Questions tagged [experimental-physics]

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

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How to demonstrate “Things aren't always as they appear”?

My task is to create an experiment (for middle school through College Freshman) that demonstrates that things aren't always as they appear. (Note: NOT Homework -- TV Production company) My first draft ...
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39 views

Experimental lower bound on the lifetime of a supercurrent?

Nothing is perfect, everything has friction---except in quantum physics, where macroscopic superconductors allow for dissipationless currents. It's an astounding theoretical prediction, and so it is ...
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53 views

Is there an index of common spectral lineshapes or table of common lineshape functions?

Is there an index of common spectral lineshapes in physics? Is there a program that automatically tries fitting to many different lineshapes? By line shape I mean the function that, given ...
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18 views

Location of diffraction pattern on the image plane/detector plane

I am trying to make a spectrometer. At the moment, I have an optical setup consisting of a laser, diffraction grating and a screen/detector in a straight line. I am trying to understand how to ...
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2answers
44 views

Measuring strong coupling constant

How can the strong coupling constant be measured?
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47 views

Standing out in experimental physics laboratory [on hold]

In a week I will begin a course called "Advanced experimental physics", where my team and I will have to do complex experimental physics (at least compared to the usual basic things done in the ...
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What is the effect of dopant on the crystalite size?

Crystal size decreases with doping and then increases with increase in dopant concentration, why? the ionic radii of dopant is greater than the host atoms.
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2answers
85 views

Is it possible that this electromagnetic field propulsion system would not violate any conservation laws? [on hold]

I have recently come up with a design of a conceptual electromagntic field propulsion system which should not violate any conservation laws, particularly the Law of Conservation of Momentum and the ...
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9 views

Measuring inner choke point on non-uniform silica capillary tube

I hope this is an appropriate place to be asking questions like these (google brought me here when I was searching for a solution)! I make an assembly where a small silica capillary tube (OD of 1mm) ...
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2answers
63 views

Why do we don't get exact answers to our experiment but rather an approx value to it?

Why do we face a problem of not getting to the exact answer but to an approx to it, mostly everything we come through in practical physics is a approx but not the exact one.
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1answer
67 views

Is there a way to test whether dimensionless physical constants are rational?

This question is related to a question asked 3 years ago on SE (I was not the OP), but not quite the same. I would like to know if there is a way to test whether a dimensionless physical constant is ...
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6answers
944 views

What is the most precise physical measurement ever performed?

Obviously some things, such as the speed of light in a vacuum, are defined to be a precise value. The kilogram was recently defined to have a specific value by fixing Plank's constant to $6.62607015\...
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2answers
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Rutherford/Geiger–Marsden gold foil experiment: what did they really think about alpha particles?

Most tellings of the experiment where alpha particles were fired at a thin gold foil point out the following: atomic model being tested was the plum pudding model: negatively charged particles (...
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21 views

What should be the real error band of a fit function?

This is a question concerning data analysis. It could relate to particle/nuclear physics or other field. Please note that this question has nothing to do with technical problems, and is more of a ...
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1answer
33 views

Do we need to know Earth's magnetic field locally?

I'm a high school student and in our course we have elements of earth's magnetic field (dip and other stuff) that lets us know the value and direction of magnetic field at any point on the planet. I ...
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1answer
37 views

Electromagnetic wave and skin depth, skin effect

In EM theory concept of skin depth is induced which is a measure of how much a EM wave can penetrate the medium, from it arises the concept of skin effect which is for EM wave but we use this to ...
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33 views

Focusing a Gaussian beam into a nonlinear crystal

Boyd analyzes in his book (Boyd's book), section 2.10.3, the case of harmonic generation using a focused Gaussian beam and he mentions that an analytic solution can be evaluated for certain special ...
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1answer
70 views

Experiment: Magnet falling in a copper/aluminum pipe

We know that when we release a magnet in conducting pipe (aluminum, copper, etc..) it will be subjected to a magnetic force induced by the induced current. This magnetic field will be created in a ...
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18 views

How to calculate the final temperature the hot liquid when mixed with a cold liquid in an isolated system? [duplicate]

Is there any formula to calculate the temperature when hot and cold liquid mixes together?
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25 views

Method for making graphene plausible?

Gallium does not wet quartz or graphite. I’m pretty sure graphite doesn’t stick to quartz (or not well) especially if smooth. So what if on a round flat plate of polished fused quartz you set a small ...
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2answers
109 views

Is Young Earth universe distinguishable from non-creationist one? [closed]

While talking today about some religious beliefs I was struck by the next question: So what if some super-natural being forks our universe 6,000 years ago, i.e. creates the exact same copy of ...
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2answers
37 views

How to fit the data for the asymptotic limit?

Suppose we have a pretty good experiment data with very small random error. But our theory is limited, which makes the systematic error significant. Sometimes we do have a nice theory for the weak ...
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3answers
2k views

On the Rømer experiments and the speed of light

In 1676, Rømer determined that the speed of light must be finite. His experiment consisted on observing the eclipses of Io, one of Jupiter's moons, by Jupiter itself. He timed these eclipses over a ...
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2answers
91 views

Is there any full Compton scattering experiment done with x-ray since 1923?

The original paper of A.H.Compton 1923 did not provide data of a full experiment; he provided 3 points. Was his result corroborated by others? Can someone provide a real full set of data for Compton ...
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4answers
84 views

Do fractal objects exist in the real world?

I'm talking about a fractal in terms of Hausdorff or Minkowski–Bouligand dimension. Thinking about the Chaos Theory for a while, I have a question about real-world fractals. I've found appropriate ...
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0answers
46 views

Is it possible to calculate pressure without a barometer?

