Wikipedia:Reference desk/Archives/Science/2008 August 6

= August 6 =

Shoe polish and solubility
Are there any household liquids that can dissolve shoe polish? It's obviously not very soluble in water. SDY (talk) 01:49, 6 August 2008 (UTC)
 * Warm water with detergent works just fine. If that didn't help for some reason, try petroleum ether. --Dr Dima (talk) 01:59, 6 August 2008 (UTC)
 * Hi, in the article Shoe polish there's this. Being made up of waxes and oils, then a solvent for these would be turps as a cleaner for oils. Another solvent is Kerosine. Julia Rossi (talk) 02:01, 6 August 2008 (UTC)
 * Swarfega is fine for removing polish from the hands. Algebraist 12:58, 6 August 2008 (UTC)
 * I don't know bout household liquids, perhaps fingernail polish remover? I keep a very inexpensive product called 'Goop' hand cleaner. It was originally used by auto mechanics, but I use it after oil painting. Also, it's great for grease stains if you haven't washed the clothing yet.Kissnmakeup (talk) 04:14, 7 August 2008 (UTC)

Recycling plastic
Recently read about plastic refuse not only creating an island of junk the size of Texas or New South Wales but breaking down to particles the size of plankton without the eco benefits. I forget the name for them, but they end up eaten, then as part of the food that ends up on our plates. Given this process, rather than just landfill or ocean jetsam, is there an better option to crumble and mix plastics back into semi-permanent materials such as concrete, or road surfaces, or building foundations? Is anyone doing this already? Julia Rossi (talk) 01:53, 6 August 2008 (UTC)


 * To some extent. Did you check out plastic recycling?--Shantavira|feed me 06:43, 6 August 2008 (UTC)


 * With today's and tomorrow's energy costs, also incineration with energy recovery is one of several waste-to-energy (WtE) technologies. In summary, plastics are like biomass, you can reuse it or burn it. --Ayacop (talk) 08:32, 6 August 2008 (UTC)


 * Do you mean the Great Pacific Garbage Patch? Much of it is in tiny pieces, not yet plankton size, but too small to strain back out. Franamax (talk) 09:05, 7 August 2008 (UTC)
 * In what I read, it mentioned that as well as the synthetic plankton stuff. Maybe someone will sell real estate on the patch and it will just sail around on the currents something like a floating Howl's castle. I was more interested in what's being done in the gap between the big stuff that's already out there, the stuff that's being recycled up to a point, and the stuff that slips through the system and simply distintegrates without going away. Julia Rossi (talk) 11:42, 7 August 2008 (UTC)
 * Well the stuff in the ocean is there mostly because of carelessness. If you throw plastic out the car window and it blows into the ocean, it stays there for (almost)ever. Plastics that can be separated by type can be directly recycled. I don't think there's much that can biologically digest plastic, no matter how small the pieces are, I suspect they just come out the other end. As for the "gap", waste-to-energy is probably the best solution (if the emissions can be controlled). As far as I know, plastic is not a good mix with construction materials as it weakens them too much, but the fly-ash left after combustion is. The big problem here is collecting the materials. Recycling at source works well, if people throw things out the window, into the water, or into general garbage it becomes "energetically unfavourable" to recover the materials. And if manufacturers wouldn't put three layers of plastic around their products and stores wouldn't give out a plastic bag when you buy a pack of chewing gum, we would have less of a problem in the first place. Reduce, reuse, recycle - in that order. Franamax (talk) 20:20, 8 August 2008 (UTC)
 * Ah, thanks guys, thanks F'max. Julia Rossi (talk) 10:18, 10 August 2008 (UTC)

Gasoline Expiration Date?
I own an automobile that hasn't been driven since 2001. It has 80% of a tank of gas left in it from the last time I filled it up, when gas was somewhere around $1.30 a gallon. Now, I'm wondering if I could siphon it to another gas tank and it work just like new, $4 per gallon gasoline. Thanks. Danthemankhan 03:51, 6 August 2008 (UTC)


