Jump to content

John Cuthber

Resident Experts
  • Content Count

    16967
  • Joined

  • Last visited

  • Days Won

    26

Everything posted by John Cuthber

  1. OK, that seems to be a picture of a female; how do we know it's you? Mind you, since I'm a Martian I think the annonymity of the internet is very useful. You earthlings seem very prejudiced about those of us with green skin.
  2. Since the ancient Romans didn't have soap but did have a warm climate I'm not sure they would have noticed the after effect of using spoiled urne as a detergent. Lots of perfume was probably a good idea.
  3. I think the only way to conclusively prove it would be to get a large un-exposed population, inoculate half of them with HIV and see who went on to develop aids. I don't think it's weird that nobody has done that experiment, so I don't think it's weird that there's no conclusive evidence. Biology seldom produces strictly conclusive evidence. Everyone knows that smoking is bad for you but we have all heard of people who smoked for decades yet lived to grand old ages. Biology is awkward that way.
  4. It's a lot easier to make 2 lenses that are both reasonably powerfull than to make 1 that's very powerful. Combining the 2 easy lenses gives the same magnification with less hassle.
  5. I too didn't do a lot of homework but did OK in exams- perhaps I'm a genius perhaps I'm just lucky. The difference is that I also didn't ask my friendsto do my homework for me; not because they wouldn't have helped, but because I could have done it perfectly adequately myself. This guy seems to be asking us to do it because he hasn't a clue. I didn't do my homework because I knew that I understood the stuff and would do OK in the tests so why bother to waste my time going over it in my own time. That's a really important difference.
  6. Never mind CO poisoning. Explain what you mean by "It is possible to model the cell in terms of one variable, i.e., hydrogen bonding. " Trust me, the lack of experimental data isn't the real issue here as far as I can see; it's the fact that you don't seem able to explain what you are on about.
  7. If I ask the same question a 3rd time will you get the message and answer it? What does this mean? "It is possible to model the cell in terms of one variable, i.e., hydrogen bonding."
  8. I'm sorry that I can't think of a way to express this that doesn't sound like I'm being dismissive of the idea and condescending; that's not my intention but I have to ask; Do monkeys have regional accents? If they do then you might not be looking at the effect of captivity, just the fact that they didn't sound like each other. Even if you can't be certain of the reason for any difference between the vocalisations of the 2 groups then it's still a valid piece of research to see if such a difference exists.
  9. The earth has 2 different diameters (polar and equatorial), presumably they can't both fit. Ever heard of an annular eclipse? It's what you get when the moon doesn't appear to be the same size as the sun. Not as pretty as a total eclipse, but here are some pictures anyway. http://www.clocktower.demon.co.uk/eclipse2003/ No great shock that it happens, the earth's orbit is not circular. "Swansont's question "What happens to your mystical numbers if you use Fahrenheit?" is a good one. OK the Rankine (sp?) scale uses Fahrenheit degrees above absolute zero in the same way the Kelvin scale uses celsius degrees above zero. The boiling point of water is 671.7 and the freezing point is 491.7 The difference is 180 and the ratio is 2.73 to 1 again. (well it is if I got the maths right). It's true that the ratio of the difference between two temperatures to the lower one will stay the same when you change units in this way. Ratios are like that. Anyway, the more important problem is that the temperatures are by no means fixed. The freezing point of water falls slightly when pressure is applied (about 1/100 degrees per atmosphere pressure). On the other hand the boiling point rises quite quickly with pressure. So this "magical" ratio only works at exactly 760mmHg. Most of the time where I live the pressure is rather lower than that. I could move to somewhere like the dead sea and then it would be higher. That ratio only works (so far as it does) at sea level. There's the killer, like the moon's apparent size, sea level varies. Sorry Typiko Abdul, but if you want to base a new theory of the origin of life on the magical properties of some number, make sure it's a constant otherwise your reason for life disappears every time the weather changes.
  10. What does this mean? "It is possible to model the cell in terms of one variable, i.e., hydrogen bonding."
  11. Steam engines ran on water too, but I don't think many people would have overlooked the need for fuel as well.
