Wikipedia:Reference desk/Archives/Science/2009 September 19

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September 19

Alcohol by volume myths

In college a friend told me that the difference between 3.2% ABV beer and 4.5% (or whatever other beer is) was very small and only amounted to a difference of a beer per case. After doing the math though, this seems clearly untrue (it should take 2 three-percent beers to equal one six-percent). First, is my math reasoning correct and if I am, what is the origin of this myth? I've heard it from lots of people but the math seems easy (double the percent, double the amount). I need help knowing where people are making the mistake.

Well, let's see. there are 24 beers in a case and there are 12oz in a beer, then that is 288oz of liquid per case. For a 3.2% alcohol beer, that is 9.2 oz of alcohol per case and 0.38oz of alcohol per beer. So the "extra beer" in this exact case would be in increments of 0.38oz of pure ethanol...follow me? Let's look at the 4.5% case, it has 13oz of alcohol per case. This is a difference of 3.8oz!! In terms of "extra beers" as we defined earlier, that is 10 more beers! Looks like the difference is bigger than even I thought before I walked myself thought it.Mrdeath5493 (talk) 03:10, 19 September 2009 (UTC)

Now after doing some more math I see that if you want to find a rough one "extra beer" beer increment then multiply the ABV of any beer by 0.04 (4%) and that represents the 1 beer "step." So for the previous example if I multiply 3.2% by 0.04 I get 0.128ABV...this means that every 0.128% ABV difference between my reference beer and a different one represents an "extra beer." So, looking at the previous example I can just say 4.5-3.2 = 1.3% abv difference. 1.3/0.128 = ~10 extra beers. Cheers!Mrdeath5493 (talk) 03:20, 19 September 2009 (UTC)

As far as I can tell, you're absolutely correct and I don't know why people would say it's 1 beer worth ((4.5/3.2)*24 = 33.75 beers, so about 10 extra per case of 24). There are other things to take into account besides just the amount of alcohol when considering how drunk someone will get, for example you'll get more drunk on an empty stomach. However that seems to work in the favor of the higher alcohol beer, since you'll have less non-alcohol stuff in you for the same amount of alcohol. Maybe it has to do with perception? How drunk people act might be related to how drunk they think they should be, so if they've had more beers they might feel more drunk even if they've had less total alcohol? Rckrone (talk) 03:44, 19 September 2009 (UTC)

Thank you for the responses. I agree, I don't understand how people believed it was less. Thank for confirming that my math was right. Part of my question is how others could have come to the opposite conclusion. I wonder now if it was due to someone using addition and not multiplication on the numbers. Although even after doing those numbers it doesn't make sense. Does anyone else have any info on the myth (thank you for confirming those numbers are right).

Possibly due to someone noting the shrinkage effect on dilution - take 50ml pure ethanol and 50ml pure water - you won't get 50% ABV - as the mix will be around 97ml total (IIRC), so the strength is 50/97*100 = 51.5%. But for low figures, any effect is negligible.  Ronhjones  ^(Talk) 18:45, 19 September 2009 (UTC)

Alkene Nomenclature

Hello. Is it internationally acceptable to name 1-alkenes larger than propene with one carbon double bond by simply their parent chain? For example, could 1-butene be simply called butene since there are no other isomers? Thanks in advance. --Mayfare (talk) 02:27, 19 September 2009 (UTC)

There's also 2-butene (with cis and trans isomers) and isobutene. You should stick with calling 1-butene by its proper name, and not just "butene" -- the latter could be any of 4 different things. 98.234.126.251 (talk) 02:59, 19 September 2009 (UTC)

There's also cyclobutane and methylcyclopropane which are isomers of butene (though, not themselves alkenes). And to confirm the above response, the name "butene" is ambiguous, because it does not indicate where the double bond occurs. You would need to specify 1-butene or 2-butene. For shorter chains (propene, ethene), there is exactly 1 version of the molecule, so it does not have to be numbered, because "propene" and "ethene" can ONLY be one structure. --Jayron32 05:55, 19 September 2009 (UTC)

Just a small addition, the IUPAC name is actually but-1-ene. Rkr1991 ^{(Wanna chat?)} 07:47, 19 September 2009 (UTC)

No it's not. eg shell (company) does this http://www.shell.com/home/content/chemicals/products_services/our_products/lower_olefins/1_butene/index_1_butene.html 83.100.251.196 (talk) 11:06, 19 September 2009 (UTC)

Lots of companies (and people, etc) don't use the current standard naming conventions...as long as the name is unambiguous enough for the speaker to communicate to the desired audience, it's not important to be formally "correct". I get lots of ads for "alpha olefins" even though they are properly called "alkenes" and positions should be specified with numbers:) IUPAC makes an official ruling, and only people who care about being formally correct bother to listen:) Interestingly, the infix-numbering is the one used in our article about IUPAC scheme for alkenes, but I think the IUPAC Blue Book uses prefix-notation for simple cases. DMacks (talk) 20:51, 19 September 2009 (UTC)

It's work noting that for industrial chemical processes the distinction bewteen 1 and 2 butene is very improtant - since they undergo different chemical reactions giving different products.83.100.251.196 (talk) 12:30, 19 September 2009 (UTC)

Just ignore these ugly IUPAC names. Say ethylene and propylene and butylene like God intended. --Trovatore (talk) 20:32, 19 September 2009 (UTC)

But which butylene? There's four of'em, y'know, and they're all different... 98.234.126.251 (talk) 04:56, 21 September 2009 (UTC)

Sure, and they all have names. Don't see the problem. --Trovatore (talk) 05:21, 21 September 2009 (UTC)

What I mean is, you can't just say "butylene" if you're talking about a particular isomer -- you have to specify "1-butylene" or "2-butylene" or "isobutylene" or something like that (and for 2-butylene you also gotta specify cis or trans unless it's a mixture of both as it often is). 98.234.126.251 (talk) 06:34, 21 September 2009 (UTC)

Does a knife wound to the stomach cause immediate death?

I've just watched the high-quality film Faster Pussycat! Kill! Kill! on TCM. In the course of almost every member of the cast getting murdered, the cute girl with the Italian accent gets stabbed three times in the abdomen and dies immediately.

