Wikipedia:Reference desk/Archives/Science/2010 July 12

= July 12 =

Potable water caulking
Is anyone aware of a commercial product that's marketed or made for sealing potable water systems. In other words, it can come into contact with drinking water without risks? Obviously plumbing solder does this, but is there anything that's applied like a caulking? Even better if it can both metal and plastics, and withstand heat (up to 100 C)? Shadowjams (talk) 00:18, 12 July 2010 (UTC)
 * Wouldn't most silicone based caulks work fine for that? Here's one. I think if you look you will find lots of them. Ariel. (talk) 00:44, 12 July 2010 (UTC)


 * Some silicone caulks contain additives which may leach into water on prolonged (or high-temperature) contact. Kitchen and bathroom silicone caulking may contain antifungal agents (to discourage mildew).  Products marked as meeting ANSI/NSF Standard 61 (for potable water contact) are a good bet.  (Dow Corning's 732 and 748 sealants meet these standards: .)  Here's a searchable index of NSF-certified products. TenOfAllTrades(talk) 02:03, 12 July 2010 (UTC)


 * Thank you, that's perfect. I just hope I can find them. Shadowjams (talk) 02:57, 12 July 2010 (UTC)
 * They should be available at most decent sized home improvement stores. I am not sure what your location is, but in the US, places like Lowes or Home Depot should carry some of those.  Googlemeister (talk) 13:27, 12 July 2010 (UTC)

Symptoms of vasular dementia
Several years before he was diagnosed with vascular dementia, my grandfather had difficulty controlling the movement of his hands; we thought that it was perhaps Parkinson's disease, but (for reasons that I don't remember, as I was only a child then) the doctors eventually decided that it wasn't. Can vascular dementia cause symptoms like those of Parkinson's?  I've read the vascular dementia article and some things I found online, but nothing I've seen talks about it. By the way, please don't think that I'm asking for medical advice; my grandfather died in 2006. 71.79.87.249 (talk) 02:01, 12 July 2010 (UTC)


 * Many people dont realise the difference between Parkinsonism and Parkinsons disease. Parkinsonism refers to any condition that causes a combination of the movement abnormalities seen in Parkinson's disease — such as tremors, slow movement, impaired speech or muscle stiffness resulting from the loss of dopamine containing nerve cells (neurons). Not everyone who has parkinsonism has Parkinson's disease.

In the case of your Granddad, I THINK you are refering to a condition, what we doctors, call Lewy Body Dementia, which shares characteristics with both Alzheimer's disease and Parkinson's disease. Like Alzheimer's, it causes confusion. Like Parkinson's, it can result in rigid muscles, slowed movement and tremors.


 * But the most striking symptom of Lewy body dementia may be its visual hallucinations, which can be one of the first signs of the disorder. Hallucinations may range from abstract shapes or colors to conversations with deceased loved ones.


 * Apart from Lewy Body Dementia which I briefly explained earlier, other causes of parkinsonism include:


 * Stroke
 * Encephalitis, Progressive supranuclear palsy,
 * Multiple system atrophy, Corticobasal degeneration, Certain medications, such as some antipsychotics and metoclopramide
 * Head trauma, isolated or repeated, such as injuries sustained in boxing.--Fragrantforever 06:07, 12 July 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)
 * You might like to take a look at our article on Parkinson's disease, which describes the many different signs that a doctor would look for if s/he suspected Parkinson's in a patient. To add to FF's comment above, not all tremor in old people is parkinsonianism: parkinsonianism is quite distinctive to a doctor, although not necessarily to family members. Because Parkinson's disease is fairly well known among the general public and associated with "shaking hands", it is obvious to ask the question "does Granddad have Parkinson's, look how his hands are shaking", but the answer isn't always "yes". Physchim62 (talk) 11:32, 12 July 2010 (UTC)

The "vascular" in "vascular dementia" means that the problem is caused by an impairment of blood supply to the brain. The "dementia" part means that the problem has damaged parts of the brain involved in memory and cognition. Normally damage to those parts of the brain won't in itself cause tremor, but the vascular issues can easily extend to other parts of the brain such as the cerebellum and basal ganglia where damage can produce tremor. In other words, vascular dementia shouldn't cause tremor in itself, but the vascular problems that cause the dementia can also independently cause tremor. Looie496 (talk) 16:06, 12 July 2010 (UTC)

Simple circuit to charge my bike light batteries to supply my lights
I would like to charge a battery (possibly lead acid or possibly just a number of NiCds in a battery-pack) from my bike dynamo and in turn use those batteries to power rear and front lights arranged from LEDs. Can the simple circuit, suggested by Katie, 6 years old, from Sussex, do what I want? I only own a soldering iron and solder, so I don't want to use a PCB if I can avoid. There are some complicated designs out there for powering LED bike lights, but they would be very expensive and time consuming to build, considering I'd only produce one.

Notice that the lights are two-deep in series and then in parallel - if the forward voltage drop on the LEDs is 3.2-3.6v, should that be fine? I'd sooner not use a resistor, since I figure that just wasted energy.

Also, is the ammeter really necessary? It was just there in the design I copied with no explanation. --78.148.136.27 (talk) 03:08, 12 July 2010 (UTC)


 * (EC) As it turns out I'm somewhat interested in a similar thing although decided to go with a 18650 li-ion rechargable li-ion battery flashlight. But in the same vein I do like to understand what I'm buying so I have some knowledge of LEDs. Am I right you are planning to use an array of 5mm LEDs or something similar? Have you consider using one or more high powered LEDs like an Cree XP-G or XP-E or even a Cree MC-E or SSC P7 or heck if you really want a bright like may be a SST-50 or even a SST-90 (although I'm not sure if you really want to be generating 30W+ for the light) or something of that sort? This may be helpful. You may want to work out what sort of brightness you want (have you seen the output of a power LED?) and have some idea of what sort of beam profile you want (do you want it to throw a lot? Do you want it mostly flood?) Depending on what you use the heatsinked LED it self may bost around US$8-$15 shipped (well not if you want a SST-50 let alone a SST-90), a constant current driver of some sort (for your usage either a linear regulator or buck) from a place like DealExtreme or Kaidomain or Lightake would cost about US$3-US$5 or so shipped. This does have a PCB, but I don't exactly understand you aversion. If you get a already solder PCB you may need to do some touchup soldering particularly if it's from something like DX/LT/KD but it's not like you need to assemble everything from scratch. In fact depending on your set-up and how good your board is you the soldering may only involve wiring the LED to the driver and then the power supply. You will need to consider heat-sinking and probably water proofing. If you do want to use an array of LEDs you may still want to consider some sort of driver, again probably either a linear regulator or some sort of buck (see e.g. ). You could try direct driving and/or a simple resistor but of course this will mean the output will vary depending on battery charge and also is likely to be a lot more fiddly. The power supply I admit is not something I'm that familiar with particularly since you want a dynamo/battery set up but I presume it's something that's largely seperate. BTW, while you may be able to get some decent advice here, may I suggest a more specialised forum like  (be aware people in CPF in general may sometimes be a bit snobbish or have fairly extreme recommendations/ideas)   and maybe . Nil Einne (talk) 03:35, 12 July 2010 (UTC)
 * P.S. A constant current regulator which at best would likely have an efficiency of 90% may seem like a waste. But consider what I mentioned about maintaining a constant output. Also consider that if you overdrive the LEDs other then reducing life (potentially fairly drasticly) you don't necessarily get much more light output, on other words your efficiency isn't exactly improving. In any case, if you do choose a power LED, direct driving under you setup is probably not possible. Also if you are worried about efficiency, the efficiency of the LED clearly matters too, in such a case the XP-G driven at a lowish current may be a good bet as it's fairly efficient although you may also want to consider how this affects the pricing, complexity of the design and beam profile. Of course an XM-L would probably be even better but that probably won't be widely available until the end of the year. Nil Einne (talk) 04:02, 12 July 2010 (UTC)


 * Hey, thanks for your suggestions. I've moved my query to candlepowerforums and I seem to be getting good help - there's already a fair few people that have been addressing similar problems for some time. I've ultimately decided to power two XP-G LEDs and recharge a single NiCd while moving and use the NiCd to power some 5 mm lights while stationary.


