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

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2
votes
2answers
61 views

Weighted mean from data [on hold]

Suppose we have 3 experimental groups measuring "x", they measure $$x_1=\mu_1\pm \sigma_1$$ $$x_2=\mu_2\pm \sigma_2$$ $$x_3=\mu_3\pm \sigma_3$$ In the 3 experiments, we have done N measurements of ...
-2
votes
1answer
70 views

Emission and absorption of photons by electrons [closed]

Two questions occur at a critical review of the two famous experiments devised by Millikan in 1914, respectively Duane, Hunt and others in 1917-1920, which confirmed the action constant calculated by ...
1
vote
1answer
82 views

Thought Experiment: Force on magnets in a Stern Gerlach Experiment

Background: In the SG experiment, an inhomogenous magnetic field affects a force on particles passing between two magnets. "Measurement" takes place when a screen is placed on one end, blocking one ...
2
votes
1answer
194 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 ...
12
votes
3answers
822 views

What is the most compelling evidence of General Relativity in the presence of matter and energy?

The most oft-cited triumphs of GR are things such as the shifting perihelion of Mercury, gravitational redshift experiments, and gravitational lensing. But, as far as I know, these are only ...
0
votes
0answers
35 views

Experimental physics book suited for a math student [on hold]

I am currently a Master's student in Mathematics who is very much interested to learn advanced physics (QFT, Particle Physics, GR,Cosmology). The main focus of my undergraduate programme was on ...
0
votes
2answers
44 views

At what point do researchers in physics make the leap from wild theoretical ideas to physical experiments? [on hold]

Dark Matter, on the surface, appears to be a wild idea... Some invisible thing that we can't see that controls the movement of most of the universe. Yet, we are searching for it. Why? What evidence ...
1
vote
1answer
59 views

Research papers readable by first years? [on hold]

This coming Spring I'll be running a Mechanics I lab for freshman (as a teaching assistant) and I'll have some say as to the way I do it. So I was thinking it would be nice if I could find some ...
1
vote
1answer
112 views

Moment of inertia from torque and angular acceleration measurements

I tried to calculate the moment of inertia of a quadcopter along its roll axis using two different methods and the results do not match. Method 1: measuring the period of a bifilar pendulum, I obtain ...
3
votes
1answer
88 views

Can LIGO measure anything?

LIGO, Laser Interferometer Gravitational-Wave Observatory, is a large-scale physics experiment aiming to directly detect gravitational waves. The device measures the phase shift laser beams. If I ...
0
votes
0answers
3 views

how to completely remove the charge from the glass bubble particles?

Do you have any idea on how to completely remove the charge from the glass bubble particles (25-32 micrometer diameter)? Thanks
-1
votes
1answer
32 views

Ways to measure the focal length of a convex lens with only natural sun light [on hold]

What are the common ways to measure the focal length of a convex lens with only natural sun light?
2
votes
0answers
16 views

How to measure the permittivity of a gas sensor? [on hold]

I looking for a simple method to measure the permittivity of a gas sensor silicone.
0
votes
0answers
21 views

Need more details on How to Make a Water Bottle Cap Pop Off With Air Pressure [on hold]

i have been assigned the topic air pressure in physics presentations,so i decided to do the above experiment but the teacher has asked for a technical report on the experiment.I am a bit confused on ...
0
votes
2answers
50 views

Experimentally, what categorizes a measurement as corresponding to a certain observable?

I want to write a computer program. The input to the program is: A description of an experimental device (for instance a Stern-Gerlach apparatus, or a laser and a polarizer) What the experimenter ...
0
votes
0answers
11 views

Hydrogen spectrum intensity using a monochromator

Using a monochromator (350->800 nm) and a hydrogen gas lamp, I find this spectrum : We can see 3->2, 4->2, 5->2 transitions from Balmer series, but not 6->2 (which we should expect at 410 nm). As ...
9
votes
2answers
569 views

Mechanical Equivalent of Heat

Recently I have been looking up James Joule's experiment regarding the mechanical equivalent of heat. After viewing some drawings of the apparatus, I assumed that the lines holding the weights would ...
1
vote
1answer
282 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 ...
3
votes
1answer
109 views

Why is the relationship between velocity and radius curved, in circular motion?

An experiment to model planetary motion: The brown rubber was supposed to model a planet, while we varied the radius $r$ and the mass hanging from the string. Varying the masses was to show ...
-4
votes
2answers
582 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 ...
-4
votes
1answer
56 views

Temperature limit of the increase in heat

If the sun is the hottest known thing to humans is it possible to have a temperature greater than the sun?.
-4
votes
1answer
77 views

Free 'fall' on an Inclined Plane

I guess we can say that two identical balls on the same inclined plane with different heigths reach the ground at the same time. So, who was the first one to observe it?. ...
0
votes
1answer
62 views

Orifice Jet Flow experiment

I am writing up a report on Orifice jet flow experiment in which I am required to find coefficient of flow velocity, $C_v$, and the Coefficient of discharge, $C_d$. There are couple of things that I ...
0
votes
1answer
137 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 ...
-2
votes
1answer
131 views

What happens if we put a pinch of salt on the ice cubes which is melting in the water?