Would this happen in real life? Assuming a major abdominal artery was severed, how long would it take to bleed out sufficient to lose consciousness? Alternatively, how near the ribcage would the knifeblow need to be to hit the solar plexus and would that produce immediate death? (This is not a homework question :) Franamax (talk) 07:40, 19 September 2009 (UTC)

Depends on where you stabbed and how big the knife was. It's very possible it could happen immediately, for example bullets cause almost instant death if they hit certain areas of the body and they are about as damaging as a knife.--Patton123 (talk) 09:04, 19 September 2009 (UTC)

It was in the mid-lower abdomen area, with an approx. 19mm X 150mm knife, sharp on one side. No bullets, so no sonic shock, just stabbing. Straight thrusts. Slender actress, so the penetration would have been 50-75% of the body width. Now that I think of it, maybe she just fainted from pain, and bled out later. Franamax (talk) 09:50, 19 September 2009 (UTC)

That's dramatic license. Keep in mind that gunshots and stabbings are often presented differently than in real life. Unless a bullet or knife hits you square in the heart, immediate death (or very fast death) from such a wound (as with the "rumble" in West Side Story) seems unlikely. Typically stab and gunshot victims die of loss of blood, which takes a little while. Lee Oswald was shot through the abdomen, the bullet hitting several vital organs, and fell to the ground moaning and groaning, taking a minute or so to pass out, and dying later. John Lennon was hit in a major artery, and had time to cry, "I'm shot!" before passing out. Lincoln and RFK were shot in the back of the head and it took a number of hours before they succumbed. Baseball Bugs ^{What's up, Doc?} carrots 09:17, 19 September 2009 (UTC)

Well, B-dramatic license anyway. ;) How did Oswald get shot through several vital organs? Ruby shot him straight-on, so I would have thought only one would have been pierced! That seems to be the closest to my OQ, about abdomen wounds, but even there you have bullet trauma (supersonic shock). I'm talking straight knife-thrust here. Franamax (talk) 09:54, 19 September 2009 (UTC)

I think he was hit in the spleen, among other things. As I understand it, he wasn't actually hit straight-on, but maybe it would be useful to study the videos. I haven't seen them for awhile. Maybe I need to watch some snuff films to brighten an otherwise dull afternoon. Baseball Bugs ^{What's up, Doc?} carrots 10:28, 19 September 2009 (UTC)

In this photo, at least,[1] it appears Oswald was hit from an angle. Baseball Bugs ^{What's up, Doc?} carrots 10:31, 19 September 2009 (UTC)

That altered photo is actually a joke. I can supply the punch line, if you're interested. This pair of photos [2] suggests he was hit at a significant angle. Baseball Bugs ^{What's up, Doc?} carrots 10:33, 19 September 2009 (UTC)

Well d'uhh! Of course I'll need closure on the punchline. :) Given the musical theme, is it "don't you want me baby?" And yes, Ruby did come from the side and Oswald turned away, which would expose a significant cross-section of organs in the gut. At least that's what every one of the faked photos shows. Can't remember where I saw the real one now. ;) Franamax (talk) 11:17, 19 September 2009 (UTC)

The second set of photos aren't fakes, they're widely circulated. The punch line I've seen to that first (altered and morbidly funny) photo is, "Thank you, Dallas! Good night!" Baseball Bugs ^{What's up, Doc?} carrots 11:29, 19 September 2009 (UTC)

Here's a youtube with a melodramatically-narrated newsreel of the shooting. [3] Notice they freeze-frame it at the moment the famous photo was taken, i.e. when its flashbulb went off and illuminated the moment. One subtlety is that Ruby (real name "Rubinstein", as the narrator points out) fired with his middle finger, as he was missing most of his index finger - subliminally "giving the finger" to Oswald, in deadly fashion. Baseball Bugs ^{What's up, Doc?} carrots 11:37, 19 September 2009 (UTC)

FYI, it took Oswald nearly two hours to die, despite his severe wounds. Baseball Bugs ^{What's up, Doc?} carrots 11:47, 19 September 2009 (UTC)

A bullet wound would knock you unconscious pretty much instantly from shock or whatever, and you'd die very quickly after that. Also bullets do a tremendous amount of damage in a radius much, much larger than the bullet itself. Knives aren't so damaging though, but they could ill you fairly fast (Certainly a powerful stab in the lower abdomen woould kill you within a few seconds, hence why the Romans were taught to "punch" that location with their swords).92.251.186.199 (talk) 09:31, 19 September 2009 (UTC)

Do you have a ref where I could read up on lower abdomen wounds? I could see a sword-stab to the solar plexus, but down farther in the gut it just seems like a fairly slow and painful death would result. What is down there that would result in death in a few seconds? Franamax (talk) 09:56, 19 September 2009 (UTC)

I can't think of anything either but it's what I've read about hte Romans they hit the lower abdomen and it apparently resulted in a swift death.92.251.159.145 (talk) 10:07, 19 September 2009 (UTC)

I guess the issue is what is meant by "immediately". Even if you get your head lopped off, the organs are going to be alive for a few seconds until they run out of oxygen. I was thinking of the scene in West Side Story where one gang member stabs another in the belly with a switchblade (which is not much larger than a pocket knife) and he immediately falls, apparently dead. Dramatic license. Baseball Bugs ^{What's up, Doc?} carrots 09:44, 19 September 2009 (UTC)

With respect Franamax I think you need to brush up on your anatomy a bit. In the lower abdomen there are at least two major arteries that when severed or punctured would lead to pretty rapid internal bleeding and subsequent death. As for Lee Harvey Oswald being shot 'straight on', if you look at realistic abdominal anatomy you will see that several of the organs overlap when viewed front to back (or vice versa!) Talking about 'belly', 'abdomen', 'stomach' or 'thorax' is not very helpful, one needs to be more precise about position and angle. IMHO a quick death would occur from a direct heart stabbing which could be achieved from several directions and angles, but it would mean a front entry either through the hypochondriacal area or intercostally. Equally, using a badly directed fictional example like West Side Story is not really helpful either. Who knows how the director guessed or obtained information about the realism of the stabbing. 86.4.186.107 (talk) 10:11, 19 September 2009 (UTC)

(multi e/c's) I'm talking of course about the movie "fall-to-the-ground-and-never-move-again" thing, but more generally immediate incapacitation (within 5 seconds) from a stab wound with a slender knife to the stomach. And I don't think they ever actually signed the license to rip off West Side Story from Shakespeare anyway. ;) But yes, I was really asking about stab wounds in the stomach, and you would always want to bring a gun to a knife-fight. Incidentally, from what I'm aware, when you get your head lopped off, your head will also stay alive for a few seconds - so when you got guillotined, there would be enough time for you to be conscious of being held up before the crowd as just a head.

