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Everything posted by exchemist

  1. I presume you mean rate of precipitation. Rates of reaction in solution depend on various factors in addition to the reactants involved, notably concentration and temperature. So I don't think it is possible to answer your question. But @John Cuthber may be able to provide some examples of reactions in which a product precipitates rapidly. My inorganic chemistry is too rusty for me to able to do that without looking things up. Though, as I recall, BaSO4 precipitates quickly from mixing suitable solutions e.g. BaCL2 and Na2SO4.
  2. Not sure. He seems to have fizzled out. He does seem to have a special knack of quarrelling with just about everyone, eventually. But now that Philip E Johnson, the lawyer who founded the ID movement in the USA, has died, I think all those guys will soon be looking for other things to do.
  3. Haha, yes could be. But I suspect it may be one of these creationist "seagulls" that I've encountered before. At one time William Dembski ran a course, at some Baptist university in the Southern USA, in which he awarded points to students on one module of the course for signing up to science sites and attacking evolution. Normally there would be a flurry of posts for 24-48hrs - and then radio silence. The posts varied in inanity. But the idea of it not being possible for order to emerge spontaneously cropped up quit a bit. Dembski is history now (he got sacked), but maybe someone else is doing something similar.
  4. Not if you understand the principle of natural selection. But from your short posting history here (not to mention your choice of user name), my guess is you will sidestep what natural selection says and come up with non-analogies like "tornadoes in junkyards". If you continue to post at all, that is. I will content myself with pointing out that the order in an open system can increase by purely natural processes, so long as entropy (or disorder) is increased elsewhere. This happens all the time in nature. So "garbage in garbage out" is not applicable.
  5. I found this on Wiki: Another size and format was that of radio transcription discs beginning in the 1940s. These records were usually vinyl, 33 rpm, and 16 inches in diameter. No home record player could accommodate such large records, and they were used mainly by radio stations. They were on average 15 minutes per side and contained several songs or radio program material. These records became less common in the United States when tape recorders began being used for radio transcriptions around 1949. In the UK, analog discs continued to be the preferred medium for the licence of BBC transcriptions to overseas broadcasters until the use of CDs became a practical alternative. From: https://en.wikipedia.org/wiki/Phonograph_record#78_rpm_disc_sizes
  6. You've already done this, haven't you, 8 years ago? What do you hope to gain by repeating it?
  7. I think that will be because of where volcanism occurs. Volcanism arises in three types of location: - spreading centres, such as mid-ocean ridges, - subduction zones, such as island arcs - mid-plate hot spots Whereas for hydrocarbon deposits one needs a sedimentary location that has not been subject to subduction or intense heating for several tens of millions of years. Subduction zones and spreading centre, where crust is turning over or being newly formed, thus seem very unlikely to be places where hydrocarbons can accumulate. In principle one could get a new hot spot, from time to time, in the middle of a plate carrying continental crust, which might contain hydrocarbons. But the chance of that is pretty small, I'd have thought. Other way round surely? Magma originates in zone of partial melting in the upper mantle or lower crust, whereas hydrocarbons form from living organisms on the surface that have become buried, in sedimentary formations.
  8. If you were to confine yourself to discussing the historical evidence, as I am trying to do, there would be no problem. Personal opinions on Christianity as a whole, however, have no bearing on historical evidence. That distinction does not seem confusing to me.
  9. The historian, however, will consider the evidence of the sources. As in science, proof is not to be expected, but evidence that is consistent can suggest what may have occurred. So far as I am aware, there is no evidence that Saul of Tarsus was an invention, whereas there seems to be evidence from more than one source for his historical existence. Enough to persuade non-Christian (ex-Christian) historians like MacCulloch, at any rate. In a thread about Jesus, this about St. Paul is a bit of a side-issue, admittedly, but perhaps for him too, one needs to distinguish evidence from personal prejudices. Where Jesus is concerned, MacCulloch seems to think the main evidence for Jesus as a historical person comes from his preaching style as reported in the gospels, which he seems to find highly idiosyncratic: the use of parables, the repeated use of the enigmatic phrase "Son of Man" and so on. He feels like a real person. But MacCulloch seems more non-committal about Jesus than about Paul, whom he confidently describes as a businessman (in fact a tent-maker) from Tarsus.
  10. Agreed. A fascinating book. I'd also nominate Martin Brasier's "Darwin's Lost World". This is a readable, first hand account of palaeontological research into the development of preCambrian life, i.e. the mysterious stage before things had hard parts that fossilise well. It introduced me to the enigmatic Ediacaran fauna and insights such as as the impact on life of the coming of the mouth.