 * According to Gasoline: "When gasoline is left for a period of time, gums and varnishes may build up and precipitate in the gasoline, causing "stale fuel." This will cause gums to build up in the fuel tank, lines, and carburetor or fuel injection components making it harder to start the engine. Motor gasoline may be stored up to 60 days in an approved container. If it is to be stored for a longer period of time, a fuel stabilizer may be used."
 * There are many other Internet users with similar questions. Here is an anecdotal account in which 18-month-old cans of gasoline still powered a car perfectly.  Also see these Yahoo! Answers responses.  The Straight Dope has this article claiming gasoline has a shelf life of months to years, and degradation is due to oxidation, evaporation, and contamination by water.  --Bowlhover (talk) 05:00, 6 August 2008 (UTC)


 * There are several microorganisms living on fuel, the German language WP has de:Kerosinpilz (kerosene fungus, Amorphotheca resinae, also growing in diesel) and a short mention exists in microbial corrosion about some other bacteria. Both types, however, need a certain percentage of water, so they appear only at specific places in the tank, where water condenses or collects on the inside or within the fuel at the bottom. Kerosene fungus is a big problem for the aviation industry. Probably much of what the links above claim as degradation is due to microorganisms. --Ayacop (talk) 08:15, 6 August 2008 (UTC)
 * There's also the problem of exactly when you filled it up. If you live somewhere with major seasonal temperature variation, then the winter fuel might not be suitable for summer use. Algebraist 12:55, 6 August 2008 (UTC)
 * It is important to know if this is diesel or unleaded. Diesel is considered to have a much shorter useful life than gasoline as diesel has problem with bacteria. Using winter gas in summer might cause vapor lock - but the extra higher volatility compounds may have already evaporated, effectively turning a winter mix into a summer one or worse. Rmhermen (talk) 14:19, 6 August 2008 (UTC)

I would also have reservations because gasoline is made up of many different components. Some of the hydrocarbons in there are light and could well have evaporated by now, with the heavier ones sticking around. This will make combustion very difficult and could cause the gumming up issues mentioned earlier. In short, as expensive as gasoline is now, given the risk and the conflicting information on the matter, safe is better than sorry. EagleFalconn (talk) 19:08, 6 August 2008 (UTC)


 * If you decide to throw it away, don't just pour it on the ground; although its properties of combustion may have degraded, it's still plenty potent enough to contaminate ground water.
 * Now, I'm sure you knew that, and the only reason I wrote it is to provide another alternative. Siphon it out, if you wish, and dilute it with newer gas, 5:1 or maybe 10:1.  OR, use it in a lawnmower -- the gumming-up-the-innards stuff has already been done, and lawnmowers are ridiculously ignorant of octane and fuel quality.
 * You still have to deal with any potential damage done by the old product in the old vehicle. For that, I strongly recommend replacing the old fuel with new as soon as possible after emptying the tank, the goal being to minimize "drying out" the internal parts.  If the car starts, it will probably not run well for a while, but the only way it's going to improve (in the short term) is to run more fuel through it
 * HTH! --Danh, 63.231.153.235 (talk) 21:10, 6 August 2008 (UTC)

Genital herpes Outbreaks
I dont have herpes, but was wondering that if someone does, and they take their medication everyday, do they ever have an outbreak again? —Preceding unsigned comment added by 76.168.89.122 (talk) 04:52, 6 August 2008 (UTC)
 * You might like to plod through the treatment section of the Herpes article or try google. Julia Rossi (talk) 05:21, 6 August 2008 (UTC)
 * (ec) There is more than one strain of the herpes virus, but immunity to even one of them will make a second herpes infection very unlikely (see http://chealth.canoe.ca/channel_section_details.asp?text_id=1370&channel_id=16&relation_id=27918). Infection is still possible as the 1980 study showed. --Bowlhover (talk) 05:27, 6 August 2008 (UTC)
 * By my understanding, it's common for a herpes infection to never be completely eradicated and just to lay dormant and then break out again later. That would suggest getting an infection doesn't yield immunity for the future. --Tango (talk) 05:35, 6 August 2008 (UTC)