I think I've found my answer anyway - fainting due to severe pain, with subsequent henorrhage lowering blood pressure nd inducing shock, leading to loss of life while still in an unconscious state. Certainly in the movies they don't often have EMT's rushing in after those stabby moments. Thanks for the feedback! Franamax (talk) 10:17, 19 September 2009 (UTC)

Indeed, I read about a guy who was going to be beheaded and told his friends to watch him blinking, he blinked for a couple of seconds after decapitation.

I recall reading in On Killing that the quickest and most silent "takedown" knife kill involves stabbing someone through their lower back, into their kidneys, I think? I don't exactly recall the anatomy. It was brought up in the context of how people actually kill with a knife, rather than how they do it in the movies (where they like to "slash" the throat, which is really not the quickest or the most silent approach). --98.217.14.211 (talk) 13:26, 19 September 2009 (UTC)

It seems like what's really needed here is a definition of "immediate". Or more accurately, some information on how fast you (1) go unconscious; and (2) die after various kinds of attacks to various parts of the body. For example, with a malaria mosquito, it takes a while. With a guillotine, it's pretty fast - though maybe not "instantly". Baseball Bugs ^{What's up, Doc?} carrots 13:30, 19 September 2009 (UTC)

I know of a case where a person was stabbed in the heart and was taken to the local casualty unit with the knife still stuck in him. A surgeon who was just going out at the time and saw him called for some stitches to be brought and opened his chest up right there in reception and massaged the heart and stitched it up. A very effective way of clearing patients :) The person was awake and asking for breakfast the next morning and was out in a week. So no even being stabbed in the heart isn't necessarily fatal, though I wouldn't advise such heroic surgery in general even if it worked in this case. Stomach wounds tend to be very nasty because of the stomach juices and bacteria but at least you get a little more time to try and fix the problem. Dmcq (talk) 16:10, 19 September 2009 (UTC)

One of the things that movies most consistently get wrong is the ease with which people die: somebody gets a fatal wound and just immediately flops down and lies there. The only movie I know that comes close to showing what actually happens is Saving Private Ryan. Looie496 (talk) 18:01, 19 September 2009 (UTC)

Maybe that's because they only have 90-120 minutes to cover everything in a film. In Walk the Line, when Johnny Cash's brother gets severely injured by a saw, they portray him dying that afternoon. He actually went through a week of agony before succumbing. Baseball Bugs ^{What's up, Doc?} carrots 18:53, 19 September 2009 (UTC)

In the photo of the Oswald shooting, Ruby was at about a 45 degree angle to Oswald's left. The doctor who performed the autopsy said the bullet entered the "lower left chest" and "it was fairly obvious that the bullet had transgressed virtually every major organ and vessel in the abdominal cavity, which later proved to be the case." These included the aorta and the inferior vena cava. The initial massive blood loss killed him from anoxia. 3 liters of blood (out of 5 in the body) had leaked into the abdominal cavity. The right kidney and liver were hit, as were the stomach, pancreas, and spleen. Despite this, the doctor thought they might have saved him if he had been closer to the hospital. Edison (talk) 19:56, 19 September 2009 (UTC)

Genetically engineered corn seed

What would be the impact of genetically engineered corn seed that required a proprietary germination activator and had a proprietary terminator gene if it became dominant? -- Taxa (talk) 09:14, 19 September 2009 (UTC)

What are you talking about? Baseball Bugs ^{What's up, Doc?} carrots 09:18, 19 September 2009 (UTC)

Watch the documentary, "The Future of Food." -- Taxa (talk) 09:24, 19 September 2009 (UTC)

Where corn (i.e. maize) is concerned, it's not much of an issue, since you can't save selected ears and plant the next generation of hybrid corn anyway. Well, you can, but you won't get hybrid corn, as the Mendel effect will kick in and you'll get a combination of tall plants, short plants, high-yield plants, low-yield plants, etc. Then you'd be back in the business of trying to create your own open-pollinate varieties - which are significantly less hardy than hybrid corn is. Might be more of an issue with other crops like wheat and soybeans. Keep in mind that maize is a thoroughly domestic crop. It does not and cannot exist in the wild in its familiar form. Baseball Bugs ^{What's up, Doc?} carrots 09:41, 19 September 2009 (UTC)

Perhaps not in the US where industrialized production and genetically engineered corn designed specifically for High Fructose Corn Syrup and a mired of other genetically engineered products including spermicide, herbicide, pesticide, pharmaceuticals and plastic has wiped out virtually all other varieties of corn. Not in Mexico, however, where domestic corn is typically open-pollinated to gain or revitalize various strengths which wild varieties may have. Unfortunately the large varieties of corn in Mexico today are a great risk from the thing in the US that special purpose varieties are the only ones that count despite our knowledge that preserving natural bio-diversity is what it is all about unless you want to be setup for a catastrophe worse than the Potato Famine. -- Taxa (talk) 10:07, 19 September 2009 (UTC)

The USA used to use largely open-pollinate varieties. When the drought came along in the early 1930s, those who had planted hybrids got some yield, and those who had planted open-pollinate varieties didn't. That pretty much wrapped it up for the open-pollinate varieties in America. Sure, you can still do open-pollinate varieties. But if you're wanting to sell your grain to the local elevator, you're not likely to make as much money from open-pollinates as from hybrids, simply because the yield likely won't be as high. Lack of genetic diversity is certainly a concern, which is why there are conscious efforts made to maintain some biodiversity. Baseball Bugs ^{What's up, Doc?} carrots 10:23, 19 September 2009 (UTC)

If a genetic variant had a "proprietary germination activator and had a proprietary terminator gene", how do you propose that these genes would become dominant? Wouldn't the variant be selected out in the first generation? I'm not sure where the controversy about gene contamination of indigenous Mexican corn (teosinte) varieties is at nowadays, but that's a little different than the question on gene diversity. The problem there is that agrobusiness tends to favour stable variants and market them heavily. This reduces natural genetic variation within the cropped varieties of plants. But that has been happening long before genetic engineering came along. Most banana plants in the world are a single clone. Apis mellifera is a single widely used species at great risk right now. The basic problem is: which farmers are you going to tell not to use the most productive variety? Which pollination companies are you going to tell not to use the most productive and available bees? Answer those questions and you will have solved the problem of maintaining genetic diversity. :( Franamax (talk) 10:36, 19 September 2009 (UTC)

