Wikipedia:Reference desk/Archives/Science/2006 August 16

"Black threads" in tilapia (edible fish) ?
I regularly eat freshwater, farm raised tilapia. It often contains what I would describe as "black threads". They seem to break apart easily. What are they ? Two thoughts I had were some kind of worm and blood vessels. I cook the fish before eating it, but still, if it's worms I think I'll switch to some other type of fish. I can try to take a pic, but they are quite small and my digicam is so-so, so I'm not sure how well they will show up. StuRat 01:28, 16 August 2006 (UTC)
 * Are you sure its not what was in the intestines of the tilapia? — [  Mac Davis ] (talk)


 * Sounds like veins to me. But it would depend on how thick they are. BenC7 04:44, 16 August 2006 (UTC)


 * I agree - it sounds like the blood vessels. - Cybergoth 22:36, 16 August 2006 (UTC)


 * I think I've seen the same, and I'd say it's veins / blood vessels. Nimur 23:28, 16 August 2006 (UTC)


 * Good, I'm not so grossed out now. StuRat 03:39, 17 August 2006 (UTC)

Safety Glasses
I recently sustained an eye injury, and my doctor insists I wear protective lenses to prevent something happening to the other eye and rendering me entirely blind. I've gotten polycarbonate lenses, which work well enough, but a friend of mine (whose father is, he says, a welder) wears a nifty set of dark glasses that are, he claims, actually shop goggles, capable of defending against flying metal debris. I handled them, though, and they seemed like the same sort of thin plastic thing you could get at WalMart. They must have been reasonably high quality, though, since they were so good at cutting out glare without effecting much else. What do you think? If I got a pair, would they really protect me? If so, can anyone offhand point me to a source? Black Carrot 05:44, 16 August 2006 (UTC)


 * I think having 100% coverage is more important than the material. So, try to get glasses that cover the sides as well as the front.  Most object flying towards the eye can be stopped by any glasses, so long as the object actually hits the glasses. StuRat 07:43, 16 August 2006 (UTC)

Polycarbonate is the toughest thing you can get for protective eyeware. The side-shields are necessary when you are working with flying debris. In Canada, nobody gets away with working on a job site without approved eyeware. --Zeizmic 11:56, 16 August 2006 (UTC)


 * They've got great coverage. In fact, that's part of why I'm interested in them - my damaged eye is still very sensitive to light at the edges, even though it doesn't really get an image, so I've been wearing those huge post-surgery shield glasses for awhile. The glasses my friend has, though, hug the edges of the eyesocket, so they keep out just as much peripheral light. As for the material, though, what do you figure these might be made of, and does it sound like they might actually be an acceptable substitute for the approved material? About the worst thing I can think of is having my glasses actually shatter into my eyes. Black Carrot 16:29, 16 August 2006 (UTC)


 * Polycarbonate is strong -- it's the stuff they make bulletproof glass out of. And based on the mechanical properties described in the article, it's a very ductile material, so you don't need to worry about it shattering: if something hits your glasses hard enough to go through, it's got enough energy to continue through your brain and exit the back of your skull. --Serie 23:20, 16 August 2006 (UTC)


 * Well, right. I recognize that. It's the glasses my friend has that I'm not sure about. I'm asking whether anyone can suggest based on the information I have (related to welding, full coverage, cut out glare, thin and flexible, etc.) what they might be made of, how strong they might be, and perhaps where I can get a pair cheaply if the first two work out. Black Carrot 05:33, 17 August 2006 (UTC)


 * Surely the thing to do is to ask your friend where he got them from, and then see if they are marketed there as safety glasses. In Britain I expect they would be marked with something that indicated that they complied with a British standard for safety glasses - but I'm only guessing.


 * I did ask him for details, but he couldn't remember any, and I don't remember any obvious markings on the glasses themselves. I've also asked him to see if he can get me a pair, which may or may not happen. I actually posted the question right after I first talked to him, figuring I could get a quick answer and perhaps order them online. Black Carrot 22:01, 18 August 2006 (UTC)

Bananas inducing gag reflex
I have an unusual question, but I'm sure you're used to that around here.

