Wikipedia:Reference desk/Archives/Science/2006 June 23

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Name of a Phobia?

Someone I know is scared of wrists. Not that she constantly fears them or anything, she just doesn't like looking at them. She'll be fine as soon as she stops looking at a wrist so it's not like it really affects her in a huge way. However, everytime you show her a wrist, she'll cover her face with her arms and whimper. She wears short sleeved shirts quite often and says she avoids looking at her own wrists completely as well. Is this even a phobia and if it is, is there a name for it? --71.235.83.132

According to our article Greek and Latin roots, carp- is either Latin or Greek for wrist. It's probably Latin. In that case it wouldn't work because the suffix -phobia is Greek. In any case, carpophobia would most likely work because there are a lot of phobias that mix Greek and Latin roots. I don't know for sure though. schyler 01:52, 23 June 2006 (UTC)

please see or write the article wrist cutting. 82.131.184.195 01:52, 23 June 2006 (UTC)

On this page there are messages from a number of people who fear wrists. (May not display entirely in Firefox; IE is ok.) -R. S. Shaw 06:42, 23 June 2006 (UTC)

Every person's phobia doesn't have to have some silly Greco-Latin name. What your friend is experiencing is a specific phobia, and what it happens to be attached to is probably not that significant.--Pharos 07:11, 23 June 2006 (UTC)

percolated coffee

Why does percolated coffee loose its aroma and flavor after the first cycle of percolation? ...IMHO (Talk) 01:55, 23 June 2006 (UTC)

I believe that a lot of the flavor in coffee comes from certain volatile oils that are released when you heat the coffee. Since the percolation process is in effect cooking the coffee over and over, more and more of those oils evaporate into the air instead of remaining in the liquid.--Tachikoma 05:05, 23 June 2006 (UTC)

I thought the oils broke down during percolation, but it may be that they evaporate. — The Mac Davis] ⌇☢ ญƛ. 21:16, 23 June 2006 (UTC)

Why doesn't this happen when roasting? ...IMHO (Talk) 23:32, 23 June 2006 (UTC)

The oils might break down too, I forget--this was from a book on coffee I read a long time ago. In any case, I don't recommend percolation as a way to make coffee.

I assume that only whole beans would be roasted, so maybe the exterior of the bean is impermeable enough to keep the flavor in, at least for a while.--Tachikoma 23:41, 23 June 2006 (UTC)

mesh-ups

What is a mesh-up?

I am asking in the context of the related term called "Mashing". The term mash-up is borrowed from the world of music, where it refers to the unauthorised combination of the vocal from one song with the musical backing of another, usually from a completely different genre. Web mash-ups do the same sort of thing, combining websites to produce useful hybrid sites and illustrating the internet's underlying philosophy: that open standards allow and promote unexpected forms of innovation.

Apparently, this is actually a manifestation of MESHING, of finding bridge points between disparate pieces to make a new "sense" of something. In fact, this might be a very early community indicator, as mash/meshes point out areas of shared interest.

NOTE: there is also another meaning of "mesh-up" in the computer world of 3-D imaging. It is the term that describes the creation of 3-D shapes which are "meshed-up" into an interactive plane. This is not to be confused in our context!

So I am not sure that this is accurate and cant find information other than perhaps a book on the subject called: "Web 2.0: Web Services Mesh-up" by Alexander Peter.

Can you clarify this subject area?

breaking down .rar file into little parts

I've often seen this done (especially on torrents) but never been able to find out how to do it myself. Say I have a .rar file 2 GB large and want it to be broken into little files of 10 MB each. What programs can do it? -- Миборовский 08:00, 23 June 2006 (UTC)

If you have WinRAR installed then, unpack the RAR rile, now right-click on the file or directory you want to split and select the Add to archive... option, a dialogue box will pop up and the quickest way to split the file is edit the option in the bottom right corner that indicated "Split to volumes, bytes". Since you want 10MB files then fill in 10000000. You may also want to play around with the archiving options (specifically create solid archive, put authenticity verification, and put recovery record).--69.171.123.148 08:31, 23 June 2006 (UTC)

Actually, 10MB would be 104857600 (bytes).  freshofftheufoΓΛĿЌ  13:27, 24 June 2006 (UTC)

Not necessarily. See binary prefix for the details. --cesarb 17:13, 24 June 2006 (UTC)

Since nobody uses "mebibytes" in normal conversation yet, it's safe to assume that we're all talking about plain old 1999 megabytes here. Regardless, 10000000 is still wrong.  freshofftheufoΓΛĿЌ  06:58, 25 June 2006 (UTC)

Memory

Does a full hard-drive weigh more than an empty hard drive?