There is a common conspiracist notion (conspiracy theories being the basis of most of that user's questions on these pages) that somehow companies are "imposing" genetically modified organisms on the market. In fact, they are driven by demand. The farmers want the highest possible yield, and that's what these products deliver. The companies also recognize the risks and try to do something about it. You're right about the banana. Through artificial selection they've got one that's really good, and also vulnerable. This happens in nature also, of course. The pink dogwood has been severely beaten back by a particular disease that apparently hasn't affected the more common white dogwood. But we know a lot more about genetics than we did during the potato famine. In fact, we knew nothing about genetics during the potato famine, except by vague inference. So the potential to prevent a disaster is much better than it was in the 1840s. Baseball Bugs ^{What's up, Doc?} carrots 10:46, 19 September 2009 (UTC)

I'll have to temper this now. There are at least two "conspiracy" theories which arise quite naturally from market forces but nonetheless pose a threat:

• Contrary to most of recorded history, in the last 20-30 years the producers of plant seed and the producers of pesticide (primarily herbicide) have converged. So now we have companies such as Syngenta, Monsanto and Pioneer/DuPont whose economic incentive is to produce crop varieties synergic with their own pesticide products. Admittedly, as far as herbicides go, Roundup is a least-awful one and genetically-engineered Roundup-ready seed (soybean and canola especially) may (or may not) have reduced environmental impact (key assumption being that crop acreage stayed the same and use of more toxic herbicides decreased, but at least one of those assumptions is broken). The really big problem here is the corporate conbination of pesticide research and seed research. Who ever said that was a good idea? Instead, the space was captured by profit-seeking interests in a free market. But it's not necessarily true that the pursuit of profit always results in a net benefit to society. As always, what external costs are generated?
• And genetically-modified organisms to a degree enjoy a "free ride" in that if they are deemed harmless, they get sold within the existing system, undifferentiated. All of the canola and soybeans get mixed together in the grain elevator, so the consumer is not even given a choice. The natural consequence of this is that producers have an incentive to adopt the most profitable commodity practice, rather than the one which delivers the most desirable benefit to the consumer. In similar fashion, US consumers get recombinant BST-stimulated milk, whereas we in Canada do not. Is there any difference? I'm not sure, but I'd sure like to have the choice.

In summary, no it's not a huge conspiracy - but market forces aren't always beneficial. The cheapest food isn't always beneficial either. Food is pretty fundamental and it needs extra scrutiny, since it's, like, what we need to survive. Franamax (talk) 12:32, 19 September 2009 (UTC)

There's much more scrutiny now than there was a hundred years ago. Baseball Bugs ^{What's up, Doc?} carrots 12:37, 19 September 2009 (UTC)

True. Hardly anyone dies of dropsy or scrofula nowadays. I think my points stand though. Franamax (talk) 13:06, 19 September 2009 (UTC)

People could always plant their own crops like they used to. But the natural trend seems to be away from small farms and towards big ones, as with other types of industries. You get more efficiency in trade for less diversity. Baseball Bugs ^{What's up, Doc?} carrots 13:14, 19 September 2009 (UTC)

It's only a "natural trend" because of the way agricultural subsidies are handed out. Honestly, if you want to take a "free-market" approach, big aggro is possibly the worst example you can find, as it is one of the most highly subsidized government industries there is in the United States. It has about as much to do with the free market as does Social Security. --98.217.14.211 (talk) 13:47, 19 September 2009 (UTC)

Agriculture is one thing the USA does very well. We seem to outsource everything else. If we outsource our core agriculture, we're doomed. I'm fine with my tax dollars going to support the ag industry. Baseball Bugs ^{What's up, Doc?} carrots 13:54, 19 September 2009 (UTC)

I suggest that you might not have a full grasp on the pertinent issues. Basically the entire industry is vastly warped by government involvement—that's why corn is so cheap, and so high fructose corn syrup is so cheap, and why it is everything. It's not good for us, and it's not a legitimate economy—it's government propped up subsidies that vastly encourage large farms run by a small number of people and production of gigantic monocultures. You can't simultaneously appeal to the importance of the free market and then use as your example something that is a completely government-mandated situation, one that has major economic and health implications. --98.217.14.211 (talk) 21:50, 19 September 2009 (UTC)

Not to drag this out more, but genetically engineered food is a huge boon and vastly safer than the alternative; The problem of corn in America has little to do with genetics, as is being said. The problem has everything to do with post-Depression era policies and a Nixon era racist named Earl Butz. Agribusiness is just that, a business, and diversity is bad for mass production. Say what you will about the current system, but without it a lot of people would die. As Bugs says, it's an industry worth subsidizing. We're doing it backwards (Butz pulled the rug out) but it usually works. That being said, there are tons of other problems, mostly related to nitrogen and antibiotics. ~ Amory (user • talk • contribs) 20:37, 19 September 2009 (UTC)

You seem to be implying that the alternatives are "everybody starves" or "we subsidize the industry the way we are currently doing it." That is not even remotely true, and it's a ridiculous false dilemma, and there are plenty of well-thought-out suggestions as to better ways to do it, both in terms of crop health and public health. Who are all of these people who would die without the current system? --98.217.14.211 (talk) 21:50, 19 September 2009 (UTC)

Plumbing - tap not running properly

I'm not sure if this is the best place to ask this question but here goes anyway.

The hot water tap on the sink in my bathroom isn't working properly. Even when fully turned on, there is only a trickle of water. The hot tap on the adjacent bath works fine. I have traced the pipework as far as I can but I can't trace it all the way back to the hot water tank because it goes into the concrete floor. The tank is located the other side of the wall from the offending tap. I am pretty sure that there is NOT one of those mini stop valves on the pipe feeding the tank as I can't see one and the pipework looks like it is original from the installation (1960s), when those valves were not commonplace. The HW tank outlet pipe has a red tap on it but as there is only one outlet then that can't be the issue if the bath HW supply is fine.

I also thought the tap itself might have seized up so I removed the screw and the head and that all looks fine. I have attempted to remove the main part of the tap but it is reluctant to come off (the whole tap moves rather than the part that is supposed to unscrew. I don't want to apply too much force in case it damages the ceramic basin. If there is anything that might be causing it then I will have another go at removing it but I'm not sure if there is any benefit from doing so. I have a book on basic plumbing and it has lots on dealing with a dripping tap but nothing about the opposite problem!

Any ideas please?

