John Cuthber

"I`de like to see how Titration would work with the silver nitrate reaction!" Your wish is my comand. Personally I'd use fluorescein as an absorption indicator because it's pretty.

Guess what, my dear parents were not generally watching when I was falling out of trees etc. Not because they didn't care but precisely because they did. Surely I'm not the only one who deliberately waited till there were no grown-ups about to tell me not to before doing something dumb. If CBS were being deliberately negligent of the duty of care they would be prosecuted (and possibly sued too) in spite of the "disclaimer". The disclaimer can only cover events that are not the result of CBS's actions. The kids may well hurt themselves. If that happens then a court will see if CBS were negligent. It may be that the court finds that the misfortune that befalls some child is an accident and that CBS are not criminally liable through negligence. The disclaimer will stop any civil claim at that point. I think that's all it can do. The problem isn't that CBS's lawyers insist on a disclaimer. The problem is that anyone thinks this is anything other than child abuse.

If you are planning to weigh the AgCl then this is gravimetry*. If you are planning to use a solution of a known concentration and add exactly enough to ppt all the Cl then it's called titration. * Gravimetry is also the word for measuring the local strength of gravity.

Presumably your talents and gifts don't include the use of capital letters, punctuation or how to use spoilers. Just out of idle curiosity, how likely was it that one of the teachers from your school would reply and what would you say to them here that you can't say in person at school?

Water is miuch more viscous and doesn't have much oxygen in it so there's a lot of energy needed to pull enough water through the gills to get enough oxygen.

I guess he's not fussed about whether you believe facts either. If it doesn't work with whiskey (and, unless you are calling him a liar, I think we can take that as a fact) then, since vodka and whiskey have similar alcohol contents it can't be due to alcohol. My personal guess is that it's at least partly due to acetaldehyde. but I still can't explain the difference between spirits.

The blue/grey triangle shaded on the graph is the clue. The slope of that tangent is the change in y divided by the change in x. In this case its the change in concentration of butyl chloride divided by the time over which that change took place. The values can be found by reading off the axes. Look at the line drawn as a tangent to the graph. At 400 sec the concentration is 0.042M at 800 sec its 0.018M and so the difference is 0.024M. Divide that by the difference in time and you get the rate of change.

http://www.britannica.com/eb/article-9020249/carbon-dioxide

I got some from ebay but the easy way is to buy it from a chemical supplier. It's not a restricted product.

Thanks for that reference. It seems I'm not the only one who thinks a thin layer of water won't help much "In 2002, Dr. Salmeron and colleagues performed an experiment. They dragged the tip of an atomic force microscope, resembling a tiny phonograph needle, across the surface of ice. "We found the friction of ice to be very high," Dr. Salmeron said. That is, ice is not really that slippery, after all. Dr. Salmeron said that this finding indicates that while the top layer of ice may be liquid, it is too thin to contribute much to slipperiness except near the melting temperature. In his view, friction is the primary reason ice is slippery. (The microscope tip was so small that its friction melted only a tiny bit of water, which immediately refroze and therefore did not provide the usual lubrication, he said.) Dr. Salmeron concedes, however, that he cannot definitively prove that his view is the correct one. "It's amazing," he said. "We're in 2006, and we're still talking about this thing." " Well, now it's 2007 and I don't see this as fully resolved yet.

When I was a kid I used to climb trees, swim in the canal and ride a bike on main roads. Any of these could have led to my death (or to serious injury). Is CBS simply accepting that kids playing are sometimes exposed to danger and that they don't want to face an essentially unlimited lawsuit? Having said that, the whole idea seems wrong to me. It looks exploitative at best and I don't think children are born to be "used" in this sort of way. To me that seems to be a bigger problem than a contract that probably wouldn't be enforceable.

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.

"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.

"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.

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.

"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)

"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.

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?

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.

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.

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.

It's 3 hydroxy propanoic acid, but I also think it's the wrong answer. What do you know about alcohols and permanganate?

"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.

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?

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.