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

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2
votes
5answers
345 views

Why mathematical equations can describe this world? [closed]

Since I want to understand the world, I learn physics from textbooks. But I feel there is a gap between the textbook and the world. I do not know why the equations in the textbook can control the ...
0
votes
0answers
46 views

Error calculation from measures in a Stephan-Boltzmann experiment

If we are taking values from an experiment and we have them ordered in vectors as this: Temperature: 55, 56, 67, 77, 56, 124, 56, Voltage: 5. 23, 12, 12, 12, 12, 34, 34 $$ ...
2
votes
2answers
194 views

What does one need to learn to become a experimental particles physicist? [closed]

I know one needs E&M, classical, quantum, statmech at the graduate level. But what more does one need? Are quantum field theory, relativistic QM, advanced math needed? or just an advanced course ...
4
votes
1answer
138 views

Need to weigh a sack of kittens

Hypothetical brain teaser here, no real kittens involved! - For some bizarre reason I have a sack of kittens, I need to find the total weight of the kittens and the sack but I'm only allowed to use ...
4
votes
2answers
128 views

Energy measurement of W- and Z- bosons

W bosons decay into an electron and electron-neutrino or into a muon and muon-neutrino. The W lifetime is about $3 \cdot 10^{-25} s$, that means the decay occurs close to the collision point, not in ...
1
vote
1answer
1k views

Radius of curvature of lens: Newtons Ring method vs spherometer

I have to do an experiment to find out the radius of curvature of a lens using the Newtons ring method given that you know the wavelength of the monochromatic light used in the experiment. What the ...
0
votes
3answers
61 views

Predicting the mass of the Higgs particle

Physicists in Europe said that only after combining data collected at a laboratory in Switzerland with data collected at a laboratory in the U.S, were they finally able to announce the discovery of a ...
16
votes
4answers
798 views

Does a magnetically suspended frog feel weightless?

Magnetic levitation has been used to suspend frogs in midair. I was wondering: Does the animal still feel gravitational pull? I mean: Does the frog feel like an astronaut on the ISS, or does he feel ...
0
votes
0answers
90 views

Measuring a quantity using two measuring devices

I would like to ask how I can reduce uncertainty by designing an experiment. I need to measure a quantity( say speed, in m/s). I have to calibrate the device and then move the device to measure ...
5
votes
2answers
168 views

Celestial Time-Keeping and Navigation

Say, for sake of argument, someone was randomly transported in time and space. Would it be possible for them to determine their location on Earth and the current time using just observations of the ...
1
vote
1answer
464 views

Is the total angular momentum of the universe zero? [duplicate]

I know that having a net angular momentum will contradict isotropy of the universe by preferring a specific direction. But is there any experimental data on the total angular momentum of the universe ...
0
votes
0answers
105 views

Determing aperture size for space-based-solar-power laser transmitter

I have hit a bit of a roadblock in my simulation. In the equation I require the aperture size for the laser source. $$I_a ≈ \frac{\lambda d}{A}$$ $I_a$ = aperture atop the atmosphere ($m$) ...
0
votes
0answers
35 views

Walking problem physics

How could you measure someone's walking speed at a constant rate? What types of errors could you potentially come across? And what are some different ways of modelling walking motion?
5
votes
1answer
383 views

Atoms' excitation energies as derived from Frank-Hertz experiment data

I'm analyzing the experimental data obtained during Frank-Hertz experiment (conducted with Hg atoms): Accelerating voltage values were multiplied by 0.1 during measurement (i.e. the mean value of ...
1
vote
0answers
106 views

Quantum physics and separation fallacy

I'm deeply interested in understanding delayed choice eraser experiment. Although I understand the experimental results, the retro causality is causing a big headache. From what I understand, the ...
2
votes
1answer
196 views

Diffraction Gratings

Is it possible to use the sawtooth shape diffraction grating instead of rectangular grating if yes then which parameters will affect at the output ? Secondly, what is special in blaze grating ...
1
vote
2answers
62 views

Ultrafast Lasers

The main idea of femtosecond or Attosecond lasers is to achive the high energy or do we have any other parameters achieved by ultra-fast lasers ?
5
votes
5answers
460 views

How to prove that we are living in a 3D world?

