Wikipedia:Reference desk/Archives/Science/2007 July 4

=July 4=

Identify this lizard
We saw this lizard in Galveston, TX. It is approximately 3 to 4 inches in length, and we've seen it several times at night. Does anyone know what it is?



anonymous6494 02:10, 4 July 2007 (UTC)


 * Mediterranean House Gecko, Hemidactylus turcicus ? --mglg(talk) 02:33, 4 July 2007 (UTC)


 * I think it looks like a Tropical house gecko, though the one in the article is a bit different. A.Z. 20:57, 9 July 2007 (UTC)


 * I see such small lizzards every summer in Greece in my House so I would agree with the author of the first reply. This one seems to be a bit bigger though or the picture is not very clear.

dealcoholize alcohol?
I love the tastes of certain beers, but I don't want to get drunk. (I'm extremely easy drunk.) Is there something I can do to the alcohol to keep the original flavour and fizziness but remove all or some of the alcoholic content?--Sonjaaa 03:49, 4 July 2007 (UTC)


 * Try near beer 161.222.160.8 04:39, 4 July 2007 (UTC)


 * I feel really terrible for suggesting this, but if you insist on drinking beer for the flavor, it might be better to try to get your tolerance up. Sadly, the near beer article doesn't say how dealcoholization is done, but judging from the terribly reception that near beers get, it cannot possibly be good for the flavor!  See Effects of alcohol on the body, Ethanol and Hangover for more information that you could possibly need.  My personal recommendation is to drink slower, and alternate a glass of water between each glass of beer.  Eat something, too!  Finally, check the label!  Great beers are not necessarily high in alcohol! --Mdwyer 04:51, 4 July 2007 (UTC)
 * Easy drunk = cheap date. Yah, per what Mdwyer said, drink a lot and soon your liver will be like a chunk of concrete, and you will have a huge tolerance for alcohol, and you will literally be able to drink your peers under the table. However, this does not bode well for your longevity. Edison 05:22, 4 July 2007 (UTC)


 * Huh? Drinking low-alcohol beers and drinking slower are bad for your liver? Sorry, Edison, you're not living up to your name here. For centuries, Europeans have drunk beer in stead of plain water because it was less disease-ridden. But it was also extremely light beer. I don't know if such beer is still made. Also, judging by Sonjaaa's post, she's never going to be able to drink others under the table. Some people have a lower tolerance for beer than others. I wonder if that also affects how much damage the same alcohol-consumption will do to the liver (if any). DirkvdM 10:00, 4 July 2007 (UTC)


 * I thought I read somewhere before that in medieval times the "beer" that they have are a lot stronger than what we have nowadays... --antilivedT 22:56, 4 July 2007 (UTC)


 * See Small beer. Also, unless Edison has edited his comments since you replied Dirk, you seem to have drawn the opposite conclusion to that which his words suggest to me :-) Skittle 14:54, 5 July 2007 (UTC)


 * Getting back to the original question, it's an interesting problem in physical chemistry. Distillation and freeze distillation/fractional freezing come to mind immediately, but distillation is no good because the CO2 would come out of solution before you could boil off a significant amount of ethanol (leaving you with flat beer), and freeze distillation is no good because most of the flavor compounds would remain in the alcohol-rich liquid portion and the solid would be almost pure water ice.
 * There seem to be two major commercial methods of adjusting the alcohol level of wine (which should be applicable to other alcoholic beverages as well). Both methods involve first separating the color and flavor components ("retentate" or "essence"), then decreasing the alcohol level of the remaining alcohol-water fraction, then re-adding the flavor components. Vinovation's method involves reverse osmosis, and ConeTech's method uses some complicated apparatus to achieve something similar to steam distillation (please correct me if that's wrong).
 * Anyhow, those are both large-scale industrial process that would be difficult to recreate in your kitchen, so if you like the taste of a certain beer, you'll have to either live with the alcohol content, or hope they produce a light version. —Keenan Pepper 02:43, 5 July 2007 (UTC)

Need to identify soundfile
- I need to identify which of the four goldfinch articles this belongs to. Original clip came form here. Borisblue 05:22, 4 July 2007 (UTC)

Planet of the Apes
I was watching the old Planet of the Apes, specifically the second one Beneath the Planet of the Apes and in the movie the doomsday device is an atomic bomb with a cobalt casing. How does the cobalt casing affect the efficency of the bomb?68.120.85.164 05:33, 4 July 2007 (UTC)


 * See cobalt bomb for a full explanation, but the idea is that the cobalt casing would be turned into the extremely nasty isotope cobalt-60, which would be spread as fallout, and remain lethal for a couple of decades. --Bob Mellish 07:13, 4 July 2007 (UTC)

