John Cuthber

Why do there appear to be iron impurities? I dissolved the stuff in a green (impure) solution of strong HCl,

"The time average of the force (presumably we are talking about the contact force between the car and whatever it hits) is tied to momentum, not energy. " The mass and velocity are probably known. It would certainly be odd not to have a fair idea of the mass. So the relation between energy and momentum is know, so... It's like that absurd idea where people say "it's not the voltage that kills, it's the current." Well, since one is directly proportional to, and not independent of, the other... "Conservation of momentum will be a helpful principle in this problem." I doubt that.

"a force such as a vacuum." What?

The reason for adding the acid (Hydrochloric or sulphuric) is to turn the borax into boric acid. As you already have boric acid you don't need to do that.

About a quarter or half the length of the car- which is good enough to give you an order of magnitude or so for the force.

Almost certainly just bad luck. But don't stop trying to be funny anyway. Some days the only helpful thing you can do is laugh.

No If you gave me a short summary and some sort of reason I might, But I'm not going to bother just because someone who doesn't realise what "Too long" means tells me to.

QOW, if you vote this post up I will vote spyman's post up. He gets 2 points for getting the right answer and I get one for answering Michel's question for you.

Honey is fine unless you are really unlucky and very young. "Honey is the only known dietary reservoir of C. botulinum spores linked to infant botulism" from http://en.wikipedia.org/wiki/Botulism#Infant_botulism

"It specifically states "assorted eye colors" " The xkcd version does. The OP version does not.

Probably, if you pay enough. But most people just turn the slide the other way up.

"But they don't say that. If they did then it'd be common knowledge (in the case of just 1 blue existing)." Congratulations! You may have just saved the life of everyone on the island. If they don't know that there are (exactly) two eye colours, and what they are, then they have no reason to die. Any islander can think " I may see lots of blues and browns, but for all I know my eyes are grey, or yellow, or pink with purple stripes. I have no real idea what colour my eyes are- so I don't need to commit suicide." For the puzzle to work they need to know that there are only two colours "available" and what those colours are. "The initial conditions in the asked quiz does not include a syncronization point and it is also assumed that the society can last." It is, indeed, so assumed- but I don't think the assumption is valid.

I think your friend is probably right. A green flame test, and no sodium (or anything else much) in the PIXE elemental analysis , the crystals shape etc are fairly good evidence to support boric acid as a conclusion. If it was borax it would have a lot more sodium in it. I'd be a fool to claim I can do analysis by looking at a picture on the web, but I think it is very likely that the material you have is boric acid.

Altogether now! The people's flag is deepest red, It shrouded oft our martyred dead, And ere their limbs grew stiff and cold, Their hearts' blood dyed its every fold. Then raise the scarlet standard high. (chorus) Within its shade we live and die, Though cowards flinch and traitors sneer, We'll keep the red flag flying here. Well, perhaps that's a bit far, but I think we need to seriously consider the one way to balance the books that (as far as I can tell) no government has put forward. Why doesn't the government try taxing rich people?

Boric acid is a very poor acid so the pH looks OK to me. It should crystallise out as flakes from hot water. The other way that often gets good crystals is to let a solution of it evaporate slowly. Incidentally, I just noticed in the first post you talk about boric acid and borax. They are not the same thing. Which one do you mean?

Science didn't avoid a "start", it just labelled it as the "big bang" (somewhat tongue in cheek) , and put a date on it ( 13.75 ± 0.11 billion years ago). What did the OP in this thread think it was about?

Imagine a bunch of islanders with the same characteristics except that they are not very bright. They don't realise what other people think. Then one day suddenly the God of "setting up logic puzzles" gives them perfect logic. ( This is a long time before the traveller arrives or the Guru speaks.) As far as I can see they all suddenly become aware that everyone knows that lots of people have blue eyes and that starts the destruction. Lets look at the simple cases One blue. It depends- but as long as the rules say that they know that there are blue eyed and brown eyed people on the island and he sees no blues, he knows he must be It. So he knows his eye colour and leaves or dies depending on which version of the puzzle If they don't explicitly know there are two colours nothing happens with just 1 blue. With 2 blues clearly they all know there is more than one colour. The two blues now know that there is either 1 blue (the other guy) or there are two and they are one of them. If they see the other guy the next day then they know they are the 2nd blue. And so on. The clock doesn't start ticking when the traveller arrives or when the notice is posted. The notice doesn't tell them anything. The presence of lots of blue eyes is already common knowledge. Any of them could post the notice. None of them would learn anything from it. So the clock starts when the initial conditions of the puzzle are set up. This society cannot last more than 100 days. As spyman says "It is NOT the knowledge of that there exists islanders with blue eyes that sets this off, it is the synchronization of all islanders simultaneously with the shared knowledge that all others also are synchronizated." But this synchronisation starts when they realise their circumstances. That happens as soon as those circumstances arise. (they are perfectly logical. why would they wait for the traveller to tell them something they already know, and they know that their fellow islanders know.) OTOH Spyman also says "Since they where forbidden by their religion to discuss eye-colour an outsider is necessary for this synchronization to ever happen. " They are forbidden to discuss it, but my point is that they don't need to. They know "if I can see lots of blue eyes- so can everybody else"- that is common knowledge. And the answer to MD65536's jibe about me explaining why everybody else got it wrong is that they were distracted by the traveller. Nobody thought to ask what happened a year before he arrived.