 * I didn't want a PCB because I don't own the equipment to prepare one. What's the cheapest option? Any way to make my own circuit without having to eat away copper with acid?


 * Also, do you know why power LEDs are so frequently mounted on strange ninja stars?


 * Here is my present design (two other designs cobbled together). I don't understand it for the most part, but the designers of the other two circuits are very helpful!


 * I'm actually trying to modify the design to make it something that I can comprehend. Can you explain the highlighted region? Apparently, it boosts the power at moderate speeds, though I really don't see how. If anything, it should just slow current flow since it's flowing into a a capacitor rather than through the circuit. R1 looks like it compromises the rectifier. 92.25.105.88 (talk) 23:09, 13 July 2010 (UTC)


 * It is probably some sort of series resonant circuit (RLC_circuit) that uses the inductance of the generator. A capacitor in series with a inductance can have lower impedance ("AC resistance") than the inductance in it self. R1 has so high resistance that it should have a small effect on the rectifyer, it is probably there to make sure the electrolytic capasitors is never charged in reverse since that would destroy them. Without the data for the generator (frequency range, inductance, recistance, flux linkage) it is hard to analyze that ciurcit.--Gr8xoz (talk) 08:48, 15 July 2010 (UTC)

free GIS software that can do orthorectification?
(am putting this on the Science desk because I think that the type of people who use and understand GIS would be more prevalent here than on Computing)

Could someone please recommend a free GIS application that can handle orthorectification? I've got some maps with slight scanning distortions that I need to rectify and I can't pony up for a private license of ArcGIS :-) 218.25.32.210 (talk) 03:20, 12 July 2010 (UTC)

Question on 3D TVs
We were planning to buy a 3D TV and Samsung has launched the latest 3D LED TV which seems mouthwatering. My question is, will such 3D TVs show all programmes in 3 dimension or will it show only SELECTIVE/ special programmes which have to be shot with a 3D camera? Meaning to say will tennis balls and footballs appear to jump into our living room irrespective of whether the programme is shot in 3D or not?--Fragrantforever 04:28, 12 July 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)


 * Only selective. Keep in mind there are no 3D tv shows being broadcast, but you can get 3D movies. Ariel. (talk) 04:45, 12 July 2010 (UTC)
 * In the UK, the FIFA World Cup and Wimbledon were shown in 3D, certainly on Sky and, IIRC, on Freeview HD. See 3D_TV for further details. CS Miller (talk) 08:42, 12 July 2010 (UTC)

Thanks Ariel, so the TV doesnt convert 2D programmes into 3D? --Fragrantforever 05:02, 12 July 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)
 * No. The camera only records the image in 2D. You can't convert 2D into 3D (there are fake things movie studios do to make it look 3D, but it's not automatic). --mboverload @ 05:06, 12 July 2010 (UTC)


 * The TV cameras have to take two pictures for each frame of video - one for the left eye and one for the right. So this definitely requires special efforts on behalf of the TV companies.  There are a couple of movies that were made right before the 3D boom which were "converted" to 3D at some vast expense using clever computer technologies - but from what I understand, the result 3D experience was kinda pathetic.


 * There are much bigger problems with 3D though. A co-worker friend of mine bought a 3D TV to watch the World Cup on - and reported bad headaches after watching the first game.


 * There are many problems with using 3D technology for real-world footage. In a computer-generated movie (ToyStory/Shrek/etc), the graphics system can keep everything in perfect focus from zero feet out to infinity feet from the 'camera'.  In real world photography, they can't do that.  The Director has to decide at which distance the camera will be focussed and things that are closer or further than that are blurry.  When you see things in 2D, your brain somehow realizes that it's looking at a moving picture on a 2D screen and that your eyes should focus on the plane of the screen to get everything correctly focussed.  But in a 3D situation, you're being tricked into seeing the at all sorts of distances depending on the 3D cues in the movie.  But when you do that, your eyes are not focussing properly because the blurriness was 'built into' the image when it was filmed.   This is likely the cause of the headaches my co-worker felt.  It is hoped that producers and cameramen will learn to minimize this effect - but it's far from certain that they'll ever be able to get this 100% right.


 * Also, in order to produce 3D, two pictures have to be generated by the TV - some do that by halving the frame rate (resulting in somewhat jerky pictures) - others do it by halving the horizontal resolution of the screen (resulting in blurrier images than your TV would normally produce). So there is always some loss of quality when going to 3D.


 * Of course everyone watching the TV has to wear the special 3D glasses. My friend reports that this is OK when everyone in the family sits down to watch something...but when the TV is on for just one person - and the others are reading or playing with the computer or something - and only glance at the TV once in a while, the double-imaging you get without the glasses is really annoying/distracting.  (He also had one of his three pairs break when someone sat on them...they cost him $75 to replace).


 * So this is very definitely a "try before you buy" thing. You need to find someone who already has one of these - and watch at least a selection of 3D programs before you commit to spending a small fortune on one of these gizmos.   If you can't do that - then at least be sure that the store you buy it from will take it back and return your money within 30 days if you decide you can't stand it.


 * It's also a gamble at this point. Will a lot of people find the downsides to be something they can't live with?  If so, then 3D TV will die because the additional cost of broadcasting in 3D will not be cost-effective unless most families have the equipment to view them.  It's bad enough that they have to broadcast a separate Hi-Def signal as well as a regular TV picture.  To have to broadcast in 3D AS WELL will be painful when the initial novelty wears off.


 * SteveBaker (talk) 14:49, 12 July 2010 (UTC)


 * Another issue with 3d television and movies that doesn't seem widely understood is that the 3d effect only works properly if you keep your head upright. If you like to watch movies laying on your side, or even with your head at an angle leaning on your date, the 3d effect will be broken for you. I think this accounts for a good percentage of the headaches and "it doesn't work for me". (Though it's also true that some people have a very poor sense stereoscopy.) APL (talk) 16:13, 12 July 2010 (UTC)
 * Yeah - I didn't think to mention that - but you're right. If your head leans over to one side, the image will start to flicker "vertically" for you and the 3D illusion will gradually diminish.  Also it's not just that some people have poor sense of stereoscopy - it's that 5% of people don't have it at all! (See Stereoblindness) SteveBaker (talk) 14:55, 14 July 2010 (UTC)

Thanks everyone for such interesting and informative answers. Fragrantforever 06:24, 13 July 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)


 * keeping head upright - depends on the 3D technology in use. Some types use circular polarisation which continues to work properly at any angle. Others though, do suffer if you tip your head to the side. --203.202.43.53 (talk) 04:11, 15 July 2010 (UTC)


 * That is not true, the polarisation is not the only problem with leaning the head, the more fundamental is that the pictures shown are taken with a horizontal ofset while the brain expect a vertical ofset if you lean your head 90 degrees. If you turn the TV the same angle as you lean the head there will not be any problem but that is unpractical, especialy if more than one person is viewing the TV.--Gr8xoz (talk) 08:53, 15 July 2010 (UTC)

Gulf of Mexico Oil Spill
I understand the ecological brouhaha that Greenpeace and other champions cryout loud. But what I dont understand is, BP is a company which has agreed to explore the ocean surface to extract crude and supply the US Govt so that the crude can be used for its use. No company, in its right bearings, would deliberately sabotage itself and burst the pipes and kill its own staff to cause such a catastrophic oil spill. People argue, BP had subcontracted the operations of the rig to a third party who didnt maintain strict quality and good standards which resulted in this tragedy.

My question is moral issues aside, when a company agrees to undertake such difficult scientific procedure, like extracting crude from below the ocean floor, cant they have a clause in the contract which protects them from such unforseen calamities? Because everyone seems happy to blame the organisation while very little seems to be the focus on actually sitting together and using technology to solve this issue. ( Im not supporting BP here but was annoyed to see Obama's repeated press and tv statements blaming BP and offering nothing constructive as a viable option).

