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

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0
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0answers
39 views

What might be the reason that more dense materials are better at shielding? [on hold]

So in the experiment for radioactive shielding we used post-its as a shield but we have to come up with a reason why this material isn't the best and why more dense materials are better at shielding, ...
0
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0answers
23 views

Cooling power for cloud chamber

I'd like to build a small Peltier cell cooled cloud chamber. The cold surface would be a copper sheet with a surface of 200x200 millimeters. Is there a way to even guess the cooling power needed to ...
0
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1answer
38 views

Stern Gerlach Experiment

Since l=0 for a valence electron in 5s state of silver, L=0 and therefore magnetic dipole moment is also 0 which means that the beam should not have deflected at all. So, we introduced the property of ...
0
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1answer
20 views

Resonance and a tuning fork

I carried out this experiment in class: I struck a tuning fork with a hammer. The sound lasted for some time. However, when I connected the tuning fork onto a wooden sounding box, the sound lasted ...
2
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2answers
89 views

Franck and Hertz graph function [on hold]

I need a function whom graph is the following (the Frank and Hertz experiment graph): Currently I wrote the following function: ...
2
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4answers
190 views

What's the difference between $10\%$ of $10\text{ cm}$ and $1\text{ cm}$?

I overhead a physics professor at my university on the phone: I interviewed that student you sent me, but he didn't know the difference between increasing the length of a $10\text{ cm}$ rod by ...
4
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1answer
57 views

How use the Higgs branching ratio plot to extract information about the Higgs mass compared to experiment?

What does the plot of higgs branching ratio (see figure below) say about the higgs mass anyway? How can one use it as a guide to find the higgs mass experimentally? If we e.g. go to $M_H=126$ GeV ...
1
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0answers
11 views

Time scale when measuring total activity from radioactive sample

I have measured the total activity from a radioactive sample during an experiment by counting the number of decays happening in 3 seconds intervals. I got data as: Time bin: 0 1 2 3 4 5 6 7 ... ...
1
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1answer
59 views

Can doppler shift be used to find the MH370 black boxes?

The Australian ship Ocean Shield has detected multiple pings from the black boxes onboard the missing Malaysia Airline Flight 370, specifically on 4 lines of bearing according to this article. The ...
0
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1answer
64 views

Illustrating black body radiation by examples of temperature to color relation

[rewritten to better describe the point of the question] I'm looking for a set of examples to illustrate the relation of temperature and color. It should allow to build an intuitive understanding of ...
1
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1answer
41 views

Under what circumstances is observing a superposition possible?

According to Ian Stewart's 2013 Symmetry: A Very Short Introduction (pp. 119-120), Experiment and theory suggest that superposed states should not be observable as such; only individual ...
1
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3answers
125 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. ...
5
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2answers
146 views

Why must an integrating sphere be a sphere?

Why must an integrating sphere be a sphere? Why can't it be an integrating cube? What is the difference? Could I use a cube to measure total illuminance like an integrating sphere does?
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6answers
4k views

Why is jumping into water from high altitude fatal?

If I jump from an airplane straight positioned upright into the ocean, why is it the same as jumping straight on the ground? Water is a liquid as opposed to the ground, so I would expect that by ...
1
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5answers
97 views

Ice cube on a scale

Lets put an ice cube on a fairly precise scale and take readings over a period of several hours. The ice cube is situated in a saucer so that the water is retained after melting. What will the ...
0
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3answers
165 views

Pendulum (highschool)

I have a question concerning pendulum. On our physics lessons we built simple pendulum consisting of weight and a thread ($\ell=0.31$ m). We tried to calculate $g$ from the well known formula $$T_m ...
0
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0answers
40 views

Beryllium Vacuum Sphere Boat/Aircraft

Is it possible to make a solid rigid evacuated "balloon" out of Beryllium or other elements or alloys? The critical buckling pressure at which an evacuated sphere is given as $$ ...
0
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0answers
11 views

Figuring out a film thickness when the wrong metal was chosen for the thickness monitor?

I made a silly mistake and was wondering if someone had a clever solution. I evaporated two metals, A and then B. However, when I evaporated metal B, I forgot to switch the thickness monitor to metal ...
0
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0answers
7 views

Can we say that nanomaterials have higher cohesive energies compared to coarse-grained counterparts?

Can we say that nanomaterials have higher cohesive energies compared to coarse-grained counterparts?
0
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1answer
30 views

Is There an Equation To Calculate Water Evaporation Taking Into Account Environmental Variables

I am starting to learn more in my area of science...Meteorology and the fact that I own a pool, I have the perfect testing environment. I just so happened to have a water level drop from an actual ...
0
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1answer
19 views

Alpha scattering, observations and conclusions

For Rutherford's alpha scattering experiment where he fired alpha particles at a thin sheet of metal to determine the size of the nucleus, please can someone give me the direct link between his ...
0
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0answers
17 views

Are there any useful site/papers that provides data about variability in a composites material properties such as G1C,G12,E11,E22,V12 or fibre angles?

I realise this is a question that borders on Mechanical Engineering, but I was hoping someone could help. I am looking at finding experimental data that will point to variability in a composites ...
1
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2answers
61 views

NMR Analysis of Ethylene glycol [closed]

I have the spectrum obtained by an NMR analysis of Ethylene glycol : I would like to explain the number of peaks in this spectrum, and assign them to the proton spins present in the molecule. I ...
1
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0answers
26 views

charged oil drop in electric field [closed]

I am currently doing coursework for my A2 physics course. I am dropping a charged oil drop in a horizontal electric field and I was wondering how to calculate how much the droplet would deviate given ...
2
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0answers
99 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 ...
2
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0answers
24 views

Experiments proving/disproving extra dimensions [duplicate]

I have been recently reading quite a little about Kaluza Klein theories. I am still far from mastering this but I am curious if any experiment that may disprove or give hints of the existence of extra ...
13
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5answers
1k views

Why is it easier to break a tightened or stretched string than a loose one?