Careful reading of the hard disk article would suggest not. Rockpocket 08:17, 23 June 2006 (UTC)

No, a "full" harddrive merely has all of its mini-magnets rearranged by the write head into patterns recognisable by the read head. AFAIK. -- Миборовский 08:19, 23 June 2006 (UTC)

However, if you save your word documents in smaller fonts and increase the font size only when you open them, that might save some weight. – b_jonas 08:55, 23 June 2006 (UTC)

I don't think this is true, because hard drives don't contain paper. They're already miniature sized representations. Is b_jonas just trying to mislead you?

I really must remember not to read the reference desk while drinking coffee. There's a high risk of drowning. Grutness...wha? 09:32, 23 June 2006 (UTC)

Certainly not, writing to a hard drive just rearranges existing magnetized particles, it doesn't add any mass (where would it come from?) EAi 10:12, 23 June 2006 (UTC)

It depends on how you define "full" and "empty". First, if you mean full or empty relating to meaningful information, then there is no mass difference since the orientation of a dipole does not affect the atomic mass of its composing particles. (Or does it? I'll have to doublecheck this assumption.) Second, say that by empty you mean demagnetized (that is, the same material exactly but not magnetized or magnetizable) vs a full (that is, a magnetized one), then the masses have to be different, because some of the electrons will occupy different atomic orbits (different energy levels), thus will have very slightly different mass.--JLdesAlpins 14:49, 23 June 2006 (UTC)

I was just thinking about whether a charged capacitor weighs more (on an electron mass scale), but I don't think so, since more electrons on one plate means less on the other. I wonder if any electronic (computer) component experiences a change of mass. --Zeizmic 12:18, 23 June 2006 (UTC)

Would a USB flash disk, with all the tunneling of electrons? I haven't looked at the article to see a detailed description, so this is just a guess. --80.229.152.246 15:58, 23 June 2006 (UTC)

Guessing, a new one would weight less, although even if it was wiped and empty, if it was used, it still has the electrons in it all set to whatever 0 or 1 positions your wiping software did. — The Mac Davis] ⌇☢ ญƛ. 21:18, 23 June 2006 (UTC)

A charged capacitor has an electric field between its plates; this field has energy and therefore mass. The energy in a capacitor is $CV^{2}/2$; typical values for a computer-type application are $C=1\mu F$ and $V=5V$, giving $E=1.25\times 10^{-5}J=1.53\times 10^{8}m_{e}c^{2}$. So the energy stored in a capacitor can easily have mass equal to that of millions of electrons. But remember that the capacitor will have many more electrons than that: a gram of iron contains $2.80\times 10^{23}$ electrons! --Tardis 02:13, 24 June 2006 (UTC)

Given that a computer is a modelisation of our own thinking processes : When we learn something, whe should gain weight. --DLL 10:12, 24 June 2006 (UTC)

That explains why the really nerdy students at university get so fat ... Confusing Manifestation 03:56, 25 June 2006 (UTC)

Why don't ships sink?

Paddling a canoe the weigh of the paddler is spread over a large area. Given the weigh of a large ship, for example aircraft carrier of oil tanker, and the small area in the water, why doesn't it sink?

Einstein's Shadow

--Einstein's shadow 10:03, 23 June 2006 (UTC)

Due to Buoyancy. The water surrounding a boat exerts a force on it. The angled sides of the boat channel this force upwards, i.e. pushing the boat out of the water. As soon as the entire boat is under water, an equal force is exerted on all sides (i.e. there's water on top of it) and the boat sinks (well, actually the force is marginally higher at the bottom due to the fact that the pressure of a liquid increases as the depth increases, but gravity outweighs this). EAi 10:11, 23 June 2006 (UTC)

From what I remember of buoyancy, the shape of the boat isn't really relevant to whether it sinks or floats, is it? Buoyancy helps you decide whether things float, and how high in the water they would be, but really it's as simple as this: things that are heavier than water (like stones) sink; things that are lighter than water (like wood) float. Big ships have a lot of metal, but they also have a lot of air inside, and it is this that makes them, overall, lighter than the water. ("Lighter than water" is shorthand for "having a lower density than water"). Of course, if a ship is badly designed so that water can get in and replace the air, it will probably sink. To return to terms in the original question: the area is not important, but the volume is critical. Notinasnaid 10:52, 23 June 2006 (UTC)