The reason why I ask this Question is, if hypothetically speaking the new cap fails to stop the flow and oil ccontinues to gush out, how long are we going to indulge in sabre rattling?--Fragrantforever 05:14, 12 July 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)


 * That's a political question and not appropriate for this Reference desk. Looie496 (talk) 05:25, 12 July 2010 (UTC)
 * It might make a good question for the humanities or misc desk, though - it's a basic problem with laissez faire - who pays for incidental damages that go beyond the ability of the one who caused it? And who is paying for damage to the Commons? --Stephan Schulz (talk) 09:29, 12 July 2010 (UTC)
 * You make it sound like BP was forced into extracting oil from the surface of the ocean; I'll throw you a hint: they weren't. They explored for the best locations containing the most oil, and either bought the drilling rights from another company or applied to the U.S. authorities for the right to drill there. They weren't forced into anything, they went into it for profit.
 * I do agree that disproportionate blame has been placed on BP given the regulations in the U.S. allowed for BP to do exactly what they did. They didn't break the law, and this could have happened to any oil-drilling company. Oh, yeah, and Transocean is an American company that is now owned by BP. I think morally that the company actually responsible for the disaster should cough up the funds, but of course, legally, the way it works is that the backbone company coughs up.
 * To answer your last question, the answer would be "until it's fixed". They're very confident the new 80,000 barrel cap will work, and they're confident the leak will stop completely by August, but if it doesn't then they'll just have to spend more and more on R&D, and on clean up and compensation. Eventually, if the matter is not solved, their worth will have dropped so low that a takeover is likely. There is speculation already that Exxon are looking at a buyout, and there is speculation that the British government would intervene should a takeover occur (because, unlike Cadbury, this is serious and if the UK loses BP, they're going to face serious consequences with pensions). As I say, though, that's just newspaper speculation.
 * In future, I'd go to the miscellaneous desk as this isn't really a science question. Regards, --— Cyclonenim | Chat 09:34, 12 July 2010 (UTC)
 * As a minor point of clarification, BP are not meaningfully a 'UK company' and the UK government itself does not own any BP shares (although both were the case some some years ago). BP is a multinational company and from our article "Around 40% of BP shares are held by UK shareholders, and 39% in the USA. BP's UK dividends represent approximately one-seventh of all dividend payments in the UK and form the basis of many pension schemes." Presumably their fractional share of US dividend payments will be somewhat less because the US economy is larger, but nonetheless BP's financial woes resulting from the accident will be not much less of a headache for the US as for the UK (as well as for the owners of those other 21% of their shares). 87.81.230.195 (talk) 22:14, 12 July 2010 (UTC)
 * As a minor point to the above, BP no longer pays dividends. Googlemeister (talk) 13:01, 13 July 2010 (UTC)
 * Indeed in terms of holding BP responsible, a lot of people have criticised the requirement for BP to pay the wages for all people affected by the moratorium (indeed I think it may go further then wages), BP themselves initially seemed to make a noise then I guess realised they weren't going to win that war so gave up. It is an odd thing because the moratorium is government imposed and while in response to the recent disaster, BP isn't responsible (okay as lobbyists they may be partially responsible but that's a bit far) for whatever shortcomings in US regulations and enforcement allows companies to operate faulty drilling sites which this disaster seem to have highlighted which have resulted in the moratorium. BTW Transocean is not owned by BP. The well that failed was built by Transocean but under lease to BP however. Transocean have a rather complicated history with a variety of mergers, acquisitions etc. They are listed in the NYSE and SIX and their headquarters is in Switzerland (was in the Cayman Islands for a while). Nil Einne (talk) 16:17, 12 July 2010 (UTC)

Thanks everyone for the answers... Im still new to Wikipedia and had by mistake posted this question here. I was replying to a few threads here on the science desk and instead of posting this in the Misc Section had inadvertently left this q here. My apologies. Only after posting I realised the folly but dint know how to shift the question to the Misc desk hence left this here.--Fragrantforever 09:45, 12 July 2010 (UTC) —Preceding unsigned comment added by Fragrantforever (talk • contribs)


 * Doesn't matter now, probably since the question is established on this desk, it won't be moved. --Chemicalinterest (talk) 11:01, 12 July 2010 (UTC)


 * The problem with insulating the oil companies from blame is that removes the incentive for them to take all necessary safety precautions - these companies need to understand that an oil spill of this magnitude is probably going to bankrupt them. Ideally, that should make them focus on well safety to a greater degree than they have been in the past.  As it happens, there is a 'cap' of (I believe) just 15 million dollars on the direct liability of an oil company for an accident like this - although they could be sued for much more.  BP agreed to waive that and are already several billions of dollars in the hole.


 * As for the time it's going to take, I should point out that:
 * The 1979 Ixtoc I oil spill in the Gulf of Mexico took 9 months to shut off - and it was in only 160 feet of water (versus 5,000 in this case).
 * The Exxon Valdez oil spill dumped just one tanker-load of oil onto the coastline in the Gulf of Alaska - yet the best efforts of their large cleanup crew was able to remove just 4% of the oil from the beaches for each year they worked on it.
 * 20 years after the Exxon Valdez disaster, an ecological survey said that it would take an additional 30 years for the ocean ecology in the area to recover.
 * So, since this leak is harder to get at than Ixtoc and spilled VASTLY more oil than the Exxon Valdez, the very best we should expect is for it to take more than 9 months to cap the well, more than 25 years to clean up the beaches and wetlands - and at least 50 years for the marine habitat to recover. But those are likely to be under-estimates if history is to be believed.  SteveBaker (talk) 14:29, 12 July 2010 (UTC)
 * Not if history is to be believed Steve, if the people who did the ecological survey are to be believed. It has been my experience (having lived in effected areas of Alaska) that these ecologists are not frauds necessarily, but the do seem to have an inherent bias against oil production.  Googlemeister (talk) 16:14, 12 July 2010 (UTC)
 * That's fairly irrelevant if they do their work properly. Do you have any evidence to the contrary? --Stephan Schulz (talk) 16:21, 12 July 2010 (UTC)
 * The burden of proof would be on them, not me. It is their paper and their hypothesis after all.  Googlemeister (talk) 19:52, 12 July 2010 (UTC)
 * They already did prove it. The folks at University of North Carolina at Chapel Hill (a well respected research establishment) did the study, referenced numerous other prior studies, and wrote a paper which was subsequently published in a reputable, peer-reviewed journal ("Science", Dec 19th, 2003).  The people who wrote the paper appear to be well respected in the field and have entirely appropriate qualifications.  That's the gold standard for scientific proof.  If you think they screwed up - you now need to do your own study and get yours published in a reputable, peer-reviewed journal.  Failing that, everyone should believe the UNC study and ignore your random, totally unsubstantiated (and...given the wealth of convincing evidence UNC presented...almost certainly wrong) opinion.  So either come up with some bloody good references - or give it up and admit that you have no real idea about whether they were right or wrong. SteveBaker (talk) 23:48, 14 July 2010 (UTC)


 * There's a legal concept: torts.  Guess what?  One might be liable for the extended damages caused by one's accidents.  Look it up.  To repeat:  "torts."  I realize it's terribly obscure and no one has ever heard of it, hardly, and for some reason Obama et al. are suggesting it applies to BP.  Crazy newfangled liberal idea! 63.17.82.101 (talk) 10:03, 14 July 2010 (UTC)
 * Right. I can't agree with those above who suggest that BP can avoid responsibility simply because they were operating within regulations.  Oh, criminal responsibility, sure; no mens rea and all that, but not liability for cleaning it up.  Suppose there hadn't been any regulations?  Would you then say they wouldn't be liable under any circumstances?
 * It could be different, I suppose, if the regulations had been not weak but simply bad &mdash; if they had actively required BP to do something that contributed to the disaster, or forbidden them to do something that might have stopped it. I vaguely recall that something like that was alleged against the Indian state in the Bhopal disaster; can't remember the details.  --Trovatore (talk) 23:39, 14 July 2010 (UTC)