I want to know, why is it that it is easier to cut through a string which is tightened then a loose one? The question arose when I was watching - "What Happened Next?". In a part, they showed two ...
2
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1answer
68 views

Specific heat of aluminium as a function of temperature

I am trying to find the curve describing the specific heat of aluminum as a function of temperature between about 50K to 300K(or room temperature) for an experiment I am doing. Ultimately I need to ...
8
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2answers
2k views

Which is the smallest known particle that scientists have actually *seen with their eyes*? [closed]

Which is the smallest particle that has been actually seen by the scientists? When I say "actually seen", (may be using some ultra advanced microscope or any other man made eye, using any wavelength ...
6
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3answers
84 views

Experimentally Verifying a Clock's Accuracy

So recently one of my professors went off on a tangent, and we ended up discussing atomic clocks and how they work, which is something I've always been fascinated with and thoroughly enjoyed. But it ...
0
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1answer
46 views

Measuring a fluctuating quantity: Instrument error vs. uncertainty, or both?

Say I am measuring a quantity $x$ in physical system whose true value is approximately sinusoidal in time. I have an instrument to sample this quantity, for which the manufacturer gives an accuracy ...
-4
votes
1answer
143 views

Is the interpretation of BICEP2 data being due to “graviational waves” concerning considering the negative results of the LIGO's experiments? [closed]

Gravitational waves are a yet unproven idea... The lack of positive results from LIGO indicates these are still theoretical constructs not yet supported by experimental data. Is not the explanation of ...
0
votes
3answers
62 views

Single mode fibers

Is it possible to focus white light into a single mode optical fiber? I thought no because in order to focus it should be a solution to the Helmholtz equation but I am not too sure about it. Also ...
-1
votes
1answer
92 views

What are the problems in analyzing an experiment with non-ideal collisions? [closed]

For a two-dimensional collision experiment, I must explain in one of the questions the problems in analyzing a non-ideal two-dimensional collision. As the question states: Suppose that the ...
1
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1answer
54 views

Numerical aperture of a lens

Using a laser setup, I was asked to determine the aperture of a given lens and then use some geometrical arguments and compare the theoretical value from the manufacturer and the experimental value. ...
5
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2answers
237 views

What experiments compete with BICEP 2, and when are their results expected?

The recent results of the BICEP 2 experiment published on March 17th 2014, has generated a lot of media attention, with the general consensus being that "this is a major discovery" perhaps leading to ...
0
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3answers
49 views

Creating electricity from mains water pressure.

Could someone cleverer than me help me out? I had a crazy thought going through my head the other day and I can't lay my mind to rest until I get an answer. Q. How much energy could be produced by ...
66
votes
5answers
5k views

What was the major discovery on gravitational waves made March 17th, 2014, in the BICEP2 experiment?

The Harvard-Smithsonian Centre for Astrophysics held a press conference today to announce a major discovery relating to gravitational waves. What was their announcement, and what are the implications? ...
0
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2answers
52 views

Photoelectric effect: current vs wavelength

In an experiment where the type of metal,intensity of light and potential difference across a battery is kept constant at 2V the results show that an increase in wavelength, obviously in turn ...
1
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5answers
92 views

EPR paradox: instantaneous vs very fast?

An EPR quantum experiment can be explained by instantaneous collapse of the wave function regardless of the distance separating a pair of entangled particles. But do we have the certainty that the ...
2
votes
0answers
29 views

need data-point: count rate of APD (avalanche photo-diode) for specific aperture and stellar magnitude

I hope lab / experimental physics is fair game for this web-site. If not, sorry! I'm designing a sensor system to perform specialized [astronomy and space-sciences] experiments, and need a "reality ...
1
vote
1answer
20 views

Measurements for thermal diffusivity of graphene?

We have known for a long time that graphene has in-plane thermal conductivity ranging between 2000 and 4000 $W m^{-1} K^{-1}$. But in order to model heat transport on a sheet of graphene, we need more ...
4
votes
1answer
138 views

Why would a pendulum experiment give $g > 9.8\ \mathrm{m/s^2}$?

I am taking an introductory lab course in which we've done an experiment on the physical pendulum. We've seen that for small oscillations, the period is ...
1
vote
2answers
44 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 ...
1
vote
1answer
52 views

Getting nonphysical results when solving for the index of refraction of a slab?

I'm trying to computationally find the refractive indices (real and imaginary) for a thin slab suspended in air (so the only indices to deal with are air and my material's). I've experimentally taken ...
2
votes
1answer
66 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 ...
3
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0answers
23 views

Experimental results regarding non-extensivity in small systems

From a statistical mechanics point of view, the extensivity of thermodynamics arises from the fact that we can neglect interaction terms in the Hamiltonian. This allows us to infer that when we put ...
0
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0answers
32 views

Quantum distance ladder

There is a lecture on how facts about the cosmos can be derived form rather simple observation. Is there an analogy for the small scale? Is there a technically simple observation that would imply, ...
1
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3answers
58 views

Cart on Ramp with Varying Acceleration

For a lab that I have to do, the teacher has given me a data table of the displacement of a cart on a ramp after successive intervals of time. I have used this data to derive the velocities and ...
2
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0answers
35 views

Fractional quantum number induced in a soliton profile

It has been known there is fractional quantum number induced in a soliton profile, such as this Jeffrey Goldstone and Frank Wilczek paper and many works of Jackiw. For example the electric charge ...