Shape sure does make a difference - if a boat capsizes, the air will leak out (to be replaced with water), and the boat will sink. If the ship were hermetically sealed, the shape would not make a difference as the average buoyancy would be unchanging, but in the real world (other than a submarine) that's not how it works. Raul654 11:54, 23 June 2006 (UTC)

I think we're just agreeing with each other, but let's try to be clear: the shape itself doesn't dictate whether an object floats, but of course if the shape is badly thought out the boat may capsize, and if the boat is badly designed a capsized boat will leak, so it will replace air by water and it will sink. However, I don't think it makes any difference to buoyancy whether the area below the water is slope edged or square box or anything else, except in as much as this shifts the centre of gravity and affects how much can be above the waterline and remain stable; and some shapes are better for moving through water (which isn't the issue). Notinasnaid 12:01, 23 June 2006 (UTC)

You may have a look at the wiki article - waterline...

Pupunwiki 12:08, 23 June 2006 (UTC)

Shape will determine how it floats - what level the water rises to, and which direction points up.... Nimur 19:46, 23 June 2006 (UTC)

Because a ship weighs less than the water it displaces? Obviously! remeber a cubic metre of water weighs a tonne, its not light stuff. And with all that air on board, its bound to be lighter. Philc _T^E_C^I 21:35, 23 June 2006 (UTC)

Thanks for answering my question........so is it yes? or no?

er.. the intial question isn't a yes/no question. Philc _T^E_C^I 01:33, 24 June 2006 (UTC)

A QUESTION ABOUT C PROGRAMMING.

Hello, I was recently reading a book "Structured C Programming" by some author. In it he has mentioned one code which i am not able to understand. It goes as follows :

printf("%d %8.2f %d %hn",i,x,j,&count);

He says that : " If you need to verify the number of input or output characters, you can do so by specifying the n code. This code requires a matching variable address into which scanf or printf places the count of the characters input or output. If the code is prefaced with an h, the matching variable must be short; if it is l, the variable must be long. Since the operation places the results in the variable, its address must be used in the parameter list. In the following example, "count" is a short integer that is to receive the number of characters written".

And then he mentions the forthmentioned code.

My question is that what is the variable count doing? And if I want to see the value of this variable "count", how should I get it printed, because I tried the usual way : printf("%d",count), but it didnt work ! Then I tried to print it using the "%hn" specifier as mentioned by the author, but it also didnt work !

So some help is needed. Thank You.

Perhaps a programming website would be more suitable for such a question? Theres many of them. See [1] for documentation on printf. This code:

short count = 0;
int i = 1, x = 2, j = 3;
printf ( "%d %8.2f %d %hn", i, x, j, &count );

Would store the value '3' in count as three values: i, x and j have been outputted so far. I've never used or seen this functionality and can't see much reason to.

%hn means: output the number of variables written so far to the short specified. The h indicates that the argument is a short, not (as assumed by default) a long. Hence, the variable count in the example above is defined as short. Read that linked documentation for more info. EAi 11:01, 23 June 2006 (UTC)

printf("%d",count) should be fine, provided count has a suitable type. For instance if you've used int count. If count is another type (like long or double) you need to use a suitable, different, format string. Indeed you should spend some time looking at the specification of printf strings, though it can be pretty confusing; if you are just starting out, maybe stick to some recipes for the types you use, and come back to learn format strings later. (Even as a C programmer for over 10 years, I still have to go back to check the rules for printf sometimes). Notinasnaid 11:53, 23 June 2006 (UTC)

Well, its going to be a short, not an int as its %hn :) EAi 12:01, 23 June 2006 (UTC)

Human genetic variation by continent

Not too long ago, I was confronted with the following multiple choice question in an exam (freely translated):

The human population of which continent shows the highest degree of genetic variation?

1. Europe
2. Africa
3. North America
4. Asia
5. South America

Now, the correct answer according to them is Africa. I answered it right by feeling, but I still thought it can't really be true. I mean, even with the "out of Africa" hypothesis, which would mean that modern humans in Africa had the most time to evolve etc., there are people of African origin in all parts of the world. So my natural feeling was that Northern America, with its most recent, but most mixed population should have the highest degree of genetic variation. Is Africa the correct answer? Would Africa only be the correct answer if the question would be: "The native/original human population ..."? Is the question just plain dumb and not clearly answerable? Thanks, -- Totti (talk) 11:37, 23 June 2006 (UTC)

