^-$ decay ...
1
vote
1answer
167 views

Resolution in a Fourier transform spectroscopy setup

I am a bachelor physics student and as an assignment we had to perform measurements on an FT spectroscopy setup. Context. Our setup consisted of a Michelson interferometer through which the light ...
0
votes
1answer
207 views

Apparatus for recieving Radiant Energy by Nikola Tesla

http://www.keelynet.com/tesla/00685958.pdf An elevated, insulated copper plate, a patented Tesla Condenser, and a voltage inverter, we've got free electricity right? admittedly small, but as a ...
6
votes
4answers
734 views

Power fit to some experimental data

I have to fit some data to a power law $$ F=\alpha q^{\beta}$$ being $q$ and $F$ the experimental data points. What I usually do is taking logs so that $$ \ln(F) = \beta \ln(q)+\ln(\alpha)$$ and ...
4
votes
0answers
183 views

Baryonic density in collision experiments

Does anyone know any way of estimating the net baryon density in collision experiments, e.g. in LHC, RHIC, or the upcoming ones at GSI-FAIR? I have comes across many hand-waving arguments, sample - ...
1
vote
2answers
64 views

How do you stop wobbling in a carbon nano tube elevator to space?

If there was a carbon nanotube elevator that went to space how would you keep it from wobbling? As I picture it I see the structure being very strong, but would that prevent wobbling? It would be ...
9
votes
1answer
82 views

LIGO sensitivity in terms of minimum received power per area

I've been looking at LIGO figures for gravitational wave sensitivity here and it seem to be displayed in an adimensional strain ratio (which I assume that is more or less equivalent to metric ...
5
votes
2answers
327 views

A modified version of the famous double-slit experiment

As far as I know, all the double slit experiments that were performed uses a light source (or electron source...) that emits photons at a "perpendicular" angle as this image shows: (will call it ...
10
votes
1answer
840 views

Icecube experiment at the North pole instead of the South?

Is there a particular reason, why the Icecube experiment has been installed at the South pole and not at the North pole?
3
votes
0answers
93 views

Has the existence of anyons been experimentally verified?

I've been wondering whether there has been any experimental evidence for the existence of anyons or are they just objects of purely mathematical interest?
1
vote
3answers
175 views

Solar neutrino problem in 1968 and experimental verification of neutrino oscillation in 2001. Why the huge delay?

Solar neutrino deficit was first observed in the late 1960's. And theory of neutrino oscillation was developed in 1967. But,in 2001, the first convincing evidence of solar neutrino oscillation came in ...
4
votes
1answer
59 views

What technological advance would allow LEP3 to surpass LEP2?

I learned that for electron accelerators synchrotron radiation and acceleration are the limiting factors. This article, that I found in one answer to this question mentions that one would not use the ...
0
votes
1answer
155 views

How the gravitational constant $G$ is determined?

We know the gravitational constant is $G=6.67545 \times 10^{-11} m^3 kg^{-1} s^{-2}$. But how this value is determined at first?
18
votes
4answers
1k views

Is there experimental evidence that massless particles such as photons attract massive objects?

For instance evidence that a highly energetic laser beam attracts objects nearby? In the framework of Einstein's general relativity all energy curves spacetime and hence exerts an attraction, but my ...
0
votes
1answer
126 views

Is there any way to find difference between two same sounds of different people?

I am trying to understand and find a way to distinguish two same sounds of different people by some physics formula, so could you guys help me? OK I'll try to explain my question in this way that, ...
0
votes
1answer
830 views

Measuring flow rate of gases

Flow rates of liquids could be easily measured with a stopwatch and a known volume container. But gases, if entrapped in a container will create a back pressure, and may lead to decreased flow. I ...
0
votes
1answer
343 views

Maximum magnetic strength achievable

What will be the maximum magnetic strength to which a piece of ferromagnetic substance can be magnetised? What will the maximum strength possible for a piece of iron? How would the shape of the ...
3
votes
1answer
189 views

What is making these subatomic honeycomb shapes and gaps in this graphene image?

