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

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0
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2answers
47 views

Interference or something beyond?

I have an experiment with He-Ne laser in my practical syllabus. In curiosity I took a photo of the incoming radiation directly from the laser with my mobile camera. Some strange pattern is observed. ...
1
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0answers
45 views

Estimate heating wires temperature

Im design a power supply to work with heating wires and one of the task is to estimate the temperature of the bare wire for a given current or power consumption. I've tried to measure the ...
-6
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2answers
169 views

Why is it that the refrigerators (ice houses) from long ago can't be reconstructed in modern times? [closed]

A Long time ago (a couple of hundreds of years), people could make a refrigerator by applying a certain procedure with pieces of ice, harvested in winter, and other stuff. The ice hadn´t molten at the ...
0
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2answers
37 views

Measuring potential

I apologize if the question below has been asked -- I could not find an answer. A charged conductor some distance above ground generates an electric field and corresponding potential profile. How ...
0
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1answer
36 views

Why is the standard deviation the error on the singular measurement?

I'm a beginner with the study in data analysis in Physics. I'm trying to understand the meaning, in the field of experimental Physics, of the standard deviation $\sigma$ of a series of data. There ...
6
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1answer
279 views

Why is the gravitational constant so difficult to measure?

The gravitational constant seems to be very low precision. For example, in the Wikipedia article recent measurements are given as having the significands of 6.67 and 6.69, a difference of 2 parts in ...
3
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0answers
45 views

What experiments confirmed Poynting's Theorem?

Actually, I have two related questions. The fist is the above question. The second is, what experiments confirmed that $\varepsilon_0\left(\frac{E^2}{2} + c^2 \frac{B^2}{2}\right)$ is the ...
0
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1answer
48 views

Propagation error for a third grade equation

I am trying to find the value for the roots$\pm$error for a set of experimental data. The function that fit the best is $$\epsilon(t)=a+bt+ct^2+dt^3.$$ Which is the best way to calculate the roots $\...
3
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1answer
47 views

Are asymptotic states in scattering experiments really momentum eigenstates?

In a typical collider experiment, two particles, generally in approximate momentum eigenstates at $t=-\infty$, are collided with each other and we measure the probability of finding particular ...
0
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0answers
32 views

I need results or to conduct a simple experiment for a dynamics problem involving the range of a projectile launched from a pendulum

I have created a model to show how the maximum range of a projectile varies with respect to the velocity and angle of when the object is launched from a swing. I now need to compare these results ...
3
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0answers
38 views

Why would oscillation of a gas column inhibit rather than promote mixing?

Many years ago I helped to support an experiment conducted in Japan which investigated the effects of high frequency oscillation ventilation (HFOV) on the mixing and distribution of gas into the lungs....
0
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0answers
17 views

Springs and Cantilevers - how linear and repeatable are they under deformation?

I know you guys only deal with the ideal, but in practice how linear and repeatable is the response of a spring or cantilever when deformed under a test mass?
2
votes
1answer
64 views

What is the minimum sample sizes to show the error bar in an experiment?

In scientific experiment, people often try to show an error bar based on the standard deviation around a mean (average) value. My question is twofold: How to estimate the minimum but adequate ...
3
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1answer
49 views

Does the human body have a measurable gravitational field?

I am researching communication other than speech or vision. The human body emits radiation in the form of heat; As the body has mass, will it have a gravitational field?
0
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0answers
8 views

Optimum “fur” dimensions for absorbing ultrasound at a given wavelength?

By "fur" I mean an array of bendable fibres aligned vertically on a substrate. The ultrasound hits it at an oblique angle. Is there a spacing that will provide optimum absorption? A basic thought ...
4
votes
4answers
121 views

Intensity fluctuations at the output of a single mode fiber coupled to a He Ne laser

I have coupled a Thorlabs HNL050L-EC - HeNe, 632.8 nm, 5 mW, Polarized Laser to a 2 meter long single mode fiber patch chord using a Thorlabs F230-FC-B aspheric lens. While I am certainly able to ...
1
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0answers
45 views

Lab experiment: hysteresis disappears, reappears and then disappears again. How?