Thank you.67.121.105.12 02:02, 5 July 2007 (UTC)

Humming Bee?
I saw the strangest animal the other day. It looked like a cross between a bee and a humming bird. It was about an inch long (2.5cm) had a brown body, and a small fan tail, like a bird. It's wings looked slightly like bird's but were moving so quick it was hard to tell. It also had a long 'beak' which it was using to suck stuff out of flowers, and two 'antennae' on top of it's head, also long and thin like the 'beak'. It hovered while sucking, moved about quickly, and was the only thing of it's kind, in a patch of flowers with many bees. This was in central Europe. Any ideas what sort of creature this was, I am clueless? Cyta 08:07, 4 July 2007 (UTC)
 * Take a look at Sphingidae. --Mdwyer 08:55, 4 July 2007 (UTC)
 * Thanks a lot, that's definitely the one. What a crazy animal! Cyta 09:11, 4 July 2007 (UTC)


 * The article doesn't say where they live, but a friend in the Netherlands spotted one in his garden. Nor did the article mention that this is a nice example of convergent evolution, so I added that. DirkvdM 09:50, 4 July 2007 (UTC)
 * Your description was spot on for http://en.wikipedia.org/wiki/Image:Bee_hawk_moth_newspaper.jpg . They look pretty interesting. Lanfear&#39;s Bane

Here in south eastern ontario, canada the larval forms/caterpillars are called "hornworms". They use thier large size, colour patterns and the biotoxins from the very specific plants that they eat to ward off would be predators. Sadly, most people who love to see the adult kill the larval forms! OOPS, forgot to sign. I'm a newbie, mea culpa. Rana sylvatica.


 * The article on Macroglossum stellatarum mentions their distribution. What it doesn't mention is that these critters are on the increase now in places such as southern England and the Netherlands. People are blaming global warming.--Shantavira|feed me 13:27, 4 July 2007 (UTC)

Earth Natural Satellites
Completely by chance I came across the article 6R10DB9. It says that further study will be avaliable around 14 June 2007. As i'm sure you're all aware this date has passed. Do we have any more information about this object? Can we expand the article? 213.48.15.234 11:10, 4 July 2007 (UTC)


 * The article has a link to the Great Shefford Observatory's page about this object, which includes an update from 16th June. I feel sure that this could be used to expand the article, however lack the aastronimical knowledge to do this myself. DuncanHill 11:20, 4 July 2007 (UTC)


 * I've tagged it with an request.--Shantavira|feed me 13:22, 4 July 2007 (UTC)


 * Great, i'm new to all this :) 213.48.15.234 13:29, 4 July 2007 (UTC)

Jar lid motion on counter top
Hi - My wife has challenged me to see if there is a formal name of the oscillation/rotation motion that a jar lid makes when dropped onto a counter top. Any suggestions? ````Cavermedic


 * No. There isn't. For more information on this phenomenon see Euler's disk. 213.48.15.234 12:22, 4 July 2007 (UTC)
 * Scrap that, a manufacturer of the disk uses the verb "spoll" as a portmanteau of spin and roll. I can't find it in any dictionary though. I don't think it's a real word. 213.48.15.234 12:30, 4 July 2007 (UTC)


 * I would go with Precession. The lid is acting kinda like a gyroscope. SteveBaker 16:16, 4 July 2007 (UTC)
 * Hmm, I'm not sure. The contact point of the disc isnt fixed, it's rolling/slipping. 80.229.228.229 18:45, 4 July 2007 (UTC)
 * Well, yes - that's why I said kinda' like a gyro, however, precession is still the right word. SteveBaker 22:08, 4 July 2007 (UTC)
 * I don't believe that the motion is the same, though. If you watch it, The disc is hardly spinning. You always get that funny bit at the end where the coin doesnt look like it's vibrating at all, it's just hovering and turning slowly. I think this (and the similar movement before that when you can see the oscillation) is what they refer to as "spolling" and is what the OP is looking for. It's certainly a very interesting phenomenon. 213.48.15.234 06:41, 5 July 2007 (UTC)
 * I googled 'spolling' and I only see a handful of relevent hits (most are typo's for spelling or spooling) - all but one of them come from www.eulersdisk.com and that one comes from a patent filed by that same company. I don't find the word in any of the four dictionaries I have at hand right now.  So, no - spolling is a neologism at best - most likely it's a word that one guy made up that hasn't been taken up by the worlds of physics and mathematics.  The rate of wobble of the axis of rotation is not equal to the rate of rotation around that axis - that's what precession is - and that's what the lid is doing.  What's happening with the lid is certainly interesting though. SteveBaker 14:43, 5 July 2007 (UTC)
 * I'm aware that it's a made up word :). The precession that's happenning with the lid is certainly happening at a very different rate to what I would normally consider to be precession. The resultant motion is quite different. Capuchin 06:46, 6 July 2007 (UTC)
 * I'm unaware of any definition of the word 'precession' that specifies any limits on the rate of the motion. SteveBaker 13:49, 6 July 2007 (UTC)

efficiency?
hey friends ..