Have a read of this article (about a quarter of the way down it mentions this specifically). It doesn't make it seem as cut-and-dry as the question suggests. You could also see table 2 on page 3 of this document - it gets pretty technical, but you could probably find some help there. This article is also very accessible and could be interesting to you. EAi 11:48, 23 June 2006 (UTC)

Thank you, although not really answering my question (which I expected), those links were very useful. -- Totti (talk) 14:10, 23 June 2006 (UTC)

The answer is correct based on all of the population genetics research of the last 4 decades. The question requires a relatively sophisticated understanding of human population genetics. As you mention, most people would assume that the population of North America has the greatest diversity, which might be true if the question were posed as "which continent shows the greatest degree of diversity of geographical location of 3 century ancestors?" The gene polymorphisms responsible for the most obvious outward differences of human skin and face shapes are fewer and less ancient and fundamental than a variety of other less visible polymorphisms present in the African population. Nearly all of the populations of the other continents share many of these genes with one subset of the African population. I assume this was a higher-level exam? alteripse 13:08, 23 June 2006 (UTC)

Yeah, I do have advanced understanding of population genetics, and I knew about most of that (visible vs. hidden polymorphisms), but I just thought the question itself was biased, because as I said, due to migration, I'm pretty sure no one can clearly say what continent has, at the given time being now, the highest amount of genetic diversity. Of course I both agree and would naturally assume (and also it's undoubted because of research), that the original population of Africa would match this criteria. Or do you mean that despite migration, Africa still has a larger gene pool (e.g. more Africans would have to emmigrate to reduce Africa's gene pool or expand other continent's gene pools enough)? It's a question from my finals (second semester, medicine, Medical University of Vienna), and in my opinion a bad one. -- Totti (talk) 14:10, 23 June 2006 (UTC)

I don't know from genetics. But the blacks in blacks in Africa that descend from slaves are of the Bantu variety. But in Africa there are also nilotic people in the East, who are a completely different 'race' (insofar as there are human races), more closely realted to semites, I believe (actually, they look like whites, except that their skin is black. And there are also pygmees in the centre and bushmen in the south. And especially these last two groups you won't likely find elsewhere. But 'races' from other parts of the Earth are found in Africa, namely whites and Asians. No Indians, though, I suppose (American Indians, I mean). But I suppose the nilotic people, pygmees and bushmen tip the balance. DirkvdM 18:44, 23 June 2006 (UTC)

The answer is correct, and is consistent with the Out-of-Africa theory of human migration. Non-Africans are genetically more related to each other than they are to Africans because they are all descended from a small group of humans that migrated out of Africa. - Cybergoth 22:14, 23 June 2006 (UTC)

If one person from "one end of the human gene" born in Africa moved to South America, and a person from the "opposite end of the human gene" born in Africa moved to South America too, wouldn't the contrast between only those two people qualify SA as the continent with the highest amount of genetic variation? Or would that only count as genetic range? I find it difficult to accept such a simple answer to the multiple choice question.  freshofftheufoΓΛĿЌ  12:21, 24 June 2006 (UTC)

The exam question is not very detailed and probably makes a few assumptions. I assume that it refers to the native population of these continents (excluding recent migration?). In your example of individual Africans moving to South America, yes, it would increase the genetic range and the variation slightly. Because of the large number of native South Americans, the population would still be more genetically homogenous than the African population. - Cybergoth 16:02, 24 June 2006 (UTC)

Dream

Sometimes I dream I stumble and fall and during that I shudder in bed. Is it because of the fall of the muscular tone? --Brand спойт 12:11, 23 June 2006 (UTC)

Since you are interested, this is a great opportunity to look up sleep and dreaming in this encyclopedia. You will find that when you dream, the brain turns off its ability to control muscles. However, this is not perfect, and some 'leakage' occurs. If you watch a dog dream, you can see that their 'switch' is not that good. --Zeizmic 12:24, 23 June 2006 (UTC)

And lets not even start about sleepwalkers...

You have possibley fallen victom to the Hypnic jerk, which more interestingly happens to teenagers at night than say, adults, or younger kids. Otherwise, its just a Myoclonic twitch. If you actually made it to the full dreaming stage, and drempt you fell, and woke up because of your unconcious body moving around, that came from (I forget) some kind of falling-from-the-tree-impulse, because we used to sleep in trees. If we started falling, the impulse would make us immediatley wake up and already have our limbs moving out to try and grab a branch or at least break our fall with a lmib instead of a head. The only times I wake up from deep sleep this way are when I am actually falling off the side of the bed. It is amazing to me that I can wake up and pull myself back up before I hit the ground. Guess its working!! — The Mac Davis] ⌇☢ ญƛ. 21:23, 23 June 2006 (UTC)