When I eat a banana, it often induces my gag reflex. I have nothing against the taste of banana, and, yes I do chew it (ie. not deepthroating a banana!). Any suggestions what might cause this?

Aaadddaaammm 09:43, 16 August 2006 (UTC)


 * Do you get similar sensations from other squishy foods? Sometimes the physical mouthfeel of food can be a very negative sensation. I don't mind the chemical taste of broccoli but the wet slippery squishy slightly grainy feel of it boiled...YUCK! Oh, and thanks for mentioning the chewing issue, that was my first thought when I started reading your question :-) Weregerbil 12:24, 16 August 2006 (UTC)
 * Try steaming it, or stir-frying it with a bit of garlic and some salt. Crispy broccoli isn't squishy! :-) Anchoress 05:42, 17 August 2006 (UTC)


 * A fellow programmer here had his gall bladder removed. Now, he throws up every time he eats bananas.  He doesn't know why (and is upset because he normally had a banana for breakfast every day).  I wonder if there is a relation between your problem and his. --Kainaw (talk) 13:00, 16 August 2006 (UTC)


 * The old banana gag : peel it and throw it some place, to see if someone shall fall. Please subscribe to a good insurance first :) -- DLL .. T 19:11, 16 August 2006 (UTC)


 * Bananas give me a similar feeling (like I want to gag), which is why I don't like them. I attribute it to the texture. Ironically, my husband, who won't eat fresh tomatoes because of the texture, enjoys bananas. --Ginkgo100 talk · e@ 20:24, 16 August 2006 (UTC)


 * I feel queasy and often have a gagging reflex when I eat a banana or anything banana flavored. I avoided banana for a long time and eventually mentioned this to an allergist.  It turns out that I was diagnosed as allergic to bananas and that this is actually a relatively common symptom for this relatively common food allergy.  For me, eating bananas produces no effects (rashes, swelling, etc) other than nausea.  Maybe you have the same issue? (The preceding comment is not meant to reflect any medical advise.  Please consult your physician.) -- C. S. Joiner (talk) 21:19, 16 August 2006 (UTC)

Two suggestions:

1) Make sure you don't eat any of the little strands that are between the meat and the peel.

2) If the sliminess bothers you, try eating them in oatmeal. I've noticed that this counters the effect, and I don't end up with my mouth feeling like it's coated with slime. StuRat 21:55, 16 August 2006 (UTC)


 * I had a cat who would put his ears down and run from the room whenever a banana was peeled, making me wonder what banana-related trauma he suffered before we got him. :-) StuRat 21:59, 16 August 2006 (UTC)


 * Lots of cats (such as my cat) do not like bananas either. Nimur 22:49, 16 August 2006 (UTC)

Bananas shouldn't leave your mouth feeling like slime unless they're under-ripe. Try giving them a day or two more before you peel them. (Not too long, though. Waiting till they're black is waiting too long, unless you're making a banana cake). And broccoli should never be boiled. No wonder you find it distasteful. Steaming (and light steaming at that) is the only humane thing to do to a broccoli, if you don't want to eat it raw. JackofOz 01:24, 17 August 2006 (UTC)


 * I disagree. All bananas leave a slimy feeling in my mouth.  I suspect they have something in them which isn't water soluble (perhaps a potassium compound ?).  I rarely eat a plain banana, for this reason. StuRat 03:33, 17 August 2006 (UTC)


 * Hmmm. Well, it seems you're not eating the same variety of bananas as I'm eating.  Or maybe they use some sort of pesticide or ripening agent over there that affects the taste/texture.  I've never had that problem with Australian bananas, and I eat lots of them.  JackofOz 09:36, 17 August 2006 (UTC)


 * You've apparently built up a tolerance to having slimy things in your mouth. StuRat 19:26, 17 August 2006 (UTC)


 * For the sake of common decency, I'll pretend you didn't say that. JackofOz 23:08, 17 August 2006 (UTC)


 * LOL. StuRat 00:56, 18 August 2006 (UTC)


 * I'm talking about the ubiquitous Cavendish banana. Many other people I know have made the same observation about the slimy feel they leave behind. StuRat 18:34, 17 August 2006 (UTC)


