# Tag Info

0

The only answer I can think of would be: 1- how much substance is disolved in the water, and 2 - at what elevation are you boiling your water. Salt water has a higher boiling point than pure water. Reduced ambient air pressure will lower the boiling point.

1

I'm not an optics guy, but I can think of a few issues you'd want to think about until a pro comes a long and explains it all to us: The beam will diffract from the new aperture affecting both collimation and coherence length. Only a concern for very small beam diameters or long optical paths; and something that any other method for reducing the beam ...

6

The spin of the neutron was measured by the Stern-Gerlach experiment by Sherwood, Stephenson and Bernstein (1954) (sadly paywalled, free links welcome), Abstract: A neutron beam was polarized by total reflection from a magnetized iron mirror. The beam was then analyzed by passing it through an inhomogeneous magnetic field. From the deflection pattern ...

0

The truth of the Lorentz transformation as an accurate description of the co-ordinate transformation between relatively uniformly moving observers needfully implies relativity of simultaneity. Contrapositively, the Lorentz transformation cannot be sound if simulteneity is not relative. So, in the sense that the soundness of the Lorentz transformation has a ...

4

Do we have any tunneling current for $0 < V \leq V_c$? Yes. If yes, then why don't we show it in the diagram? It is in the diagram, you just have to understand how that diagram was measured. Junction basics The Josephson junction is governed by two equations \begin{align} I &= I_c \sin(\delta) \\ V &= (\Phi_0 / 2\pi) \dot{\delta} ...

2

I am sorry to disappoint you, but there is no such formula that you can just apply. This is because it strongly depends on how and under what exact conditions and with wwhich tools you did the experiment. Think of this: If every methanol molecule reacts (burns) at once all at the same time, then the exact same amount of energy is spent, but it went really ...

1

It has been pointed out that this cannot simply be done by examining the mass distribution (first and second moment of mass). But there is a way to "look inside" most common objects: Take a CT scan. Not sure if you consider that "typical" lab equipment - but it's equipment I have in my lab... Of course depending on the size of the object and the material ...

1

Some background. You want to detect the image of an object. First, either 1) you illuminate it with some light source [a lamp, the sun] or 2) the object itself radiates light out [a star, a fluorescent sample]. Imagine to divide the object in many small parts (voxels): to reconstruct the image of the object, you need to detect independently the light coming ...

0

I think there is still a current flowing. I found this picture on this website. The gist is that above a certain voltage $V_c=2E_g/e$ (twice the energy gap divided by elementary charge), the voltage large enough to overcome the band gap and Cooper pairs can flow. EDIT: Also look at this excellent post.

1

As boyfarrell pointed out, the IR peak that you observe is due to second order reflection from the diffraction grating of the spectrometer. Strong spectral lines are often seen in the second order (with the advantage of better resolution). You can easily verify it by inserting a long-pass filter that blocks 370 nm (some orange glass or even sunglasses) ...

0

I would add to that list the masses and mixing angles of the three known neutrinos, which are just as arbitrary as the others within the confines of the standard model. This adds seven parameters to the 19 listed in the Wikipedia article https://en.wikipedia.org/wiki/Standard_Model#Construction_of_the_Standard_Model_Lagrangian

1

There is one, very limited and very deceptive, experimental case in which a large object can "cover more distance" than a smaller object at the same speed: Say you have two small cannons in a gymnasium and are going to launch two projectiles - a round cannonball and a long pole - to the opposite wall. The gymnasium wall is 100ft from the back of each ...

0

There is no size or weight in speed The speed of an object does not depend on its size or its weight The units for speed is distance / time Distance is speed X time 100 miles / hour for time of 1 hour (100 miles / hour) X 1 hour = 100 miles

3

Time taken to cover a distance L by an object moving at a speed V is given by $$t = \frac{L}{V}$$ where t is the time taken. Therefore, the size of the object does not matter at all. Whatever be the size of two objects; if they have the same speed, they will cover the same distance in a given time. But, usually objects with a better aerodynamic design ...

-2

We don't currently have an underlying theory for these parameters, we obtain their values experimentally, not theoretically. No, but one day I think the Standard Model will be enhanced to derive some of these paramaters from first principles. I've spoken to a medical doctor called Andrew Worsley who has some interesting "quantum harmonics" ideas about ...