can anyone help me regarding increasing the efficiency of an ic (2-stroke) engine by temperature variations.

Sameerdubey.sbp


 * Have you looked at heat engine or carnot cycle ? Nimur 16:43, 4 July 2007 (UTC)

i have read that article ,it is clearly stating that increasing temperature of source(inlet/atmospheric air in case of 2-stroke engine) or decreasing the temperature of sink(exhaust gas in case of 2-stroke engine) would increase the efficiency.so ..a freak but why dont we increase the temperature of inlet gases using some heaters or decrease the temperature of exhaust gases by some coolers.please comment that why?/why dont? we use those procedures. Sameerdubey.sbp
 * In short form, because you can't get that energy for free. Where does the heat energy come from?  Another engine.  Does that engine use less energy than the energy saved on the initial engine?  No.  Entropy increases. &mdash; Lomn 13:24, 5 July 2007 (UTC)
 * I disagree. Firstly, I'm surprised that heating the inlet would help - it certainly doesn't on a 4-stroke engine.  In fact, most cars run significantly more efficiently in cooler air because there is more oxygen present and that allows a more efficient fuel burn and less energy goes into driving the coolant around and providing energy to the radiator fan.  I've actually dyno'ed my MINI Cooper S and found that I get about 10% more horsepower in winter than in summer (that's in Texas).  Note also that we do in fact employ special 'engines' to compress (and thereby heat) the air on the way into car engines - we call them 'Turbochargers' and 'Superchargers'.  In fact, they heat the air up so much that some cars use a secondary radiator called an Intercooler to try to drop the temperature back to ambient again before the air gets into the cylinders.  The Turbo is powered by the waste energy in the exhaust gasses (the fact that they are emitted at higher than ambient pressure means that the exhaust gas can spin a little turbine to power the pump that pushes the extra air in.  The Supercharger is powered from a belt taking power directly from the engine - the supercharger produces more extra efficiency than it consumes - so this is a worthwhile thing to do.  So clearly you can do something to help without invoking Entropy and saying "it's impossible" - millions of cars out on the roads today prove conclusively that this is true! SteveBaker 14:31, 5 July 2007 (UTC)
 * You're correct; I was looking at the question in terms of "why don't we go above and beyond present engine technology", assuming that turbos, etc, were assumed as integral where appropriate. Heat engines are more or less as efficient as they're going to get from a conceptual standpoint, and hooking up an air conditioner to cool the exhaust is a net loss. &mdash; Lomn 15:34, 5 July 2007 (UTC)
 * Well, if cooling the exhaust helped (and I honestly don't see how it could!) you could simply provide a big expansion chamber somewhere shortly after the engine - the exhaust gas is under pressure - so letting it expand out into a big chamber would certainly cool it down - and at zero energy cost. But aside from the issue of back-pressure (which is actually somewhat advantageous in some cases), once the exhaust is outside of the engine block, who cares what temperature it's at?! SteveBaker 19:29, 5 July 2007 (UTC)
 * SteveBaker, the idea of the heat engine is that the action of cooling has the ability to perform work. You could "waste" that work by allowing the gas to cool adiabatically, as you mention.  If a hypothetical method to use the remaining heat existed, that energy could be used by the engine (powering the drive shaft, or something).  That is why cooling the output would make the "theoretical" engine more efficient.  In a practical scheme, I don't know that it's so trivial to harness excess energy outside the combustion chamber just by refrigerating the exhaust gas.  On the other hand, a more efficient engine would inherently yield cooler exhaust gases.  Nimur 04:35, 6 July 2007 (UTC)
 * Yeah - I agree entirely - if you can capture some of the heat from the exhaust (and thereby cool it) but use that heat to do more work - then for sure, it's a win/win situation. But forcably cooling it with refrigeration is nuts!  The idea that a heat engine that happens to have a cooler exhaust is more efficient than one with a hotter exhaust is also true - but we're turning that around and saying that cooling the exhaust of a hot-exhaust heat engine makes it more efficient - and that's just nuts!  FWIW, BMW have been playing with using the exhaust heat to do some work - they've demonstrated a small steam engine (powered by engine exhaust heat) that would have enough power to run the cars' A/C and recharge the battery - thereby relieving the main engine of that work and resulting in a more efficient car overall.  Since the exhaust gasses will have been routed through those pipes which are full of cold water, the exhaust gasses are indeed cooled by doing this.  But that's not refrigeration.  As I also mentioned earlier, lots of cars have Turbochargers that extract power from the exhaust gasses in order to get more engine efficiency.  So this is a well-understood phenomena. SteveBaker 13:46, 6 July 2007 (UTC)

