Podcast #128: We chat with Kent C Dodds about why he loves React and discuss what life was like in the dark days before Git. Listen now.

Questions tagged [experimental-technique]

filling in the unspecified details of elegant-sounding descriptions of experimental methods.

Filter by
Sorted by
Tagged with
2
votes
1answer
90 views

In the Homestake experiment, why did they alternate runs with $^{36}\rm Ar$ and $^{38}\rm Ar$?

In the Homestake experiment, why did they alternate runs with $^{36}\rm Ar$ and $^{38}\rm Ar$? I understand why they use a carrier isotope like $^{36}\rm Ar$ or $^{38}\rm Ar$ to mesure the efficiency ...
1
vote
2answers
147 views

Creating nanosecond pulses from a CW laser source

Experimental setup question. If anyone aware of a technique to create pulses of several nanoseconds at a around 10Hz repetition rate from a CW laser source?
1
vote
0answers
43 views

Linear dependence on photoelectric current

I have done a lab experiment in which we had to determine the Planck's constant through photoelectric effect. The equation reigning this experiment is: $$eV_c=h\nu-W$$ Where $\nu$ is the radiation ...
4
votes
1answer
269 views

How to maximize Peltier devices' cooling capacity?

I am currently working on a project requiring the use of Peltier devices. I have attached the cool side of the device to a copper plate and the hot side to a heat sink with a fan. What would be the ...
0
votes
1answer
270 views

Strain gauge vs linear variable displacement transducer

For measuring deformation experiments, it seems that strain gauges and linear variable displacement transducers (LVDT) are commonly used. If the material exhibits geometric linearity, then couldn't we ...
1
vote
0answers
35 views

For experiments, how to ensure two photons arrive at beam splitter at the same time?

I'm working on work related DLCZ protocol. In DLCZ protocol, a beam splitter will be settled in the central of two ensembles (you can think it as light source). Ensembles will emit photons ...
3
votes
0answers
67 views

How is a spectrometer is calibrated for intensity?

For the case of spectrophotometers, we can easily calibrate the device(intensity wise) taking the light source inside the device as the reference, without any need of precise knowledge about its ...
0
votes
1answer
303 views

How to determine the focal length of a combination of two convex lenses separated by a distance $d$ experimentally without formula?

I have done this experiment to find out the equivalent focal length of a combination of 2 convex lenses of slightly different focal length and have applied the formula for the equivalent focal length ...
2
votes
1answer
257 views

What is the most efficient way to pour a liquid through a funnel?

Be it in cooking or an experiment, when transferring liquid from one container to another using a funnel should you: (a) pour it all straight into the funnel, filling it up and waiting for the liquid ...
1
vote
1answer
93 views

How is the electron $g$-factor determined?

I found a description of the experiments at CERN where a Penning trap is used to to determine the g-factor but I could not find the value of the radius of the circle of precession, nor could I (surely ...
0
votes
1answer
382 views

How to find out the wavelength for the blue led diode?

I need your help as I am stuck and I dont know where to start. I have got four blue leds diode that come with dark blue led lights that I really want to get the same led colours for my 3 fans, but I ...
1
vote
2answers
40 views

Linear Regressions vs Algebra & Averaging in Solving for a Constant

I'm current taking AP Physics, and in both of the labs performed so far (Snell's Law/Refraction and Galileo's Inclined Plane), I have been trying to calculate some constant from a linear relationship ...
1
vote
1answer
20 views

Would SiPMs respond differently to scintillation light from neutrons vs. gammas?

I have a fast-neutron scintillator which also is sensitive to gammas (much less so, though). When I connect it to a SiPM instead of a PMT, the gamma pulses (obtained from performing pulse shape ...
3
votes
1answer
5k views

What are the purposes of slits inside a spectrometer (Czerny-Turner)?

I am building a Raman spectrometer with a Czerny Turner configuration (with RamanPi). Why does the light source (A) appear to be converging into the entrance slit (B)? When a sample is excited by a ...
0
votes
1answer
29 views

Why photodiode measures random phase superpositions on continuous-wave (10kHz) white light?