 * Or as Demetri Martin would say - Glitter is the herpes of craft supplies... You think you've got rid it of it then go out into the sun then flare-up. 194.221.133.226 (talk) 08:00, 6 August 2008 (UTC)

Windowboxes
moved from the misc desk for better information Julia Rossi (talk) 10:03, 6 August 2008 (UTC) Which are the best flower plants to use in windowboxes that are in full sun?TerryBohle (talk) 08:03, 6 August 2008 (UTC)
 * Now where were we, have you looked at cactus, geraniums, succulents? Julia Rossi (talk) 10:06, 6 August 2008 (UTC)
 * Wallflowers could work. DuncanHill (talk) 10:11, 6 August 2008 (UTC)
 * This site suggests herbs and vegetables. DuncanHill (talk) 10:20, 6 August 2008 (UTC)
 * Other suggestions include miniature roses, dwarf gladioli, sunflowers, and daisies. DuncanHill (talk) 10:22, 6 August 2008 (UTC)

how to submit a picture with an question?
i need to submit a picture for detail of a question in help desk. how to do it ? —Preceding unsigned comment added by Shamiul (talk • contribs) 10:04, 6 August 2008 (UTC)


 * You scroll to the top of this page, click on Help desk on the right hand side under See also, and ask there for how to use wikipedia. Julia Rossi (talk) 10:34, 6 August 2008 (UTC)


 * Click on "Upload file" on the left. --Bowlhover (talk) 10:56, 6 August 2008 (UTC)


 * This assumes that the pic isn't already on the Internet. If it is, use a link like this: .  You can do the same thing for an image you've uploaded.  It's also possible to have the pic display directly on this page, instead of by picking a link, but that's generally discouraged, because it slows down the page loading speed to a crawl. StuRat (talk) 13:33, 6 August 2008 (UTC)

Buoyancy on the ocean floor
If I take a cylinder (with its axis vertical) and immerse it in water, it will experience an upwards force due to buoyancy. As per the article, this is cause by the difference in pressure acting on the top and bottom surfaces of the cylinder (there are also pressures on the vertical walls of the cylinder, but these cancel out, and in any case they only act normal to the surface, ie in a horizontal direction). If I now push the cylinder all the way to the bottom of the body of water (eg the ocean floor), so that it is in contact with the (assumed to be smooth and flat) surface of the ocean floor, will the buoyancy force suddenly reverse direction and point downward?

Experience says no, but from the way I understand buoyancy, if the cylinder is sitting on the ocean floor, there is no more water underneath it exerting an upwards pressure force, so the only pressure forces acting on it are on its top and its sides. Since the sides are vertical and pressure acts normal to the surface, these forces act horizontally, leaving only a downward pressure force from the water on the cylinder's top surface. Therefore, the cylinder on the ocean floor has both its own weight and water pressure pushing it down, hence no more buoyancy, which would mean that even a light, air-filled cylinder would stay on the ocean floor. Where have I gone wrong? &mdash; QuantumEleven 12:24, 6 August 2008 (UTC)
 * It'd still be less dense than the water it displaces; thus it will still rise a little. --Kjoonlee 12:34, 6 August 2008 (UTC)


 * If you create a water-tight seal between the cylinder and the sea-floor and pump out any water in between them, then yes, the cylinder will be held on the sea floor by water pressure - you have, in effect, created an underwater suction cup. Gandalf61 (talk) 12:39, 6 August 2008 (UTC)


