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

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3
votes
1answer
94 views

Using a laser to overhear a room conversation

Movies with science based tricks and gimmicks are generally silly and sometimes even annoying. The science based trick that I don't know enough about to judge is the following (and I have seen it in a ...
4
votes
0answers
61 views

To what depth can a whirlpool descend?

My question is based around comparing the physics of a tornado against, what I imagine/assume to be the marine equivalent of a tornado, that is a whirlpool located either at sea, in a tidal region or ...
1
vote
0answers
11 views

Why is it necessary to break symmetry to get magnetoelectric effect in multiferroics?

Spatial or time symmetry needs to be broken for both magnetic and electric to happen in the same material. But how is symmetry hindering the process?
0
votes
1answer
23 views

How does rainbow stay for such long time even it is caused due to raindrops?

Rainbow forms when light rays pass through a raindrop (usually, it can be a watet droplet also) and it undergoes several phenomenon like refraction , reflection , dispersion , But after the rainbow is ...
1
vote
1answer
21 views

Experiment to test flatness of prism

I have a Prism glued to a prism plate. Let's say the method of using optical glue is good enough, and minimal human error is tolerated. What experiment would be a good to check if the prism is not ...
0
votes
1answer
12 views

Why would the acoustic absorption coefficient of hexane in air be less than air?

Why would the acoustic absorption coefficient of hexane in air be less than air? That is, a 120kHz pulse train shows a bigger amplitude after traveling in a hexane/air mix than in pure air? My ...
11
votes
1answer
389 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 ...
0
votes
1answer
19 views

Hydrogen Spectra using Hydrogen Gas Discharge Tube

I am doing an experiment for my lab work which include determination of value of Rydberg Constant using method of Interpolation. For this we first plot calibration curve for various wavalengths ...
1
vote
0answers
12 views

Detector vs mixer

I'd like to measure the power of an incoming laser beam, which could be modulated to carry a signal. My laser will be in the range of 100um to 200um. So I think a Schottky diode detection system would ...
0
votes
1answer
41 views

What will happen if all the population all over the world jumped together at the same time in sea? [duplicate]

What can happen if a magnitude of such huge force is applied over the sea water of earth? Force applied will be average mass of each person *7 billion *9.8 .
28
votes
2answers
3k views

Pouring oil on choppy water to calm it , does it work and if so how?

Near where I live, local fishermen often bring cans of castor oil with them, to calm the water around their boats, if they feel bad weather is due. They claim this method of sea calming works, ...
-8
votes
0answers
43 views

Why teachers use red ink for checking, why are traffic signals show red for stop? [on hold]

Why is red colour used to check copies .Does it help us in anyway ?Many say writings with red inks retain in our memory for long . How does this happen? Does it has something to do with wavelength or ...
0
votes
0answers
21 views

What is the maximum level of heat that can be reached? [duplicate]

Heating is what everyone knows about . But does it have any limits . How much hot can anything become?
1
vote
1answer
85 views

The strength and control over the strength of electromagnets, correlation between the strength and weight of the magnets

I am currently working on a project that aims to use the attraction & repulsion between two electromagnets as an alternative to weights, from a physiotherapy and rehabilitation perspective to help ...
5
votes
2answers
194 views

Determining the refractive index of a foil

(59th Polish Olympiad in Physics, final stage, experimental part, 2010) You have at your disposal: a sample of blue foil of a homogeneous material, placed between two glass panes in a ...
0
votes
2answers
120 views

What kinds of behavioural anomalies can a zero-field-cooled (ZFC) / field-cooled (FC) split indicate?

If a material shows a spiltting in the ZFC and FC curves, is it necessarily superparamagnetic, or could there be any other reason for the irreversibility? I have heard spin glasses also show ZFC-FC ...
0
votes
2answers
64 views

Magnets And Charges [duplicate]

What is the reason that like charges repel and unlike changes attract each other ? is there something acting in atomic level? Why do charges that are like that donot attract each other ?
-2
votes
0answers
19 views

If the flowing speed of river increase can the direction of river can be changed with respect to decrease in speed? [closed]

I'm going to work on a project where I'm gonna club solar energy and flood decrease system.And my question is that, can we decrease the speed while the water flowing which results not in breakage of ...
9
votes
4answers
934 views

How much effect does the Bernoulli effect have on lift?

I understand that the Bernoulli effect is a flawed explanation for the cause of lift, and does not cause much at all, but how much? Is there any experimental data on the force caused by the ...
4
votes
1answer
1k views

Is it possible to use “negative sound waves” to “cancel out” a sound to create silence?

I saw youtube videos that claimed to do this, although I'm quite certain the videos just excluded sound and lied. However, I am wondering if the physics of this is actually possible - to create a ...
0
votes
1answer
41 views

Is possible to use optical fiber to transmit light to streetlights? [closed]

I was thinking about this idea: Only one lamp, inside a optical fiber structure, transmitting all the light through a lot of optical fiber cables direct to streetlights. (I guess that the cables ...
1
vote
0answers
39 views

A follow up on “Double Slit Experiment in a Bubble Chamber”

The exact title is "Has a double slit experiment ever been done using a track chamber or even contemplated?". I was totally unfamiliar with the concept of the bubble chamber, so I did some amateur ...
2
votes
2answers
102 views

Reference frequency

In my experiment, I have to obtain a relation between magnetic field of a solenoid and the applied Vp-p. The setup is as follows. http://www.teachspin.com/instruments/faraday/ Does my choice of ...
1
vote
2answers
440 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
2answers
433 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
2answers
238 views