I measured a 10 kHz modulated white light using a photodiode (Thorlabs PDA10A): Unexpectedly, the photodiode output sensitively depends on the orientation and position of the photodiode. For two ...
0
votes
1answer
351 views

Equation to describe the magnetic field sensed by a magnetometer

There are a magnetometer and a magnet placed at some distance D from it. We can assume that the magnet is a generic bar magnet. We can also assume that the Earth magnetic field is zero since the ...
1
vote
0answers
80 views

Initial conditions in QM

My questions are about initial conditions in QM in experiment and in lab. We consider many different initial wave functions, and we solve the problem on paper. Now, I have 2 questions about this in ...
4
votes
3answers
134 views

Does frequency of light change in the LIGO interferometer arms?

There are a number of questions on the internet and on this site asking about how the LIGO interferometer measurement works given that the gravitation wave stretches both the length of the ...
3
votes
2answers
129 views

Alternative ways to take particle tracks photographs in a cloud chamber

I know that the most common type of particle tracks photography is in photographic plates, but i'm using a cloud chamber and I would like to know if there are alternative ways to take photographs of ...
5
votes
2answers
333 views

How to measure transverse current-current correlation at arbitrary wave vector and frequency

Let $\hat J^{\mu}(t,\boldsymbol r) \equiv (c \hat \rho(t,\boldsymbol r), \hat{\boldsymbol J}(t,\boldsymbol r))$ be the density-current operator at spacetime coordinate $(t,\boldsymbol r)$, in the ...
1
vote
1answer
133 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 ...
1
vote
1answer
37 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 ...
3
votes
1answer
113 views

Determining the spatial imaging resolution based on a pinhole diffraction pattern

I aimed a 780 nm/1mW laser at a 1μm pinhole and took a picture of it using a lens and a CCD camera. The magnification of my imaging system is ~25 times. I wrote some code that takes the image of the ...
2
votes
0answers
30 views

How to identify properties of a concave diffraction grating

As a little side project I want to build a spectrometer. The main components are an entrance slit, a concave diffraction grating and a CCD sensor (also the electronics). I bought a used diffraction ...
1
vote
1answer
145 views

Means to improve precision and accuracy

I have sensor measuring a distance to a rotating disk. Later on I want to use these values to produce some results like the range of the values. What options do I have to improve accuracy and ...
1
vote
3answers
68 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....
2
votes
1answer
186 views

Exclusion limits on particle dark matter

I'm trying to make sense of how the upper limits of the cross-section of particle dark matter (WIMPs) are computed, like in the figure below. This is taken from an article on dark matter searches. ...
1
vote
2answers
90 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 ...
2
votes
5answers
2k views

Glass pipe cutting

I want to know how to quickly create the straightest possible breaks in glass pipes I apologise if this is only borderline suitable for a physics forum - I just hope experts with a lot of experience ...
4
votes
0answers
116 views

How do measurements of $G$ account for variations in the local gravitational field?

One of the notable discrepancies of modern physics is the current disagreement of measurements of the gravitational constant $G$, well beyond reported uncertainties (and agreeing only to about 1 part ...
0
votes
0answers
31 views

Experimental preparation of quantum states of macroscopic systems

What will be the experimental procedure to put the center of mass degree of freedom of a macroscopic object in a quantum superposition of widely separated states? I have been reading some papers ...
0
votes
1answer
74 views

Monte Carlo Closure Test in Particle Physics

What is the principle behind a MC Closure Test employed while analysing data in particle physics? So, what I understand here is that this test checks if one's code is working properly or not ...
0
votes
0answers
25 views

Why doesn't a lock-in measure the full voltage from a function generator? (3$omega$ setup)

I'm trying to build a setup for the 3$\omega$ technique, and the equipment is making my brain hurt. When I send a signal directly from the function generator to the lock-in, it only measures about 71% ...
0
votes
0answers
14 views

