# Tag Info

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The light emitted from the electron stream comes from nitrogen and oxygen molecules. Green is mostly from oxygen. The negative electrons are pulled strongly enough by the positively charged anode that they whack the electrons in the O2 and N2 molecules, putting them into higher energy states or knocking them free of the molecule. In a short time, seconds ...

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The LHC is a discovery machine, and a lot of phenomenologists have worked hard to make predictions from various models , some of them using mainstream theories, some of them not. Searching on the net I found this preprint which proposes checking the data for such signatures: The existence of the dark matter with amount about five times the ordinary ...

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Notice the "Air at very low pressure"? That thin air is what glows. And it has to be very thin or it disrupts the "ray" nature of the phenomena. I'm not sure what exactly was glowing in the earliest experiments, but it might well be the $\mathrm{N}_2$. Later it was normal to put some mercury in the tubes because it works really well. In fact, that is what ...

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The curvature of the universe can be derived from the temperature fluctuations in the Cosmic Microwave Background. For a given amount of radiation, baryons, dark matter and dark energy in the universe, these temperature fluctuations can be calculated theoretically, and compared with observations, and so one searches for the values that yield the ...

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There is no universal, cheap, easy way to do identify unknown materials. There are some easy methods that apply to some materials: if something is attracted to a magnet then it is ferromagnetic, and probably contains a substantial amount of iron, nickel, or cobalt. There are a few other rules of thumb, but the general problem is complex and is the reason ...

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Well, the fancy experimental way would be to use things like mass spectrometry or x-ray diffraction, or many other techniques. Doing it without those machines though... maybe chemistry would be your best bet. If you had a suspicion of what the material might be, you could use known chemical reactions to see what it does and doesn't react with, what it ...

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Bernoulli to the rescue! Does this answer the question? Keep in mind, hurricane speeds are often twice small aircraft stall speeds, and typical aircraft wing loading is in the range of $50 kg/m^2$, so a roof could see 4 times that. Roofing material would have to be really heavy not to be lifted by that.

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Refer Bernoulli's Theorem. Watch this video for demonstration http://dornsife.usc.edu/labs/lecture-support-lab/wind-storm/. Brief explanation: When the velocity of the wind is great enough, the air pressure above the surface is lower compared to that underneath. This cause the roof to blow off. The aeroplane work in the same principle (lower pressure on top ...

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It's been a decade since I last used an SEM, but back then you would start using a fast scan that was real time i.e. you could move the sample around, change focus, etc and see the effect in real time. However the realtime image is noisy because the numbers of electrons being captured is small. Once you had the picture you wanted you would record them image ...

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Pressure is force per unit area, yes, but it also represents the difference in kinetic energy density across a surface - only the energy of random motion of particles, though not large-scale coherent motion like wind. Accordingly, the faster a fluid moves, the more of its kinetic energy goes into large-scale motion, and the less is left for random motion of ...

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Scalar fields do transfer momentum in classical physics. Just take a look at acoustic signals in a gas. A strong sound can cause your windows to rattle. A well known example of energy transference by means of sound (pressure waves) is demonstrated with tuning forks. Quantum theory speaks of sound as particles (phonons), the discrete quanta of quantized ...

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The way I have heard it explained is not by the container but the water drops themselves. Statistically there is no way you can get a perfectly neutral water drop every single time. Eventually you will get a drop with a charge of 0.000000001 Farads. This tiny imbalance is enough to set the experiment in motion into a positive feedback system. You can think ...

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You might be looking for the tautochrone curve (found by Huygens). The corresponding surface is not an "inclined plane", which might explain the difficulty in googling it.

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I don't know if you have already solved the problem, but the same think happened to me when I ran the experiment. It turned out that whenever using a 90Sr source, you actually have a 90Sr/90Y radioactive source and they both undergo beta decay, but with different energies (2.28 MeV and 0.546 MeV). So for short distances you have the sum of the two spectra ...

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Physics presupposes Mathematics. So any "Final Theory of Physics" would also need to presuppose Mathematics for it to have efficacy. Therefore, because this 'Final Theory must presuppose Mathematics, it cannot prove (or disprove) the validity of Mathematics. Likewise, Mathematics presuppose the validity of Logic, so Mathematics cannot therefore prove (or ...

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This is similar, but not quite identical to Newton's cradle, with the difference being the heavy objects placed on the middle coins. To explain things, first consider the simpler case where there is no heavy object on top of the coins, and suppose the 5 nonmoving coins in "frame 1" are separated by a distance $L$. When two objects of mass $m$ and ...

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We know what the solar neutrino spectrum looks like from direct measurement (Super-K has even imaged the sun in neutrinos). Likewise we know what the spectrum of neutrinos coming from cosimc ray interactions in the atmosphere and the body of the early looks like. And the spectrum for our nuclear reactors and that from the uranium and thorium in the deep ...

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A way to get long-range interactions in cold atoms is to use polar molecules, which is a rapidly growing field in the cold atoms community.

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