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

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5
votes
2answers
216 views

Impossible microwave interference?

I was doing a microwave experiment with the following set up: there is a Gunn diode which emmits microwave radiation and a receiver (both work with polarised light). The strange thing is that when ...
20
votes
5answers
6k views

Is this kids experiment a legitimate way to show that air has mass?

Consider the experiment in this link. The experiment includes using a ruler as a lever, with an inflated balloon on one side and a balloon which is not inflated on the other. The aim of the ...
3
votes
1answer
123 views

How to determine the order of indications of a clock?

Given the description of a clock $\mathcal A$, as (1) a set $A$ of all (more than 2) distinct indications of this clock, in no particular order (where the individual indications contained in set ...
0
votes
2answers
30 views

Peak at zero in one device and not the other

I was wondering if anyone could shed some light on this problem. I have placed two accelerometers on an animal one sampling at 50 Hz the other at 100 Hz. They were placed in the same position. I then ...
8
votes
6answers
2k views

What methods can astronomers use to find a black hole?

How can astronomers say, we know there are black holes at the centre of each galaxy? What methods of indirect detection are there to know where and how big a black hole is?
12
votes
2answers
882 views

Evidence of why the Standard Model is a successful theory of particle physics

When discussing physics with laypersons, I'm often in the situation where I have to explain what the Standard Model is, and why it's a successful theory of particle physics. To help in such ...
2
votes
0answers
20 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. ...
1
vote
2answers
40 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). ...
11
votes
3answers
1k views

Interpretation of “transition rate” in Fermi's golden rule

This is a question I asked myself a couple of years back, and which a student recently reminded me of. My off-the-cuff answer is wrong, and whilst I can make some hand-waving responses I'd like a ...
2
votes
3answers
948 views

Active gravitational mass of the electron

In PSE here electrons are added to a sphere and gravitational modifications are expected. My question is: Is there any experiment that show that a negatively charged object is source of a stronger ...
2
votes
2answers
63 views

Measurements from inside conductors

We have known for some time now that when electric field is applied across any conducting shell, then electric field inside it would be zero. It also has some fantastic applications such as ...
4
votes
2answers
287 views

Why do plastic bags make less noise when immersed in water and crushed?

When a plastic bag is crushed in air it makes noise. But when immersed in water and then crushed we hear very little noise. Why is it so? Even if I go inside water, I do not hear the noise the same ...
0
votes
2answers
37 views

What are experimental techniques to probe band structure of solids?

What are experimental techniques to probe band structure of solids? I am not looking for exhaustive list. Few simple to understand techniques will suffice.
1
vote
0answers
17 views

Help to find nature of noise gotten from digital oscilloscope [closed]

I've got strange noise while using digital oscilloscope (Auris B-424). Spectrogram of this signal presented on this image: (X time in seconds, Y frequency in Hertz, in this image case from 0 to 50 ...
3
votes
0answers
9 views

What is the advantage of segmented particle traps?

I'm currently trying to familiarize myself with the physics of ion and particle traps, especially with linear Paul traps. Many scientific experiments I've come across use segmented electrodes (like in ...
1
vote
1answer
160 views

Questions about MTW's _“thousand” tests of the Einstein principle_ (Box 16.4)

In Misner, Thorne, Wheeler (henceforth written as "MTW"), "Gravitation", Box 16.4, there's an experimental setup construction (or method) presented by which "Each geodesic clock is constructed and ...
8
votes
3answers
517 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 ...
0
votes
1answer
133 views
-5
votes
0answers
21 views

what is the focal length of concave lense? [closed]

I need just the formula . Please help me anybody ? And the sign convention used in the focal length formula. And any sites ?
1
vote
1answer
26 views

What will be the effect of placing a light source very close to a photodiode?

What will be the effect of placing a photodiode really close to a laser source and what should be the appropriate distance between a light source and photodiode to get maximum output current?
2
votes
4answers
1k views

How can we detect X-rays?

I know that X-rays can be detected by various ways, like ionizing of air particles. Is there a way to detect X-rays,which are photons, by detecting? Can something absorb the energy of the X-rays and ...
3
votes
1answer
141 views

Electrons skip randomly around their orbits

I read where the electron (as well as a few other particles) skips around in its orbit randomly rather than move around the orbit smoothly. This effect has been repeatedly observed in the laboratory ...
5
votes
2answers
379 views

Does light really “travel”?

From what I've so far understood about light, a photon is emitted somewhere and after some time it's absorbed somewhere else. Have we had experiments that confirm the path taken or something akin to ...
1
vote
4answers
188 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
2answers
55 views

How organic impurities in the air affects laser?

