Jump to content

John Cuthber

Resident Experts
  • Content Count

    17085
  • Joined

  • Last visited

  • Days Won

    30

Everything posted by John Cuthber

  1. Baking powder and water is pretty safe. Bicarbonate of soda add vinegar is a long way from what most people think of as a pair of dangerous chemicals. BTW CO2 really does have a smell, you can smell it over dry ice and I don't think there are any bursting bubbles spraying anything there.
  2. "unless you're talking about tritium water(not naturally occuring) or DDO, heavy water has a molecular mass of very slightly less than 19" Rocket man, DDO is heavy water so, yes, I'm talking about D2O. "where did you get 18.053 for water?" Oops!, I'm not sure, probably by missreading/ mistyping from wiki http://en.wikipedia.org/wiki/Vienna_Standard_Mean_Ocean_Water gives 18.015268 grams per mole The Merck index gives 18.016.
  3. "You don't have anything on the other side to bond with. An individual molecule can always break free, since there will be random changes in its KE. Ice will sublimate, as anyone with a frost-free freezer can attest, so forming a liquid layer should not really be a surprise." OK, that's a molecule tick layer and I guess it could reasonable explain a layer2 molecules thick because the "next to the outside layer" layer might be affected. On the other hand, somewhere this effect has to stop or the whole sample melts. Are we talking about a single monomolecular layer? That's not going to offer a lot of lubrication unless the surface is smooth. What evidence is given for this liquid layer? You can still sublime water at very low temperatures so I don't think that's relevant here.
  4. Last time I looked at an economics book it talked about economies of scale. In the light of that can someone please explain to me why a government run system (which is big) will always be less efficient than a private one (which is small)? I can see that it could be inefficient, but the assumption here seems to be that it will be lousy, just because it's run by a government. I think that if it's run badly by a government or a government agency like the UK's NHS, that means you have the wrong management. Because they are big they have big buying power and such; they ought to be able to do it more efficiently than a small scale operator.
  5. "Have you ever thought about taking the time to explain WHY your method might be better?" Yes, that's why I pointed out that in the real world, or in an exam, one method would be better because it's faster. Did you notice the word "if" in my post- it's used to refer to things like hypothetical cases. For example, rather than the absolute case of answering the question in this forum (for which nobody does get paid) I was inviting people to consider the case where someone was paying by pointing out what my preference would be in that case. I'm also amused that you refer to it as my method. If you had read the thread firstly you might have spotted that it was Dcowboy's method. (The hint there is that I called it "Dcowboys' method " if you look carefully you might notice the proper noun with an apostrophe and a s- this form is called a possessive). Secondly you might have noticed that I didn't provide a method for calculating the answer, I just commented on the 2 that had been given. Thirdly, you might have noticed that I was tacitly stating why I preferred one method to the other. The clear implication was that I preferred it because it was quicker. Perhaps, if you had taken 5 minutes to look at what had been written, you might "not come across as an arrogant cock". Incidentally, the method DCowboy used gives as accurate an answer as it's ever going to if you work to 4 decimal places. On the other hand dttom's method (because it involves squaring things) requires more places of decimals to get the right answer. Since your calculator will do this for you it doesn't matter much but, if you were repeatedly doing something like this inside a loop in a computer program, the one with less maths would get the right answer quicker. OK, that's a second reason why the quick easy method is better. And, just in case jdurg missed it again, its a second reason why the quick easy method is better. (That's not so much an arrogant cock as a patronising one BTW)
  6. "heavy water is 17th heavier than ordinary water" In the very real senses that heavy water has a molecular weight of 20.04 where ordinary water is 18.053. Of course, that quote might have meant its density is 1/17 greater which would have been roughly equally wrong since it's about 1/9 greater. About 1 molecule in 6400 of ordinary water is HDO (a lot fewer ar DDO). I'd have to sit and think about it but I have a feeling that the relatively large amount of oxygen present messes up the 6ml from 1L idea. If anyone wants to do the 1 litre of water is so many moles so it has so many molecules which gives 1/6400 molecules of D2 which would give so many moles of heavy water ie such and such a volume maths it might be interesting. I'd still like to know where the 60% figure came from.
  7. The idea that there's always a surface layer of water is interesting. How does the water know that it's near the surface and, therefore, shouldn't freeze?
  8. Much as I like coconut, I understand it has very high levels of saturated fat. I also understand that such fats are not good for you. Here's a page I found that claims to be from an expert.
  9. Was this " I think the only ethical course of action left is to stand up for your smake your viewpoint and make your protest more explicit by deleting your bookmarks to this site and never returning." a parody or a cock-up? If it was meant to be a snide comment at Bettina's expense then I think you may have just shot yourself in the foot. Perhaps you ought to avoid similar mistakes "by deleting your bookmarks to this site and never returning." On the other hand you might just not bother to make comments like that about a perfectly reasonable viewpoint.