In my college laboratory we were assigned an experiment to measure the hysteresis curves of a certain ferromagnetic material at different temperatures. Sounds simple, right? Well, the block of Monel ...
0
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0answers
57 views

Speed of the Coulomb Field Measured To Be “Infinite”

The paper "Measuring Propagation Speed of Coulomb Fields" by R. de Sangro et al points out that: ...the Lienard-Weichert retarded potential leads to the same formula as the one obtained assuming ...
0
votes
1answer
19 views

Mach-Zehnder probabilities

Where can I find the computations of probabilities for Mach-Zehnder experiments, say at the undergraduate level? For example I'm thinking of the type of experiments described at the beginning of David ...
2
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0answers
38 views

Any method to determine the gravitational constant $G$ from observations in cosmological scale?

By the observations in cosmological scale, I mean observations by astrophysicists like motions of quasars in far distance from us, relative motions of our galaxy to others, etc. I know the famous ...
0
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1answer
46 views

Reverse osmosis Water desalination

Is it feasible to submerge a reverse osmosis system in the sea in order to use the increasing pressure to push through the membrane and as the salt was removed would the lighter water rise on its own?
1
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0answers
26 views

what is the effect of temperature on the resistance of a photoconductor?

As we know, for a photo conductor resistance tends to decrease with increase in irradiance, but with greater irradiance comes greater temperature. Also we know, photo conductors are semiconductors,...
0
votes
2answers
27 views

Probability of Millikan's drop gaining or losing charge during the experiment

I performed Millikan's experiment with latex drops. I did not get the "step graph" that I wanted (though the precision of the experiment was really bad as seen in the figure). My first drop is ...
0
votes
1answer
61 views

Coulomb law and photons

When we consider process like $e^- e^- \to e^- e^-$ in QED, we see that from exchanges of one photon (tree-level diagrams) one can obtain Coulomb's law, while loop-diagrams give quantum corrections ...
0
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0answers
29 views

What is the smallest practical milliKelvin temperature sensor or technique?

I need to track the temperature of a mass of less than 1 gram, and the two constraints are accuracy and mass of the attached sensor/circuitry (it must be less than 1.5g). Ideally it should be a non ...
0
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0answers
25 views

How does sound propagate through a mesh structure?

I am assuming that the material and holes are approximately the same dimensions and also similar to the wavelength of the sound. In my case, around 2mm. How does varying those dimensions affect the ...
0
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0answers
11 views

Change in Q factor on tuning external magnetic field in Electron spin resonance experiment

Does the Q factor of the cavity resonator show a dip at the resonant value of the external magnetic field while performing an ESR experiment?If so, what is the physical reason behind it?
28
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3answers
4k views

How can an electron fake a jet?

This is a question for experimentalists. I have seen in several ATLAS papers (see for example chapter 4 in arXiv:1602.09058, 6th paragraph), that after objects have been correctly identified, any jet ...
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votes
1answer
55 views

I can get a heating strip - why can't I get a cooling strip?

A typical heating strip is a flexible silicone material containing a resistive heater. However, I would like the opposite - something I can wrap around my experiment and use in a similar way to the ...
0
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0answers
21 views

GEN3's 10nm-30nm Contiuum Radiation Measurements

What is the most likely explanation for the 10nm-30nm continuum radiation reported in "Validation of the Observation of Soft X-ray Continuum Radiation from Low-Energy Pinch Discharges in the Presence ...
1
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0answers
28 views

How is mass of observable universe calculated? [duplicate]

How is even mass of earth known ? How do we get to know them? Whilst I was studying about dark matter it was listed about 'mass of observable universe' and density and so on...so what is the procedure?...
1
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1answer
171 views

Difference between theoretical equations and empirical equations

Some equations are theoretical in the sense that they are derived from an underlying theory. Other equations are empirical in the sense that they were selected only because they fit experimental data ...
3
votes
1answer
88 views

Measuring very long half lives accurately

There are already some questions about long half life times for radioactive elements, explaining how to calculate the half life time. Now I am wondering: When you have some radioactive material and ...
0
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1answer
26 views

Why is this ice cloudy at the center and has a transparent layer?