Skin Effect in two cilindrical conductors in contact

I have to prepare an experiment for my lab class and I'm planning on measuring the resistivity of an aluminum cilinder at different temperatures by putting it inside a coil with an alternating current....
1
vote
2answers
80 views

Experimental setup for 1 dimensional constrained frictionless motion

Physics textbooks are full of examples considering one dimensional constrained motion (in the gravitational field) with neglectible friction. However I have never seen setups with curved paths where ...
0
votes
0answers
25 views

is there any experimental method for measurement of thickness at atomic scale?

is there any experimental method for measurement of thickness at atomic scale? there are some methods for measurement of thickness even at nano scales such as AFM,TEM but my question is about atomic ...
1
vote
0answers
59 views

Photo Multiplier Tube (PMT) and charge sensitive pre-amplifier

I have an H7195 assembly type Photo Multiplier Tube (PMT) used to be tested for single photon measurement. I would like to use the dynode output to check the spectrum by connecting to a charge ...
2
votes
0answers
55 views

How Is Are Parton Distribution Functions (PDFs) Determined In Practice And In Theory?

I have put my actual questions in bold normal font, and the rest of this question clarifies what I mean to be asking, especially in terms of the depth and kinds of information I am looking for. ...
2
votes
1answer
74 views

Simple heater (radiation) model for PID constants tuning

I've searched around a lot and maybe I just don't know what exactly to search (and even ask here) for, but I'd like to create a simple model/function of a heater dissipating heat to surrounding air, ...
1
vote
1answer
41 views

What does it mean to hear the gravitational waves?

In last few years, I watched a lot of YouTube videos claiming that gravitational waves can be and has been heard. They also play a short audio signal. How do experiments such as LIGO replicate the ...
1
vote
0answers
23 views

How to change the diameter of a water stream?

So I am conducting experiments investigating the change of sound as a bucket fills up with water. One of the parameters which changes the sound heard is the diameter of the stream of water filling up ...
11
votes
1answer
868 views

Laser beam alignment: best practices

I have to build a complex optical setup consisting of many mirrors, lenses, beam-splitters, multiple wavelengths lasers to be coupled, etc. I am looking for the "best practices" to efficiently (and ...
0
votes
1answer
2k views

What is the reason for using mercury, neon, or argon in Franck and Hertz experiment?

In the book of Modern Physics Experiment by Melissinos, it is stated at page 13 that Another important point is that in principle tbe experiment must be performed with a monatomic gas; since if a ...
1
vote
2answers
112 views

Does Michelson-Morley experiment really disprove the existence of aether?

In the MM experiment, the speed of one light beam was supposed to slow down as it moved against the flow of aether, but when it bounced off the mirror, it would be moving in the opposite direction--...
1
vote
1answer
35 views

spot welding technique

I am trying to make electrical contacts by the spot welding technique. For Hall effect measurements, the contact size should be as small as possible and the sample is very very thin(0.025mm). But ...
6
votes
2answers
216 views

Why do we learn only two computations, cross sections and decay rates, in such a fundamental theory as QFT?

When I learned Newtonian mechanics I found a vast variety of computations that I could do and that was so interesting. And it was so when I learned Maxwell theory. When I started learning QFT I hoped ...
0
votes
0answers
25 views

Generic modes of light

Typically in second quantization one employs creation and destruction operators for modes which are eigenstates of the momentum: $a_{k}, a^{\dagger}_{k}$ where $k$ is the momentum eigenvalue. The "...
3
votes
2answers
459 views

How did Newton prove the equivalence principle with pendulums?

I know pendulums may be equivalent to a free fall but I would appreciate any further explanation for it.
24
votes
3answers
1k views

How to fix a bad KF flange?

Here is an interesting question for those who are familiar with vacuum science techniques. In the attached picture we have a damaged surface of a KF flange, which comes from the turbo pump outlet and ...
1
vote
0answers
31 views

What are the dynamics of a rope wrapping around a pole of given radius?

Suppose we drop a mass m from an initial angle $\theta_o$ connected to the pole of radius r with a rope of initial length $l_o$. As the system is released, the rope wraps around the pole, decreasing ...