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

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How do I measure speed accurately without any turning wheels?

Consider a pod (about 50 ft long and 15 square feet wide) that levitates using air pressure that shoots through the bottom and travels through a tube that's at low air pressure (about 100 Pa). It ...
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1answer
53 views

Graphing $E_p = E_k + E_{rot}$

I am measuring the moment of inertia of a flywheel and using conservation of energy to work out the value (I am ignoring friction). So for the experiment I have to roll the flywheel down a slope (I ...
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2answers
118 views

Magnetic flux density of a solenoidal electromagnet

I am designing an electromagnet which will be used to test magnetic sensors. So I used to formula found at hyperphysics which relates the magnetic field flux density to the number of turns, the ...
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1answer
27 views

Residuals are normally distributed

I did not know whether to post this question in the Physics or Statistics section of StackExchange, but the question involves the application of statistics to the analysis of experimental results. I ...
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3answers
270 views

Can someone clarify whether the recent experiment closing all remaining loopholes to Bell's Theorem really shut the door on local realism for good?

I saw this recent article on Phys.org that purports to close all remaining loopholes that previous experiments on violations of Bell's inequality left open. My question is, does this really close the ...
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1answer
71 views

Effects of massive magnetic field generated by operation of the large hadron collider?

I read an article about the CERN large hadron collider in which it talks about the magnetic field that is generated while the LHC is operating. A magnetic field more than 100,000 times more powerful ...
2
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1answer
33 views

What techniques are used in the Analyzer part of an Ellipsometer?

Specifically, what technique is used where the analyzer does not involve mechanical rotation? I assume it is a device to electronically rotate the plane of polarization of incoming light. Faraday ...
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0answers
23 views

LED characteristics to use in heating a material sample?

I am looking to be able to heat a sample of material, typically less than 500mg and sitting in a fused silica sample holder about 10mm diameter. Wondering about using (say) a 5W LED with narrow ...
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2answers
59 views

different energies for the same k vector for free electrons in a solid

when we use the nearly free electron approximations for electrons in a solid and get them as plane waves the energy becomes $E=\frac{\hbar^2k^2}{2m}$, which gives us a parabola. but when we see the ...
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1answer
46 views

Is there a beam splitter in time?

I have a train of pulses (with some known time separation between them) and I want to mix two of these (perform an XOR - beam splitter transformation - between them), leaving the rest alone. How do I ...
4
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4answers
185 views

What is the way to prevent the cream from settling on the surface of hot milk with least manual labour?

I have seen Cooling a cup of coffee with help of a spoon but that question has a restriction of using only a spoon. My problem is that I have to boil the milk before pouring it in the bottle for the ...
1
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1answer
104 views

Half wave rectifier at high frequency and small amplitude ac signal

This is the picture taken from my oscilloscope where I was just checking how a standard half wave rectifier properties. The yellow one is input signal of frequency 20.5KHz and peak to peak value is ...
4
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1answer
39 views

What is an experimental method that could be used to determine and measure impurities in a lens?

Part of my work (as a lab tech) is to check and double check the lenses we have to make sure that they are suitable for the experiments that my employers wish to use them for (as well as experiments ...
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1answer
133 views

How to measure Torsion and Non-metricity?

In General Relativity, we most often work with the Levi-Civita connection (metric and torsion-free). What kind of experiment can we make to be sure that our physical space-time indeed is torsion-free ...
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3answers
74 views

why do coiled wire create so much heat?

I am wondering how coiled wire creates so much heat when a current is passed through it. Is it just a larger surface area of heated substance is available or are interacting forces at work eg ...
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4answers
67 views

What instrument should I use to vary the power given to a heating element? [closed]

I have a nickel-chrome wire as a heating element and I want to vary the power given to it to control the amount of heating the wire produces. Which instrument should I use? Please don't give ...
4
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2answers
124 views

What books are good about reproducing physical experiments?

I want to know a book that minutely describes how to perform thousands of experiments in todays lab, the equipments required, etc. I need to perform the Young's interference experiment.
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0answers
41 views

How much damage do high energy experiments impose on the LHC detection equipment?

