Jump to content

John Cuthber

Resident Experts
  • Content Count

    17595
  • Joined

  • Last visited

  • Days Won

    37

Everything posted by John Cuthber

  1. "there are only 3 metals that are naturally ferromagnetic" these 3 are Fe, Ni, Co, Gd and (I'm told) Pu.
  2. "In this span of time, chemical affects should be the dominant affect." Why? It's far to hot for any bonds to form and, until the hydrogen has colapsed into stars waited till they burned down a bit and got fused into the heavier elements, there's only hydrogen. Only one element doesn't give you a lot of scope for chemistry. Essentially no chemistry takes place until planets start to form.
  3. I don't think "a few mil of Alu and then Lead plate " will get you anywhere at all as a neturon shield. I've only got tables of thermal neutron capture cross sections but I don't think that will matter much. I wouldn't want to be hiding behind Al or Pb from a neutron source. The capture probabilities are rather small. A thick layer of water to slow them down then a layer of borax to actually capture them then a layer of more shielding to block the energy released by the capture. A microgram of barium is about 1/130 µmol so about 5 *10^15 atoms. Lets say you get a smoke detector as the ne
  4. Shaddowacct I'm puzzled by some of thepoints you raise. "Religion is about hope, about a better future." That's not a definition I had heard before. I though it was about faith; the antithesis of evidence. The "better future" bit generally kicks in after you are dead- that's remarkably useful in terms of finding dissatisfied customers comming back to complain "Keep your eyes open, do you really think all those old religions have nothing to say?" Not that can't be said more logically by other things. "These old books really have very little useful information?? " OK, what can I really
  5. Sory Shadowacct, but I don't know much about Kim Il sung's regimen. Given the context in which you mentioned it I presume that when the evidence showed that it had problems it was scrapped and replaced. Either that or you seem to have missed my point. Have you read 1984? It is about a state that exists by telling lies- the very antithesis of one based on evaluating the whole of the evidence. It's also one of the most desperately bleak books I have read. If anything it's a point in favour of my belief that an evidence based government would be good by showing what an evidence free world would
  6. Personally I'm an atheist because I prefer to believe the evidence of my own eyes rather than the fairy tales told to me by a man in a dress. I also think that evangelising the message "don't ask me to think for you" is rather less bad than the other evangelisms I have seen. (And I'm not sure it really counts as arrogant) I wouldn't mind the idea of people believing ridiculous things if it didn't impact on me. On the other hand, as I have mentioned elsewhere on this site, I think that these daft beliefs are the pathway to an irrational outlook on life and that bothers me. Accepting th
  7. It seems that if you make sure there's a fire to light the gas you get quite a hazardous effect. http://www.youtube.com/watch?v=QFPedGsqtrs Dear me! did I just cite youtube as a reference?
  8. People don't, as a rule, kill people. In order to get your soldiers to kill the oppositions soldiers its easiest to make believe that they are not killing other humans at all. You need to find some way to label the opposition so that they are, for example, vermin. Then it's not killing people; it's just pest control. A good way to make the "other side" look like vermin is to label them as dirty unbelievers (I accept that labeleing them as dirty believers of the "wrong" faith worked very well for Hitler but the difference between "no faith" and "not our faith" is easilly overlooked). Rel
  9. Well, I may have missed a few things but here's my thoughts. Last time I looked NMR used radio waves to do the spectroscopy. I guess they might be into the microwave region by now so that's a tacit spatial resolution of a centimetre or so. With some clever tricks you can get MRI images with resolutions of a milimetre or so. I thought the half micron that you could get with a laser was hopeless. Half a milimetre is a whole lot worse. It gets even worse still if you think about the signal to noise ratio. In general terms the higher the energy photons you use, the easier it is to see them
  10. Glad to help. (fom the man who has grown Rochellle salt crystals a couple of inches square and 3/8 thick, and has wondered ever since why he bothered)