Fiber optics with broadband, incoherent light

I wonder if someone could help clarify waveguiding with broadband, incoherent light please. If we take a telecomms fiber, which is single-moded above ~1.4 μm and couple a laser beam in, we assume ...
2
votes
2answers
169 views

Has the speed of gravity been measured experimentally? How? [duplicate]

In Newtonian physics, changes in gravity propagate instantly. In general and special relativity, gravity propagates at the speed of light, $c$. From reading answers to questions about gravity on this ...
0
votes
0answers
29 views

Why we want to convert a voltmeter to an ammeter or vice versa? [migrated]

Why in laboratory experiments do we want to convert a voltmeter to an ammeter and vice versa? What is our main aim here that is for what we are doing it? If our goal was to change the range of the ...
9
votes
2answers
853 views

ATLAS and CMS calorimeters

I was reading this interesting recent review on arXiv about particle identification: "Particle Identification" by Christian Lippmann (2011), arXiv:1101.3276 In figure 2, there is an interesting ...
3
votes
2answers
360 views

Why do physicists always give “event rates”?

Many times I see plots for expected/measured "event rates", but what's the motivation for this? Why not generate/use plots for expected/measured event numbers/counts instead?
3
votes
1answer
132 views

Motion in a Paul trap: $2n^{\text{th}}$ 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 ...
1
vote
0answers
38 views

3D Simulation Software

I need a software capable of simulating the physics of a car going off a ramp. This is a stunt that I will be attempting and looks like the following: A car, going off a curved ramp, doing a barrel ...
2
votes
2answers
69 views

Appartus for Young's double slit?

I am wanting a full description of an apparatus used for Young's double slit (not necessarily the one that Young himself used though), which takes monochromatic light (though not laser light) and ...
2
votes
1answer
441 views

Why are mass flow rates found using Venturi meter and pitot tube different?

Regarding an experiment to find the mass flow rate of a fluid (air) using a venturi meter and a pitot tube: What could be the cause of a variance in results obtained using the 2 instruments mentioned? ...
0
votes
0answers
16 views

Could diamagnetism be used to create an airbag for your internals?

Could a massively strong magnetic field be used to shield a human body from the effects of excessive +/- accelerations? My understanding is that say for a pilot suitably strapped in that the strain ...
1
vote
1answer
32 views

How many pairs of nuclei collide in heavy ion collisions?

As each bunch of heavy ions consist of a large number of nuclei it does not seem unlikely that multiple binary ion collisions will occur as it does in p-p collisions. However, should this be the case, ...
3
votes
1answer
139 views

Is this the correct way to I combine multiple interdependant pressure readings?

I want to measure the density in different layers of a suspension. To do this I want to place pressure sensors at different heights. Let's assume that the sensors are not by orders of magnitude more ...
0
votes
2answers
53 views

If two bodies move opposite to each other when brought in contact, what is the direction of force of friction?

We know that when a body is at rest and other is dragged over it then a force is produced which opposes the motion and consequently its direction is negative to the force applied on body to produce ...
6
votes
1answer
161 views

Has anyone experimentally shown the quantized thermal hall conductivity in Quantum Hall systems?

For background: In a $D=2+1$ state with edge modes described by a chiral $( c_L \neq c_R )$ CFT there is a predicted thermal Hall conductance associated with the gravitational anomaly at the edge. ...
0
votes
0answers
50 views

Has string theory predicted any experimently verified results? [duplicate]

I'm just getting into string theory and I'm wondering if it has made any unique predictions that have been verified by experiment?
4
votes
6answers
397 views

Detecting absolute motion inside a box

This is not a contradiction and I know it is impossible but still consider a thought experiment by me and point out if something is wrong. See the following picture and then the explanation follows. ...
1
vote
1answer
134 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 ...
2
votes
0answers
34 views

Estimate Uncertainties in Rietveld Refinement

I have the output of an x-ray diffraction experiment made on a thin film. Here I report the output of the experiment (I analyzed those data using powdercell and coloured regions have been excluded ...
4
votes
2answers
56 views

Is circular masking a laser beam an acceptable way to get the beam diameter you require?

I am wondering what are the down sides to just masking a laser to get the beam diameter you require? For example if you have a collimated eliptical beam of say 2mm width and 4mm height, but you ...
2
votes
2answers
6k 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
44 views

Do we regularly measure and update our physical constants (By using the LHC)?

This question is motivated by sheer curiosity. I certainly do not expect that the free parameters we use in the standard model have changed in value since we started measuring them with a "modern" ...
1
vote
1answer
101 views

Which g factor in an EPR spectra is the right one?

I was reading this introduction to EPR and it seems to imply both that there is a unique g-factor of a given compound, but also that we can calculate multiple g-factors for a compound. For example, ...
4
votes
2answers
4k views

Wheatstone bridge galvanometer error

We had to measure the resistance of $R_x$, we balanced the Wheatstone bridge and did calculations. My question is: we didn't include galvanometer error into calculations. Why is that? I read that it's ...
-1
votes
1answer
37 views

What is the freezing/melting point tap water?

Yes, I know purity is not a constant and depends on area etc. Does anyone have any experimental results on freezing/melting point of any tap water, as opposed to distilled, de-ionized, saline etc? I ...
2
votes
0answers
26 views

Is there a resonance within the earth, separate from the Schuman resonance?

In a very recent biography of Nikola Tesla by Bernard Carlson, the author explains that Tesla measured the resonant frequency of the earth using his invention - the amplifying transmitter. Tesla came ...