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John Cuthber

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Posts posted by John Cuthber

  1. Butter shouldn't have a lot of water in it, a "Butter flavored spread" or margarine might.... thinking back to way back when, when we did the compulsory 6 weeks of home ec. in school, I think we were told to use a double boiler for melting butter/marge.

     

    Butter is typically 80% fat and a lot of the rest is water. Since that water will expand over a thousandfold when it boils...

  2. Al will certainly react with water- quite vigorously. Normally it doesn't because there's a layer of oxide in the way. The CuCl (I bet that should be CuCl2) disrupts this layer.

    Mercury does an even better job- but is rather more toxic so it's not generally done as a school experiment.

    The true story is a whole mess of equilibria between hydrated Al+++ species and Cl-.

  3. Whatever rules the US may cuurently have for choosing their president, as far as I can see, it makes no difference to my answer to DoG's question

    Q "Why should the President be the result of a popularity contest decided by a poorly informed public? "

    A "Last time I checked, that was called democracy".

    Whether or not it is, according to some strict deffinition, democracy isn't important. I didn't say it was. I said it was called democracy.

     

    One could take the view that, if the rules say he has to be an American, but the people voted him in anyway, the rules are wrong.

  4. So you'd be okay with an American running for your Prime Minister?

     

    If so I applaud your consistency but I don't think the majority of your fellow countrymen would agree. At any rate it's a moot point -- it's written into the constitution, so we can't elect an outsider even if we want to.

     

    I'd be perfectly happy with an American as PM. I'm not sure if our rules permit it but that's not important, we could alsways change the rules.

    I agreee that not all my countrymen (and countrywomen and those from the other 3 countries involved) would accept it so it's not going to happen any time soon but that's democracy for you. What the people want they get (Doesn't always work of course, but that's the idea).

     

    At the moment, the PM is not actually from my country, it doesn't bother me at all.

  5. Why? The President is NOT a representative, he/she is the executive. Why should the President be the result of a popularity contest decided by a poorly informed public?

     

    Last time I checked, that was called democracy

    Anyway, I must be missing something here. Who cares if he's from Mars? He was voted in.

  6. So far ineligable is joint leader with Obama.

    I wonder if you thought about putting in the option "don't care anymore just get the thing over and done with" for the roughly 95% of the world's population who don't live in the US?

  7. The use of commas and dots is a matter of convention, and there are two conventions. Mathematically, the dot is used to denote scaler multiplication and the stop is generally used to indicate decimals but there's a fair argument that it should be a dot too. (one's further up than the other and you only usually get the stop on a keyboard.)

     

    On a related note, Avogadro has a capital A and "it's" has an apostrophe.

    None of this makes any difference to the chemistry (not chemestry).

  8. I don't think you can get magnetic waves without an electric effect too.

    Also, the fastest you can get something moving with a jet of air is the sopeed of the molecules in that air- roughly the speed of sound. So you end up with a tangential velocity of roughly mach 1. The frequency that gives rise to is about the same as a musical wind or woodwind isntrument the same size as the rotor. For a rotor about an inch caross you would have freqencies comparable with a dog-whistle i.e. a few tens of KHz. This isn't going to give a very high frequency unless the devide is very small, then it won't generate much radiation.

  9. Big 314MP, thanks for the paper. I think the bit I was looking for is this

    "To explain the existence of these cracks Kapitza made the suggestion that in solidifying, bismuth, which normally has a rhombohedral structure, passes through a cubic modification. The bismuth must then change structure while solid, and it would be conceivable that the strains resulting from such a process might be responsible for the development of cracks. This view was based on the experiments of Curie,* who found that the anomalously large dia- magnetism of solid bismuth disappeared at a temperature appreciably below the melting point." The paper goes on to say thet the change in magnetism happens at the melting point rather than near it (as M. Curie thought) but the fact is that molten Bi isn't anomalously diamagnetic so the diamagnetism must arise from the crystal structure.

    I think we can assume that M. Curie knew what a Curie temperature was.

  10. I got a reference to that paper from Google and the few fractured sentences that Google gave sugested that the original paper might answer the question of what happens to the diamagnetism of Bi when it melts.

    I'd like to know what the whole paper says.

     

    There's certainly some effect of crystal structure as shown by the second paper I cited.

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