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exchemist last won the day on April 4

exchemist had the most liked content!

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About exchemist

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    Rowing, choral singing, walking.
  • College Major/Degree
    Chemistry MA, Oxford
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  • Biography
    Trained as a patent agent, then gave it up and worked for Shell, in the lubricants business for 33 years. Widowed, with one teenage son.
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  1. I think this idea - that the sum of gravitational, mass energy and other energy in the cosmos equates to zero - has been around for quite a long time. I seem to recall reading about it over ten years ago. The thing I always struggle to keep in mind is that energy is not an entity, but merely a property of a physical system of some kind. So if you have no system, there can't be any energy. Presumably in this model the physical system of the cosmos came into existence - somehow or other - with a net zero of energy, which then became divided between -ve gravitational energy and +ve energy i
  2. I had to look up the Armstrong Limit, so I've learnt something as a result of your post. So thanks for that. 🙂 But this limit is, specifically, the pressure at which water, not any other liquid, boils at 37C, which is the temperature of the human body. The relevance of the Armstrong Limit is solely to do with the survival of human beings at high altitude without a pressure suit. It does not tell you anything about other fluids, or about boiling at other temperatures. Also, you get no energy from something boiling. You have to put energy in, in order to make it boil, because the Late
  3. Excellent! I see this company does this sort of thing in general. Good for them - makes a change to treat your customers, or potential customers, as if they can think. Respect!
  4. Cities are attractive, especially to young people, because of the variety they offer and the social life. If you are not sure yet what you want to spend your life doing, the city offers you the chance to try one thing and change if you find something better. Also it offers you the chance to meet more people like yourself, or more people who are very different, if that's what you are looking for. And it offers a variety of entertainment. Rural life, all too often, has very few types of job available, very few like-minded people to socialise with, and nowhere to go for fun. QED. Of cour
  5. I'm not entirely sure I follow all this. But as a rule city housing is expensive because the land it stands on is expensive, due to its location - in the city. People want to live in cities, so demand is high and prices rise in response. What your question comes down to, it seems to me, is why it is that people want so much to live in cities. It is partly the variety of jobs available - many of them well-paid - and partly the amenities of cities, I guess: the bars, cafes and restaurants, the entertainment, the night life, the culture (theatres, concert halls, museums, art galleries) etc.
  6. Your belief in purpose is not a scientific belief, so you won't get much help from asking about purpose in a science thread. What is the "purpose" of a shark? Or a mosquito? It makes little sense, scientifically, to ask such a question. There is no "evolutionary intention". Evolution favours traits that permit reproduction, and traits that do that will depend on the environment the organism is in. And that's about it, really. Religion may consider Mankind has a purpose, but this is not an idea that is supported by science. Not quite. Evolution preferentially selects fea
  7. Perhaps if you could explain a bit about the route that you have seen described as "associatively dissociative, we could suggest an alternative description that does not seem so self-contradictory. I tried googling this term in relation to fuel cells and could not find it. The closest thing I found was something about dissociative adsorption of oxygen.
  8. Something in that. I recall reading an article about the psychology of conspiracy theorists which said it was a general mindset rather than a fixation on one topic. Believers in one thus tend to go in for many. It may the same with cold fusion: people who just want conventional science to be wrong, for reasons of their own, or who want there to be an easy source of energy - and they latch onto cold fusion. But it seems to be quite a little cottage industry, with groups all over the place, conferences, and even this "E-CAT" bloke Andrea Rossi (who I think may have actually done time for fr
  9. What the article does not touch on is that cold fusion has spawned a "zombie science" that continues to this day. If you google LENR (for low energy nuclear reaction), you will get pages of references to groups, self-published papers and even conferences that continue to tend the flame of Fleischmann and Pons, in the hope of limitless cheap energy. It seems impossible to kill this off - and I suppose we should not worry too much. Time will eventually do that if, as seems certain, there is nothing in the idea. But I find myself wondering if it was always like this with dead ends in science
  10. You mean, neither claims to heal physical ailments, I presume. Yes, I think that's right. Or is that not what you mean?
  11. I think a distinction can be drawn between religion and pseudoscience. Astrology and crystal healing are pseudoscience, in that they make claims about observable physical phenomena, based on theories for which there is no evidence and which conflict with science. Attacking pseudoscience is fair enough, I would say, for anyone with a scientific education. Religion, at least in its more reasonable manifestations, is something different from pseudoscience. It is mainly a guide for living one's life, inspired by stories and ideas that don't make testable physical claims. However one can cer
  12. Haven't we just had an economic crash, bigger than anything in the last 300 years? That seems to be what the papers have been telling us.
  13. Thanks for the link to the paper, which satisfies my curiosity. Agree we should not pursue the topic of H bonds further here, interesting though I find it.
  14. Yes, I agree, I don't think I would expect bore width to affect pitch. As I understand it, that will be a function of tube length, as you say. What the article I linked seems to say is that width affects the degree to which various harmonics are excited, which alters the character of the tone rather than its pitch.
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