"but they take a default position and say that there is no evidence or possibility for the existence of God." That's not a "default position" it's the sensible one. Clearly there is no evidence for God (or at least, no convincing evidence) or we would believe it. Also the bible rules out providing such evidence* so even the theists should agree with it. * it's the "test not thy God thing.

A lot of uranium compounds are nice colours and look pretty under UV light. It is still hypothetically possible that some heavier elements are relatively stable. But the definition of " relatively stable" doesn't mean you will find them in the chemicals supplier's catalogues.

Who, before they read the notice, did not know that there were islanders with blue eyes?

Weigh out some boric acid (say 100 grams). Put it in a suitable container. A glass saucepan would be good. Add 4 times as much water (so, for 100 grams you need about 400 ml of water). Heat the mixture until it boils gently and stir it. Once the liquid is boiling all the boric acid should dissolve. (Borates have a reputation for dissolving rather slowly so it may take some time. Keep an eye on the water level. If lots of it evaporates as you boil it you might need to add some more hot water.). Once all, or almost all of the solid has dissolved stop stirring and stop heating the solution. Let any solid material settle out. Pour the liquid into another container leaving any undissolved material behind. Let the hot solution cool slowly. It should form crystals like those in the picture you linked to. Pour off the liquid from the crystals ( it probably makes sense to put it back in the saucepan.) Wash the crystals with a little cold water and filter them out of the solution. A fairly fine sieve is probably better than filter paper for this because you won't get bits of paper in the crystals. You should get most (about 60% or 70%) of the boric acid back as crystals.

"What would be the "perks" for becoming Atheist? " Getting a lie in on Sunday morning. Not wasting time and effort on the "stake" in Pascal's wager in which it's odds on that you pick the wrong faith and so lose anyway. Freedom of thought and, to some degree, of action.

"The ribozymes of the RNA world are itself complex biomolecules which requires more time than the age of this universe to self organize itself through a random walk." So what? Nobody knows what the original forerunners of DNA were. I read some time ago that clay particles had been put forward as a suggestion. Since RNA is more recent that whatever came before it, and is probably just one jump short of DNA, it's no shock that it's rather good at its job. "I have to ask you, is there any evidence that qualia are mere patterns in the brain? " Yes, and it's odd that you didn't notice it. The study of synaesthesia and the effect of the God helmet are supporting evidence, though not (yet) proof. " if it was then we should have been able to copy that pattern and implement it in a neural network." Thanks for reminding me. The way neural networks work is more evidence. "It is better to say we don't know at this stage." Yippee! I knew we would agree on something. Now, the original point was that you seemed to think that we should just shrug and accept that we didn't know. My point is that, while we can, we should try to find out. You can call that "scientism" if you like, but I call it common sense. "Genome is not DNA, its an abstract concept, infact one can scramble the whole genome, rearrange the correlations between the nucleotide bases and if you measure the information content in bits or bytes before the rearrangement and after the scramble of the genome, the information content will be the same in both occassions." I don't think anyone said it was. In particular, when I said you could get it from the human genome project people, I didn't expect them to stick some DNA in an envelope. I expected them to send you the information (probably as a string of A's G's C's and T's).

"Dear lord, don't tell me that we now have to prove that proof by induction is a valid form of proof, before you'll accept the solution?!" No. You just have to explain why it doesn't work for the unexpected hanging paradox. There are lots of versions but the idea is the same. Here's one A teacher tells the class that there will be a test next week but that (in order not to spoil their evening) they will not know about the test on the evening before it happens. The kids soon realise that the test cannot be on Friday. Because if it were, then they would know about it on Thursday night. But, since they know the test can't be on Friday, then if, on Wednesday night they haven't had the test, they realise it must be on Thursday (because Friday was already ruled out. But that breaks the rule so the test can't happen on Thursday. So, if, on Tuesday night they haven't had the test yet, they know it cant't be on Friday or Thursday- so it must be on Wednesday. But, once again, that breaks the rule- so the test can't be on Wednesday. You can carry on this inductive argument and show that the test cannot take place. But in the real world, the teacher can set the test any day but Friday and meet the terms of the rules. So the inductive reasoning gives the wrong answer. My view is that the islanders' fate is similar (but the other way round). So you can't rely on an inductive proof. If the all read the notice board every morning the board is the equivalent of the traveller. But it adds no new knowledge. So why is there a sudden countdown to death?

I guess that a large number of Christians would consider the fact that the Vatican accepts evolution as being evidence to support it, but that's not really a valid reason. It's an appeal to authority.