 * I'm pretty sure we eat Cavendish here too. I still reckon there must be something in the way they're treated before they get to the mouths of the American consumer that makes them that way.  Australian bananas are just not like that.  JackofOz 23:08, 17 August 2006 (UTC)


 * We use carbon dioxide to ripen them, I think. I can't see how that would make them slimy, however. StuRat 00:56, 18 August 2006 (UTC)
 * They probably use ethene to ripen them. --liquidGhoul 00:45, 23 August 2006 (UTC)

Numerical study of rotational effects for rotors
Numerical study of rotational effects for rotors It has been recognized that rotational effects can increase lift and at the mean time delay dynamic stall. Studying such phenomenon is very important for predicting rotor performance and optimising rotor shapes. A quantitative study of rotational effects has increasing needs for industrial usage. The project will focus on (1) numerical development of a modified Quasi-3D model based on the previous Quasi-3D model and (2) study the rotational effects at different spanwise distances and different angles of attack. please help me that how to design things(CFD/EFD etc ) that would help me in this research
 * When asking for free help, it is best not to cut&paste the exact assignment. Otherwise people might feel that they are being taken advantage of.  In fact, I remember there is something about this at the top of the discussion. --Zeizmic 15:18, 16 August 2006 (UTC)

Time course of evolution
Over what period of time or number of generations have evolutionary changes been seen? Specifically, have Sherpas and other peoples living in higher elevations shown genetic adaptation to the high altitude conditions? Thanks!24.5.103.166 17:01, 16 August 2006 (UTC) Scott


 * Modern humans are not under as strict selective pressures as other species (due to healthcare, the welfare state, and other societal considerations etc). This, combined with long lifespans, means "evolutionary changes" among humans are very difficult to quantify over generational timescales. Founder effects precipitate "evolutionary changes", but are often not advantageous (evolution does not occur with forethought, remember). There are examples of genetic variation that could, one could hypothesise, shape modern human evolution over quite short generation times, in the absence of modern healthcare. Consider the potential selective advantage of the CCR5-Δ32 allele during a global HIV/AIDS pandemic, for example.  Rockpock e  t  17:35, 16 August 2006 (UTC)


 * Outside of humans, there are many animals that have shown changes due to both natural selection (classical evolution) and human-controlled selected (breeding). For example, the common pet hedgehog has an abnormally high chance of being albino because humans have purposely overbred albino hedgehogs.  In the natural world, there was an article from National Geographic last month about evolutionary changes in the birds on the Galapagos Islands (the Darwin Species).  Also, I recently read about some green-brown tree frogs that are beginning to have the ability to turn white.  If it propagates throughout the tree frog population and doesn't die out as a weird mutation, it will be another evolutionary step for them. --Kainaw (talk) 17:51, 16 August 2006 (UTC)


 * There's always the same story about birch butterflies growing darker with pollution that darkens boughs. -- DLL .. T 18:59, 16 August 2006 (UTC)


 * Bacteria becoming resistant to antibiotics is a form of evolution. And, like Kainaw said, since you didn't specifically ask for natural evolution (natural selection), breeding animals to give them the characteristics we want them to have can also be seen as evolution. Actually, I think that farmers must have come up with the idea of evolution from the time they started doing that, thousands of years ago. The notion of evolution is a whole lot older than Charles Darwin (his father was a protagonist of the idea, for one). DirkvdM 19:02, 16 August 2006 (UTC)


 * You mean Charles Darwin's grandfather, not his father (who was an immensely large society doctor, like his grandfather, but not a reknown scientist, unlike his grandfather). Darwin did not invent the idea of evolution, of course, but is the one credited with the development of natural selection in particular as the mechanism of evolution, and propelled it into serious scientific discussion. But in any case selection by itself is not the idea of evolution, per se, which generally indicates population-wide effects and speciation, which breeders generally did not have any grasp of. It is actually quite a conceptual leap from manipulation of passive stocks to the idea that organisms can transmute into other organisms over generations, though it seems obvious once you know it. --Fastfission 00:16, 17 August 2006 (UTC)


 * Did I just become a referenced source? Black Carrot 19:54, 16 August 2006 (UTC)