 * That's true, but it's not what Kjoonlee was asking. If the object is just resting on the ocean floor, and there's no seal (and partial vacuum) to make a suction cup, then it will rise off the floor and water will rush in under it. The reason is that the solid material that forms the ocean floor is also under pressure (the same pressure as the water touching it, because they are in mechanical equilibrium), so the floor itself exerts an upwards force on the object. 128.165.101.105 (talk) 14:03, 6 August 2008 (UTC)
 * I'm not sure that's true at all. You're assuming a semi-fluid sea floor. But the cylinder would still float even if it landed on solid rock. The reason is that the cylinder without the seal floats upwards because there is pressurized water underneath it, even if only a tiny bit. APL (talk) 16:34, 6 August 2008 (UTC)
 * Kjoonlee, You've just described exactly how suction cups work. The obvious practical problem is making sure that fluid does not get between the sea floor and your cylinder, which is why suction cups are typically made of rubber so that they can deform and create a seal with the surface they're sticking to. APL (talk) 16:34, 6 August 2008 (UTC)

I think Gandalf is right. In highly skilled metalworking, such as tool and die making, they use Johannsen (spelling?) blocks. These are metal blocks that have an exceedingly smooth and flat surface. If one surface of two of these blocks is made very clean and free of grit, and the two surfaces are then pressed together and rubbed together a bit, it will squeeze out all air between the blocks. One block can then hang below the other solely because of air pressure. The blocks are not magnetized.66.52.8.128 (talk) 16:58, 6 August 2008 (UTC)


 * That sounds like a cold weld. StuRat (talk) 17:06, 6 August 2008 (UTC)

Maybe I'm missing something here, and correct me if I'm wrong, but I think I'm detecting a slight error in logic. Assume the cylinder is less dense than water. If the cylinder is submerged in the middle of the water, the net force due to the pressure of the water existing is going to be zero because the water pressure will be equal in all directions (assuming still water of homogenous temperature etc etc). The model you guys are using for buoyancy only works at the surface. When submerged, the cylinder rises because of a difference in density. If it is more dense than water, it sinks. If it is less dense, it floats. As buoyancy explains (slightly poorly) the issue is weight difference manifesting as density difference. Because an object displaces a volume of water equal to its own volume, if the weight of the object is less than the weight of the water it displaces the water flowing downward decreases the overall potential energy of the system more. Therefore, water goes down, cylinder goes up. In the case where the (perfectly smooth) cylinder is on the (perfectly smooth) bottom, the cylinder will not rise because of the effect that 66.* mentioned. There is no path for the surrounding water to be under the cylinder to push up on it, so it stays put. If neither the cylinder or the bottom are perfectly smooth, water has access to the area underneath so it can push up. (Clarification: Collisions are pushing force only). EagleFalconn (talk) 19:21, 6 August 2008 (UTC)


 * The second part of your explanation is fine, but the first part is incorrect. When the cylinder is in mid-water the net force due to water pressure is not zero. It is equal in magnitude to the weight of an equivalent volume of water at that depth, but opposite in direction i.e. upwards - this has to be so, because the water pressure must be sufficient to support an equivalent volume of water in equilibrium. The net upwards pressure force arises because the water pressure at the bottom of the cylinder is greater than the water pressure at the top because pressure increases with depth. And this upwards pressure force is what we call buoyancy. This is explained in the Forces and equilibrium section of our buoyancy article. Gandalf61 (talk) 19:42, 6 August 2008 (UTC)


 * My mistake, let me rephrase. I did not mean net force due to water pressure. I meant the net force on the cylinder due to the water molecules colliding with the cylinder. A subtle difference, but my point was that the water colliding with the cylinder has nothing to do with the motion up or down, and that the motion was due entirely to the weight displacement of the water. EagleFalconn (talk) 14:22, 7 August 2008 (UTC)