This fell at my place during a hailstorm. I can not figure it out why it is like this.
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0answers
10 views

Thickness uniformity comparison between a bilayer and superlattice

For a heterostructure grown using pulsed laser deposition to be used in polarized neutron reflectometry, is there any difference between a superlattice and a bilayer in terms of thickness uniformity ...
1
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1answer
28 views

Is it possible to measure the spin of an electron without moving it?

I know that the position and spin operators commute, so it is theoretically possible. What I want to know is, what experiments currently exist that achieve this?
1
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0answers
35 views

Is it possible to create a double slit experiment that can predict when photons have 'likely' passed through the slits?

This question asked:Is it possible to determine the slit a photon went through in the double slit experiment by measuring its flight time? My question is similar, but doesn't require such detailed ...
0
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0answers
24 views

How to get rid of optical reflections in microscopy?

I am running a Raman microscopy experiment with polished silicon wafers. Each time I make an optical image of the wafer surface, reflections appear to the left of the image. This is even worse for ...
0
votes
1answer
29 views

Is there any experimental evidence to distinguish the total gravitational force exerted by the two proton and a helium nucleus?

I know that the sum of the mass of the two proton is greater than the mass of a helium nucleus (two proton). As the mass different is transformed into energy by the Einstein mass energy-equivalence. ...
59
votes
9answers
6k views

What are the next generation physics experiments? [closed]

The LHC and LIGO are two recent examples of hugely ambitious experiments in fundamental physics, both of which took decades to develop. What are the next major experiments currently being planned and ...
1
vote
1answer
60 views

When does the shock occurred?

I'm between this 2 conditions that when does the shock occurred over an airfoil. When the speed of point of an airfoil reach to sonic velocity of environment. When the speed of point of an airfoil ...
1
vote
0answers
20 views

Making a conductive paint out of graphite powder [closed]

I want to make a conductive paint out of graphite powder and gum to use as an electrode. What shall be the best gum to use, as i need a low resistance of around some kilo Ohms. I am getting very high ...
0
votes
0answers
18 views

Why is graviton not found yet? [duplicate]

Why is graviton not found yet? Newton said gravity pulls us, Einstein said space is bent and it pushes us, hawking predicts the existence of graviton and 'hawking radiation'. How far are we from ...
0
votes
1answer
63 views

Angular Acceleration of a Pendulum

I am trying to work out the mathematics behind the design of an old mechanical brake tester. The device sits in the passenger foot well of a vehicle and tests the brake efficiency. The device is ...
0
votes
0answers
11 views

Temperature equalization by radiation between two coaxial cylinders - independent of diameters?

Ignoring end effects, assume I have a cylinder of diameter d0 at controlled temperature k0 and then introduce a smaller diameter cylinder of diameter d1 and temperature k1 to the interior. Does the ...
1
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0answers
41 views

Relevance of pure mathematics vs statistics to physics [closed]

For someone currently studying physics, with an interest in experimental physics, would pure mathematics or statistics be more relevant?
1
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0answers
44 views

How Does Silicon Surface Barrier (SSB) radiation detectors work?

I'm dealing whith some old detectors (about 1980) called Silicon Surface Barrier, searching online I've seen that they consist on metal-semiconductor(Si n-type) junction (schottky diode) and in one ...
1
vote
0answers
19 views

Polarized Coherent Beam Hits a Polarizer Off-Polarization Angle While Varying Distance?

Just wondering about an experiment that should be easy to perform on an optical bench: A coherent beam is polarized. It then hits another polarizer which is set to permit a polarization angle off ...
3
votes
2answers
59 views

Optics to correct focal distance across a plane

I have a laser beam which is focused to a point at a certain distance. I'm then going to use a galvanometer to scan that beam across a plane. Obviously, as the beam scans across the plane, the ...
1
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0answers
37 views

Logarithm of the voltage of the inductor in RL circuit experiment is nonlinear with time

I performed an experiment about the RL circuit, with following circuit: (I used the PASCO RLC circuit lab.) By Kirchhoff's voltage law, (denoting the emf of the signal generator $\mathscr E$, ...