 * I don't think so, and if you have, its been misinterpreted. Its unlikely that the tree frogs Kainaw refers to have recently evolved the ability to turn white. Most frogs and reptiles have this capacity so some extent (see chromatophore), they just don't tend to use it that often. Moreover, even if they recently acquire this trait, its unlikely it would become fixed in the population. There would be no obvious selective advantage to it. Infact, it is more likely to be disadvantageous, as the dearth of naturally occuring albinos demonstrates.
 * However, there are some interesting examples of pigmentary adaptation that has evolved over (relatively) short time periods. My particular favorite is the Rock pocket mouse. See also a recent study on Peromyscus .  Rockpock e  t  20:18, 16 August 2006 (UTC)


 * Actually, it was Black Carrot's question that led me to hunt down the article on white tree frogs in our library. Going from memory, the study (which didn't have conclusions - only study data) showed that tree frogs in northern Florida and southern Georgia were increasingly turning white when on white surfaces.  Tree frogs found in other areas turned green.  So, they wanted a grant to study if this is an evolutionary step in the tree frogs or have they always turned white and nobody noticed.  I don't remember who it was and I don't know if they got the grant.  But, I remember the tree frogs turning white.  I just remember weird facts and lose the source of them all the time. --Kainaw (talk) 20:16, 16 August 2006 (UTC)


 * Sorry, Kainaw, i accidently edited my comment after you reply. The grant you mention is asking the right question, of course, but i would be very surprising if it was a novel adaptive trait. There could be the result of subtle variation in chromatophore distribution or hormonal control. However, if this was a genuine novel trait, i would guess it is a subsequence of selection for another function of the gene involved, rather than selection for the colour change per se. This is usually the case with pigmentary variations that are not obviously cryptic in purpose.  Rockpock e  t  20:32, 16 August 2006 (UTC)


 * Humans do show evolutionary adaptations to different environments. For high altitude, there are three responses.  Humans who are from sea-level populations react to high altitude with increased concentration of red blood cells (and thus thicker blood) and a higher respiration rate.  I don't remember the details of the other two reactions, but peoples from the Andes mountains have a reaction similar to that of sea-leve peoples, while Sherpas and other peoples from the Himalyan Plateau have a different reaction entirely.  The time scales for these changes aren't known, but the Andes changes could not have taken more than 15,000 years. --Serie 23:36, 16 August 2006 (UTC)


 * I don't believe there is any evidence that these physiological adaptations are genetically encoded and thus a result of natural selection. Athletes from all populations undergo high altitude training to obtain the same effect. A similar example is from the Moken sea gypsies. This remarkable study showed that Moken children have underwater visual acuity that is more than twice as good as that of European children. This, it was suggested, could be the result of a novel evolutionary adaptation to underwater vision. This would have been an amazing find, but just this year the same authors demonstrated that it is actually a skill that can be learned, irrespective of genetic background . Of course, there is no doubt that human populations have evolved under selective pressures (or the lack thereof) - differences in skin tone between Equatorial and Northern European populations demonstrate that. Its just that correlating positive selection of an allele to phenotype is tricky at the best of times in outbred human populations. Putting a time scale on it is even harder.  Rockpock e  t  01:04, 17 August 2006 (UTC)


 * It is common for people to confuse evolution with adaptation. A single person will never ever evolve.  All of your evolution was done when your father's sperm hit your mother's egg.  Everything after that is mere adaptation.  Unfortunately, "evolution" is often used in place of "adaptation" in what should be credible sources.  It confuses the issue and fuels the fire for anti-evolution people who want to find any reason at all to prove that science is wrong. --Kainaw (talk) 01:15, 17 August 2006 (UTC)


 * It is genetic: that's why a flatlander will react in one way to high altitude, a Andean will react in another, simliar way, and a Himalyan will react in a third, entirely different way. --Serie 21:36, 17 August 2006 (UTC)
 * Do you have the primary source illustrating this genetic variation?  Rockpock e  t  06:39, 18 August 2006 (UTC)

There have been a few recent papers on selection in the human genome in different population, like this one.--Peta 00:19, 17 August 2006 (UTC)

Other things which seem to have evolved recently  MeltBanana  00:27, 17 August 2006 (UTC)