2

Within the standard model alone, all these parameters are independent, and to those you can add the masses and mixing angles of the neutrinos. Possible additional symmetries beyond the standard model suggest some relations between the gauge couplings, since renormalization group analyses based on these symmetries lead to unification of these couplings at ...

0

The solution has to have with the 'surface tension' of the exterior surface. Google for 'surface tension' satin water repellent synthetic tissue and find: 'Liquid water is prevented by surface tension from penetrating' on Polyester Microfilament Woven Fabrics Conclusion : the exterior surface of the duvet (and not the interior material) is blocking the ...

0

I have no actual information, but I believe that it's highly likely that the protons will again run at the same energy as in the pp run. By doing this, the operations team will not have to redo the various manipulations (injection, ramping, bunching...) that have been already done for the protons.

2

So, "phenomenological quantum gravity" is the particular field where we consider experimental tests of quantum gravity (with the hopes of winnowing the 3 dozen competing theories down to a handfull). To the best of my knowledge, Giovanni Amelino-Camelia pioneered the field (c.f., Amelino-Camelia's review article). At any rate, when focusing on loop quantum ...

2

Please correct me if I'm wrong, but I thought that no one had been able to show how General Relativity (GR) emerged from LQG in the semi classical limit ? In this context, it may make sense to ask for experimental manifestations but to me it would seem more important to make sure first that LQG gives in some limit a classical theory of gravitation before ...

3

My intuition is that creating H gas in the lab is very hard (as opposed to H$_2$ gas). Not at all; any sufficiently hot hydrogen plasma will have a greater abundance of H than of H$_2$. To see why this is so, it is sufficient to consider the energies of the molecular bond relative to the ionization energy. The energy of the bond in a hydrogen molecule ...

1

the reason for enclosing the gold leaf in a container is simply that gold leaf is exceedingly delicate. The container protects the gold leaf from air currents that would otherwise move the gold leaves or even tear them. The exact nature of the container isn't important, and any container would work, though obviously we need it to be transparent so we can ...

2

As noted in the comments, weight must be evenly distributed or the washing machine will spin off center and shut down. Clothes are a lot of small pieces. When spinning starts, they fly to the outside. Usually they are uniformly distributed. A duvet is a single large piece. It is easy for it to be off center. For example, if you wrap it around the ...

4

Here is an experiment trying to limit dark energy theories which predict detectable interactions with matter: If dark energy --- which drives the accelerated expansion of the universe --- consists of a light scalar field, it might be detectable as a "fifth force" between normal-matter objects, in potential conflict with precision tests of gravity. ...

8

If there are enough data and the prior is not completely unreasonable, the frequentist and the Bayesian approach give essentially the same answer. This is related to the central limit theorem. If data are fairly scarce, the two approaches may differ a lot. In this case the Bayesian approach is far preferable but only if the prior reflects true prior ...

1

Imagine that the sended electron interacts with the surface electrons from the slits edges. Together they form a quantized electric field. This field is not static in the sence that the position of the incoming electron is slightly different and the surface electrons are not standing still. The incoming electrons get deflected from the surface electrons (or ...

16

Yes, the interference pattern will occur, although you'll have to wait a while to be able to see it. As long as the average arrival time between photons is markedly greater than the travel time from slit to detector, the actual rates don't matter - each photon interacts with the slits by itself. This URL shows such an experiment, in which a laser beam was ...

1

To quote from Will's book (Theory and Experiment in Gravitational Physics, Rev. Ed., Cambridge, 1993), "[...] in almost all experiments discussed in this book, the observable effects of torsion are negligible". Will then mentions a counterexample (Ni, Phys. Rev. D 19, 2260 (1979)), but that example is a specific theory in which torsion propagates and ...

0

Yes, the electron is discribed not by a path, like a macroscopic object, but by a wavefunction. And if an undisturbed electron (we better say an undisturbed wavefuction associated with an electron) goes through the slit it, just like a normal wave, interferes with itself, producing an interference pattern that will become visible if you only wait long ...