  11. I can't immediately see what this has to do with the issue of the probable first language of Saul of Tarsus, a.k.a. St. Paul. Do you simply mean you decided long ago that Christianity is bunk and that therefore none of the dramatis personae, St. Paul included, can be based on real historical figures?
  12. He does not give any references. It just seems to be generally understood. If there were much doubt about it, I would expect MacCulloch to indicate that. I presume it is because Paul came from Tarsus, in modern day Turkey, which like most of the Eastern Med. spoke Greek at the time. (According to MacCulloch there was already a centuries old diaspora of Jews around the region.)
  13. No, this is also as stated in Diarmaid MacCulloch's "A History of Christianity", MacCulloch being Professor of Church History at Oxford.
  14. Surely that cannot be right. If the metric itself expands, it must affect everything in the cosmos, mustn't it? Obviously in a bound system all that would happen is the dimensions stretch a bit locally, i.e. not enough to materially alter its configuration. But I can't see how anything can be exempt from a change in the metric. The metric defines the unit of length itself, doesn't it?
  15. Are you sure about that? I should have thought that if the metric itself expands, then the dimensions of everything must do so, though the change for points close together would be very small.
  16. St Paul (Saul of Tarsus) was a Roman citizen and travelled extensively in the Eastern Med. According to the Wiki entry on him, Koine Greek was probably his first language, even though he was a Jew. https://en.wikipedia.org/wiki/Paul_the_Apostle. This lists what sources we have for his life. There seems no particular reason to doubt that he was a real person.
  17. Hmm, do you mean that a glass prism gains mass if you shine a light through it? I struggle to see how that would work, I must admit. Unless..........you mean that the coupling of the radiation to the medium "lends" some of its energy to it as it passes through, which I guess it does if its refractive index deviates from unity.
  18. Surely St. Paul wrote in Greek because he was not writing to Aramaic-speaking Jews, but to people in and around Asia Minor (Colossians, Ephesians, Galatians, Corinthians, Thessalonians etc.) who spoke Greek, it being the end of the Hellenistic period in the Eastern Med.
  19. Sort of, ish. Light is not energy of course: it has energy (E=pc = νλ), which can be added to that of an entity that absorbs it, which will then gain mass according to E=mc².
  20. Sure. My interest in the issue was merely that I often, when explaining E=mc² to lay people, use the example of charging and discharging a battery, to show that the formula says mass and energy go hand in hand, rather one being converted into the other, which is what the uninitiated frequently seem to think, probably due to the association of Einstein's formula with the mass defect in nuclear fission. And then it struck me suddenly that, while it may seem comprehensible that an object with mass, like a battery, may in theory gain or lose a tiny amount of mass, it is less obvious what happens to something nebulous and apparently massless, like the magnetic field of a solenoid when it is energised. So I wanted to make sure my way of explaining it covered that case as well.
  21. Oh I see what you mean. But as there isn't really a classical picture of covalent bonding in chemistry, it's a tiny bit artificial.
  22. Not sure that's a great example, as elemental silicon has a giant covalent structure, in which the bonding involves electrons in motion in orbitals shared between atoms, but no doubt one could consider changes to a purely ionic structure that would alter the energy of the lattice and thus its mass. So I do take your point.
  23. No indeed. My question was far more basic, simply whether a static electric or magnetic field has mass as a consequence of its stored energy. I realise now that my question was at one level a bit stupid, since if a battery gains mass when charged (albeit to an unmeasurably small degree ), it means the energy in the chemical bonding goes up and gains mass - and the energy of that bonding is a sum of the electrostatic potential and kinetic energy of the electrons. So it seems to me now that a static field must indeed have an associated mass, even though this feels unintuitive when one thinks of the magnetic field of a solenoid for example. Also, from the other (very interesting) replies, it dawns on me that I should not find this idea of fields having mass unintuitive, since (as I understand it, very vaguely) fundamental particles are considered in QED to be excitations of a field. I probably need to let go of this rather 6th form idea of mass applying to things called "particles" of matter, as distinct from insubstantial things called "fields". You are psychic! I was just replying. (I was out most of yesterday.) There is some excellent food for thought in this thread and I'm glad I left it long enough for those replies to come in before responding.
  24. Responding today to the thread in Speculations, it struck me I don't know how to treat the stored energy in a static EM field, according to E² = (mc²)² + p²c². Since, unlike the situation with EM radiation, there is no motion involved, I presume the second term does not apply. But does a static field gain rest mass, as its stored energy increases? Seems weird if true. I've a feeling I'm missing something here. Can anyone help?
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