for questions about design, process, data, or analysis of experiments and observations.
4
votes
0answers
45 views
Best current bounds on nonconservation of momentum?
It's not straightforward to test conservation of momentum experimentally, and many experiments that seem like tests really aren't. For example, in a Newtonian system of identical particles that ...
1
vote
1answer
74 views
Why can I add the Atomic form factors in the calculation of the Diamond Structure factor
When trying to calculate the structur factor for diamond I came across the calculation on the wikipedia. In the calculation they just add up the atomic form factors of alle the atoms in the unit cell ...
0
votes
0answers
13 views
Potential E alternation
Considering a permanent magnet moving in a trajectory perpendicular to a straight wire of a given lenght, in a way that the magnet expose always the north face towards the wire, no matter the ...
1
vote
0answers
21 views
Easy to do experiments that clearly show outstanding properties of graphene
By chance we received for free some monolayer graphene sheets (20 cm x 20 cm) and mixed coper-graphene wires at our University. I would like to prepare some very easy to do experiments for the ...
0
votes
2answers
355 views
Are there experiments that are banned from being done at the LHC?
Are there experiments that are banned from being done at the LHC because they are too dangerous?
15
votes
4answers
195 views
How can I determine whether the mass of an object is evenly distributed?
How can I determine whether the mass of an object is evenly distributed without doing any permanent damage? Suppose I got all the typical lab equipment. I guess I can calculate its center of mass and ...
1
vote
1answer
40 views
Interpreting the results
I have preformed the muon lifetime experiment at my uni's lab, and got the data. It's text file with 8190 numbers. My TDC unit was set so that the time gates were at 10 $\mu s$, and it has 8192 ...
1
vote
0answers
76 views
Easy question about magnetism?
I have to build a simple electric motor by attaching a magnet to a battery, extending the terminals of the battery (with stiff wires so they could act as supports), and placing a coil of wire on top ...
4
votes
1answer
49 views
Optics alignment of scanning microscope
I am facing a challenge in my project regarding optical alignment.
See the figure:
The challenge is with the vertical optical system alignment. I considered placing a mirror and check back if the ...
4
votes
0answers
74 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 ...
2
votes
1answer
47 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 ...
3
votes
0answers
49 views
List of cross sections?
Sometimes I need to look up a certain cross section, say the inclusive Z production cross section at $\sqrt{s}$ = 7 TeV. Is there a place where 'all the' cross sections are tabulated ...
0
votes
1answer
233 views
Where to find experimental/theoretical value of (charge) radius of particles?
Where to find experimental/theoretical value of (charge) radius of particles like proton, neutron, $pi^+$, etc. ?
1
vote
2answers
181 views
Where to find cross section data for e- + p -> p + e-?
Where to find cross section data for e- + p -> p + e-?
PDG's cross section data listing does not include it.
10
votes
2answers
261 views
Is there a way to directly observe the spin texture of the surface states of topological insulators?
Is there a way to directly, here I means in real space, observe the interaction of the surface states of 3D topological insulators with defects (dopings and adatoms)? How to observe the spin texture ...
0
votes
2answers
298 views
Microsoft Excel not graphing $x = y^{1/2}$
The experiment was relating the period of one "bounce" when you hang a weight on a spring and let it bounce. I have this data here, one being mass and one being time.
The time is an average of 5 ...
5
votes
3answers
221 views
How can I determine the coefficient $k$ in $ \dfrac{dT}{dt} = -k(T - 100 \mathrm{^\circ C}) $?
I recently spend some time on cooking and I'm curious about the time evolution of the temperature of the water. I did some experiment and the temperature is of the form
$$ T = 100 \mathrm{^\circ C} + ...
4
votes
2answers
68 views
Cosmological triangle with PLANCK results
Is there an updated version of the cosmological triangle with recent PLANCK results included?
2
votes
1answer
31 views
Experiment to find Ammeter Resistance [closed]
I've been studying experimental electrodynamics and I needed to describe an experiment to find the resistance of an ammeter if I just have the ammeter together with one voltmeter and a protection ...
7
votes
6answers
982 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?
1
vote
3answers
208 views
Intensity distribution of a LED light source
The light source: 190 high power LEDs in NIR.
I have the datasheet of the LED.
I want to make a graph showing the spatial distribution, and to measure the intensity of the beam on the whole field of ...
2
votes
1answer
121 views
How was Be-8's Half-Life of 7E-17 Second Determined?
Radionuclides occur with half-lives in a vast range of over 37 magnitudes as listed in this site. In question 7584, Lubos Motl explained how Gyr half-lives were determined. This method doesn't appear ...
-1
votes
0answers
48 views
What is the difference between various fields of physics? [closed]
what is the difference between the fields of physics? like high energy physics, particle physics, cosmology, quantum physics, quantum mechanics, experimental physics, theoretical physics, applied ...
160
votes
19answers
55k 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 ...
6
votes
0answers
85 views
Status of experimental searches for tachyons?
Now that the dust has settled on the 2011 superluminal neutrino debacle at OPERA, I'm interested in understanding the current status of experimental searches for neutrinos. Although the OPERA claim ...
0
votes
1answer
36 views
Why pulse waves results in wave packets?
I was doing experiments of measuring sonic velocity and I generate pulse waves from sensor 1, but when they are received by sensor 2, I saw wave packets on the oscilloscope, can you explain why?
I was ...
