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Showing content with the highest reputation on 08/28/20 in all areas

  1. Exciting update! IDoNotCare had now been permanently banned for similar offences.
    2 points
  2. Really ? You guys are arguing about her use of the English language ? Aside from the fact that she is not a native English speaker, the word best is singular. There is only one 'best', and there is no differentiation between 'the best' and 'best'. In both cases it is the one that is better than all the rest. This 'tempest in a teapot' is not worth discussing, in comparison to the fact that she 'supports' her husband, which is worth discussing.
    1 point
  3. I am rather amazed that you have spent a decade researching this and you do not understand the difference between basic physics concepts. This is not a vernacular problem, this is a conceptual problem. You should go to a basic physics site and look up the definitions of velocity, acceleration, momentum, force and energy.
    1 point
  4. Did I read it right? You want to sleep 2 hours per day.. ? For how long? (that's silly to be honest) If you want to examine sleep, better get camera with IR, which will be pointing at you during sleeping, and recording your movements, and equipment measuring pulse of heart, and breathing, brain activity etc. etc. If you will be waking up in the wrong stage of sleep, you will be astonishingly tired.. People who known more about this stuff even made smartphone apps which are measuring at which stage user is, and starting alert prior hour and minute alert was set.. Because it is im
    1 point
  5. Worth mentioning that prevention is better than cure. Are you doing this in consultation with a doctor to monitor your health?
    1 point
  6. Both? I was sitting about 2 meters behind the flag, and zoomed in to the maximum. To be sure that the autofocus would not focus on the flag itself instead of the interference pattern, I focused manually, and exposed 2 stops (That is what they call it in Dutch) less than the lighting meter would normally do. And then on the computer I increased contrast, made it even a bit darker, and cropped to the pattern itself, so yes, it is pretty magnified. With my bare eyes I nearly could not see the colours. It was super, everything, everybody. I especially enjoyed the wine: very light, maybe on
    1 point
  7. You're just missing a pair of square brackets.
    1 point
  8. C J Smith was Director of the Physics Laboratory at Kings College, University of London in the mid 20th century. He wrote several important texbooks for the sixth form and undergraduates. This was from the baby of them (mine is 1957) - only one thousand three hundred and thirty two pages -- Intermediate Physics. The undergraduate version runs to 5 volumes. Some of these older books have lots of useful subject matter in them that is no longer commonly taught.
    1 point
  9. I gave +1 because you have identified all the important features of the situation. The difference between heated and not heated The difference between the inerior and surface environments. I was offering a treatment along the lines provided by Prof Smith, along with some additional diagrams and explanations of my own.
    1 point
  10. I think you have a point that the OP's confusion comes from different defining conditions. I hadn't seen that. Evaporation would take place on the surface. Boiling would correspond to the situation when the water is heated (frequently it's from below). But evaporation, as generally understood, doesn't have to be an equilibrium situation: https://www.britannica.com/science/evaporation https://en.wikipedia.org/wiki/Evaporation The equilibrium situation (in my understanding) would correspond to equal amounts of molecules leaving the water than coming back. You need a closed co
    1 point
  11. I agree. +1. I have already stated that there are two separate situations described in the OP. They are thermodynamically and kinetically different. Evaporation is an equilibrium process. Heating to(wards) boiling is not. There is also the fact that liquid molecules at the surface have (on average) more energy than those in the interior, when the liquid is in equilibrium. I takes a specific amount of energy to bring a molecule to the surface. All this is most conveniently illustrated with simple diagrams.
    1 point
  12. If the water could be uniformly heated then we would see the same result of water vapor bubbling through the surface, but if you are excluding boiling from evaporation altogether then I would say it is impossible for evaporation to occur below the level of the water since by definition evaporation requires vaporization and that implies a decrease in density which would result in a bubble if it occurred beneath the surface. The dictionary.com definition of evaporate says "to change from a liquid or solid state into vapor; pass off in vapor", which does not include any qualification of what temp
    1 point
  13. Question: Do molecules below the surface of the liquid evaporate? Your answer: Water molecules below the water level can become gaseous. That explains the bubbling of water vapor through the surface of boiling water. I don't think that explains it, nor does it answer the OP question. Starting with: There is no such a thing as a "gaseous molecule". Bubbles are small domains of gaseous phase that form locally due to fluctuations (little variations of under-density, excess temperature, or both) which, by virtue of their lower density, and helped by convection, make it to the surfac