  10. Just a quick point. Galileo knew he didn't need to do the experiment because he could work out what the outcome would be. He imagined 2 items tied together and dropped. First of all, lets assume Aristotle was right. The light object falls and the heavy one overtakes it pulling on the string. The heavy object falls but is slowed down because the light one is holding it back. Overall the combined object of the 2 balls and the string is clearly heavier than any of its components and it has to fall faster than any of them would do on its own. So the big ball is falling slower than it would (on its own) because the small one is holding it back, but faster than it would fall because it's now part of the combined object. That's a contradiction so the assumption (ie Aristotle's view) must have been wrong. Galileo only did the experiment to demonstrate this to people who couldn't understand the argument.
  11. It's 3 hydroxy propanoic acid, but I also think it's the wrong answer. What do you know about alcohols and permanganate?
  12. "Dawkins conveniently overlooks that faith has actually been the catalyst for progress, if you take that away, however ridiculous the grounds of that faith is, it can be positive (as well as negative)...think of the architecture (just one example) that has stemmed from an irrational belief in something. " Er, actually he doesn't overlook it, he just points out that the rich and powerful are in a position to patronise art (in all its forms) so a lot of art used to be "inspired by the church". An interesting question might be (though perhaps for another thread) "How come the church has got that much money; has poverty been eliminated?" The interesting thing about people who believe that God or an elephant tells them what to think is that they sometimes get some strange ideas about what God wants. Peter sutcliff would be a case in point "After two days of intensive questioning, he suddenly, on the afternoon of 4 January 1981 declared he was the Ripper and, over the next day, calmly described his many attacks, only weeks later claiming to have been told by God to murder the women. He was charged on 6 January and went to trial in May. The basis of his defence was his claim that he was the tool of God's will." from http://en.wikipedia.org/wiki/Peter_Sutcliffe If you don't believe in a God you can't think that He expects you to do hideous things; it forces you to think for yourself. It's quite possible that he would still have killed those women for money but I doubt it.
  13. A result that is statistically significant at the 95% level has a 1 in 20 chance of being a fluke. Well over 20 tests of homeopathy have been done so some of them are bound to "work". Also, was it a double blind trial ie was the effect measured by someone who didn't know which samples were control samples?
  14. There's nothing to stop me giving up my job as a scientist and retraining as an accountant. Except that I value an interesting job more than I value the extra money I might earn. Perhaps that's the reason why academia doesn't pay as well as might be expected. People are prepared to do it for the money on offer; if they were not then the salaries would have to go up in order to recruit academic staff. Of course the best way to gain success is to make sure you have rich parents.
  15. Well, if I was paying them by the hour I'd prefer Dcowboys' method to Dttom's and If I was stuck in an exam with only however many hours to finish the paper I know which method I'd use.
  16. "Apparently, Arnold has embarked on his own campaign to do universal health coverage, giving the rest of the world another reason to move to California besides the year-round 70 degree weather." The weather might be a reason for me to move but I already have cradle to grave state-funded healthcare. I think most of Europe does too, so I don't see the rest of the world being very impressed.
  17. Where do you get the 60% figure from?
  18. I might look after the elderly because I want society to be in the habit of doing so when I am elderly. A sort of ongoing social contract. Straightforward self-interest makes it a rational plan. Now, why does anyone need a God or an elephant to tell them to do something that is in their best interest anyway? What's hypocritical about it?
  19. If you have a society that looks for evidence then it will discount the elephant believer's views and come to a rational point of view about old people. It will do this whatever muddled ideas are dreamed up by mystics. Surely it's better to look after the elderly because it's the right thing to do rather than because someone says that a fairy told him to tell you to do it?
  20. Do you know how little heavy water there is inn ordinary water? Also, letting the water evaporate does concentrate the heavy water, but not very well. A lot of the heavy water evaporates along with the light water. How will you tell if you have increased the heavy water concentration?
  21. selenate, biselenide or (probably better) hydrogenselenide biselenite or hydrogenselenite (with the oxidation states in roman numerals in brackets if you want to be fussy.)
  22. Or you could do it the easy way like the original poster did.
  23. This was BS before http://www.scienceforums.net/forum/showthread.php?t=7869&highlight=ormus and it's still BS now.
  24. I haven't measured it, but it seems less strongly atracted to a magnet than a typical bit of steel when it's at room temperature. On the other hand I can pick it up with a magnet.
  25. I just wonder; if she does claim that she didn't hear the question properly, would anyone care to tell me; if that was meant to be the answer, what on earth was the question?
×
×
  • 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.