Is there any scientific experiment that can lead us to conclude we live in 3 dimensions without the premise of the conception of limited dimensions? Thank you all who helped in the improvement of ...
2
votes
0answers
158 views

Mechanics of Materials (pressure and temperature)

A solid right cylinder of rock core is surrounded by four rods made of mild steel (all-thread rods). The rods are placed equidistantly around the core in a square formation. The tops and bottoms of ...
0
votes
0answers
22 views

Shock-turbulence interaction problem

Can any one suggest a good reference for implementation of the shock-tube interaction problem ? I managed to that for the shock tube only, but for extreme test of some numerical implementations, I ...
4
votes
0answers
104 views

Statistical analysis of data in Physics

Analysis of data is integral in bridging the gap between theory and experiment. My question is about the two major methods of approaching the analysis - Bayesian and Frequentist. How much do the ...
1
vote
1answer
156 views

Isentropic vs Total pressure

I am confused between these two quantities: Isentropic pressure and Total pressure. Are they the same?
3
votes
2answers
300 views

Electromagnetic Momentum

My book says : The fact that electromagnetic radiation of energy carried momentum was known from classical theory and from the experiments of Nichols and Hull in 1903. This relation is also consistent ...
3
votes
0answers
131 views

Pockels effect/Kerr effect

In Pockels electro-optic effect, change in Electric field produces change in refractive index/ birefringence. Moreover this effect becomes electric field squared in the case of Kerr effect. If we ...
14
votes
1answer
196 views

GHz rate single photon counting

The fluorescent lifetimes of molecules used in biological applications tend to be in the sub-ns to a few ns timescale (let's say 0.8-4). The most direct methods to measure lifetimes typically involve ...
3
votes
1answer
177 views

Frank-Hertz experiment setup

The usual schematic representing the setup of Frank-Hertz experiment is the following: However, sometimes, you can see a bit different schematic: My question is: what function does $V_{G_1K}$ ...
2
votes
1answer
179 views

How do you build a simple low cost single photon detector?

Rather than buying a 4K-10K single photon detector, I was wondering if there were simple ways to build a simple single photon detector, of decent quality...
0
votes
1answer
72 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 ...
6
votes
2answers
145 views

Hollow gold bar

A scammer got a hollow gold bar and fills it with a combination of lead and air, with the same average density as gold. What's the simplest way of discovering the fraud? I know that x-rays will see ...
2
votes
0answers
42 views

Are there multiple ways to determine the redshift of the CMB experimentally?

I know that by using Boltzmann equation and all that one can calculate that photons become decoupled around T~3000K and because temperature scales as T~1/a we can determine that the redshift of the ...
8
votes
1answer
511 views

Experimental signature of topological superconductor

I was wondering if someone can provides some clear experimental signatures of a topological superconductors ? I was thinking about that, because for topological insulator, one of the hallmarks is ...
2
votes
0answers
53 views

Intensity of particles with zenith angle dependence

The intensity of particles come to sea level depend to the zenith angle $I=Iv (\cos(z))^n$, where $z$ is the zenith angle and $n$ depend to the particle. I know the vertical intensity depend to the ...
-5
votes
1answer
175 views

home made atom destruction unit [closed]

Today we learnt at school that atoms can be destructed. I believe Physics is a great science to do experiment and I would like to try it at home. Could you tell me what I need to do it? and is it ...
3
votes
1answer
345 views

Perfect pinhole diffraction pattern with sharp fringes using a 632nm laser

I'm trying to produce a diffraction pattern with pinhole using a laser of 632nm wavelength .The pinholes' diameter are ranging from 10um , 25um , 50 um , 0.1mm and so on . I also have good lenses for ...
4
votes
3answers
145 views