    1 point
  14. You need to provide that much energy to create the plasma. It is not a source of energy.
    1 point
  15. ! Moderator Note First, without the maths, you don't have a model. Second, we won't be discussing religion-related ANYTHING in a scientific speculation. ! Moderator Note Third, science isn't interested in proof. Science works with theory, which is our best current explanation for various phenomena. Your whole approach is flawed because you think your "answer" is right and now you're trying to "prove" it no matter what, and that's NOT doing science. Belief is based on how trustworthy the explanation is, and the current model p
    1 point
  16. In mathematical terms, Omega is the same to-be-determined variable as in Example 2. In terms of Physics, it is the https://en.wikipedia.org/wiki/Angular_frequency. Example solution for Example 3: If I take x = x0 cos (wt) + v0/w sin (wt) and plug in x(t=0) = 0, then I get the condition x0 cos (0) + v0/w sin(0) = 0. Hence, x0 = 0. The first derivative of the function is dx/dt = w x0 (-sin(wt)) + v0 cos (wt). Plugging in the constraint dx/dt (x=0) = 1 yields w x0 (-sin(0)) + v0 cos (0) = 1. Hence, v0 = 1. The 2nd derivative of the
    1 point
  17. How are these a vibration of the molecule as a whole? Indeed so, did I not say say that the key motion is translation of the whole molecule ? How is this a vibration?
    1 point
  18. Better tell all these people, then. https://phys.org/news/2014-05-molecular-vibrations-hydrogen.html https://www.sciencedaily.com/releases/2014/05/140501142227.htm http://www.schoolphysics.co.uk/age16-19/Wave properties/Wave properties/text/Microwave_ovens/index.html https://www.azonano.com/news.aspx?newsID=36282 http://www.wiredchemist.com/chemistry/instructional/supplemental-material-for-chemistry/chapter-7/animations That last one also describes the most obvious form of vibration, which is also temperature dependent and so, presumably, what the O
    1 point
  19. Conduction will take place as well. But, in a liquid, heat transfer by convection will be much faster.
    1 point
  20. To give an even simpler answer: they get to the surface and then escape! That may be too simple to be useful. But as you add heat from the bottom, it will cause convection which brings those molecules up to the surface. Also, as the fastest molecules at the surface escape, the average kinetic energy of the top layer decreases; in other words it cools and so will sink lower in the container.
    1 point
  21. Something I posted in the 'what are you listening to right now' thread. Edit: Just to note, the above video isn't posted with humour in mind. It just something I thought was appropriate given the thread title, and the fact people were discussing it. Edit 2: really sorry if I've offended anyone with this. I found the film really moving, and I'll admit, fascinating too. I don't think the film is made with bad intentions.
    0 points
  22. Well, I would rather say it is based on what society deems harmful which overlaps only imperfectly with things being harmful. There are plenty of laws that are actually harmful, but were not recognized as such, for example.
    0 points
  23. Disclaimer : This is just a JOKE. If inbreeding was legal in the US, then all states would vote like southern states currently do, and we'd always have Presidents like D Trump. ( who incidentally, has made comments about how sexy his daughter is; creeeepy ! ) That alone should make it illegal as it is detrimental to society. This is serious. Laws are not based on whether they do harm or not. they are based on what society deems acceptable. You can get fined for spitting on a sidewalk, even if there is no one around, and every bar once had a 'spitoon
    0 points
  24. Given that any typical sexual relationship will fail with some degree of lasting animosity, the consequences of such actions in a familial situation would be catastrophic for the wider family. I think that is ample reason for it to be taboo.
    0 points
  25. What is the human form? Should I be able to remember my conception (the human form), would I be able to change form by thinking of that moment and, for example, deciding to become "an alien." Would have to wait for my conception to reach the moment I made that decision? : 0-------->1-------->2 ---------->0-------->1 Would a woman be able to become pregnant by thinking of her conception, and deciding that she was so???
    -1 points
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