I do appreciate that I am second guessing lots of experts who have already considered this aspect of high energy experimentation, but I have not seen a similar question, my apologies if I missed a ...
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3answers
129 views

New particles found using the LHC

After finding the Higgs boson in 2012, CERN. What did the CERN found recently using the large Hadron Collider?
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0answers
23 views

Procedure for wrapping a superconducting coil around a cylindrical shell?

I don't know if experimental physics questions are allowed on this site - please direct me to the proper SE if it doesn't belong here. I need to wrap a few layers of superconducting wire (~80 ...
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0answers
62 views

Does this phrase in “Knocking On Heaven's Door”, refer to gravitons?

This is an extract from Knocking On Heaven's Door, by Randall (2011) The suprising fact is that if you have a stable particle whose mass corresponds to the weak energy scale that the LHC will ...
3
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1answer
102 views

Inaccuracy at measuring gravity constant with Cavendish experiment

For a scientific work for school I decided to measure the gravity constant with the Cavendish experiment. I set up a structure like the one suggested on this website: ...
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0answers
151 views

Synthesis of Fe-based superconductors

Polycrystal cuprate superconductors are generally prepared by solid state reactions: Starting reagents are in powder form, they are mixed to each other and placed into furnace on high temperature ...
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17 views

Interferences while using two ToF cameras

Im using two time-of-flight (ToF) cameras, a DS325 from SoftKinetic and a Creative Senz3D, at the same time with the DepthSense-SDK and the Point-Cloud-Library (on Ubuntu 15.04). But I got strong ...
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0answers
31 views

What is the “point” of STM?

Scanning tunneling microscopy (STM) measures density of states (DOS) in a sample. But angle-resolved photoemission spectroscopy (ARPES) measures the bandstructure $E(\mathbf{k})$ in a sample, from ...
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0answers
26 views

How to produce sine wave heat generator?

I have taken a lab course this semester and in the experiment of finding thermal diffusivity of brass they are using square wave heat generator(by a simple circuit which gets on and off at regular ...
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0answers
26 views

Help me in the measurement of small deformation of a gas-liquid interface

I am new to optical measurements and sorry for any stupid question? I am also not sure whether this is a right place to discuss the experimental issues... Recently, I am trying to measure the small ...
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1answer
1k views

How is it possible to store antimatter?

Antimatter is simply the opposite of regular matter and will destroy itself and any regular matter it contacts in a flash of raw energy, emitting radiation. Now somehow, scientists have been able to ...
3
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2answers
213 views

Can I use fluorescent light bulbs to calculate Planck's constant?

We did an experiment today to calculate Planck's constant, $h$. We measured the knee voltages $V$ of different LEDs (red, green, orange, blue, violet) and plotted them against the frequencies $f$ of ...
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0answers
37 views

Selecting an epi-illuminated objective for optical microscopy

I am currently trying to improve my silicon microphotography. To provide context: this is what I get with a 10x epi plan objective¹: This is what I get with 40x epi plan objectve with NA=0.65: I ...
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1answer
104 views

How does a 1,000 mph car maintain vertical stability with tiny front wings?

Formula 1 cars have wings to help keep them on the road during cornering, they don't need them whilst moving in a straight line. And that's ok , they "only" travel at 220 mph. In a different speed ...
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0answers
54 views

Relationship between electric field and distance

I am working on a lab report that asks a conceptual question related to one of the labs we did on electrostatic fields. For the context of my question, here is how the experiment is set up. We have ...
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1answer
121 views

Influence of acceleration in acoustic doppler's effect experiment

Recently I've done an acoustic doppler's effect experiment for physics lab assignment. The setup was two microphones in a straight line, movable object with sound source and a pc with the usual sound ...
0
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1answer
73 views

Does the charge of an atom or molecule change after absorbing a photon

I know atoms or molecules will absorb a photon of the right frequency but will this change the charge. If you have a neutral molecule once it absorbs a photon will the charge change to a positive or ...
3
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0answers
135 views

Free-Fall Lab Help - Getting weird results

So, I am doing a free-fall lab for my physics class. We got the values and I have the results here(we used a infrared photo-gate). Basically, we have a brass cylinder and a wood cylinder. Each are ...
4
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1answer
60 views

Is blowing bubbles a decent means to stir a liquid?