Odysseus build his bed in an old olive tree and his house around. His wife recognizes him when he hints at that. --DLL 10:07, 24 June 2006 (UTC)

Referrence

Can you exolain me and give refference to me on destructive distillation of wood?With pictures.--Saksham Sharma 12:58, 23 June 2006 (UTC)

You already asked this question and it was answered: Wikipedia:Reference desk/Science#Environmental Question. — QuantumEleven 13:16, 23 June 2006 (UTC)

ocean currents

Please tell me about ocean currents in full detail.Please give me the referrence also.--Saksham Sharma 13:05, 23 June 2006 (UTC)

There is a very nice little box on the left side of your screen, labelled "search". Type in "ocean current". Hit "Go". It will take you to our article on ocean currents, where you should find anything you need to know. The article even has some external links for further information if you need more. — QuantumEleven 13:08, 23 June 2006 (UTC)

Also note that just saying "please" at the beginning of every question doesn't necessarily make them polite. The requests have to be reasonable and you have to say please for the question to sound polite.  freshofftheufoΓΛĿЌ  12:14, 24 June 2006 (UTC)

Glycol-modified PET

I'm looking for the chemical structure of a plastic, but all my web searches have been fruitless. The plastic in question is PETG (Glycol-modified PET). Wikipedia has a nice article on PET, but not PETG. Can sombody help me figure out where the glycol modifications are on this molecule? Many thanks. - M

I was having lots of fun looking up 'petg' and 'chemical structure petg' on Google, but then I discovered that this was a standard university homework assignment. --Zeizmic 17:13, 23 June 2006 (UTC)

Not, not homework: my lab is growing endothelial cells on PETG disks, and we want to modify the plastic so as to be more hydrophilic. I was hoping somebody would know exactly how glycol-modified PET is glycol-modified so that we can figure out whether it's worth it. - M

Chemical structure of polyethylene terephthalate

PET is poly(ethylene terephthalate) while PETG is poly(ethylene terephthalate) glycol. The only difference between the two is that PET has a hydrogen at one end and a hydroxyl at the other, while PETG is a glycol, with two terminal hydroxyls. – ClockworkSoul 19:06, 23 June 2006 (UTC)

IAU and the naming of satellites

Inspired by the recent naming of Nix and Hydra (moons of Pluto), I have a couple of questions about the formalities of satellite-naming:

1. When the IAU officially accepts a name for a satellite, what form does the official announcement take? Is it always in an IAU Circular?
2. Does the IAU have several official languages in which it makes such announcements, like the UN? Or are the announcements only made in English?

Thanks, Cam 14:57, 23 June 2006 (UTC)

• After some reading, I'll attempt to answer my own questions:

1. The body that names natural satellites is the IAU's Working Group for Planetary System Nomenclature (WGPSN). When the WGPSN comes up with a name for a satellite, the decision is usually (but perhaps not always?) announced in an IAU Circular.
2. As near as I can tell, the WGPSN does all its work in English and the IAU Circulars are only published in English. It seems that spelling is important, for example the name of Jupiter XXXV is Orthosie, not Orthosia; Pluto II is Nix, not Nyx, despite the fact that these goddesses can be referred to by all these spellings in English. How this works out for other languages that can't make these distinctions in their writing systems is not clear to me. Any thoughts?

• Cam 19:47, 25 June 2006 (UTC)

entomogamy

I've been translating Clematis vitalba from the French article, and there is a word "entomogame", which it appears means something like "transferring seeds by the wind". I guessed the English translation would be entomogamy or something similar. Does Wikipedia have an article on this, or something the same? I assume we would anyway. --Brandnewuser 15:44, 23 June 2006 (UTC)

No, not by the winds, by insects. See the related word entomology. The -gamy bit relates to reproduction (i.e. here pollination), see the related word gamete. Arbitrary username 16:31, 23 June 2006 (UTC)

It turns out that entomophily is the actual term. But entomogamy seems to be listed elsewhere, so I'll create a redirect. Arbitrary username 16:33, 23 June 2006 (UTC)

Good work. How about the phrase "méso à eutrophiles", which was listed under the "habitats" section? --Brandnewuser 23:23, 23 June 2006 (UTC)

Méso is greek for middle - medium habitat I'd guess. eutrophile indicates a living form that loves good food : like some water plants where there's plenty of nitrates dissolved. --DLL 10:02, 24 June 2006 (UTC)

Sugar Granule Size - Does It Really Matter?