Is it Normal, guys ?
A few question above someone's placed a question about an electronic circuit and given a link to it. What I find interesting and well...disturbing is the fact that the person is a six years old child ! I can't even imagine an Indian kid asking such question, they can't even wipe their noses properly at this age ! I doubt even if a high school passed out actually understands it fully ! What I want to know is this : Is it considered normal (by you wiseguys in West), or it is just once in while like Siamese twins! How do people view this trait in kids, especially the rightwing folks... Jon Ascton    (talk)  06:02, 12 July 2010 (UTC)
 * Just because it says 6yr on it, doesn't mean it actually is. 6 year olds can certainly copy a drawing like that, but don't think they could create the circuit on their own. Ariel. (talk) 06:12, 12 July 2010 (UTC)
 * In the UK, a child of six-year old wouldn't understand circuits. You might get a very, very basic knowledge (where the cells go, where the light bulb will go) at Primary education (say between 8-11) but the only real understanding of circuits comes during GCSE education, ages 15-16. This is then reinforced at A-level education if you choose to study electronics. I very much doubt a six-year old could have designed a circuit of this complexity. Regards, --— Cyclonenim | Chat 09:26, 12 July 2010 (UTC)


 * Haha! Sorry about that; it was just my quirky sense of humour - I put "Katie, 6 yr" since I noticed that it looked like something a child had drawn and sent in. I should try to find an open-source program for drawing circuits. :D 92.28.80.71 (talk) 09:54, 12 July 2010 (UTC)
 * You could try something like Eagle. It's not open source but it does work on more than just Windows (thought you might be on a Linux system).  Dismas |(talk) 10:30, 12 July 2010 (UTC)
 * I could understand circuits (like oscillators, timers, and light-sensing circuits (cover the photo cell and the streetlight turns on.)) when I was about 10 years old, but not 6 unless you have some very special training and high IQ. P.S. When I was around 10 or 11, I designed and built a circuit that would make noise if you left a door open. So much for Cyclonenim's understanding. --Chemicalinterest (talk) 10:56, 12 July 2010 (UTC)
 * Yeah - I think 6 years old would be a hell of a stretch. My father owned a TV repair shop and did aircraft radio and radar work on the side.  I remember that he had me playing with flashlight bulbs, switches and batteries before I went to primary school - so that would be at about age 5 or 6.  I had a reasonable understanding of series and parallel circuits and concepts like when you have the lights in series they don't glow as brightly - but there is no way I could have made the diagram that '92 drew.  At age 8, I became fascinated with relays and I built a little game using relays and light bulbs.  Each player had a button and a light bulb.  When you turned the machine on, a large capacitor (scavenged from an old TV set) would charge up over several seconds, causing a relay to suddenly trip and turn on a third light marked "GO!" - then the two players had to push their buttons as fast as possible.  The first person to do so lit up their light and prevented their opponent's light from turning on - so the person with the fastest reaction time won.  The "GO" light discharged the capacitor, untripped the relays and started the whole machine running again.  It took me weeks of fiddling around to get it all to work right - and it certainly involved a lot of trial and error because I didn't have the math to figure out capacitor time constants and such.  My father kept the gizmo in his office in a plexiglass case with my photo in it for several decades.  He brought it to show everyone at my wedding reception "as a warning for my wife" - and it was still working then.  But sadly, I don't know what eventually became of it. SteveBaker (talk) 14:12, 12 July 2010 (UTC)
 * Is it normal? No.  Do I think the person can't be six? No.  There are six billion people on this world.  At least one of them has to be smart enough to figure that sort of stuff out at age 6.  I've heard of (extraordinarily smart) people doing algebra at 4.  If I remember from physics, all you need is algebra to calculate how everything in your simple circuit should work. Falconus p  t   c 15:22, 12 July 2010 (UTC)

What's wrong with you Westerners. My parents taught me serial v. parallel around the age of six. I became especially interested in electricity at tha age of 8 after I picked up a book about it, and constructed my own galvanic cells and electroplating devices. (Didn't really understand the Nernst equation at the time though...redox potentials at the age of 10). Now if I had been shown those books at a younger age, maybe I could have drawn circuit diagrams at the age of six. I remember drawing blueprints for an especially large castle (I still <3 castles) at the age of six for a school project, and that's much harder than drawing a circuit diagram. John Riemann Soong (talk) 16:18, 12 July 2010 (UTC)

Oh interest and motivation are such more important than intelligence at this age. To this day, the foundation of my science knowledge started with the Magic School Bus and books on science and technology I picked out of my elementary school library. They actually contain a lot of info, which will lead you to learn how to draw a circuit diagram. The teaching method of the teacher is more important than the ability of the student. When I was in third grade in AMERICA, our teacher had us build telegraph circuits.... we had to know how an electromagnet worked. How to prevent short circuits. Things like switches and path of least resistance. For a third grader, trying not to mix up the receiver and transmitter citcuits took some thinking.

Then, when we wanted to hook everyone one of us (all 23) into a single telegraph network, we had to think hard how to do it. To me that's harder than figuring out that current*potential difference = power. Okay our teacher helped us a little, but we were in fucking third grade. Don't insult the ability of grade school children. John Riemann Soong (talk) 16:28, 12 July 2010 (UTC)


 * Just because education doesn't teach it doesn't mean a child couldn't learn it at that age. We have the Internet nowadays, as well as other sources. For example, I learned the basic times table at age three. There are also plenty of recorded cases of extraordinary mathematical or scientific talent in young children. Some preteens and teenagers have even been shown to be able to perform calculations that regular adults fail to complete. Never underestimate nerd power (what, no article?!). ~ A H  1 (TCU) 00:57, 13 July 2010 (UTC)


 * @John Reimann Soong - 3rd grade (here, at least) is quite different to age 6. My 3rd grade (9 year old) daughter is capable of a whole lot of understanding and practical thought. At age 6, in kindergaten (the year before 1st grade), she was not nearly so capable. --203.202.43.54 (talk) 04:21, 15 July 2010 (UTC)

omniverse
Does the omniverse exist? —Preceding unsigned comment added by 220.253.104.38 (talk) 09:36, 12 July 2010 (UTC)


 * That rather depends on what you mean by "exist". As a self-consistent concept, it certainly exists in the same sense as the empty set, aleph null, democracy and Luke Skywalker exist. However, I don't think I would put it on the same plane of existence as the can of Diet Coke that I just drank, or the chair on which I am sitting. Gandalf61 (talk) 09:51, 12 July 2010 (UTC)


 * Maybe. We don't know.  It's very likely that we cannot possibly know.  The Many-worlds interpretation of quantum mechanics is (I believe) gaining traction as an explanation for some of the wierder things we observe here in our universe - but it is a smaller concept than the omniverse because it doesn't include universes where the laws of physics are different.  However, we probably can't formulate an experiment to prove the existence of a multiverse either.  But we've figured out some pretty weird stuff over the years - it's not impossible that we might some day know the answer.  Mind you, the concept of the existence of a can of Diet Coke that you just drank is philosophically tricky too! SteveBaker (talk) 13:45, 12 July 2010 (UTC)


 * Indeed ! But maybe that Diet Coke still exists in some parallel universe in which I decided to have a coffee instead. Gandalf61 (talk) 13:53, 12 July 2010 (UTC)


 * Actually the many worlds interpretation would not include an omniverse. Many worlds only describes universes with the same physical laws. Also, the diet coke/coffee thing is incorrect. The many worlds only splits when there is a non-deterministic quantum event. Deterministic events do not split. And it's extremely rare for a quantum event to influence the macro world (unless the brain is a quantum device - which would be very interesting if true, but I have not heard anything like that). Ariel. (talk) 14:41, 12 July 2010 (UTC)


 * Roger Penrose believes there is an intimate connection between quantum physics and conciousness - see The Emperor's New Mind. One possible explanation of free will is that it is a manifestation of quantum wave-function collapse at a macroscopic level. On the other hand, maybe I don't have free will at all, in which case I drank Diet Coke in every possible universe, and my Diet Coke now has even less existence than I thought ! Gandalf61 (talk) 16:07, 12 July 2010 (UTC)

I believe it exists, simply because any formally describable structure can be simulated using a computer. In our own universe described by the Standard model Lagrangian, there will always be a finite probability for some civilization to do exactly the right kind of computer simulation that gives rise to virtual observers living in a universe described by any other Lagrangian. You can think of this other Lagrangian as an effective Lagrangian implemented by the computer. Count Iblis (talk) 14:18, 12 July 2010 (UTC)
 * Simulation hypothesis. SteveBaker (talk) 02:25, 13 July 2010 (UTC)

Where the hell is Metadata?
Why this time I get no Metadata? Jon Ascton   (talk)  10:25, 12 July 2010 (UTC)


 * Some images have image metadata (data about the data), stored in a format like EXIF. And some don't. -- Finlay McWalter • Talk 10:33, 12 July 2010 (UTC)


 * I know that. All images taken by me have meta, this is the sole exception, why ?