 * Water pressure is due to water molecules colliding with the cylinder - these are just macroscopic and microscopic descriptions of the same phenomenon - see this section of the kinetic theory article. Water molecules colliding is pressure; pressure difference between bottom and top surfaces gives rise to net upward force that we call buoyancy; buoyancy force equals weight of equivalent volume of water. The displacement of the water has nothing to do with buoyancy - when you pour water from a jug into a glass you displace the water, but you don't create mysterious buoyancy forces. Gandalf61 (talk) 14:44, 7 August 2008 (UTC)

Let us suppose that the cylinder is a cylinder of water enclosed by an infinitely thin weightless skin. Even though the pressure of the surrounding water is greater at the bottom, the cylinder will not rise because its weight is such that the total pressure exerted by the cylinder on the water beneath it is equal to the pressure on it. The difference in pressure between the water under the cylinder and the bottom of the cylinder occurs when the cylinder weighs less than water. Then the total weight of the cylinder and the water above it is not the same as the weight of the water beside it. The difference in pressure is not just caused by the difference in pressure of the water between the top and bottom of the cylinder. It is also caused by the difference in the weight of the cylinder and an equal amount of water. Even when the cylinder sits on the bottom of the body of water, it weighs less than water. The pressure of the bottom of the cylinder on the bottom of the body of water will not be the same as the pressure of the water around it on the bottom of the body of water because it doesn't weigh as much, therefore the weight of the the cylinder and the water above the cylinder is not the same as the weight of the water beside it, regardless of where it is. So picture a free body diagram of the cylinder. The normal force of the bottom on the cylinder, the weight of the cylinder and the weight of all the water above the cylinder are acting on the cylinder. Are there any other forces in the vertical direction? Are these forces equal but opposite? I believe that if I took a wooden block in freshman physics lab and placed it on the bottom of a beaker full of water, its gonna float to the top because it's lighter than the water that it's in. If I take an ice cube and put it at the bottom of a glass of water, it might stick to the bottom of the glass because of dangling surface bonds, but I think it would float to the top. What do you guys think?Kissnmakeup (talk) 03:58, 7 August 2008 (UTC)


 * The problem with the idea that buoyancy force = weight of displaced water regardless of whether the object is on the bottom or not is that you then have to invoke some sort of negative pressure theory to explain the action of a suction cup, which will remain on the bottom despite weighing less than an equivalent volume of water. Returning to the block in a glass example, if the bottom of the block and the glass were sufficiently smooth to exclude water molecules from their interface (not going to be possible with a wooden block, but maybe possible with a plastic block ??) then, yes, the block would stay on the bottom, held there by its weight and the unopposed water pressure on its top surface. Our intuition is at fault here because our experience comes from objects that are not sufficiently smooth to observe this phenomenon. Gandalf61 (talk) 09:28, 7 August 2008 (UTC)


 * Yes, after further consideration, I agree. By sufficiently smooth, what you mean is that there cannot be even as much as the width of a water molecule of space between the surfaces of the container and cylinder, because if there is even that much space, the pressure will force the water up under the cylinder and there you will have it, via Pascal's Principle, buoyancy.Kissnmakeup (talk) 11:00, 7 August 2008 (UTC)


 * That was one hell of an explanation - thank you very much everyone, I think I've understood it now. Kudos! :) &mdash; QuantumEleven 11:52, 8 August 2008 (UTC)

Epileptology and Neurophysiology
A quick question about titles in the UK. Are the above 2 titles (Epileptologist and neurophysiologist) restricted to Medical Doctors only, or can a Clinical Physiologist (Neuro) call themselves either of those. Obviously they'd have to have further study in epilepsy, but if they had a masters in epileptology, would they be allowed to call themselves an epileptologist? Thanks 92.4.122.75 (talk) 14:33, 6 August 2008 (UTC)
 * I don't know if epileptology is a term regulated or licensed by a medical board, but it probably varies by region. Nimur (talk) 17:10, 6 August 2008 (UTC)