If it's going to get disolved in water, what possible difference does it make, whether I use caster sugar or icing sugar? Why not just granulated sugar? When it's dissolved, it's just sugar water, no matter what size the granules were to begin with? http://www.supercook.co.uk/inspiration/recipe-ideas/details/12011 --Username132 (talk) 17:21, 23 June 2006 (UTC)

Dissolving is a reaction that occurs on the surface. The smaller the sugar granules the more surface for a given amount of sugar (assuming the sugar is the same thing except for granule size obviously), so the faster it will dissolve. DMacks 17:41, 23 June 2006 (UTC)

Yeah, so it takes five minutes longer - big deal - at the end of it, you're left with the same solution, right? --Username132 (talk) 18:08, 23 June 2006 (UTC)

Perhaps a given volume of caster sugar is slightly more dense than the same volume of granulated sugar, thus you'd get a sweeter syrup using the former. Given the recipe you linked, you probably won't care after consuming one or two of those jellies. --LarryMac 18:18, 23 June 2006 (UTC)

If you're disolving it in water, you're right. The reason for the variety is that the texture of the granuals and their speed of entering solution matter for some cooking. Trollderella 18:21, 23 June 2006 (UTC)

According to the sugar article, in powder sugar, "The manufacturer may add a small amount of anti-caking agent to prevent clumping". DirkvdM 18:53, 23 June 2006 (UTC)

Also keep in mind that the actual shape and size of sugar is sometimes used. For example, when making cookies you start by creaming butter by adding sugar and mixing it so that the sugar crystals basically slice up the butter and introduce small pockets of air. Using a finer sugar would create smaller pockets of air and so the resulting texture would be different. There may also be times when you want to form a sort of colloid of sugar and fat, in which case the size of the sugar particles would affect the texture of the mixture (e.g. in frosting/icing). 128.197.81.181 21:41, 23 June 2006 (UTC)

When dealing with ingredients such as sugar and salt, it's important to use the same grade as the recipe calls for if the recipe amounts are volumetric (as they almost always are). Finer particles will result in adding too much of the substance and coarser ones in adding too little. Flour is so variable in density that I've seen recipes that specify a weight of flour rather than a volume. 128.197.81.181's comments are also important if the sugar is not to be dissolved. --Ginkgo100 ^{talk · contribs} 21:59, 23 June 2006 (UTC)

photosynthesis and cellular respiration

Okay i have two questions that are tied in with each other.

1a. How would the composition of earth's atmosphere change if green plants and other autotrophs disappeared?

1b. How would animal life be affected by this atmospheric change?

Any help with these questions would really be appreciated. I've looked all over and can't find answers. I don't remember anything like this being in the book, and i homeschool so there is no teacher for me to ask.

Hopless Biology Student

Your best bet is to research photosynthesis, autotrophism, and atmosphere - I think you'll see quickly that green plants contribute to the various gas cycles, release and absorb Oxygen and Carbon Dioxide, participate in the Carbon cycle, Nitrogen cycle, and probably absorb considerable solar radiation that would otherwise become heat. I imagine your questions should be answered in essay form, so you might want to do some thorough reading in your textbook as well. Nimur 19:54, 23 June 2006 (UTC)

C'mon man, read the textbook first next time!! You may not be able to copy a sentance verbetium, but you will learn the answer rather than relying on us to tell you. — The Mac Davis] ญƛ. 21:43, 23 June 2006 (UTC)

Thank you for letting me know what to look up... i kinda get it all now... thanks  :)

Macbook Pro // Bootcamp

Okay, I want to get a Macbook Pro for my next school year. But I also want to have Windows on there.

My question is this: Boot Camp is currently in beta, but it'll be official when OS X 10.5 comes out in late November I believe. However, I will need to have a laptop before August. Is it likely that Apple will release Bootcamp Final for all the saps who bought a new computer for the new school year with 10.4? — Ilyanep (Talk) 20:04, 23 June 2006 (UTC)

Well, no one can tell you that without resorting to tea leaves or tarot cards. But even as beta, Boot Camp seems quite well-behaved and problem-free. So I wouldn't wait for Bootcamp Final, as it will mostly be a name change. But if beta vs final is important, and even if not, I would consider using Parallels Desktop for Mac virtualization software [2] instead of Boot Camp, as you can run MacOS & Windows simultaneously (Windows running in a window in the Mac OS), and cut and paste between them, rather than rebooting and running only one at a time as Boot Camp requires. [3] - Nunh-huh 20:26, 23 June 2006 (UTC)