It certainly sounds like the pipe is clogged somehow. I would think the hot water feed to both the sink and the tub would be a common pipe that splits somewhere near the two. Does your book say anything about mineral buildup in pipes or anything like that? Baseball Bugs ^{What's up, Doc?} carrots 10:01, 19 September 2009 (UTC)

Thanks. Could well be limescale as I live in a hard water area but I've never heard of hot water pipes getting clogged in this way. My book mentions how to install a water softener but no mention of dealing with clogged pipes - I will look online later. 78.33.180.73 (talk) 10:08, 19 September 2009 (UTC)

The only thing you can do short of calling a plumber is to cut the water and the heater off and take the valve apart. If its clogged from build up then simply clean it good. Sometimes soaking in vinegar will help loosen lime build up. Rust buildup requires a little more aggressive chemistry. Try manual cleaning first. DISCLAIMER: This is not plumbing advice. For plumbing advice, please consult a plumber. Some States have laws. -- Taxa (talk) 10:13, 19 September 2009 (UTC)

They're obviously trying to avoid calling a plumber, as that can run into money. But unless they want to take their pipes apart, which is a risky thing to do if you don't know what you're doing, it's best to call a professional. Baseball Bugs ^{What's up, Doc?} carrots 10:16, 19 September 2009 (UTC)

About unscrewing, it may unscrew in the opposite direction. There's bits of plumbing that do that though I haven't touched any for a year or two so I've forgotten which. Dmcq (talk) 15:02, 19 September 2009 (UTC)

9 times out of 10 the tap will try to turn (rather than the top section), one has to use something like a large adjustable spanner to hold the spout of the tap - if that don't work, then it's mole grips or strap spanner on the tap body, but it's then difficult not to mark the tap body!  Ronhjones  ^(Talk) 18:39, 19 September 2009 (UTC)

Often the flow decreases because the aerator is clogged with scale.See [4]. This is a little combination of wire screen and plastic discs with hole in them, which screws onto the outlet of the faucet. If the flow is much greater (though maybe splashy) when the aerator is unscrewed, then either clean and reassemble the aerator as described in the site linked, or take the aerator to a hardware store (plumbing supply) and there should be a screwthread checker which you can try it on to determine the thread, then buy a replacement and install it. A plumber once quoted me a $3000 pipe replacement job to correct low flow, when the clogged screen in the aerator was the problem. It is the weakest link in the whole system, and the cheapest/easiest to correct. Edison (talk) 19:42, 19 September 2009 (UTC)

To get a feel for what is going on I would try to stop the water flow with a finger. If the pressure is high so that it's impossible to hold back the water, but still the water only trickles then there is a blockage in the tap or pipe leading to it. 1960's plumbing in a hard water area will almost certainly have scaling. Call a plumber. They have tools, muscles and experience to deal with this, including replacing the tap IF that is called for. Cuddlyable3 (talk) 22:16, 19 September 2009 (UTC)

If you do find that the pipes are hopelessly clogged with scale, it will be rather expensive to extract them from the concrete floor and replace them. A much cheaper alternative is to abandon the existing pipes and replace them with PEX tubing (flexible plastic tubing). You can drill a hole in the wall and run the tubing through there. Connecting the PEX tubing to the water heater and faucet may still require a plumber, but this should be far less disruptive and expensive than ripping up the floor. Another advantage is that, when the PEX tubing eventually clogs up, it will be far easier to replace. StuRat (talk) 03:34, 20 September 2009 (UTC)

A useful diagnostic test in this case is to turn the hot water off at the tank, remove what you can at the sink, and open the tap at the bath. blow in the pipe to see if the block is between the basin and the bath. Note that lots of taps wont let fluids go "backwards" through them. Polypipe Wrangler (talk) 06:27, 22 September 2009 (UTC)

Wave functions

Hi all! Another one from me again - thanks for all the help yesterday.

I'm trying to get my head around QM as best I can before the start of the year but i'm more of a pure mathematician at heart - it'd be great if I could get a hand with this!

Consider the time-independent Schrodinger equation given and show that for any real k, in 1 dimension,

ψ(x) = e^ikx(tanh(x) − ik)

is a solution for the potential $V=-{\frac {h^{2}}{m}}sech^{2}(x)$(I've done this bit), and find its (scaled) energy ε. Show that this is the wavefunction of a scattering state where the reflection probability vanishes. Find the transmission amplitude, and verify that the transmission probability is 1. Consider the extension (analytic continuation) of this solution to positive imaginary values of k. Show that for the value of k corresponding to the bound state at ε = −1, ψ(x) reduces to the bound state wavefunction, and that the transmission amplitude has a simple pole.

I'm fine with the first part and finding the scaled energy - the only way I can think of to do the next part is to consider a reflective potential barrier of height U(x,y) for some parameter y s.t. U -> V as y -> 0, wherein the limit of the wavefunction in this potential is ψ(x), but I'm not sure if that would work. After that, how do I go about finding the transmission amplitude/probability? I'm not meant to consider the integral of |ψ(x)^2| from 0 to infinity, because it's not normalisable, but I'm not sure how else to approach the rest of the question - thanks in advance for any help :)

Spamalert101 (talk) 11:50, 19 September 2009 (UTC)

For the real k case, I think you can just look at the limits of what ψ does as x goes to ±infinity, and make an argument based on that. I don't know about the imaginary k case. Rckrone (talk) 17:38, 19 September 2009 (UTC)

Obviously ψ behaves badly if k isn't real because of the e^ikx part, but maybe they just want you to consider what |tanh(x) − ik| does? That would produce a bound state at ε = -1, although I don't really know what it would all mean in terms of the physics. Rckrone (talk) 17:57, 19 September 2009 (UTC)

Oh I see. In that specific case where ε = -1, things don't go bad since the decay of |tanh(x) − ik| stops e^ikx from blowing up. ψ = sech(x). Still don't know what the physical interpretation of that is. Sorry about the rambling multiple posts. Rckrone (talk) 18:15, 19 September 2009 (UTC)

If you have a 1D wavefunction that looks like Ae^ikx before scattering and Be^ikx after scattering then the transmission amplitude is (by definition) B/A, and the transmission probability is the squared modulus of the transmission amplitude. Here "before" is to the left (−x) and "after" is to the right, since the wave is rightward-moving everywhere. -- BenRG (talk) 00:07, 20 September 2009 (UTC)

Blu Tack properties

Anyone have the thermal properties such as MP, thermal conductivity, flammability and hazards (when heated) of Bostick Blu-Tack? Also, whats it made from?--79.75.113.153 (talk) 14:58, 19 September 2009 (UTC)

[5] starts to give a description.