For an experiment, I need to pump air into a rocket with varying volumes of water, and thus air. However, I want to keep the pressure the same. Given the amount of air a bicycle pump can pump, the ...
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31 views

Time of detection for single-electron double-slit experiment

Consider the single-electron double-slit setup, where an electron gun fires a single electron, and a dot is observed on the detector screen behind the slits. We do not place any detector in the slits. ...
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18 views

Why does the ion and electron currents saturate in Langmuir probes?

From the I-V characteristics of the Langmuir probes used in Plasma diagnostics, we can calculate the plasma density, temperature, etc from the ion and electron saturation currents. But why does the ...
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1answer
77 views

How to compute the curl of the electric field, experimentally?

In order to experimentally verify Faraday's law and express the curl of the induced electric field, is there any other way to compute the curl without directly working on the cross product (ie working ...
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2answers
84 views

Is it possible to “force” two separate light sources to be coherent?

I have edited this question for three reasons. They are: 1. A possible duplicate of another question. (I believe the "answer" to that question is incorrect.) 2. I received two contradictory answers. 3....
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28 views

Investigating the relationship between a changing B field and the curl of the electric field induced

I am currently working on a 12 page lab report on Faraday's law, essentially investigating, how for different magnetic field strength through a stationary loop of wire with N number of turns, effects ...
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2answers
80 views

How did Newton know gravity force between 2 objects although he could not examine it?

Yes, Isaac Newton calculated it, I know. But he could not examine the force between 2 objects (for example apple and human hand). And we all know there is gravity force between every 2 objects even ...
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1answer
71 views

Grad student needing help with a fluid mechanics issue in project

As the subject states I have hit a wall in a fluid mechanics associated problem in designing an experiment for my grad project. Long story short, I'm an engineering undergrad who got a broad ...
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3answers
66 views

$CO_2$ heating experiment (high school)

A student is trying to run some experiments for a project to explore how the concentration of CO2 affects the temperature of air. For this, she: Drops different ammounts of dry ice (between 0 and 2....
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1answer
41 views

How to increase Sensitivity and precision of a measuring sensor?

Considering the definition that Sensitivity: Relation between the maximum of range, the sensor can $\frac{i}{p}$ to the corresponding $\frac{o}{p}$ given by the sensor due to it. Ex: A pressure ...
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17 views

mathematical relationship between height of drop and horizontal splash distance [duplicate]

I was just curious as I am still quite confused, if we vary the height of the ball when dropping it in a pool of water, is there a way to establish some mathematical relationship between the height of ...
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7 views

Terms time resolved vs. stroboscopic measurements

I use the term stroboscopic for an experiment, where the stroboscopic effect is part of the experimental setup. And I call an experiment a ...
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31 views

Are my voltmeter readings expected for a correct chua's circuit?

I am following this article Robust OP Amp Realization of Chua's Circuit by Kennedy to implement a Chua's circuit. I use exactly the same design as the article; the only difference is that I use a 15mH ...
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2answers
82 views

How Do Scientists Measure Subatomic Particles? [closed]

I'm asking for a list of experiments, machinery, technology and techniques. The only measuring device I really know of is the Stern-Gerlach contraption. Google hasn't been helpful (it only gives me ...
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26 views

Vacuum test in the laboratory

If I put some water in a plastic container and apply a vacuum pressure of -0.20bar the water comes out of plastic container which should not as per design and material of container. This is called ...
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1answer
56 views

Is possible to create black hole in laboratory? [duplicate]

Recently I came to know that black hole are the object which concentrate large amount of mass in small volume. what are the requirements to create this if possible?
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30 views

Uncertainty in length measurement

I am trying to measure the length and the uncertainty in length of a fiber optic cable for measuring the speed of light. So far, I have measured it the standard way: Using a standard meter scale. I ...
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3answers
130 views

Has the Michelson-Morley experiment been performed while moving in relationship to Earth?

I'm currently trying to debunk some geocentrist claims the Michelson-Morley experiment proves Earth isn't moving and I'm wondering - has this experiment ever been performed while in motion relative to ...
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66 views

Evolution of theories in physics [closed]

I am searching for a book on the theories of (high energy) physics to gain insight, why they are so powerful. Namely, I would like to find a book that uses the evolution of physics from classical ...
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31 views

Constant Acceleration and Displacement

How can I conduct an experiment to show that the area under a velocity-time graph equals the displacement when the velocity is changing at a constant rate? I've tried to measure free falling objects, ...
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1answer
47 views

Why small amount of water in glass, moves along it's walls?

Many times I had noticed that when a small amount of water is left in glass, it always stays sticking to it's walls, whenever I move the glass, most of the water moves along the glass's walls. I think ...
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1answer
59 views

Momentum of neutral particles in particle colliders

I understand that we can find a momentum (or a charge to momentum ratio anyhow) for a charged particle (charge $q$) in the LHC by using it's radius of curvature $r$ as $$\frac{mv}{q} = Br$$ So that ...
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21 views

Tianqin project vs LISA

How does Tianqin space-based gravitational wave detector compare to LISA? Will it be able to detect gravitational waves from e.g. inflation (considering possible upgrades)?
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How the field profile is in a diagonal end of the optical fiber?

I would like to know how is the propogation of the beam, let's say Gaussian beam profile, in the end of the fiber? Does it go in shift to the lower side? Does it change its shape? And how the near ...
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1answer
43 views

Is there a way to see the sun's outer layers from earth outside a solar eclipse using polarization?

¿Is there a way to filter sky light using light polarization? in https://en.wikipedia.org/wiki/Coronagraph#Invention it says: High Altitude Observatory's Mark IV Coronagraph on top of Mauna Loa, use ...