But I probably want to have full performance for gaming. Also, the difference between beta and final may be pretty big considering what Apple tends to do. On the other hand, the way it works now is probably enough for me. — Ilyanep (Talk) 20:47, 23 June 2006 (UTC)

How good is Bootcamp? I thought that Windows would be noticeably slower. I predict OS X 10.5 to come out later this year (oh, you said that), and it will have Bootcamp bundled in a final release. — The Mac Davis] ⌇☢ ญƛ. 21:14, 23 June 2006 (UTC)

I hear that a Mac running Boot Camp and Windows XP is almost as good and even better than some high-end PCs running Windows XP. — Ilyanep (Talk) 22:33, 23 June 2006 (UTC)

There are ways to just install both, and choose as it boots which you run. Though I cant remeber how, thoguh some clever guy programmed the choice to a tilt swith, so it booted linux one way up, and woindows the other. I'm sure a similar thing can be done with OSX and windows. though a tilt swith would be innapropriate in a laptop! Philc _T^E_C^I 21:24, 23 June 2006 (UTC)

Types of melting

i was tolt that there are two types of melting, one is called a "pasteous melting" and the other one is "frank melting", physics consider some objects like parafin and glass as liquids and when heat is added to them, they melt not like the water ice cubes, they do it slowly and they call it pasteous melting. I have found this right here -> in spanish on page one, but i am still confused on the meaning of both types of melting. What a "pasteous melting" and "frank melting" are ?--HappyApple 22:07, 23 June 2006 (UTC)

I'm not familiar with those terms, but some materials, like water ice, melt all at one temperature, while others, like glass, slowly transition from an apparent solid to a thick liquid to a thin liquid as the temp increases. StuRat 03:45, 24 June 2006 (UTC)

I'm not that familar with those terms either but I think you've almost answer the questions yourself- pasteous melting is melting of a solid that does not have a definate melting point - so it goes through a semi solid stage. Whereas 'frank melting' refers to a solid that does have a distinct melting point - this would melt directly into a liquid - with no intermediate 'gooey' or 'pastey' phase.HappyVR 13:53, 24 June 2006 (UTC)

It may be of note that nothing really has a definite melting point, but rather a melting range. This range may vary in size, from a few hundredths of a degree in very pure substances, to many degrees in less pure solids. This range is often created by imperfections in the crystalline structure of some solids (though not all solids are crystalline), but can also be effected by impurities (even impurities caused by putting a pure substance in contact with air). I would venture to say that the difference in melting behavior of wax and ice is due less to some different "type" of melting, and more to the thermal masses of the substances, and the relative liquidity of the newly melted products.Tuckerekcut 17:52, 25 June 2006 (UTC)

Optical propreties of the human eye

If you had to compare the human eye to a camera lens and sensor, how would you describe the ISO range, aperture range and focal length? --Jcmaco 22:26, 23 June 2006 (UTC)

F-number says "the f-number of the human eye varies from about f/8.3 in a very brightly lit place to about f/2.1 in the dark". The eye doesn't really have a focal length, because it's the shape of the lens that changes, not the distance from the lens to the retina. I have good eyes and I can focus from infinity to about 15 cm. —Keenan Pepper 22:49, 23 June 2006 (UTC)

ISO corresponds to adaptation to light intensity (such as night vision) and aperture is determined by the iris. The focal length is indeed fixed. I suppose this is possible because the retina is essentially part of the brain and therefore able to interpret the 'blurry image'. Though I'm not sure how that would work. DirkvdM 06:37, 24 June 2006 (UTC)

Huh? The lens of the eye changes shape to change its focal length so it can focus on objects at different distances even though the lens-retina distance is the same. It's called accommodation. This is the opposite of a camera, in which the lens stays the same shape, with the same focal length, but the lens-film distance changes. The retina and brain don't do any deconvolution, if that's what you're thinking... —Keenan Pepper 17:30, 24 June 2006 (UTC)

Oops! Of course the focal length of the lens changes. What I meant was that the distance between the lens and the retina remains the same, unlike with a camera. And then I took an odd turn. Sorry. DirkvdM 18:12, 24 June 2006 (UTC)

steriliziing an Ace bandage

I wish to know whether there is a way to sterilize an Ace bandage [redlink, needs writing] without ruining it. I have an Ace bandage that has possibly MRSA-infected bodily fluids on it.—msh210℠ 22:54, 23 June 2006 (UTC)