Name for when skin hurts
I've heard about something where someone's skin hurts as though it had a sunburn underneath the skin. First it starts around the chest. Each day, it is in a lower position and moves from around the chest, to around the stomach, to around the groin area, then down one or both legs. There are no visible marks, but there is tingling pain. What might something like that be called and does Wikipedia have any articles related to it? Thanks. Suntag (talk) 17:33, 6 August 2008 (UTC)
 * It may be an unusual form of paraesthesia. Fribbler (talk) 21:56, 6 August 2008 (UTC)


 * For me, when my skin hurts, that's a sure sign I'll be hit with severe flu symptoms a few hours from the time I notice the pain in my skin. Not sure about your localized moving patch, though. ~Amatulić (talk) 00:34, 7 August 2008 (UTC)


 * There is also a rare genetic condition which causes extreme sensitivity to touch on the front of the torso (as well as pronounced curvature to the shoulder blades). I remember the symptoms, but I have no recall of the name.  Tried googling, but found nothing. --  k a i n a w &trade; 02:22, 7 August 2008 (UTC)


 * I've read that the skin pain caused by herpes zoster moves over time as the old chicken pox virus makes its way along the nerve endings around a rib and near the skin surface. However, that is a horizontal movement rather than an up and down movement. Per the article, herpes zoster could result in residual nerve pain, but it doesn't say anything about the residual pain moving in any direction. Suntag (talk) 16:37, 7 August 2008 (UTC)


 * If I had a recurring pain that seemed to be progressing through my body, I would go to see a doctor and explain my problem, since they would be far better able to help than random people on the internet. If I couldn't see a doctor for some reason, I would visit a pharmacist as pharmacists are also trained and experienced in these things and able to give an idea of whether it is likely to be serious. 79.66.38.215 (talk) 23:18, 7 August 2008 (UTC)


 * I doubt any pharmacist with his head on right would give you any kind of diagnosis or anything other than some over the counter crap that will do nothing to cure a serious problem. A doctor would provide a credible diagnosis.--El aprendelenguas (talk) 00:20, 8 August 2008 (UTC)


 * Pharmacists are not trained in medical diagnosis. And certainly no licensed pharmacist in the US would provide medical advice except on lotions and potions he's pushing.  However, to answer Suntag's question, I have no clue, short of a full medical exam.   Zoster does not match your symptoms, but that's about all I'll say.  This is not the place to get a diagnosis.   Orange Marlin  Talk• Contributions 04:26, 8 August 2008 (UTC)


 * Here in the UK, I'd certainly expect a licensed pharmacist to say "that sounds like something you should make an appointment with a doctor for" or "you've got the picture upside down". You know, order of magnitude sort of thing... 79.66.38.215 (talk) 17:30, 9 August 2008 (UTC)

Dental membranes?
Can anyone explain to me what dental membranes are? I understand that their purpose is to help regenerate gum tissue, but what are they exactly? What are they composed of? Is it man-made or does it contain animal parts? Are there any similar membranes used on the human body? —Preceding unsigned comment added by Cap'n Louise Redbeard (talk • contribs) 22:22, 6 August 2008 (UTC)
 * Guided bone regeneration might help. Julia Rossi (talk) 03:45, 8 August 2008 (UTC)

Heat rub on the testicles?
I was told today by someone who used to be in the army that it was a common practice for soldiers to smear heat rub (Deep Heat or Tiger Balm type stuff) on their testicles before embarking on long marches in cold environments, so that they wouldn't feel the chill as much. I'm pretty sure that this he was just trying me out to see if I would be dumb enough to actually do it (I'm not going to, no way!) so that he and his buddies could have a good laugh at my expense, but just to clarify -- would this actually work as stated? Or would you just keel over in burning agony after a couple of minutes? --84.70.255.204 (talk) 22:44, 6 August 2008 (UTC)


 * Well (sorry I cant resist it), it's possible that the person who told you was talking complete bollocks! Sorry ;( —Preceding unsigned comment added by 79.76.167.200 (talk) 23:26, 6 August 2008 (UTC)