What happens if we put a pinch of salt on the ice cubes which is melting in the water? How will the ice react to the salt, and what other things will happen after mixing them?
0
votes
0answers
7 views

Air Cylinder to drive Pneumatic Pump

I am required to drive a pneumatic chemical injection pump using Compressed Air in Cylinders. The pump requires a supply pressure of 80 psi to effectively ensure. We do not have a flow meter to ...
1
vote
2answers
39 views

How are the components of the spin vector defined?

How do we distinguish between the $x$, $y$ and $z$ spin components? More precisely: how do we define the $z$ component? (according to what, it is the $z$?) for measuring the $x$ component how ...
1
vote
1answer
94 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 ...
2
votes
1answer
40 views

What is the error in a ruler?

I'm having trouble understanding simple error analysis of a ruler. Suppose we have this ruler. There is a mark for every centimeter. The precision is half a centimeter. This should mean that the ...
5
votes
3answers
871 views

Why can't echoes be heard inside a room?

If I go camping and shout anywhere, in the forest or on a cliff, I usually hear the echo of my voice. Why when I shout in my room I do not hear any echoes?
0
votes
1answer
128 views

Outcome from this experiment with solid hydrogen?

Let's say that we have two solid hydrogen blocks (or at least two solid hydrogen lattices) in a vacuum. Both blocks have perfectly smooth surfaces which are later put together. Before putting blocks ...
0
votes
1answer
55 views

How to entangle two particles? [duplicate]

After learning about quantum entanglement I wanted to know, what is the simplest way to entangle two particles in a lab?
0
votes
5answers
324 views

Can we create invisible things?

We are able to see this beautiful world because of light. When light gets reflected from the object, the reflected light enters our eye retina and thus we are able see that particular object from ...
9
votes
4answers
348 views

Has relativity of simultaneity been directly observed?

I know that thought experiment about trains when a flash of light in the middle reaches the both end simultaneously for a passenger but different times for the bystander. So were there (non-thought) ...
5
votes
1answer
84 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. ...
0
votes
1answer
51 views

How was phase randomly changing in CHSH test (M. A. Rowe and others)?

Measuring phase of photon should always be random while checking CHSH inequality, but i can't explain this: http://qudev.ethz.ch/content/courses/QSIT08/pdfs/Rowe01.pdf (the most clear experiment i ...
3
votes
1answer
580 views

Gravity is curved geometry: A fact of nature or model-dependent interpretation?

We are regularly taught in high-schools and universities that, according to General Relativity (GR), gravity is nothing but a manifestation of space-time curvature (which, in its turn, is caused by ...
1
vote
0answers
26 views

Books on experimental methods, fluid mechanics related

I need some good books on experimental methods, requirements are: Fluid mechanics related; Thermal, multi-phase etc. topics should be covered; Traditional methods are good, but it would be greater ...
1
vote
1answer
63 views

Is fluorescence from a single atom/ion visible with the naked eye (e.g. in a strongly coupled trap or cavity)

I remember sitting in on a conference talk by a person (possibly Rainer Blatt) doing research with trapped ions (or single atoms strongly coupled to light in an optical cavity), and the person showed ...
2
votes
1answer
48 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?
0
votes
1answer
17 views

What is the general definition of signal acceptance?

Suppose I have a beyond Standard Model theory and want to test it. I want to test if some experiments, say conduced in LHC, show signals of the theory. In this case, what is "signal acceptance"?
9
votes
3answers
1k views

How did Rutherford's gold foil disprove the plum pudding model?

What stops one of the two following scenarios from happening, consistent with the plum pudding model? The $\alpha$ particle, attracted by the electrons on the outer shell of the pudding, orbits ...
0
votes
0answers
14 views

An experiment in quantum theory involving a metal ring

I'm trying to remember the name of an experiment that I saw on YaleCourses in a lecture by Professor Shankar. My recollection is that something was sent around a closed metal ring. The fact that the ...
1
vote
1answer
71 views

What is logical way to calculate percentage error?

I wish to know logic behind percentage error formula. Say, $A$ is measured or calculated quantity, $B$ is theoretical or known or benchmark quantity. Then, what should be the formula for percentage ...
2
votes
5answers
255 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. ...
0
votes
0answers
13 views

Definition Of Dark Current In PhotoDetectors

What is The Definition of Dark Current In PhotoDetectore. How Can I Eliminate This Effect. I Think When Electrons Near The Conduction Band Are Excited Into It By Thermal Effect Then Dark Current Is ...
1
vote
1answer
15 views

Experiment Equipment Supplier (for use in the Classroom & at Home) [closed]

Does anyone know of an online store that sells equipment specifically designed for carrying out demos in the classroom or at home? I'm helping out a student taking college physics and chemistry. These ...
6
votes
0answers
54 views

What is the relationship between Faraday cage mesh size and attenuation of cell phone reception signals?

This is related to the question how can electromagnetic waves reach a cell phone in faraday cage?, where in the answer it was stated that the holes (=size of the mesh) would need to be smaller than ...
1
vote
1answer
231 views

Questions about MTW's “thousand” tests of the Einstein principle

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 ...
1
vote
1answer
19 views

Uncertainty of approximately sinusoidal voltage measurement

Say one is interested in measuring the mean value an approximately sinusoidal voltage with an instrument that has an accuracy of 0.01 V, according to its spec sheet. 10 periods of the oscillation have ...