2
votes
0answers
18 views
Concerning Scattering Intensity and Particle Concentration
I am trying to determine what governs my sensor output. I have an optical sensor that emits infrared radiation on a sample volume and gives me a voltage output from the scattering of (1 to 10 micron) ...
8
votes
1answer
154 views
How the inverse square law in electrodynamics is related to photon mass?
I have read somewhere that one of the tests of the inverse square law is to assume nonzero mass for photon and then, by finding a maximum limit for it , determine a maximum possible error in ...
5
votes
4answers
299 views
What is the “foamy space” hypothesis that has been debunked recently?
In "Space-Time Is Smooth, Not Foamy", a Space.com article, it is stated:
In his general theory of relativity, Einstein described space-time as fundamentally smooth, warping only under the strain ...
0
votes
0answers
29 views
Experiments related to Capacitor and Prism [closed]
I want my students to learn experiments on prism and capacitor. Can you provide me different experiments related to prism and capacitor (except charging and discharging). The experiments will be given ...
4
votes
2answers
256 views
Basic question on experimental plots
On the following Higgs $\rightarrow$ Tau Tau plot, since we are plotting the ratio of $\frac{\sigma}{\sigma_{SM}}$ on the y axis, shouldn't the expected for this be 1? i.e., shouldn't the expected 68% ...
10
votes
5answers
937 views
The square in the Newton's law of universal gravitation is really a square?
When I was in the university (in the late 90s, circa 1995) I was told there had been research investigating the $2$ (the square of distance) in the Newton's law of universal gravitation.
...
0
votes
1answer
79 views
measuring electromagnetic induction
There is a famous law which says that a potential difference is produced across a conductor when it is exposed to a varying MF. But, how do you measure it to prove? It is quite practical.
...
4
votes
1answer
131 views
On the Aharonov-Bohm effect, and the reality of the classical fields
As far as I can check, the Aharonov-Bohm effect is not -- contrary to what is claimed in the historical paper -- a demonstration that the vector potential $A$ has an intrinsic existence in quantum ...
-1
votes
1answer
115 views
Can thought experiments qualify as actual research?
I wondered whether thought experiments actually can be substituted for actual experimentation. I understand that in some cases it might be necessary, but can it be unnecessary over thinking sometimes? ...
4
votes
2answers
171 views
Why propagation of uncertainty is linear?
I'm in doubt with one thing: let's imagine that we have $n+1$ quantities, $n$ of them being directly measured, and the other one being related to the first $n$ by a function $f : \mathbb{R}^n \to ...
4
votes
1answer
89 views
How important is it, really, to clean vacuum parts?
In every lab I've seen, people are quite meticulous about cleaning parts that are to be used in ultrahigh vacuum, as well as the components of the chamber itself. The parts may be put in an ultrasonic ...
-4
votes
0answers
70 views
faster then the speed of light [closed]
if i was having a race against some one ten times biger then me building sise from the start line to the finish line is only 60 feat it will take me a wild to get ther but it will take the other guy ...
2
votes
2answers
83 views
Parabolic motion (experiment)
We performed a laboratory, performing six releases of a sphere with angles $15^\circ,30^\circ,45^\circ,60^\circ,75^\circ,40^\circ$ a parabolic movement, took five distances for each angle, the initial ...
2
votes
1answer
123 views
Consistently oscillating micron sized particles in a liquid
I have an idea that would involve the measurement of an oscillating substance whilst the substance is immersed in a liquid. However, the method that I would use to measure the frequency of these ...
2
votes
0answers
46 views
Robot controling pouring process from a bottle
I need to solve a problem within mechanic of fluids for a part of my thesis. Robot will pick up a bottle of beer, cola, julebrus or any other kind of beverage. And then it has to bring it to the glass ...
1
vote
1answer
96 views
What is Transverse Energy?
What is transverse energy? Why we use transverse total energy instead of energy and transverse momentum in place of Total momentum in the particle detectors?
3
votes
2answers
186 views
What limits the maximum attainable Fermi Energy for a material experimentally?
Either through doping or gating. What are some good terms to search for if I'm looking for some experimentally obtained values for particular materials? I'm particularly interested in what the limit ...
1
vote
1answer
21 views
Are “timed” measurements actually revealing error-distributions of the measurement apparati?
A thought experiment:
Given some object moving (swinging) from left to right and back with constant velocity, imagine a camera set up to take a picture of the scene at a fixed interval so that we can ...
8
votes
3answers
526 views
How hot is the water in the pot?
Question: How hot is the water in the pot? More precisely speaking, how can I get a temperature of the water as a function of time a priori?
Background & My attempt: Recently I started spend ...
2
votes
1answer
178 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 ...
4
votes
3answers
132 views
How quark electric charge directly have been measured?
How quarks electric charge directly have been measured when quarks never directly observed in isolation? (Due to a phenomenon known as color confinement.)
3
votes
1answer
68 views
Explain background pattern in particle tracing image
I'm trying to understand this image of a particle tracing experiment (which can be found all over the net if you google for "bubble chamber"):
(
There are two things that I can't figure out:
The ...
2
votes
1answer
33 views
Planes of graphite crystal on diffraction experiments
When doing electron diffraction on graphite (a popular experiment for students at universities) always diffraction at these two planes with distances $d_1$ and $d_2$ are observed:
But a plane ...
5
votes
1answer
90 views
Whistling on bottle tops
It is well known that if you blow horizontally on a bottle top it creates a sound. Pouring water to the bottle changes the pitch.
I have been doing experiments on the relation between the sound's ...