hymen
Can the hymen of a girl ruptutred, if her vigina is contacted(not penetrated) by a finger strongly even if she wears a trouser or under pant.
 * I don't think you know what vagina means. But, yes, hymens are damaged quite frequently by things other than penetration.  Friday (talk) 17:29, 4 July 2007 (UTC)
 * Horse riding was frequently blamed in less enlightened days. Corvus cornix 23:34, 4 July 2007 (UTC)
 * Or maybe the secret lover's name was "Horst" and she didn't enunciate. Edison 14:41, 5 July 2007 (UTC)
 * You should see Hymen. &mdash; Laura Scudder &#9742; 14:44, 5 July 2007 (UTC)

vagina
who can tell me the size of the viginal opening?


 * We can..

Determining the proper pump for a water fountain.
I have a question regarding matching the right pump for a specific purpose. I have a water pump that is 40gpm and it has 1 1/2" intake and outlet. The pump will be set below the water level by 24". I will divide the outlet into 3 seperate lines that will push water up. I have a trough that contains 11 inches of water included in the overall height to push the water. The goal is to have the water bubble above the surface of the water in this trough bu no more than 12". Do I have the right pump and how do I accomplish the task. This is also in the exterior environment.

Accuracy of Weather Forecasting
This is a rather difficult question, and although I think I read something on it several years back, I have been unable to find any statistics.

The question, in its simplest form, is something like this: as a function of time (edit: where time is defined as the time between the forecast and the event), how accurate are the modern weather forecasting computer models?

The problem is how we define accuracy, and although I have a few ideas, none of them are perfect. Can anyone find me information on this subject? Any kind of relevant statistic will be very helpful.

Thanks a lot. 69.255.38.193 19:21, 4 July 2007 (UTC)


 * One example I know of where long systematic studies have been done is in the accuracy of hurricane landfall locations. This image is a good summary.  Dragons flight 21:32, 4 July 2007 (UTC)


 * http://www.forecastadvisor.com will show you the accuracy of a range of different weather services for a particular US zipcode - and also how one particular weather forecast has changed over the five days prior to the actual day of the forecast. You can use this to see how the prediction homed in on the final value. There is a scientific-looking study of forecasting accuracy here http://www.customweather.com/accuracy/2003study.html.  Here is another www.omninerd.com/2007/02/08/articles/69. Our article on the WxChallenge explains the criteria that are used for judging weather forecasting competitions. SteveBaker 22:05, 4 July 2007 (UTC)

How could I engineer weather inside my house?
I wish to satisfy my God complex. Vitriol 22:39, 4 July 2007 (UTC)


 * Central heating and air conditioning should take care of the temperature. Fans will provide wind. To obtain rainfall, you will have to increase humidity dramatically, consider a paraffin heater (they produce a remarkable amount of water vapour). DuncanHill 22:44, 4 July 2007 (UTC)
 * Or consult our article on humidifiers. Root4(one) 22:57, 4 July 2007 (UTC)


 * If you built your "house" large enough, like the size of a gigantic aircraft hanger. You can have precipitation occurring inside your "house". Especially if you use technological devices to change the humidity and temperature inside your "house". 202.168.50.40 04:44, 5 July 2007 (UTC)


 * Would God need to ask? :) DirkvdM 06:33, 5 July 2007 (UTC)


 * One of the crucial aspects of weather is convection between air masses. You will want to make sure that you have a source of hot air and a source of cold air, and allow them to swirl around and such.  If you have sufficient temperature differences, you can induce condensation (imagine leaving a bathtub full of hot water near the open freezer - as the warm moist air rises and hits the cold freezer air, it will form a steam cloud and will almost certainly drop some precipitate water).  If you're lucky, the rapid condensation may even make some ice crystals and you can call it snow.  Using a fan will move air, but it won't be "wind" (at least not to my satisfaction).  Wind is the natural flow of air masses as a result of pressure differences.  You'll get a more realistic wind effect with the bathtub-freezer mash-up.  In summary, you should seek to provide sources and sinks for pressure, humidity, and heat, and the natural air motion will take care of the rest.  You might want to read about Biosphere 2; their engineered indoor weather was quite expensive. Nimur 07:16, 5 July 2007 (UTC)