  11. CPLuke, when you wrote "not neccessarily tre, if we were a simulation you would expect to see certain artifacts of the simulation develop, for instance there might be certain minimums that would defy eplanation, and also simulation "noise" while the theory could never be falsified it could be confirmed." how did you know what the laws of the real universe (in which our universe is a simulation) are? How can you presume to guess about noise in a realm of which you do not, and can not, have any experience. Just a thought but perhaps the limits we see in this world like the Planck time and
  12. Anybody just watched part 2 where he rips into alternative medicine? Anyway, I think Dawkins has a problem with presentation because he takes a stance that society doen't seem to like. He clearly believes (with good evidence- the difference between fundamentalism and science) that homeopathy is total nonsense. When he is talking to someone who believes (probably because they have personal experience) that homeopathy is true he has two choices. He can either come across as an appeaser and say things like "Well it's OK for you to believe that - everyone is entitled..." or he can say what he cl
  13. I like this explanation "if you go straight up you'll just come straight back down again. if your going to fall and miss the earth(which is what an orbit is) then you need to be going really fast to one side." Nicely put.
  14. My understanding of ordinary fly-spray is the it hangs in the air for a while and kills bugs anyway. You don't need a "direct hit" to get a kill. (Though it's more satisfying to squirt the bugs.)
  15. You can often get round this. I doubt that lemurs can fly, but I want to formulate a hypothesis that is positive (not least because proving a negative is "troublesome"). I therefore postulate that a thrown lemur will crash.
  16. Sulphuric acid is a good electrolyte (if rather corrosive). The sulphate ion is very stable and the sulphur all stays in solution. Also, as I answered earlier, washing soda works too. With a good electrolyte like those and reasonable sized electrodes you should be able to see the bubbles of H2 and O2 with a 1.5V cell. A couple of cells should be plenty but, while it's less efficient, using more voltage won't do any harm. Since you don't want AC and using the mains is dangerous anyway I wouldn't recommend it.
  17. What does the "E" stand for in PEM?
  18. Absurd as this sounds I think you need to add more water. Just enough to dissolve most of the solid at room temp. Then warm it up slightly to get the remaining solid into solution. Cool and add the seed crystal (that I forgot to mention earlier)- any speck of the solid. That should give you some crystals. If you let the stuff evaporate slowly you should net nice big crystals.
  19. "I got this to work really well once with tap water a nine volt battery and some wire when I was a kid. For electrodes I basically opened up a couple batteries carefully enough not to break anything" OK so you got a current to flow by using about 7 times the voltage that you need. My idea of " work really well" doesn't include something that inefficient. Think about it, if you only need about 1.2V and you end up using 12V then you are throwing away 90% of the energy. Is adding an electrolyte that difficult?
  20. Someone studying chemistry as the major part of their degree (ie a chemistry major) is not expected to be fully conversant with the subject- that's why they are still studying it so I don't see what Geneks is on about. I think finding a deffinition of linear algebra and seeing how it applies to chemistry might be a good start. I had a look at wiki and it seems to give some good ideas.
  21. Allmee, did you not understand my explanation that this does not, and can not, work?
  22. If you go to university and study biochemistry then it's a safe bet that, while you are there, you will make the sorts of connections that could lead to a research career. Of course, you still need to be good at the subject and you still need to work hard.
  23. Solutions of Rochell's salt are syrupy so you probably have the right stuff. Because these solutions are viscous the process of crystalisation can be rather slow (the molecules have to move through the solution to get to the right places to crystalise). I'd try putting the stuff in the fridge overnight then, when it's cold, taking it and stirring vigorously (classically with a glass rod if you have one).
  24. Trying to do this without an electrolyte will probably give rather disapointing results. While there are impurties in tap water that will make it a better conductor than pure water (which, btw, does conduct but rather badly) there are not many. Bicarbonate of soda would work well but it isn't very soluble. Turning it into the carbonate would improve the solubility. Of course, you could just use washing soda too start with or you could heat the bicarbonate to decompose it. If I didn't have any carbonate I would put a tablespoon full of bicarbonate in a teacup and add boiling water fairly sl
×
×
  • 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.