Fastfission, you say that "It is actually quite a conceptual leap from manipulation of passive stocks to the idea that organisms can transmute into other organisms over generations." Technical terminology aside, isn't it more likely to be the other way around? People started breeding animals for certain traits because they understood that could be possible. So they had some idea of selection. Extending that to natural selection does require some intelligence, but until not too long ago, intelligence was no guarantee to become a 'scholar', so there must have been quite a few highly intelligent farmers. Over thousands of years quite a few of those must have figured this out. Of course, lack of means to spread the knowledge meant the insight was probably lost when they died, so we won't know about them. But they must have existed. DirkvdM 06:43, 17 August 2006 (UTC)

Two things here. There are examples of Microevolution around, in which the balence of some population of a creature changes because of 'survival of the fittest' events. Examples to look at here might include The Beak of the Finch and the Peppered Moth. As for Macroevolution, the form of evolution in which new species of creature or wholly new characteristics arise, these tend to occur on a hugely longer timescale, mostly longer than we've been studying these things. One exception might be drug-resistant bacteria. DJ Clayworth 17:04, 17 August 2006 (UTC)

how to check qulaity of cyanoacrylate or super glue
i would like to know how do you check the quality of cyanoacrylate used as glue. i want to know the chemical tests possible and the common man's test, if any. what are the basic things to make sure that we get a good qulaity glue. i am looking for a super glue which sets in 1 to 2 seconds. thank you.
 * To check, apply a drop to two blocks of glass, press together for two seconds, and try to pull them apart. If you succeed, the glue was not super. --Lambiam Talk 18:08, 16 August 2006 (UTC)


 * Yes, but if you don't succeed that doesn't mean it is superglue because you might not be strong enough. The basic idea is right though (and rather obvious). I've once seen on Klokhuis (great show - I wrote the stub :) ) how glue manufacturers test this. They glued two strips of wood (or whatever material you want it for) together, overlapping, attached one end to a hook and hung weights on the other end, adding to it until it broke. If the breakage was in the wood, the glue was stonger than the wood, and therewould be little point in making it stronger than that. DirkvdM 19:11, 16 August 2006 (UTC)

living rocks
While watching a presentation on the History Channel called the Grand Canyon the narrator referred to the rocks along the Colorado River as "living rocks." What does the term living rocks mean? James L Barden


 * Well, they eat, drink, and love women. — [  Mac Davis ] (talk)
 * Living rocks! Damn straight! Well, except sometimes. --Trovatore 18:37, 16 August 2006 (UTC)


 * Living rocks are cactii. I doubt that is what the narrator was referring to. --Kainaw (talk) 18:40, 16 August 2006 (UTC)
 * Becuase there aren't any cactii anywhere near the Grand Canyon?--152.163.100.74 18:50, 16 August 2006 (UTC)
 * What is a cactius, anyway? &mdash;Tamfang 06:41, 17 August 2006 (UTC)

Next one - what are living daylights? DirkvdM 19:13, 16 August 2006 (UTC)


 * I have one link that may be tangentially helpful - this PDF file has a section entitled "Blood of the Living Rocks: What Colors the Sandstone Red", but it never really says why it is using that term. --LarryMac 19:24, 16 August 2006 (UTC)


 * "Living rock" means "in its native condition and site" OED, e.g. the Sphinx is hewn out of the living rock. So I would guess the narrator meant that what looked like individual rocks were actually part of the bedrock.--Shantavira 19:37, 16 August 2006 (UTC)


 * Some other, and possibly more obviously illustrative examples, would be the sculpture of Mount Rushmore, and the Treasury at Petra.- Nunh-huh 19:42, 16 August 2006 (UTC)

I suspect they mean the rocks change over time (from erosion) or appear to change (due to lighting conditions). They could also mean there are living things on the rocks, like lichen. StuRat 21:42, 16 August 2006 (UTC)
 * 'Living Rock' appears to be some sort of not-very-scientific jargon that is applied to the canyonlands.   There appears to be lots of literature using this, but it is not defined anywhere.  By the pictures, I'll go with the natural sculptures carved out of the bedrock.--Zeizmic 23:54, 16 August 2006 (UTC)