 * The Vehicle Assembly Building may have its own internal weather system, with reports of clouds forming inside the building on humid days. Gandalf61 10:17, 5 July 2007 (UTC)
 * I heard that happened in some of the larger sports arenas too. SteveBaker 14:20, 5 July 2007 (UTC)

Some original research - if you go to an indoor pool with warm water and cold weather outside, opening the doors to the outside will cause a cloud, and eventually precipitation, to form. It's actually quite remarkable -- Sturgeonman 23:54, 8 July 2007 (UTC)

Map of the North and South Magnetic Hemispheres
Campasses are made for both the North and the South Hemispheres. Where can I find a map of the dividing line between the two magnetic hemispheres? Ugly bag of mostly water 23:26, 4 July 2007 (UTC)


 * Compasses always point to Magnetic North, in both hemispheres. If you're talking about compass balancing, that's not essential because you can always compensate for the inclination of the magnetic field by tilting the plane of the compass away from horizontal. There's definitely no such thing as a "dividing line" such that you need one specific kind of compass to the north and a different kind to the south. Compasses work anywhere on Earth. —Keenan Pepper 01:57, 5 July 2007 (UTC)


 * Not if you're on the actual magentic poles themselves... :p --antilivedT 02:14, 5 July 2007 (UTC)


 * Sure they do! You just notice that the needle is trying to tilt away from horizontal, so you tilt the plane of the compass until the needle becomes perfectly vertical. Then you know you're at the magnetic pole. The magnetic field isn't zero at the poles; it just points straight up or down. —Keenan Pepper 02:45, 5 July 2007 (UTC)


 * Compass describes geographic "zones" - compasses are calibrated for the strength of the vertical component of the magnetic field, not the direction of the horizontal component. The compass always points towards magnetic north/south.  As far as the dividing line between the "hemispheres", I don't believe there is much use for such a distinction.  You could draw a great circle centered at either pole and set its equator.  Finally, you may be interested in a map of magnetic declination, which I have added to this section.  Nimur 03:04, 5 July 2007 (UTC)

While agreeing with both Keenan Pepper and Nimur that there is not much use for it in terms of compasses, the line that separates north from south is the line of zero inclination (not declination, although declination is much more important for actual navigation). An inclination similar to the one already posted for declination exists: and shows that the line of zero inclination is a wavy line grossly sub-parallel to (but by no means coincident with) the geographic equator. Cheers Geologyguy 04:12, 5 July 2007 (UTC)


 * Thanks. Zero degrees inclination serves my purpose well. Thanks. Ugly bag of mostly water 10:39, 11 July 2007 (UTC)

vitamin B12 and vivid dreams
I've had extremely vivid and surreal dreams the past few days, and I think it's because I've been taking 1.5 mg of vitamin B12 (orally) as a dietary supplement before sleeping. I've found some anectodal evidence and new age-y stuff on the internet that seem to confirm my suspicions, but I've found no actual medical information. Have there been any scientific studies dealing with this phenemonon? --Krsont 23:46, 4 July 2007 (UTC)


 * I don't know of scientific studies, but it is widely accepted that B12 can increase vividness/lucidity in the Lucid Dreaming community. As well as a few other things like Nicotine patches. You might be interested in reading people's experiences on ld4all.com, and if you ask around there you might also find some studies on the matter --ʇuǝɯɯoɔɐqǝɟ 00:08, 5 July 2007 (UTC)
 * Interesting... I've had a few lucid dreams in the past, but they didn't last very long. Maybe I should take the chance to experiment further with lucidity :) --Krsont 00:35, 5 July 2007 (UTC)
 * I highly recommend it. I really enjoyed doing it. I stopped doing when I started getting depressed, since those dreams were very lame anyway, and I'd rather just relax when I go to sleep than MILD myself --ʇuǝɯɯoɔɐqǝɟ 01:27, 5 July 2007 (UTC)
 * Vitamin B12 is usually considered safe with very few side effects. A quick search in PUBMED (Database for published medical literatures) did not reveal any such association. Consult your doctor and see if you can take tablets in the daytime.--Countincr ( T@lk ) 00:31, 5 July 2007 (UTC)
 * Why would I want to take them in the daytime? I guess I wasn't clear: I like the dreams, I just want to know more about it ;) --Krsont 00:35, 5 July 2007 (UTC)