3

Yes,you will see the interference pattern,time doesnt matter if the conditions are same. If you send one electron it will hit particular point on the screen,you cannot predict where it will hit,but ofcourse you can predict the probability of hitting a particular point. after many days,most of the electrons will hit the most probable regions and few hit ...

0

The answer depends very much on the white light and you will always get some coupling. In general the coupling is very low, simply by the second law of thermodynamics applied to the phase space of light: it becomes the law of increase of Optical Grasp (oka Étendue). Light at one wavelength in a one moded optical fiber at one wavelength is essentially zero ...

0

a need for coupling a white light into a SM fibre had just emerged to me. I remembered vaguely, that there is probably no better means to couple extended source, than stupid butt-coupling. So I took one FT030 SM fiber patchcord and simply put one end near to cellphone photo illumination LED, and some amount (exceptionally high to my poor expectations) passed ...

1

The absolute cheapest thing could be to wire a variable resistor in series to try to get the discharge voltage down: it's possible that you could reach a regime where you're only ionizing some of the gases in the air, without melting the resistor. Since ozone's "badness" comes from being hyper-reactive you might be able to remove it chemically by putting ...

1

This may be cheating - but ozone is generated by the interaction of the high voltage discharges and the oxygen in the air. Why not flush the system with nitrogen - if there is no oxygen, no ozone will be produced. And a few mL per minute is not a lot of nitrogen. A 70 L bottle of nitrogen at 200 bar should expand into 14000 liter of nitrogen at STP - at 3 ...

2

Experiments with trapped ions generally use fluorescence for detecting the ions. This means that they use a strongish pump to take the ion from its ground state to a dipole-allowed excited state and wait for the ion to decay by emitting a photon in a random direction, and then re-run the cycle over and over. This means that each ion essentially emits one ...

0

There's various pictures on the internet of the double-slit experiment with electrons. Some of them are badly misleading because they show the electrons passing through the slits as dots. They aren't dots, because the electron's field is what it is. It's quantum field theory, not quantum point-particle theory. And that field doesn't stop one micron from the ...

0

A performed in 1940 experiment contradicts the above calculations. H. Boersch get the deflection of 34 ekV-electrons on an edge. The lateral dimension of the beam was 140 Å, the distance to the edge 0,35 mm and the distance to the observation screen was 330 mm and the distance between maxima about 20 μm. Source: Die Naturwissenschaften, Heft 44/45 1940 ...

4

The interference pattern comes from the calculated wavefunction phase difference at a specific position of the detector. Every interaction of a particle along its paths (whether they are real/collapsed or virtual/calculated) would randomly bring a phase difference to the calculated wavefunction, therefore its coherence would be quickly destroyed as the ...

4

I'd like to expand my earlier comment into a little essay on the severe practical difficulties in performing the suggested experiment. I'm going to start my asserting that we don't care if the experiment is a "two-slit" per se. It is sufficient that it is a diffractive scattering experiment of some kind. However, we do care about having spacial ...

-1

As the comments have stated, you cannot do this experiment, because (1) the particle is wavelike when passing thru the slits, and (2) the cloud path only happens because a particle's wavefunc "collapses" the moment it interacts with the junk in the cloud chamber that causes the path to appear in the first place. You might as well ask how to measure the ...

0

I'm not so sure about the atom trap though. But I do have a cheaper alternative for your flexible plastic membrane: You can transfer Rotation Force into your "clean" chamber with the use of Magnet. This can be done by attaching a Magnet outside the chamber and another Inside the Chamber. Rotating the Outer Magnet will rotate the Inner Magnet. Depends on ...

-1

On January 24th, 2013 Mike W. (with help from Lee H) from the University of Illinois at Urbana-Champaign performed a thought experiment in which they sent a particle through a double slit in a bubble chamber. When the bubbles were smaller than the slit, no interference pattern occurred. For closer slits and larger bubbles, the results were inconclusive.

1

There are lots of tried and tested methods for visualising flows, for example mica or aluminium flakes though these tend to settle fairly quickly. In days gone by I used zirconium phosphate that had been delaminated by titrating with tetramethyl ammonia. This gives very thin flakes that are stable to sedimentation for a day or so, though you have to prepare ...

Top 50 recent answers are included