I just read yet another graphene discovery and saw this STM image: Nice photo, it begs two questions: What is that secondary honeycomb structure, the one about 20x smaller than the atoms ...
2
votes
2answers
254 views

Noise in laboratory sources of gravitational waves

Suppose you wanted to detect gravitational waves from a lab source (I know, any reasonable man-made source will be several orders of magnitude below detection technology, but humor me for a second). ...
17
votes
6answers
2k views

Which experiment gave scientists reason to believe nuclear fission/fusion produced energy?

Every piece of knowledge in science has a beginning lying in someone's experiment. I would like to know which experiment gave scientists the reason to believe nuclear fission/fusion existed and was ...
0
votes
1answer
92 views

What is the experimental uncertainty of an ensemble measurement? [duplicate]

Let's say you measure the time it takes for 10 oscillations of a mass undergoing simple harmonic motion to within ± 0.01s, what is the uncertainty of the period of one oscillation?
14
votes
3answers
900 views

What limitations are there in measuring physical properties accurately?

In a StackOverflow answer, I attempted to explain why a 32-bit float was perfectly adequate for representing the questioner's weight measurement: Physical properties are inaccurately measured ...
5
votes
2answers
669 views

What are the technological challenges to building a muon collider?

There is a strong physics case for building and running a muon collider (primarily as a Higgs factory). Currently, what is the principal technological hold-up in making the muon collider possible?
1
vote
0answers
44 views

Any photon colliders in the past?

People have been thinking about a photon-photon collider (see this and this) as an add-on or to supplement the ILC, the next generation linear collider. My question is, have there been any photon-...
0
votes
1answer
216 views

Help w/ speed of sound experiment report question

Experiment was done by using an oscilloscope and a piezoelectric transducer to generate ultrasonic sound waves. We had to move the transmitter whilst receiver remains constant on a angled 1 meter ...
0
votes
1answer
5k views

How to calibrate an Ammeter?

Calibrating an ammeter is tricky thing to do. The obvious way would be connecting it to another good ammeter and see if they get the same result. However, people have been telling you can use a ...
0
votes
2answers
351 views

Does this* refraction experiment correctly conclude faster than light travel?

This question asks if a particular experiment is correct in its conclusion. This experiment, conducted by Alfred Leitner, is shown in a 1975 physics instructional movie. It claims that the experiment ...
1
vote
0answers
76 views

Stepping into a pool of water - shock - why?

If I put my feet into a pool of water that contains a live wire, why do i get shocked? For electrons to flow through my body, there has to be a E-field/wave that passes through my body along a certain ...
-1
votes
1answer
1k views

What happens if we put a pinch of salt on the ice cubes which is melting in the water?

What happens if we put a pinch of salt on the ice cubes which is melting in the water? How will the ice react to the salt, and what other things will happen after mixing them?
1
vote
1answer
541 views

Electron Spin Resonance (ESR) Experiment: the two peaks

I am unable to figure out how we get two peaks in the Electron Spin Resonance (ESR) experiment, in which we use Helmholtz coils as B source with modulation, and a basic unit as a source of radio waves....
2
votes
1answer
72 views

Decay/Counts/Number of Nuclei

I'm writing up a lab report and have a question about the following formula $$N = N_0e^{-\lambda t}$$ $N$ indicates the number of nuclei left after a time $t$ and $N_0$ indicates how much there was ...
3
votes
1answer
79 views

Fitting an exponential when values are negative (while taking error into account)

I'm attempting to determine the half-lives of two silver isotopes (Ag-108 and Ag-110). A lab manual for a similar experiment may be found here http://web.vu.lt/ff/a.poskus/files/2013/06/NP_No08.pdf I ...
2
votes
0answers
183 views

Balloon tethering cable tension model (catenary tether)

If a moving balloon (let's say it's a blimp system with some rotors for movement) is connected to the ground by a cable that describes a catenary curve, how can we model the tension being applied on ...
0
votes
1answer
59 views

Does bragg diffraction affect intensity of transmitted light?

Is it possible to measure the plane spacing in a crystal by measuring the angle at which transmitted light intensity dips?
0
votes
0answers
101 views

Cooling power for cloud chamber

I'd like to build a small Peltier cell cooled cloud chamber. The cold surface would be a copper sheet with a surface of 200x200 millimeters. Is there a way to even guess the cooling power needed to ...