Is there a phenomenon where physicists are only interested in the standard deviation of the quantity to be measured?

or a phenomenon where we can only measure the standard deviation ($\sigma_w$) of a variable $w$ and not the mean $\overline{w}$
0
votes
1answer
87 views

how do they rip one single atom from something?

this is simple. what i actually want to ask is, when they do the subatomic particle collision experiments, how do they produce one single subatomic particle, e.g proton, neutron? how do they rip one ...
-3
votes
3answers
118 views

Current flows which way? [closed]

Current flows through a resistor (with no direction since it is not a vector/can flow from any potential)? I thinks it is with no direction since it is not a vector. Is that right?
2
votes
1answer
55 views

How does an optic-mechanical laser read and send binary bytes to a CPU?

Thid greatly concerns physics, since a more refined version of my title will be rehearsed below: How is the physical structure of the mechanical eye use a laser to read binary bits held on an optical ...
9
votes
3answers
379 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)?
8
votes
0answers
446 views

Methods to Stabilize and Maintain Extremely Low Humidity in a Lab Environment

My atomic physics lab is in a building that experiences huge swings in humidity levels during the year due to the monsoon season Our building provides temperature, but not humidity control. Using ...
4
votes
1answer
269 views

Fourier transformation, electric field and magnetic field to have a shielding lattice against particles

With Fourier-Series Expansion, we can write a function as sum of many non-repating different frequncied different amplituded sine and cosine functions. Lets assume we know electric-field and ...
1
vote
2answers
68 views

Aggregating daily readings with units of parts per million

I have a series of daily readings (NOx emissions) measured in parts per million. I need to aggregate the daily readings into a monthly measure. Clearly a sum operation will be incorrect (parts per ...
0
votes
1answer
791 views

what is the speed of push?

When we push something it moves due to the disturbance in it's molecular arrangement causing waves . How do I calculate the speed of push(waves) ? http://www.youtube.com/watch?v=Dnv-Pm4ehFs the push ...
16
votes
3answers
565 views

How do people calculate proportions of dark matter, dark energy and baryonic matter of the universe?

The Wikipedia page on dark matter mentions that the Planck mission had revealed that in our universe ordinary baryonic matter, dark matter and dark energy are present in the ratio: 4.9%, 26.8% and ...
2
votes
1answer
187 views

Abacus about the thermal expansion of copper

I am currently working on the measurement of the coefficient of thermal expansion of copper. In order to compare my experimental results with theory or experiments made by others, I am looking for ...
-3
votes
2answers
479 views

Since when were Loop Quantum Gravity (LQG) and Einstein-Cartan (EC) theories experimentally proven?

Can this template at Wikipedia be true? It seems to suggest that Einstein-Cartan theory, Gauge theory gravity, Teleparalleism and Euclidean Quantum Gravity are fully compatible with observation! It ...
3
votes
3answers
924 views

What does a curved natural log graph suggest?

Sorry if this is rather simple, but I've only just started learning about using logarithms in experimental physics. I did an experiment to test the amount of time it would take for an amount of ...
1
vote
0answers
238 views

X-Ray transparent material [duplicate]

I am looking for a material which is fully transparent to X-rays. In addition, it should be solid enough to serve as a substrate on which I will deposit some biomolecules.
2
votes
0answers
93 views

Line-shape asymmetry in undergraduate Hydrogen-Deuterium experiment

I'm working as an LA (undergraduate TA) for an undergraduate physics laboratory experiment where students test the Bohr model and use reduced mass to determine the approximate mass of the neutron. In ...
0
votes
0answers
24 views

How to calculate radius of the solvent? [duplicate]

I would to know how to calculate the radius of the (rigid sphere) solvent molecule. For example, Acetone has the radius $3.08\mathring{A}$. If i know the calculation of this radius, it would be ...