We have a Nd YAG laser pumped Optical Parameter Oscillator in our lab. A technician came to our lab (my professor called him for its maintenance) and while he was working on it, he told me that ...
341
votes
19answers
129k views

Cooling a cup of coffee with help of a spoon

During the breakfast with my colleagues, a question popped into my head: What is the fastest method to cool a cup of coffee, if your only available instrument is a spoon? A qualitative answer would ...
4
votes
3answers
278 views

Thought experiment using quantum entanglement in position and its effects

Consider we have two atoms $a$ and $b$. They are entangled with each other in position and momentum, with some wavefuction describing them in position space that is $\Psi(x_a, x_b)$. This ...
3
votes
1answer
58 views

Is this double “double slit experiment” involving entanglement possible?

The experiment goes as follows: Put a particle emitter (photon, electron etc.) between a pair of double slits. The emitter launches pairs of particles that are entangled in such a way that if one ...
4
votes
1answer
334 views

Why is there a hiss sound when water falls on a hot surface?

Why is there a hiss sound when water falls on a hot surface? I have searched a lot, asked my teachers but none of them seem to give me the logical answer to it.
1
vote
1answer
64 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 ...
1
vote
2answers
75 views

Experiments which show the phenomenon of closed electric field lines

In german physics introductory texts often the following experiment is cited which "shows" that a changing magnetic field can induce an electric field with has closed field lines. Here is a picture of ...
2
votes
3answers
47 views

Can we measure rates in real time?

I know what it means to say that my position is "X" at a particular moment in time. I can easily take a picture of my motion and observe my exact location at the instant the picture was taken. That is ...
1
vote
1answer
32 views

Regarding luminosity monitor of particle collider

I am sorry if my question is completely wrong or foolish I would feel glad to be corrected On the wiki page for Bhabha Scattering, it is mentioned that it is used as luminosity monitor in many ...
1
vote
2answers
62 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 ...
3
votes
1answer
117 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 ...
13
votes
3answers
586 views

How should I clean a part before installing it in a vacuum system?

What are proven procedures for preparing a part that comes fresh out of the workshop for ultra-high vacuum (UHV) and extremely-high vacuum (XUV)?
1
vote
1answer
102 views

Examples to illustrate temperature dependant radiation by examples of temperature to color relation

I'm looking for a set of examples to illustrate the relation of temperature and color of "glowing" bodies. It should allow to build an intuitive understanding of this relation, so it's not about ...
2
votes
1answer
63 views

A way to track a gas's expansion

I was wondering if there is a way to see, empirically, how a gas behaves. Perhaps the most natural way is to use fumes with color, but they quickly disperse, rendering partially useless. Are there ...
3
votes
4answers
277 views

Is the principle of Conservation of Energy empirically verifiable?

Before I am inundated by myriad and vociferous claims that conservation of energy is the single most well-attested and experimentally verified principle in all of science, let me say that I am well ...
1
vote
2answers
84 views

what could generate a high-pitched whine in electronics where the frequency depends on the current?

So I was operating a Laue machine recently which generates x-rays and fires them at a sample, and I noticed that there was a high-pitched whine coming from the instrument (nothing abnormal, just ...
0
votes
2answers
115 views

How could the multiverse theory be disproven?

Theorists (physicists) suggest that there is the term/entity, the Multiverse that contains a huge number of universes not necessarily like our own. I personally find this theory very elegant because ...
3
votes
1answer
91 views

Motion in a Paul trap: $2n$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 ...
0
votes
1answer
272 views

Difference between Vernier constant and least count

What is the difference between the Vernier constant and least count of a Vernier caliper?
2
votes
1answer
22 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 ...
0
votes
1answer
30 views

Plasma Treatment of LaAlO3: Surface Roughening

I'm trying to understand something I've observed in exposing LaAlO3 substrates to an oxygen plasma (yielding atomic oxygen). In literature, these substrates are frequently "cleaned" in a oxygen rich ...
1
vote
1answer
162 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 ...
2
votes
1answer
148 views

Rutherford Experiment - practical and theoretical questions

I performed the Rutherford experiment the other day, using Au thin foil of $2\,\mathrm{\mu{}m}$, a source/gun of α particles (241Am) and a detector/counter. α particles were shot from the source ...
1
vote
0answers
78 views

mathematician or physicists [closed]

Mathematicians consider physicists as people who simply use mathematics as a tool but are in a way, let's say, inaccurate, as physicists tend to make assumptions a lot in their mathematics and ...
0
votes
1answer
89 views

Scanning electron microscope imaging

In a scanning electron microscopy, secondary electrons are defined as the electrons which obey inelastic scattering whereas backscattering electron follow elastic scattering. Now my question ...
1
vote
1answer
60 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 ...