 * Probably it was striped by whatever software you used to crop it. APL (talk) 15:35, 12 July 2010 (Utc)
 * When I change a photo, even just to crop it, the meta data is stripped by my software (Canon Zoom, in my case) as soon as I save the changed version.. Bielle (talk) 16:11, 12 July 2010 (UTC)
 * Usually to keep the metadata after editing, you'd have to upload the unedited version first to Wikipedia or Commons, then use an editing software that doesn't remove it and make the edit there. ~ A H  1 (TCU) 00:51, 13 July 2010 (UTC)
 * Alternatively, you can save the metadata from the original photo, and restore it to the edited one. The program exiv2 (let's see if that comes up blue) works pretty well at that, though the UI is a little strange (requires files to be named in a certain way). --Trovatore (talk) 22:44, 14 July 2010 (UTC)
 * Update: Apparently we don't have an article, so here's an external link instead: http://www.exiv2.org . --Trovatore (talk) 22:46, 14 July 2010 (UTC)

Is it a Fraud, a Cheap marketing stunt?
Please look carefully at this site. They are telling us these pictures have been taken with a Nikon Coolpix L20, a point-and-shoot thing ! Is it possible, you can see an actual Nikon Coolpix shot (taken by myself in above question ) and make a comparison of quality. Jon Ascton   (talk)  12:16, 12 July 2010 (UTC)
 * Looks fine to me. Quite a lot of photographic quality depends on the photographer's skill and his knowledge of his equipment; I'd say the equipment itself is a secondary concern at best.  Alternately, why do you expect the photos weren't taken with the camera in question? &mdash; Lomn 13:42, 12 July 2010 (UTC)


 * What I say is that the pics on the link given above seem clearly taken with a digital SLR, ask any expert


 * It's been reduced to 400 pixels wide - I don't see how you could tell: take a look at http://commons.wikimedia.org/wiki/Category:Taken_with_Nikon_Coolpix_L20 178.78.64.206 (talk) 14:03, 12 July 2010 (UTC)


 * Probably what you're seeing is the lighting. Your photograph is horribly lit with the camera's built-in flash.  The pictures on that web page are all using either natural sunlight or studio lighting.
 * Good quality lighting is a major factor in giving photos a "professional look". It is a major part of a photographer's art, but amateurs barely even consider it. It is far more important than the quality of the camera. APL (talk) 15:46, 12 July 2010 (UTC)
 * Is there a way to hack into the camera's firmware to allow you to manually set frameshutter speeds? John Riemann Soong (talk) 15:58, 12 July 2010 (UTC)
 * You can with several Canon cameras: Regards, --— Cyclonenim | Chat  17:21, 12 July 2010 (UTC)
 * ooh before I buy any Canons from eBay...which ones? John Riemann Soong (talk) 19:00, 12 July 2010 (UTC)\
 * List of cameras supporting a raw format, specifically the Cannon's saying that they require CHDK firmware. Basically, all of the Powershot models.  I recently put it on my camera, and, while it's certainly useful for giving you more functionality with your camera, I'm not sure I'd describe it as "turning it into a super camera".  The sensor's still the same size, and the lens doesn't change; those physical parameters are largely what limits the camera's picture taking ability.  I'm also not sure what you mean by "frameshutter speeds".  If you just mean Shutter speed, then most of the Powershots are capable of manually setting shutter speed anyway, thought eh CHDK may create a larger range of available shutter speeds. Buddy431 (talk) 20:26, 12 July 2010 (UTC)


 * Yep. If you could hack your camera and get great low-light shots photographers wouldn't be spending $1800 on a single lens. --mboverload @ 03:52, 13 July 2010 (UTC)


 * And having a large quantity of light makes it possible to take crisp pictures with small-sensor cameras (like a point-and-shoot). Indoors, it becomes necessary to lower the shutter speed (risking blur), raise the ISO (increasing graininess), or turn on the flash (which, with a point-and-shoot flash, will create garish highlights, and make everything look like it has a drop shadow).  I have a point-and-shoot, and an aversion to flash, so I have a whole lot of blurry, grainy pictures.  But they look good as thumbnails! Paul (Stansifer) 17:50, 12 July 2010 (UTC)


 * It's too bad they don't make the full-size originals available -- that would make it easy to tell. As is, the only indication that this is a small-sensor camera is the "indoors in poor light" portrait: the subject's hair displays the loss of detail typical of the noise-reduction algorithms used by these cameras. --Carnildo (talk) 01:01, 14 July 2010 (UTC)


 * For what it's worth, even at 400 pixels wide, you can see at least one major optical flaw: the Vignetting is terrible.  Look especially at "outdoors 2" -- the corners are noticeably darker than the center.  Personally, none of the SLR lenses I've owned have ever had vignetting this bad; I'd probably return the lens if it did.  Certainly believable it's a point-and-shoot. 128.12.174.253 (talk) 07:28, 14 July 2010 (UTC)


 * Using a tripod would help sharpness a lot, by removing camera shake. 92.15.9.213 (talk) 09:00, 15 July 2010 (UTC)

Octopus eye
Can octopuses see colors? Thanks. --Mudupie (talk) 10:29, 12 July 2010 (UTC)


 * Octopus says that some can, and some can't. -- Finlay McWalter • Talk 10:32, 12 July 2010 (UTC)
 * It's more likely that they can see colours than that they can understand the strategy and tactics of a football team! Physchim62 (talk) 12:37, 12 July 2010 (UTC)
 * The evidence is that Paul is attracted to flags with horizontal stripes in them - and octupii are known for being attracted to horizontal lines from prior studies - so that's no surprise. Now all we have to explain is why countries that have lots of horizontal stripes in their national flags are better at soccer than those that don't (except the USA who are crap at soccer despite their obvious vexillological advantages). SteveBaker (talk) 13:37, 12 July 2010 (UTC)
 * Well then why did England only manage a tie? Googlemeister (talk) 16:08, 12 July 2010 (UTC)
 * Have you seen our flag? Please pay attention. SteveBaker (talk) 01:43, 13 July 2010 (UTC)
 * Maybe the Brits need to hire an octopus to play goal. Then when he goes down on one knee to try and stop a kick, he'll still have 7 arms left. ←Baseball Bugs What's up, Doc? carrots→ 23:10, 13 July 2010 (UTC)
 * But the US has won the last 44 football championships! And they play 33% more than the Canadians! &mdash; Lomn 13:45, 12 July 2010 (UTC)
 * That's not football, as it uses neither feet nor a proper ball. It's the girly version of Rugby. --Stephan Schulz (talk) 14:19, 12 July 2010 (UTC)
 * Outside of actual warfare, American football is likely the most brutal sport on earth. ←Baseball Bugs What's up, Doc? carrots→ 23:09, 13 July 2010 (UTC)
 * Muay Thai? Mixed martial arts?  Or just hockey?  (Or maybe hockey is "actual warfare"....) --Trovatore (talk) 00:03, 15 July 2010 (UTC)
 * It's called football because it's played on foot rather than horseback. And historically soccer, or Association Football is the more correct British name. See: Names for association football. Football alone actually refers to Rugby (or used to anyway). Ariel. (talk) 14:47, 12 July 2010 (UTC)
 * New rule: no one is allowed to use the name "football" because it just leads to fighting. From now on we have soccer, rugby, and gridiron. The word "football" is banned. Also, none of those sports should be called girly by fans of any of the others. There—no more fighting, we can all be friends now. 24.68.50.170 (talk) 09:11, 13 July 2010 (UTC)
 * What should we call Aussie rules football and Canadian football? Googlemeister (talk) 12:59, 13 July 2010 (UTC)
 * We have an article on the Manly United Football Club. So, all that seems to be required is to find a suburb called Girly which is home to  the  Girly Rugby Team. --Cookatoo.ergo.ZooM (talk) 22:47, 13 July 2010 (UTC)
 * Hockey's not that violent Rojomoke (talk) 17:13, 15 July 2010 (UTC)