Occasionally I'll catch myself with a mixed drink at home that I'd normally stir between drinks due to the contents separating. Even more occasionally I'll be having said drink while doing something ...
0
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1answer
30 views

What exactly is measured in a e.g. hadronic calorimeter - momentum or energy of a particle?

I got a little puzzled with the concept of hadronic/electromagnetic calorimeter. Do they measure the energy of the particle e.g. an electron, like the first entry of the four-momentum, or the ...
0
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1answer
53 views

Temperature change due to evaporation?

I have a bottle of Dichloromethane (say, 100cc) with air being bubbled through it at a rate of 100 cc/minute at an initial 25 degC. How do I go about determining the rate of change of temperature due ...
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3answers
2k views

Do we know if the human brain follows Moore's Law? [closed]

EDIT This question is extremely badly worded and I would appreciate it if you could ignore it's content. I cut and pasted parts of two related but unfortunately distinctly different questions ...
4
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1answer
110 views

Measuring focal length of complex lens

I'm trying to accurately measure the focal length of a lens. I have a complex computerised system lens measuring system that I don't entirely trust (I worked with Hubble) so I want to confirm the ...
27
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5answers
4k views

What does air “feel” like to a flying mosquito in terms of viscosity?

If I go for a walk at, say 4 km/hour, unless there is a breeze blowing, I probably won't notice the air around me at all. If I go for a swim though, I will immediately notice the viscosity of the ...
0
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1answer
62 views

What do we mean by saying that one clock had been “running slower” than another clock; or that two clocks had been “running equally”?

Several posts on this site, especially on the topic of relativity, refer to comparisons between clocks in terms of their "running"; one having "run faster" than the other, one having "run slower" than ...
0
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1answer
36 views

prototyping a cyclotron , a charging problem

I'd like to model a cyclotron but not with subatomic particles but with a small metallic ball but the problem is i need to charge the metallic ball with certain amount of charge and i must know it to ...
2
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2answers
55 views

In Electron Spin Resonance, what provides the energy for the transition?

I recently performed an ESR experiment at M.Sc. level. The experiment manual says that the energy for the transition is provided by magnetic field oscillating at radio frequency. I am little confused ...
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3answers
254 views

What experiment supports the axiom that quantum operations are reversible?

Among the axioms of quantum mechanics there is one axiom that says transformations of a quantum state need to be continuous, linear, and reversible (and this together with the other axioms results in ...
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1answer
37 views

How to Vary the wavelength of UV CFL? [closed]

I have a $12$ $V$ $DC$ operated UV $[CFL]$(http://en.wikipedia.org/wiki/Compact_fluorescent_lamp) with $365$ $nm$ wavelength. I need to vary this wavelength in the $250-300-350-400-450-500$ $nm$. ...
3
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1answer
52 views

How does scintillation gamma-spectrometers work?

As far as I understand, the incident photon interacts by photoelectric, Compton scattering or pair production with the electrons of the crystal (NaI(Tl) in our case). The electron that emerges from ...
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0answers
7 views

Have the BaF2 scintillator have a strong correlation with the alimentation current that cause the shifting of the centroids?

In gamma gamma correlation I suspect the presence of sistematic error maybe caused by a non optimal alimentation voltage according to someone there is a quadratic correlation between centroids ...
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2answers
1k views

Which travels further, a football or a soccer ball, when thrown?

I recently answered this question: Laminar Versus Turbulent Flow and it caused me to think of the following situation. Given that an (American) football weighs between Football 400 to 430 grams, and ...
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2answers
94 views

Could a civilisation contact us by laser from 50 light years away?

The Kepler Space Mission has discovered over 1,000 planets. These discoveries may increase the confidence of some people that other civilisations exist. That is an opinion issue, and not what I want ...