 * You would keel over in burning agony after a few seconds. The Menthol and Methyl Salicylate will cause a very bad burning sensation due to the large number of nerves in the general area.  Q  T C 23:30, 6 August 2008 (UTC)


 * So would that prevent frostbite? —Preceding unsigned comment added by 79.76.167.200 (talk) 23:33, 6 August 2008 (UTC)


 * I doubt it. Stimulating nerve endings to feel a burn isn't the same as actually warming up flesh. There may be a small benefit through increased blood circulation that may prevent freezing. ~Amatulić (talk) 00:36, 7 August 2008 (UTC)


 * So, could this be the same nonsense that says: Have another whiskey to warm you up? When it doesn't at all really? —Preceding unsigned comment added by 79.76.167.200 (talk) 01:10, 7 August 2008 (UTC)


 * Whiskey does warm up your skin, by increasing blood flow from the warm core of your body to the cool skin. The problem is that if the room isn't warmer than your skin temperature, your core body temperature will fall. --Carnildo (talk) 20:15, 7 August 2008 (UTC)


 * One reads from time to time about mountaineers or cold climate travellers having suffered frostbite of the fingers or toes. Never in my life (fairly long) have I heard of frost bite of the testicles, or indeed associated anatomy. Richard Avery (talk) 07:25, 7 August 2008 (UTC)


 * Well that is hardly surprising is it? would you go out in cold weather with your testicles hanging out of your trousers or would you keep them snugly cossetted close to your body inside your nice warm underpants/ I know which Id choose. —Preceding unsigned comment added by 79.76.225.183 (talk) 00:43, 8 August 2008 (UTC)
 * Even testicles themselves don't go outside in the cold. Julia Rossi (talk) 03:42, 8 August 2008 (UTC)

WARNING: DO NOT DO THIS unless you too want to know the pain of childbirth. Search You Tube for 'heat rub testicles' to hear the screams.

Please identify this spider
I have a bit of a spider problem. I believe I know what this spider is, as I've seen them plenty of times back home (Georgia), however nobody here (North Carolina) seems to believe they live in this area. This includes the exterminators, which puts me in a bit of a pickle. I've had five of the specimens I caught and preserved in alcohol taken by the exterminator and supposedly shipped to Atlanta for identification. They claim that Atlanta couldn't identify my spiders. Now the spiders have supposedly been shipped to Raleigh so whomever is in Raleigh can take a crack at 'em.

I find all this pretty darn silly since I'm nearly certain of what these spiders are after a few minutes of inspection with a magnifying glass. However, I'm not an entomologist, so I need other opinions (I may end up sending some of my other samples to the department of agriculture).

Just for kicks, what do you think this spider is? All of the spiders I've caught look just like this one (except with more legs), and vary in size from roughly 4 mm to 20 mm (leg span). If you happen to have studied entomology, please do mention it since that would give me a greater level of confidence. I won't tell you what I think the spider is because I'm hoping someone will provide a feasible alternative to my amateur identification.

Thanks. -- mattb 22:49, 6 August 2008 (UTC)


 * Does your university have a zoology department? They might enjoy a challenge. DuncanHill (talk) 22:53, 6 August 2008 (UTC)


 * Eh... UNC-G and Wake Forest University both have biology departments, but I can't tell whether they have anyone who specializes in entomology in particular. My best bet is probably NCSU in Raleigh, but me being in Greensboro that's a rather long drive. -- mattb 23:15, 6 August 2008 (UTC)