  12. What does this mean? "It is possible to model the cell in terms of one variable, i.e., hydrogen bonding." I suspect the answer is no because cells are really very complicated. I also think that most of the species he has talked about like H2O, OH- Cl- and so on are non-magnetic. And, I think the idea of electrons in nice circular orbits at 1/14 C are a rather simplistic way to think about orbitals in atoms and molecules.
  13. "Can you use sound of any frequency or amplitude for example to induce a chemical reaction?" Yes, it's called sonochemistry.
  14. "One needs to look at the tetrahedral system as a specialty tool." One thing this tool seems unable to do is answer the equation I posted earlier, i.e. to find a square root of minus 1. Since that's the thread's topic, this failing wouuld seem to be pretty catastrophic. "If we assume a type of symbolic parallel between God and reality" I have a better (or at least, more scientific) idea, lets' not make totally unjustified assumptions about the existence of God, the accuracy of the trinity and the idea that Western religion has got the will of God right, even if He does exist.
  15. Look at the original post. It says " Idefined a vacuum to be 'the elimination of space between particles.' " The point I was making is that a vacuum is more or less the complete oposite of that. It is what you get when you eliminate (to a greater or lesser extent) the particles from the space. Let's make this clear; every post I made in this thread has stated that the vacuua that people talk about are not, and cannot be, absolute; they are always partial. So what's the point of telling me that "people who do experimental physics talk about vacuums all the time, and none of them are discussing regions completely devoid of matter"? It certainly doesn't detract from the fact that the deffinition given in the OP is odd, to say the least.
  16. Bacterial dedgradation of urea (present in urine) will give ammonia. Ammonia is alkaline enought to disolve fats so it can be used as a cleaning agent. After using this detergent you would need to rinse the cloth very thoroughly.
  17. Incidentally, when you have finished rewriting all the vector geometry books to make them more difficult, please tell me what will be the value of x that solves the equation x squared plus one equals zero.
  18. "That's one definition of vacuum, and I already stated I wasn't using that one." Thanks Swansont, but I was actually thinking about the original poster who started talking about particles in a vacuum. Anyway, its not so much one definition of vacuum, it's essentially the definition of vacuum, for example here's Wiki's version "A vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than standard atmospheric pressure. The root of the word vacuum is the Latin adjective vacuus which means "empty," but space can never be perfectly empty"
  19. The thing about particles in a vacuum is that there aren't any. OK QM makes that impossible in theory and real life makes it impossible in practice, but the idea of a vacuum is that it's a space where there are no particles.
  20. I'm noot sure but I think he means use 4 coordinates. Take a point in the middle of a tetrahedron and draw lines to each of the points.You get something that looks like a caltrop http://en.wikipedia.org/wiki/Caltrop label the 4 points a,b,c,and d. Now you can say that the vector corresponding to -a is composed of b+c+d (with some constant, possibly even 1, to account for scaling. I don't doubt that this coordinate system could be used, but I'd much rather use 3 orthogonal ones. The "resolution of forces" in mechanics would be ugly, to say the least, in this system.
  21. Well, I got in without doing the entrance exams. I'm not sure if the system still allows students to get offered a place on the basis of an interview and the school's recomendation (and, technically, the matriculation requirement of 2 "A" level grade E or better and "O" level English). One thing to think about is that, unlike most universities, it's a 4 year course. Great if you like it but an extra year of slog if you don't. I gather that they have the biggest chem dept in Western Europe (it was only the biggest in the UK when I was there) so they must be doing something right. This http://www.ousu.org/content/index.php?page=4801 will tell you some things that the official guides leave out. (ousu is the student's union there). I had a great time there and I hope that, wherever you choose to study, you do too.
  22. You can't talk about difference with only one example (a glass ball or whatever). That's the basis of the joke about the duck. Difference between what and what?
  23. The traditional aproach is a water jet type aspirator. Cheap, easy and almost impossible to kill.
  24. Last tme I checked, tetralin had 3 double bonds. http://en.wikipedia.org/wiki/Tetralin You might want to look at the decalins. What's the aplication you are looking at?
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.