It's non conductive (I'm fairly sure), when heated the hydrocarbons will be driven off, (and can burn), when calcined the blue tack synthetic polymers also decompose leaving the mineral filler behind, as a friable white shape (the same as the original piece of blutak)

I don't know thermal conductivity.

You can search for "BluTak MSDS" , a MSDS] is a material safety data sheet which will give standard warnings and hazards for use. Found here [ http://www.bostik.co.uk/diy/safetyData/product/89] 83.100.251.196 (talk) 17:23, 19 September 2009 (UTC)

Galileo and gravity

The page on Galileo says that he did a thought experiment about dropping objects of different masses to see that they would all fall at the same rate. My question is, how would he have been able to have even thought about gravity since gravity wasn't discovered until Isaac Newton was hit on the head by a falling apple many years later? --70.129.185.53 (talk) 16:11, 19 September 2009 (UTC)

See gravity. What Galileo (might have) thought about was "dropping objects of different masses", regardless of whether he had a concept of "gravity". Nobody "discovered" gravity. What Newton did was develop a theory and give the concept a name.--Shantavira|^{feed me} 16:23, 19 September 2009 (UTC)

The key thing Newton did was work out a universal theory of gravity - that is, he worked out that what makes apples fall off trees is the same thing that keeps the Moon in orbit around the Earth. People knew that things fell down before that. --Tango (talk) 17:52, 19 September 2009 (UTC)

The real story about Galileo and dropping differently-massed objects does not involve him tossing cannonballs from the Leaning Tower of Pisa.

Galileo's actual area of expertise, both before and after his telescopic discoveries, was in the field of falling objects, usually balls rolling down an inclined plane. It hardly took someone of Galileo's brains to notice that, unless caught by the wind, objects fall downward. Aristotle's theory of gravity, in part, stated that solid objects fell toward the center of the Earth because they shared an "Earthly" nature. His followers now almost two thousand years after his time, added the corollary that the more massive the object was, the faster it would fall. Galileo (who, in fact, was an Aristotelian himself) knew from his experiments that, to the best that could be measured, this wasn't so. There were two possible alternate corollaries.

1. Suppose a heavy cannonball were chained to a much lighter one, and the combination were dropped from a height. The standard theory said that the combo should fall faster than the heavy one alone, as the lighter one's weight should be added to that of the heavy one. However, since the lighter one, under the same theory, would not be attracted to the Earth as much (notice that they hadn't yet distinguished between weight and mass), the combo should fall more slowly than the heavy one alone, as the lighter one would be holding it back. Since the same theory and reasoning resulted in contradictory and opposite results, it was clear that the theory itself was invalid.

2. Galileo proposed that the actual mass/weight didn't matter and that given certain constraints, objects experienced the same acceleration downward. (Please do not bother posting anything about terminal velocity, air pressure, the shape or cross-section of the falling object, or inexact timepieces. Don't even think about trying this experiment in a rising elevator with an infinitely long shaft.)

Now what happened is that when Galileo, in Padua published the results of his experiments, a gentleman in Pisa disputed his results. Galileo, in what was for him only a mild rebuke, suggested that the other fellow try thr experiment from his town's cockeyed Bell Tower. As far as is known, the experiment has never been tried. (The Apollo 15 test was done in vacuum.) B00P (talk) 19:31, 19 September 2009 (UTC)

Brainiac did the experiment in one episode - it was quite impressive. They tried various household objects dropped from a crane and found that, as long as both objects were very heavy (so air resistance was minimal), it really did work. A car and a tire fell at almost exactly the same rate. --Tango (talk) 21:15, 19 September 2009 (UTC)

They used to allow people to walk unsupervised to the top of the Leaning Tower. Someone must have tried the experiment at some point. -- BenRG (talk) 22:10, 19 September 2009 (UTC)

All objects with the same air resistance fall at the same rate?

Isn't this claim by Galileo false, since, while Earth would exert the same gravitational force on both objects, the heavier object would exert slightly more gravitational force on Earth, meaning it would fall slightly faster? --75.28.52.196 (talk) 16:25, 19 September 2009 (UTC)

The mass of earth is estimated at 6 * 10**24 kilograms. That's in comparison to, say, a 1 kilogram weight. Think of the difference between 1 kilogram and 10**24 kilograms and you'll get an idea of how negligible such an effect would be - basically unmeasurable. Baseball Bugs ^{What's up, Doc?} carrots 16:34, 19 September 2009 (UTC)

A bit of care with terminology is warranted in this situation. While both bodies see the same gravitational field, the massive object experiences a much stronger gravitational force than the light object, in direct proportion to their two masses. The effect is what we expect — both objects experience indentical acceleration towards the center of mass of the Earth-object system. As the original poster notes, the Earth must experience a reciprocal gravitational force, and therefore by accelerated 'upwards' towards our falling object. (This must happen in order to conserve momentum in the Earth-object system.)

That being said, for nearly any measurement one is likely to perform on or near Earth the increased acceleration will be infinitesimal. As Baseball Bugs notes, the mass of any test object is likely to be many, many, many orders of magnitude smaller than the mass of the Earth. The place where such factors is important is in modelling the interactions of astronomical objects. The Moon, for instance, weighs a little more than 1% of the Earth's mass; its orbit is therefore a little faster that it would be if we were to replace it with a smaller chunk of rock. TenOfAllTrades(talk) 16:53, 19 September 2009 (UTC)

There is no increased acceleration really - at all, not even a small negliable amount - see the link below.83.100.251.196 (talk) 17:15, 19 September 2009 (UTC)

They are talking about a difference in the acceleration of the Earth, not a difference in acceleration of the objects. Rckrone (talk) 18:03, 19 September 2009 (UTC)

The force equation is F= G M_earthM_object / r²

But acceleration is Force/mass ie a = F/M_object

Therefor the acceleration is a= G M_earthM_object / r² M_object

ie a= G Mearth / r2

Which is independent of the mass of the object.