 * I assume you're afraid it's a brown recluse. It might be, but (a) Greensboro is well outside the brown recluse's range; (b) I don't think it's as easy to identify brown recluses as our article suggests; and (c) they're not as dangerous as they're often made out to be. The information here might be helpful. (Incidentally, you technically want an arachnologist and not an entomologist, although UC Riverside seems to lump them together.) -- BenRG (talk) 23:36, 6 August 2008 (UTC)
 * And I should add that I know zilch about spiders, I just happen to have been reading about this subject a few days ago. -- BenRG (talk) 23:41, 6 August 2008 (UTC)
 * I can only add, that it does resemble a brown recluse (-4 legs) unless it's a close relation to it. Spiders can migrate through soil importing, or other vehicles of transport (building materials, climbing into cars etc), so you never know. There could be reasons why they're turning up elsewhere. Out of interest, what do the North Carolignians call them? Julia Rossi (talk) 23:48, 6 August 2008 (UTC)
 * I'm not really afraid that IT is a brown recluse so much as I'm afraid that all fifteen or so of the identical-looking spiders I've caught are brown recluses. Far more than that I'm afraid that the spiders I have not seen or caught are brown recluses, especially since this little guy sustained its damages due to being violently swatted off my face in the middle of the night.  Anyway, I've done my home work already and I'm more interested in knowing whether anyone can suggest another spider that this might possibly be. -- mattb 00:43, 7 August 2008 (UTC)

Or maybe you discovered a new species of spider. Just throwing it out there. --harej 23:49, 6 August 2008 (UTC)

A photo taken looking straight down at the body, and in daylight, would improve the accuracy of identification. It has the fiddle marking. Also, a macro closeup of the eyes would be diagnostic, since recluses have a different pattern of eye arrangement than most other spiders. They do indeed travel around outside their usual habitat, hitching rides in any old item like a box of junk, to a remote location. They seem to be getting a grand rehabilitation these days, with claims they are not very dangerous. I know 3 people who had bites from them, proven by the spider carcass being preserved, and who had a slow recvery with a depressed scar after the nasty result of the bite. They love to live in houses, and are aggressive about climbing into shoes and even into beds, then biting when we unwittingly come into contact. Yuck. Edison (talk) 18:38, 7 August 2008 (UTC)


 * I have no adequate macro lens, and this is quite a small spider anyway. Still, you should be able to see the eye arrangement from the full-size photo (I can).  Nevertheless, I'll see whether I can take a better photo of one of the larger ones today.
 * I'm certainly no arachnophobe, but I'm equally unconvinced by claims of this spider being mostly benign. I too have a friend who was bitten by one and who lost a tangerine-sized chunk of flesh as a result.  Honestly I'd rather be bitten by a black widow than one of these.  Even if less than 10% of bites result in necrotic wounds, I don't like playing the odds after having one crawl on my face. -- mattb 19:32, 7 August 2008 (UTC)


 * Well I found a nice-sized undamaged live one today as it tried in vain to escape from my kitchen sink. Here are a few decent photos of the spider in a futile effort to climb out of a porcelain bowl!  I have to admit, it's rather fun to watch and I'm going to feel bad when I finally commit this little guy/gal to the watery deep of the North Carolina sewage system. -- mattb 22:13, 8 August 2008 (UTC)
 * The dorsal markings do seem to match the Brown recluse spider. Sounds like it might have hitched a ride with someone to your current abode. Just my experience, this has been a good year for spiders: lots of insects due to the weather this spring, and the spiders are flourishing. Might be worth calling an exterminator. &mdash;  The Hand That Feeds You :Bite 17:58, 9 August 2008 (UTC)


 * Okay, new question. Does anyone have an idea of where I can quickly find some sealed plastic containers suitable for shipping these spiders in alcohol?  I've made a contact at NCSU who wants me to send him some specimens for identification. -- 98.26.182.245 (talk) 15:25, 10 August 2008 (UTC)
 * The local pharmacy could help -- screw-top specimen bottles or empty vitamin bottles are the go afaik. And you could ship those good pix to the article :) Julia Rossi (talk) 01:27, 11 August 2008 (UTC)
 * They're public domain, so you're welcome to do so yourself. -- mattb 01:44, 11 August 2008 (UTC)