I don't understand the "Quantum" in Quantum Mechanics
Despite all the definitions I looked up, and all the explanations, I still don't understand Quantum. In the notes on the Intro to Quantum Mechanics, it states

"The word "quantum" comes from the Latin word for "how much" (as does "quantity"). Something that is "quantized", like the energy of Planck's harmonic oscillators, can only take specific values. For example, in most countries money is effectively quantized, with the "quantum of money" being the lowest-value coin in circulation. "Mechanics" is the branch of science that deals with the action of forces on objects, and so "quantum mechanics" is the form of mechanics that deals with objects for which particular properties are quantized. "

But I still don't understand. Why not call in Quantity Mechanics? What's the difference? 148.168.127.10 (talk) 16:44, 12 July 2010 (UTC)


 * Why do you say you don't understand it? A quantized thing can only take on certain values.  Saying something has a "quantity" does not imply any such thing.  Friday (talk) 16:53, 12 July 2010 (UTC)


 * Because I don't understand it! When you say certain values, what do you mean? If I have five apples, that's a quantity. If I were only allowed to have five apples, would that be quantum? 148.168.127.10 (talk) 17:09, 12 July 2010 (UTC)
 * If by some bizarre twist of physics, a person could only have 3 or 5 or 9 apples but not 4 or 6.5 or 12, we might say that the number of apples is quantized. And we might call this field Quantum Appleology or some silly thing like that.  Friday (talk) 17:23, 12 July 2010 (UTC)


 * So when we say light is quantized, that means it can only be a certain frequency to eject an electron from a material right? But that's not true, that's the minimum frequency isn't it. It can be more. So if applies were quantized, then that means 5 apples would be the minimum I can have, but I can have more. Is this correct? 148.168.127.10 (talk) 17:32, 12 July 2010 (UTC)


 * No, Light is said to be quantized because it comes in a whole number of photons. A pulse of light can have one photon or one trillion photons, but it can not have one and a half photons.
 * This can seem obvious now, but since it's not observable on a human scale it was once very controversial. APL (talk) 18:12, 12 July 2010 (UTC)


 * So as long as the quantity is in whole numbers, then it's quantized? So it doesn't matter how many apples I have, if I can only have whole apples, then it's quantized? 148.168.127.10 (talk) 18:32, 12 July 2010 (UTC)


 * Pretty much. A quantity can either be 'continuous' or 'quantized'. "Quantized" could refer to quantities that are restricted to any 'discrete set', but in practice it's usually integers. The opposite is 'continuous' quantities which are not restricted to any particular set.  APL (talk) 18:50, 12 July 2010 (UTC)


 * It's worth again stressing that it is contrast to continuous values. In the initial instances where it was applied — energy and light — that is a big deal. Energy and light come in little chunks. This is fairly counterintuitive if you deal with either of them. At the level in which quanta of energy or light actually matter, the physical laws get somewhat strange. This is why it has its own field of mechanics associated with it. --Mr.98 (talk) 18:58, 12 July 2010 (UTC)


 * What does discrete set mean? I heard it before, and I have an idea of what it means, but could you clarify? 148.168.127.10 (talk) 19:54, 12 July 2010 (UTC)


 * A set of points in a topological space is a discrete set if each of its points is isolated. Informally, for any point in the set, you can draw a small circle around it that contains no other points in the set. In the real number line (with the usual topology) the set of integers is a discrete set, but the set of rational numbers is not. Gandalf61 (talk) 13:01, 13 July 2010 (UTC)


 * I think the key here is the phrase "quantum of money being the lowest-value coin". Therefore, quantum mechanics deals with the smallest things: that thing which cannot become any smaller. That's the essence of quantum mechanics: mechanics which occur at the smallest size possible, if you like.--TammyMoet (talk) 17:19, 12 July 2010 (UTC)


 * I'm not sure I would put it like that. Molecular vibration is quantized for example, and an entire molecule is kind of "big".  Friday (talk) 17:26, 12 July 2010 (UTC)


 * Historically, the term "quantum" comes from "quantized." It specifically was the name given to the lowest unit of energy, a definitional thing. "Quantum mechanics" refers to mechanics which takes place at or around the scale in which one cares about individual "quanta" of energy. If they had named it the "Quantong" or the "Kwantog" or the "Querty" or the "Energon" we'd call it a different name. The term "quantum" predates its usage for the lowest quantity of energy, mind you—it is a generic term for "something that has a quantity." It had been used in different contexts in physics as early as the 1870s, though it was its use in the term "light-quantum" in the early 20th century that gave it its more common meaning. --Mr.98 (talk) 18:53, 12 July 2010 (UTC)


 * Had Herr Planck bothered to ask, I would have suggested "discrete mechanics", since it gets the "quantized" idea across in common language, and it describes the world at a scale that is very "discreet". :) --Sean 20:09, 12 July 2010 (UTC)
 * Ja, but if Nature is discreet, how will we unravel her secrets, eh? --Mr.98 (talk) 20:56, 12 July 2010 (UTC)

This simple experiment was done just over 100 years ago and found how electric charges are quantised as whole multiples of the charge of the electron. Cuddlyable3 (talk) 20:54, 12 July 2010 (UTC)

Temperature Fluctuations at the Equator
I was doing an online quiz recently and one of the questions was "In which months is it hottest on the equator?" The answer given was March and September. Is that correct? Why would it be warmer at the equinoxes than at the solstices? Rojomoke (talk) 17:11, 12 July 2010 (UTC)
 * (Unless I've got this completely backwards...) The solstices are when the sun is the farthest North or South of the equator it could go (23 deg, corresponding to the Tropics of Cancer and Capricorn). The equinoxes are when the sun is directly over the equator. Of these two months, one of them will be when the earth is physically closer to the sun because of its elliptical orbit, so all other things being equal only one of these is "the" hottest months. Zunaid 18:12, 12 July 2010 (UTC)
 * The sun is closest to earth in December. Googlemeister (talk) 19:50, 12 July 2010 (UTC)
 * January, actually. --Sean 20:18, 12 July 2010 (UTC)
 * Note also that the hottest month tends to lag a bit behind the month of most direct sunlight, so I'd think April or October is more likely. But yes, at the equator, "hottest" should be tied to the equinoxes rather than the solstices. &mdash; Lomn 18:17, 12 July 2010 (UTC)
 * In the northern hemisphere, the hottest month is usually July while the coldest is usually January. So for the equator, ignoring apsis, the hottest months should be April and October, as stated above. ~ A H  1 (TCU) 00:47, 13 July 2010 (UTC)