EMP's affect on a crystal radio
Would an electromagnetic pulse adversely affect a crystal radio, which uses a passive circuit? --Dynamite Eleven 18:50, 16 August 2006 (UTC)


 * I don't see why it wouldn't be overloaded and fried just like any other electronic equipment. StuRat 20:07, 16 August 2006 (UTC)


 * Depends how much power was incident on the crystal radio's antenna, of course. Nimur 22:41, 16 August 2006 (UTC)


 * In its simple form, a crystal radio does not contain electronic components. It should hold up better than current electronic radios. This is not directly related to its being passive. A sufficiently powerful EMP will evaporate your cast-iron stove; it is all a matter of degree. --Lambiam Talk 22:54, 16 August 2006 (UTC)


 * It would be really hard to do this to a crystal radio set with truly old-fashioned components, as the components would be pretty large and durable.

A "modern" Crystal radio receiver contains a germanium diode, which would probably be ruined by an EMP. An antique crystal radio might contain a crystal of carborundum or galena, which has sensitive spots found by placing a fine metal "cats'whisker" on various places until a signal is detected. These sensitive spots or improvised diodes, deteriorate over time under the best of circunstances, so I would expect that an EMP would also render such a set inoperative, but it should be possible to find another spot unaffected by the EMP. I would not expect that an EMP would change the crystal structure of all galena found in nature. A good plan for survivalists would be to keep a small transistor radio (am and short wave) inside a steel container which would act as a Faraday cage to provide electromagnetic shielding. The steel would be unlikely to allow sufficient energy to reach the radio to harm it, if it has no external connections such as an antenna, earphone, or power cord.Edison 17:21, 17 August 2006 (UTC)

Even if you're using a crystal diode, it's still not possible to make a radio without wires or a speaker, both of which would be fried by an EMP. Also, keep in mind radios generally have antennae ... which are designed to absorb normally faint radiation. Blast them with an EMP and I think it'd be like a lightning rod. -- Cyde Weys 19:32, 17 August 2006 (UTC)


 * Even the thin wire in a speaker or inductance coil is tens of thousands of times thicker than the junction in a diode, and millions of times thicker than the components of a modern integrated circuit. An EMP capable of burning out a speaker will be powerful enough to electrocute you through the voltage differential it builds up between your arms. --Serie 21:42, 17 August 2006 (UTC)

Cellphones......and the jammers there of
I remember reading an article, not sure where, about commercial radio frequencies, where the author claimed that your average person with a reasonable amount of engineering experiance could probably buy $11 or $12 worth of electronics from a radioshack and be able to build a device that could blackout all cellphone reception in an area the size of Manhattan, is this true? and if it is, how would you do it?--152.163.100.74 19:08, 16 August 2006 (UTC)
 * Flood the frequencies that the phones work on with extremely powerful garbage signals. Not too hard to create, but it will not "black out" the phones.  It just makes the phone's signals appear weak in comparison.  What I think would be cool is a system that collects signals and then repeats them at higher power on a delay.  That should confuse the phones and towers. --Kainaw (talk) 20:03, 16 August 2006 (UTC)
 * You could enclose the entire area in a Faraday cage. Some secure agencies have taken to integrating one into their buildings structure, but it's not exactly feasible to build one to block all of Manhattan. It rather sounds like something that an evil genius might devise. Hmm... – ClockworkSoul 20:43, 16 August 2006 (UTC)
 * If you were to flood the frequencies enough, all that the mobile phones would pick up would be a load of noise, and no communications. I know this to be true, as I recently stayed on a military singals base, and when they had the radio transmitters on high power, the comms of civilian networks in the area would break down, with mobiles failing to ocnnect or send SMS.  M  a  rtinp23  20:47, 16 August 2006 (UTC)