This is the same equation as found at Gravitational acceleration 83.100.251.196 (talk) 17:13, 19 September 2009 (UTC)

You don't understand. The point of the question is that the test mass also accelerates the Earth (at least in principle), which causes the distance between the cetner of masses r to be reduced more rapidly than if you consider only the acceleration of the test mass alone. Hence it is correct, in principle, to say that heavier mass would fall faster (i.e. the separation distance r decreases more rapidly, everything else being equal) because in addition to it's own motion it also drags the Earth towards itself. Of course, in practice, these effects are utterly negligible unless both bodies are of astronomical size. Dragons flight (talk) 18:04, 19 September 2009 (UTC)

Oh I see - the net acceleration - that's easy it's:

acceleration = G ( M_earth + M_object )/ r²

83.100.251.196 (talk) 18:56, 19 September 2009 (UTC)

But the object comes from the earth, and so subtracts from the mass of the earth - thus M_earth + M_object is constant and independent of the mass of the object, making the mass of the object irrelevent.83.100.251.196 (talk) 19:12, 19 September 2009 (UTC)

You are saying that the feather falls just as fast as the hammer because of the attraction caused by the hammer still sitting on the lab bench? I like that answer. Completely irrelevant to the physics of the situation, but I like it. --Tango (talk) 21:18, 19 September 2009 (UTC)

Sort of.. Even weirder is this - two masses m1 and m2 in vacuo on the surface of a much larger earth sized body of mass M , radius R - then raise one of the two smaller masses to height x (x << R)..

The net accelleration of the 'earth' and falling masss bodies towards each other is larger for the smaller mass... ie the smaller mass falls faster. (equation is fairly simple to get taking into account all the forces)83.100.251.196 (talk) 22:19, 19 September 2009 (UTC)

I don't think that Galileo ever said that. It's certainly not true: a baseball and an equal-sized iron ball have the same air resistance, but fall at different rates, as Galileo knew very well. Looie496 (talk) 17:53, 19 September 2009 (UTC)

In any case, a baseball and an equal-sized smooth and round object should not have the same air resistance, due to the seams and other irregularities on the surface of a baseball. But in a vacuum, they would drop at the same rate. Baseball Bugs ^{What's up, Doc?} carrots 19:12, 19 September 2009 (UTC)

I agree that even if two objects are the same size and shape, with the same surface texture, therefore having the same "air resistance", the heavier one will fall faster in air. Edison (talk) 19:34, 19 September 2009 (UTC)

Could you expand on the justification for that - is it contrary to the inverse square law of gravitation? I got no change in acceleration for different densities as a first, and second approximation (taking in to account the motion of the earth as well see above)>83.100.251.196 (talk) 20:27, 19 September 2009 (UTC)

Let's try a thought-experiment, although the first part is easy enough to actually do. Take two idendical pieces of typing-paper. Crumple one into a ball. Hold them at arm's-length from your body, one in each hand. I would be willing to bet large amounts of money that the crumpled sheet hits the floor first.

The theoretical version takes place in a vacuum; air resistance is, therefor zero. I would imagine that most people would be willing to concede that under those circumstances the two sheet would land ximultaneously.

Now it doesn't take much to move from "same-mass, different shape" to "same-shape (and volume, thus congruenr)", but "different mass." B00P (talk) 19:54, 19 September 2009 (UTC)

An object falling with air resistance has two forces acting on it: gravity and friction. Two objects with the same shape and different masses both have equal acceleration due to gravity, caused by unequal forces (the forces are proportional to their respective masses). On the other hand the objects have equal force acting on them due to friction (assuming the same velocity), which produces unequal accelerations. Thus the net accelerations are not the same. Rckrone (talk) 21:05, 19 September 2009 (UTC)

That makes sense - so for a given velocity (same shape/size different density) the air resistance is the same, but relatively less than the accelerating force on the heavier object.83.100.251.196 (talk) 21:13, 19 September 2009 (UTC)

In a vacuum, acceleration is the same no matter the mass or shape of the object. The experiment is high school physics was a ball and a feather. Obviously they drop at different rates in air, due to air resistence. In a vacuum tube, they drop at identical rates. So far so good. Now consider a hollow pingpong ball and one filled with something. I'm trying to figure why they should drop at different rates in air. I'm supposing it's because the lighter ball has trouble "cutting through" the air - kind of like the feather. But if you take two fairly heavy balls of somewhat different sizes and drop them, they should hit the ground at pretty close to the same time. I think Aristotle claimed if one ball was twice as heavy, it would it the ground in half the time. However, it's only a small difference - the difference caused by a little more air resistance on the smaller (lighter) ball. And in a vaccuum, they fall at the same rate. Have I got it right now? Baseball Bugs ^{What's up, Doc?} carrots 21:27, 19 September 2009 (UTC)

The force of air resistance only depends on shape and speed, but the acceleration also depends on mass because a=F/m. -- BenRG (talk) 22:17, 19 September 2009 (UTC)

Something doesn't make sense here. Two objects of different masses, dropped at the same time from the same height in a vaccuum, will hit bottom together. Their acceleration is the same, regardless of their mass. Baseball Bugs ^{What's up, Doc?} carrots 05:47, 20 September 2009 (UTC)

It does make sense. Gravity depends on mass, acceleration depends on mass, air resistance does not. --194.197.235.240 (talk) 12:03, 20 September 2009 (UTC)

Are there any pleasant wildernesses left in the world?

I saw a tv programme about a man travelling on foot through the Yukon in Alaska, USA. The Yukon has I believe extremely cold temperatures in winter, and looked like it may have mosquito or midge problems. Are there any wildernesses left in the world that are pleasant places to be in, without much danger, health risks, or extreme climate? Or have all these areas now been settled by large human populations and hence are not wildernesses? 78.144.252.66 (talk) 18:54, 19 September 2009 (UTC)

I think it unlikely that there has ever been such a thing as a "pleasant" wilderness from the human viewpoint. If the climate is "pleasant", it will be teeming with life, including a variety of life forms that would be very happy and eager to consume you, or parts of you. That's why we build houses. With screens to hopefully keep the bugs out. Baseball Bugs ^{What's up, Doc?} carrots 18:57, 19 September 2009 (UTC)

The most pleasant areas are the most attractive for settlement. So no. Vranak (talk) 19:03, 19 September 2009 (UTC)

Woody Allen said it best: "Nature... is basically a gigantic restaurant." Baseball Bugs ^{What's up, Doc?} carrots 19:09, 19 September 2009 (UTC)

Parts of Tasmania or some of the cooler parts of Australia perhaps? 78.144.252.66 (talk) 19:10, 19 September 2009 (UTC)

What degree of "wilderness" are you looking for? There are certainly many national and state parks in the US that are pleasant to hike in. Rckrone (talk) 19:31, 19 September 2009 (UTC)