Insects repairing themselves
I have heard or read that insects (and maybe all arthropods) have little or no ability to repair damaged tissues, such that if you whack a flying housefly with your hand, even though you didn't squish it, the damage is sure to be mortal, as you have probably cracked its skin someplace. True? Comet Tuttle (talk) 17:37, 12 July 2010 (UTC)
 * Fascinating question. Well not all arthropods anyway : shrimp (and similar) for instance have the ability to heal - they molt their exoskeleton - and can grow back arms that have been bitten off. Don't know about insects.77.86.10.49 (talk) 18:36, 12 July 2010 (UTC)
 * A fascinating and delicious example of this is that you can break the claw from a live stone crab and then return it to the sea and it will just regrow a bigger one with little ill effect. --Sean 20:26, 12 July 2010 (UTC)
 * Here's a quote from a recent paper, : "Over a half century ago, Wigglesworth demonstrated that the large hemipteran insect Rhodnius prolixus has a robust wound healing response (Wigglesworth 1937). He characterized the response by light microscopy and described the proliferation and spreading of epidermal cells and the accumulation of blood cells (hemocytes) at the wound site. Since this pioneering work, only a few follow-up studies have appeared (Lai-Fook 1966, 1968). There has been little work on other insects aside from a number of studies of wound healing during imaginal disc and leg regeneration (Reinhardt et al. 1977; Truby 1985; Bryant and Fraser 1988) and the recent discoveries that Drosophila embryos undergo a scarless wound healing process involving actin cable formation and filopodial extension (Kiehart et al. 2000; Wood et al. 2002) and that wounded adult cells activate the Jun N-terminal kinase (JNK) signaling pathway (Ramet et al. 2002; see below)."
 * Thank you, anonymous editor. Looks like what I heard was close to the opposite of true.  Comet Tuttle (talk) 00:13, 13 July 2010 (UTC)
 * Oops, that was me. Looie496 (talk) 04:04, 13 July 2010 (UTC)
 * Insects to not experience inflammation, so the whole Wound healing cascade does not happen for them. Here's an article that is partially about that. I read a better one a while ago, but can't find it. Basically insects can repair some damage, but not as much as vertebrates. Ariel. (talk) 05:50, 13 July 2010 (UTC)
 * How about spiders? Can they actually regenerate their legs? Yaknow like when someone picks one up in a tissue to throw it outside and a leg comes off somehow and then comments 'Oh, it'll grow back - they can shed their legs to escape predators like lizards do with their tails'. Folk wisdom? --Kurt Shaped Box (talk) 06:14, 13 July 2010 (UTC)
 * They can regenerate legs when they moult, but it takes a couple of cycles to regenerate a full sized one. The legs don't directly grow back like in a lizard or starfish though. Also, I can't find any mention of this in wikipedia. Not under Moult, and not in Regeneration (biology) Ariel. (talk) 06:55, 13 July 2010 (UTC)
 * I have heard of lizards regrowing tails, but did not know they could regrow legs. Neat!  Googlemeister (talk) 12:58, 13 July 2010 (UTC)
 * Erm, uh. Sorry, that not what I meant. Lizards don't regenerate legs, just tails (but see ) - salamanders can though. Thanks for catching that. I should have written: The legs don't directly grow back like how a lizard or starfish can regenerate certain limbs. Ariel. (talk) 13:25, 13 July 2010 (UTC)

harnessing infinite?
Okay so I've been reading a lot about this stuff, searching for the answer to this question but nothing seems to address it. Pretend I'm five years old, please.

I understand that black holes are not only possible but extremely evident that they exist. But there's a mathematical freak out when you get to the center of the black hole called the singularity. Apparently this singularity thing drives scientists crazy cause we don't have any form of logic to explain what's going on, mathematical or otherwise, and to add insult to injury they keep finding more and more of these things.

Using the same logic that got them to black holes, scientist figure there could be a thing opposite of a black hole, coincidently called the white hole, which holds the same singularity as its sister. This one's weird because although it is indeed POSSIBLE scientist agree its not really likely to happen in nature.

I went on to learn that worm holes are actually a product of a pair of a black hole and a white hole. So, as long as you can survive the singularity (which you can't) you can go THROUGH the black hole and come out of the white hole.

This got me thinking (Thinking! I know. Dangerous, right?)

So, all these wise guys say that white holes are entirely possible, but they don't occur in nature. Well! I mean, coca-cola doesn't happen in nature but we make it anyways, right? And after the scare with the particle accelerator and the possibility of it sparking a black hole, I was all like, "Crap! We can MAKE them??" So, okay, if we can make a black hole can't the same be true for the white ones? Like if we were some how able to make some gadget that will stop just before the singularity, is it possible for this same gadget to have a function in which it reverses what the singularity does and create a white hole from a black one?

After having posed that question to myself, I considered the consequences of such a feat. Imagine a weapon of infinite energy or a fuel plant with the same infinite energy.

Also, while reading about this stuff, I found that Relativity suggests that once inside the event horizon time and space switch roles in that the path you are going in is inescapable like trying to avoid next Thursday. But they never addressed the properties of TIME inside the event horizon. So again, I dealt with the dangers of thinking and thought, "Hey! Wait a minute!" Can a guy with a time machine INSIDE the event horizon escape the black hole? —Preceding unsigned comment added by 65.3.131.144 (talk) 18:10, 12 July 2010 (UTC)
 * TLDR. If you want a proper answer ask a straight-up question; don't tell a long rambling story. Short answer: NO. Long answer: anything is possible in science fiction; if we were to consider such technology as causality-violating time machines to be possible then certainly gadgets that stop "just short of the singularity" and "turn black holes into white holes" can also be imagined. And no, black holes don't contain inifinite energy because they don't contain infinite mass. Zunaid 18:23, 12 July 2010 (UTC)
 * "TLDR" is rude as hell. The OP did break it up into paragraphs but they didn't get the formatting right so it wasn't clear. If it is too long for you to read and take seriously, just don't read it. Nobody is forcing you to. --Mr.98 (talk) 18:49, 12 July 2010 (UTC)


 * It's important to keep in mind that the workings of the singularity are somewhat mysterious. The "mathematical freak out" you mention is, as I understand it, considered by most to be an assertion that the current theory must be wrong (or, more likely, incomplete) in some way. As for whether we can make things that don't occur in nature, in principle, yes, indeed we can. (For example, a nuclear fission explosion can basically not occur in nature, at all, even though the principles on which it is based are utterly natural.) But in the case of black holes/white holes, I don't know enough of the details. If you introduce time travel, I think you end up going outside of the realm of what science can say. It would depend entirely on the assumption of the nature of the time travel if one was to make any sense of how it might hypothetically operate inside of a black hole. --Mr.98 (talk) 18:49, 12 July 2010 (UTC)


 * When modeling black holes in general relativity there is a singularity, meaning a place where general relativity breaks down and can't make predictions. That doesn't drive physicists crazy, it just means that we don't know (yet) what would be there. This is normal in science; there are always things that we don't know. White holes are not a source of infinite energy–they would have a finite mass/energy. It's not clear what difference there would be between a black hole and a white hole in a quantum gravity theory. In general relativity, black holes can be created but not destroyed, while white holes can be destroyed but not created. In quantum gravity, though, it appears that "black" holes evaporate after being created, which destroys them. There may be no distinction between black and white holes in reality. -- BenRG (talk) 19:26, 12 July 2010 (UTC)

The thing about the singularity at the center of a black hole is that it's safely cloaked by the event horizon. We can't know (much) about what goes on inside the event horizon - basically we know the mass, the amount of spin and the electrical charge on the black hole. So we can't ever actually know what happens inside. Maybe some unknown force at super-small distances stops the decline into a true singularity? Maybe temporal distortions inside the black hole mean that it can never actually reach that infinitely small dot - or that it'll take an infinite amount of time to actually get there. The actual result doesn't matter in any practical terms - the event horizon guarantees that nothing inside the hole can affect us out here (except for the mass, charge and spin which are all independent of whether there is an actual singularity or not). SteveBaker (talk) 22:10, 12 July 2010 (UTC)
 * I can't believe that no one's linked to the awesome cosmic censorship hypothesis yet. Sometimes, I think that physics gets all the fun stuff.  Paul (Stansifer) 03:22, 13 July 2010 (UTC)