 * Twenty years ago, cell phones used simple technology that could be jammed by sending out high-power at the system operation frequency. Modern cell phones use CDMA, or Code Division Multiple Access, which makes "brute force" jammers very ineffective.  So, perhaps ten years ago, a $10 dollar home-made 50 watt sine wave transmitter could jam the system.  CDMA is actually extremely effective at evading exactly such high-power, "dumb" jamming (it was developed for electronic warfare; it also serves to prevent thousands of legitimate cell-phone calls from "jamming" each-other..  One feature of CDMA coding is to divert power to frequency sidebands where the jam tone has no effect.  To jam such systems, you would need a more sophisticated, digitally controlled jammer, which would cost more than $10 or $20 dollars (perhaps more like... several tens of thousands of dollars, or several months to years of home-made re-engineering).  In addition, your home-engineer would now need to diversify his expertise from basic analog circuit design to include software, radio frequency electronics, and other areas of expertise. Nimur 22:36, 16 August 2006 (UTC)
 * P.S. User:Martinp23 mentions a jammer that exists on a military base. Without doubt, such jammers do exist.  However, they operate as I described above (digitally controlled, CDMA-aware systems) and certainly are not home-made.  I also doubt their operational range is more than a few hundred yards; if larger areas are covered, it is probably using multiple independent jamming devices. Nimur 22:40, 16 August 2006 (UTC)


 * I remember as a young schoolboy being told about a simple device made out of turns of wire and a spark gap, that would send out strong radio noise, and also being told not to make one - although I think I did once. I forget the details - but it was like a transformer plus a spark. It required no electronics and worked off batteries. I do wonder though if discussions like this and about explosives are not playing into the hands of terrorists and crank, many of whom must also read Wikipedia. —Preceding unsigned comment added by 81.104.12.10 (talk • contribs)
 * You mean a tesla coil? I doubt that would have much of an effect on wireless communications..--205.188.116.74 21:27, 17 August 2006 (UTC)


 * Eh - terrorists are getting plenty of practice in the nationwide terrorist training camp we (America) set up over there in Iraq. --Bmk 02:41, 18 August 2006 (UTC)


 * Information is free. Nimur 13:26, 20 August 2006 (UTC)

Ring tones
Ladies and Gentlemen,

This is a question in reference to the wikipedia article entitled "ring tones". When making a telephone call, does the ring tone that the caller hears correspond and occur at the same time the ring of the phone recieving the incoming call? In other words, if the caller hears eight dial tones, will the person receiving the call hear his or her phone ring eight times simultaneously? If not, why?

Thank you for your assistance WJK August 16, 2006


 * Not necessarily - it all depends on:


 * the length of the ring tone (recieving)
 * the length of the ring tone (sending)
 * The first one varies according to phone brand/personal preference and the latter according to country. At certain times (when a certain ring tone in a certain country is used), both will be the same, but at most other times they will be different.  M  a  rtinp23  20:52, 16 August 2006 (UTC)


 * If I ring my mobile phone from my home phone, my mobile starts ringing very slightly before I hear the rings in the home phone. The delay is very slight, however. I live in Australia. BenC7 02:21, 17 August 2006 (UTC)

Hair bleaching question
I currently have 3-foot long hair that's a mess of different colours after various dye/bleachjobs over the last couple of years. There's reds, browns, blondes, oranges, bits that look black, etc. In short, it's horrible. Is it possible to simply bleach all the different pigments out of it with peroxide, leaving it white-blonde again? Ta. --Kurt Shaped Box 23:08, 16 August 2006 (UTC)
 * From what I'm reading about hair dye, hydrogen peroxide opens up the hair cuticle and allows whatever proteins or compounds that are coloring your hair to escape. If this is true, I wouldn't think it matters whether the color is natural or synthetic as long as it's behaving the same way. And if your hair is as beautiful as you say, would it really matter if your bleach job failed? :D Hyenaste (tell) 23:40, 16 August 2006 (UTC)


 * I don't think so, but you should ask a hairdresser. Anchoress 23:51, 16 August 2006 (UTC)


 * Depends. How much damage are you willing to do to the structure of your hair? --Serie 00:01, 17 August 2006 (UTC)

I would think you would have more luck dying it black, which can cover any colors already there. And, in the future, only change your hair color when you're on the run from the cops. :-) StuRat 03:26, 17 August 2006 (UTC)

"Only your hairdresser knows for sure." I have heard horror stories of abused hair falling out when over-bleached. Be careful with do-it yourself. See Suicidegirls (They "dyed by their own hand"). Probably easiest to dye it to about your natural hair color and wait for it to grow out.Edison 17:27, 17 August 2006 (UTC)