Likewise, depends how you define pleasant. Still, I'd recommend enormous portions of the American Northeast (NYS especially) and definitely the Rockies in the West (Wyoming in particular). They are breathtaking, and as long as you have a map, compass, and some rope for a bear hang, you'll be fine. I've never been happier than when I was out there. ~ Amory (user • talk • contribs) 20:23, 19 September 2009 (UTC)

There are wildernesses both with warm (africa, S america) and cold winters (wear a bear skin etc) , but I can't think of any that lack large predators - possibly a small island somewhere - maybe madagascar, or somewhere in indonesia. Even so there are still likely to be stinging flies, tropical diseases and possibly snakes.83.100.251.196 (talk) 20:31, 19 September 2009 (UTC)

Most of the Northwestern third of the state of Maine in the U.S. is relatively wild; there aren't even any state-maintained roads or anything, its probably the closest thing to untouched wilderness in the northeatern U.S. that there is. See Maine North Woods and Maine Highlands. --Jayron32 21:32, 19 September 2009 (UTC)

There are several areas of nice moorland in England, does they count? --Tango (talk) 21:40, 19 September 2009 (UTC)

I have to make a minor correction to your post. The Yukon isn't "in Alaska", it's a Canadian territory which is adjacent to the US state of Alaska. StuRat (talk) 03:17, 20 September 2009 (UTC)

The Yukon is also the name of a river that runs through both the state of Alaska, and the Yukon Territory. I assume they were referring to the river. Googlemeister (talk) 13:29, 21 September 2009 (UTC)

Hmm, in that case "...traveling on foot through the Yukon..." river would lead to some mighty wet and cold feet, unless it was frozen over, in which case that would be traveling "over" the Yukon river, not "through" it. StuRat (talk) 19:31, 21 September 2009 (UTC)

The Olympic Wilderness is quite pleasant and generally lacks in mosquitoes and extreme weather/climate, etc. Pfly (talk) 04:30, 20 September 2009 (UTC)

English (and Scottish) moorland is pleasant but you're never far from habitation. I'd go with Tasmania. One neat thing about Tassie is that you can look up at a clear sky; unless you're north of Hobart airport there are no flightpaths overhead and therefore no contrails.--Shantavira|^{feed me} 07:34, 20 September 2009 (UTC)

+1 for Tasmania. Come and say hello too. You'd be silly to go for a wander in the south west without the right equipment and so on though. Noodle snacks (talk) 09:27, 20 September 2009 (UTC)

Scotland - You could plump for the Outer Hebrides, fairly quite - unless you go way out to St.Kilda (uninhabited) - I find you tend to get rather too many biting midges in the summer in West Scotland.  Ronhjones  ^(Talk) 19:07, 21 September 2009 (UTC)

My guess isw there are pleasant wildernesses in South America, as previously mentioned, and probably in the warmer southern parts of the former Soviet Union. As they have few people and are undeveloped (thank goodness), then necessarily they will not create much publicity. I expect that even in hot areas such as Africa or Mexico, there must be pleasant areas where altitude makes it cooler. The far east must have many wilderness areas, with a tropical climate. 84.13.198.33 (talk) 10:15, 20 September 2009 (UTC)

I may be a little biased, but I have to put in a vote for New Zealand, in the south in winter it can be a bit unpleasant but everywhere else for most of the year is very nice.

I would opt for the island of Kahoolawe in Hawaii. It was traditionally used as a bombing range, but not anymore and is not inhabited. Granted it has little in the way of fresh water, but if the intended population is very small, that is less of a concern. One note is there might be unexploded ordinance laying around. Whether it would be enough to constitute danger... Googlemeister (talk) 13:34, 21 September 2009 (UTC)

Antihallucinogenics

Is there a name or category for drugs which cure hallucinations? Now that I think about it, do any such drugs exist? Vimescarrot (talk) 22:39, 19 September 2009 (UTC)

antipsychotic drugs are one recourse for poeple who are having a 'very bad trip', though I don't know if this is to prevent panic psychosis etc, or if they actually stop the hallucinations. - though there are typically supposed to be active on the same neurological sites that are thought to be related to psychosis and halluncinations (serontin receptors etc). Looking at hallucinogen and the various receptors responsible for hallucinations might be helpful in your research as well.83.100.251.196 (talk) 22:51, 19 September 2009 (UTC)

On the web I've seen Ziprasidone described as an anti-hallucinogen - but it seems that it is conventionally classed as an anti-psycotic.83.100.251.196 (talk)

There are so many types of hallucination I think there may be other drug types that can deal with them.83.100.251.196 (talk) 22:56, 19 September 2009 (UTC)

For hallucinations induced by 5-HT2A receptor agonists (LSD and most other psychedelics), a 5-HT2A antagonist should work (which many antipsychotics are). For deliriant-induced hallucinations, muscarinic receptor agonists should work. If you have been convinced that cannabis causes hallucinations, then I guess you should believe a cannabinoid receptor antagonist will cure those hallucinations. --Mark PEA (talk) 00:31, 20 September 2009 (UTC)

Neither Wikipedia, nor her editors, nor the Wikimedia Foundation, nor any affiliates thereof assume any liability for any injury, harm, or fatality, to you or others, that may result from misuse of these medications based on advice given herein. Intelligentsium 02:41, 20 September 2009 (UTC)

I don't think any antipsychotic drug will "cure" a hallucination. They are usually part of a long-term psychological monitoring and medication process. It's very doubtful that they would have an immediate effect to "stop a bad trip" as might have been implied above. Nimur (talk) 02:50, 20 September 2009 (UTC)

Ah I just remembered the drug that is often given to "screaming lunatics" picked up by the police (a doctor does this, not the police obviously) was Temazepam which is not an anti-psychotic - but I believe is given to calm them down and prevent them harming themselves or others. Another reason to not take anecdotal evidence from strangers on the internet - sorry if that misled anyone.

Nevertheless anti-psychotics are/were used as medication for conditions that include medication, and do (in some cases) prevent the hallucinations. This can be checked via studies, I remember that Oliver Sacks described such a case in one of his popular books.83.100.251.196 (talk) 22:43, 20 September 2009 (UTC)

The situation is complicated by the fact that some hallucinations may not be 'chemical' but 'wiring' problems - synaesthasia might be an example of this, hallucinations brought on by brain damage or unusual brain structure are unlikely (?) to be dealt with by drugs.83.100.251.196 (talk) 09:41, 20 September 2009 (UTC)