 * Moreover, from the point of view of an outside observer it takes an infinite amount of time for anything to fall into the black hole (In other words, nothing ever really falls into a black hole), So sendding a gadget down the whole to change its nature is not feasible. Dauto (talk) 12:27, 13 July 2010 (UTC)

Rorschach test in job interviews
On Talk:Rorschach test/disclosure, someone made the claim that the Rorschach test is used in "job enterviews." What kind of a job would include a Rorschach test as part of its interview? The Hero of This Nation (talk) 18:13, 12 July 2010 (UTC)


 * I don't know about Rorschach in particular, but there are jobs which require psychological evaluations involved. Even quite menial jobs often have "personality assessment" as part of the application/interview process (I worked retail once for a major chain and they required me to do a multiple-choice psych form, I guess to make sure I wouldn't steal or something... it was fairly hogwash). Jobs that have high security components (like working at a nuclear power plant) probably require more in-depth evaluations. Again, I don't know about Rorschach tests specifically, but that is where I would be looking for more information. Of course, the specifics of the interview process for such jobs are likely not disclosed widely, as knowing ahead of time how they worked would probably jeopardize the purpose of such a test. --Mr.98 (talk) 18:39, 12 July 2010 (UTC)


 * For jobs that include psychological tests as part of the screening process, are the tests administered by trained psychologists? Is psychological testing regulated (in the U.S. or elsewhere) to ensure that only qualified people administer such tests? The Hero of This Nation (talk) 15:41, 13 July 2010 (UTC)
 * 1) Possibly, 2) No. Psychological treatment i.e, psychiatry is regulated but tests used by employers are often called "personality tests" which are unregulated. DISCUS is an example I encountered that consists of a PC program that puts multiple-choice questions on screen and spits out a report about what kind of job the testee is fit for. It seems the company qualifies anyone who buys their program by a short course (I have pages from the course and they are psychobabble.) There was a move by a Norwegian standards organisation to certify personality tests that ruled out DISCUS as undocumented. Cuddlyable3 (talk) 20:23, 13 July 2010 (UTC)

Is anyone here a doctor
Is anyone here a doctor? I'm sorry but not being or related to any real doctors most of what I know about the internal workings of the medical profession comes from medical TV shows ;) IN shows like House or General Hospital or Scrubs, etc., etc., the only clear division between what a doctor can and cannot do is whether they specialise in afiield of surgery or medicine. Other than that it seems an immunologist can be an emergency room doctor, a plastic surgeon can be a ("real") sergeon and a doctor of any specialty can be a GP. Is this correct? thanks —Preceding unsigned comment added by 68.76.146.113 (talk) 18:23, 12 July 2010 (UTC)


 * At least in the United States and the UK that's not the case. In the US one must be board certified, which is a test that one meets the standards for a specialty. Someone with that certification can function as that specialist (outwith the tutelage of a certified specialist). Template:Medical specialties boards lists many of the specific boards that certify specialists for different areas. That doesn't list general practice (is that what "family practice" means?). General practice is a  specialty in the UK at least - details are here. -- Finlay McWalter • Talk 18:42, 12 July 2010 (UTC)


 * I'm going to call on Finlay McWalter's phrase "In the US one must be board certified".  I don't think this is a must.  There are plenty of pediatricians, for example, who are not board certified, and plenty who are.  Comet Tuttle (talk) 20:42, 12 July 2010 (UTC)
 * I'm fairly sure you're wrong on that. Board certification exists to certify particular specialties, but in the U.S. there is no legal requirement that you be board certified to practice in a particular field. A plastic surgeon could legally change professions to neurosurgeon without any additional training or certification. Granted, malpractice insurance rates would skyrocket, and you'd probably have to set up your own practice (since most hospitals would reject that sort of career move), but an M.D. is legally allowed to practice in any field of medicine. &mdash;ShadowRanger (talk 20:44, 12 July 2010 (UTC)
 * In addition to denial of payment by many insurers, denial of admitting privileges by many hospitals, and denial of coverage by insurers, there are prohibitions against misrepresenting one's credentials, such that if a plastic surgeon said, "I am a neurosurgeon" (particularly in print or other durable material), then a variety of sanctions could be invited, both legal (fraud?) and professional (e.g. sanction by the physician's board in that state). It is true that a person trained as a plastic surgeon could practice neurosurgery - but only if the patient is foolish enough to sign up for a person who doesn't even profess the requisite credentials.  -- Scray (talk) 03:22, 13 July 2010 (UTC)
 * This section on GPs in the U.S. is pretty clear, and relevant to some of the comments above - the training of GPs in the UK is much more formalized than it has been in the U.S.; in contrast, Family Practice is a clearly-defined specialty. -- Scray (talk) 03:29, 13 July 2010 (UTC)
 * Also, in the U.S. a physician might complete a residency and be board-certified in Internal medicine, then pursue fellowship and sub-specialty board certification in nephrology. These certifications are through the ABIM. At one time, these certifications were lifelong, but around 1990 the system for renewal of certification was instituted, requiring testing and completion of training modules every 10 years (both in the specialty and in the sub-specialty) in order to represent one self as a specialist (or sub-specialist) in the respective discipline.  It is not enough to know whether the doctors has been certified, one needs to know whether they are certified (though the importance of this might be secondary in some situations where practitioners are not numerous).  -- Scray (talk) 03:37, 13 July 2010 (UTC)

I wouldnt take the TV Shows very seriously. Real life "doctoring" is much more interesting and rewarding than TV shows( Im speaking personally here). And it isnt so dramatic, we dont cry or fight at the drop of a hat and we literally dont sit and hold hands with every single patient, either. As a specialist in Emergency and Trauma Care, I see my share of busy whirlwind days and very quiet peaceful days - today is one such day;)) About your question as to how an immunologist can treat a patient in the ER or how a plastic surgeon can give GP advice, ofcourse we do it. And no one gets arrested or thrown in jail for that. Im authorised to see a walk in OPD patient ( If Im on OPD duty on that day) who might be suffering from a medical condition or surgical condition which doesnt relate directly to my specialisation. But in these days of heightened judicial activism and lawyers and patients waiting to pounce on a doctor for any small slip, normally doctors have become wary and play it safe. It ultimately boils down to what you personally choose. Medicine is an ocean and an art, a good surgeon can also be a good physican and a good gynecologist. Even though you choose to specialise in one particular field, you have to go through a vigorous rotating internship where you have to work in dirrerent wards, psychiatry, oncology, dematology and path labs and so on. So any doctor who takes his work seriously would definitely know much more than the mere basics of other specialities too. This is what they show in TV soaps albeit in a dramtic way. Usually doctors wouldnt go beyond their specilisation and give unwanted advice in other specialities only because there wudnt be much spare time to indulge in such luxuries. A specilist is always tied up with his/ her commitments and would only give advice if a specific request emanates from a friend/ another specialist. ( what we call internal referral). Another glaring error in TV "doctor" shows is that, they show doctors mixing their personal and professional lifes. In most cases, this isnt true. Even the best looking ( and most sought after) doctor would rather experiment outside his work environs. We do have patients who try and hit on us. We mostly ignore it with a smile. After all we are also responsible "thinking" humans who have loving families back home and unlike TV shows people dont drop their trousers at the drop of a hat.Fragrantforever 04:58, 13 July 2010 (UTC)
 * Dentistry works the same way -- specialty boards are basically a prank for specialty organizations to collect money. It's a cheap (er, expensive) trick that specialists use when they promote themselves as 'board-certified.'  DRosenbach  ( Talk 03:00, 14 July 2010 (UTC)

My water heater
Referring back to, I finally looked and found it is a State 510E. No web address, of course, since the concept didn't exist yet. Vchimpanzee ·  talk  ·  contributions  · 19:36, 12 July 2010 (UTC)
 * If you simply google 'state 510e water heater' (without quotes), the first several hits include forums discussing the appliance, in which you may find useful information. 87.81.230.195 (talk) 22:54, 12 July 2010 (UTC)