I see Sterilization (microbiology)#Chemical sterilization, which has some information, but I need a household-available sterilizing agent, and need to know that it won't ruin the Ace bandage. Any help would therefore be appreciated.—msh210℠ 23:09, 23 June 2006 (UTC)

Why not just get a new Ace bandage and dispose of the infected one? What makes this particular one so important? M@$+@ Ju ~ ♠ 00:36, 24 June 2006 (UTC)

Can an Ace bandage survive high temperatures? Baking it at 350 F for a few hours should kill anything. Alternatively, if you've got a pressure cooker, you could try using it as an autoclave. --67.185.172.158 04:55, 24 June 2006 (UTC)

Get rid of it. There is a reason why most medical equipment these days is disposable. It's cheaper and much safer just to get another one. Can you explain why you wish to keep an infected and soiled bandage? --mboverload@ 13:48, 24 June 2006 (UTC)

Maybe it has sentimental value. ;-) --Fastfission 17:30, 24 June 2006 (UTC)

Thanks, Mattman723, mboverload, everyone else. I didn't know what Ace bandages cost, although someone on Usenet has now told me that they're cheap, and, from growing up, I remember their being reused (not when bloodstained, though). So, yes, I'll chuck it. It? Them. I get one bloodstained daily. That leads me to my next question, which is whether my discharges are still MRSA-infected, now that I've been on vanc this long — but that's a question for my doctor, not for here. Thakns again, folks, for your responses.—msh210℠ 08:15, 25 June 2006 (UTC)

Be careful disposing of such contaminated bandages. You don't want someone (such as a sanitation worker) to come into contact with it. In fact, you should probably ask your doctor about disposal. --Ginkgo100 ^{talk · contribs} 18:55, 25 June 2006 (UTC)

...or better still, put it in a ziplok bag or some other airtight container and bring it to your doctor's office for disposal by the hazardous waste protocols there. MRSA contaminated stuff is not something you want to be casual about - leave it for the experts to deal with. --hydnjo talk 19:10, 25 June 2006 (UTC)

Get rid of it. ACE bandages are not sterilizable. - Cybergoth 21:38, 26 June 2006 (UTC)

No problem msh =D On the cost:

• $5.49 Unstretched Length - 5.3 ft.
• $2.61 for 15 feet of 2 inch bandage. (knock-off brand)

Google it. Plenty of deals --mboverload@ 04:42, 27 June 2006 (UTC)

Solquid

What is the technical/formal term for a substance that is neither solid nor liquid, but somewhere in-between? Yogurt is the best example I can think of at the moment, or perhaps a thick milkshake. --71.98.5.11 23:11, 23 June 2006 (UTC)

Custard is a Non-Newtonian fluid meaning its viscousity changes with strain, so with enough pressure applied, it can become solid. I think. Philc _T^E_C^I 23:18, 23 June 2006 (UTC)

It's either one or the other. However, you may be thinking of a suspension of solid particles in a liquid, which is known as a colloid. --Ginkgo100 ^{talk · contribs} 00:35, 24 June 2006 (UTC)

Yeah, this question was recently asked by User:Keenan_Pepper like last month. — The Mac Davis] ⌇☢ ญƛ. 03:12, 24 June 2006 (UTC)

My question was specifically about Frosties, in response to the "soquid" commercials. I think we concluded they were colloids, right? —Keenan Pepper 04:05, 24 June 2006 (UTC)

How about a plain old gel ? StuRat 03:34, 24 June 2006 (UTC)

Amorphous solids, like glass, also have characteristics of liquids (such as flowing over time), and are sometimes called "supercooled fluids". StuRat 03:40, 24 June 2006 (UTC)

There are classifications for everything... try this: Suspension (chemistry). I think that's where yogurt would fall. --Bmk 03:51, 24 June 2006 (UTC)

Frostys - it's a mixture - probably contains ice (solid) (very small ice particles) and a liquid (sugary water) plus probaly emulsifiers or thickening agents - it's not a phase of matter - but a mixture of solid and liquid. (a bit like very fine sand in honey maybe)HappyVR 14:00, 24 June 2006 (UTC)

Hmmm... how about an emulsion? - Cybergoth 16:12, 24 June 2006 (UTC)

Colloid. --Proficient 17:37, 24 June 2006 (UTC)

I guess emulsions and gels are types of colloids. - Cybergoth 17:18, 25 June 2006 (UTC)

Yellow Water-lily

Does the word hydrochore or something that may look similar mean anything, maybe meaning something like "disperses seeds through water", in the dissemination of plants, specifically the Yellow Water-lily?

Sure, a hydrochore or a hydrochoric plant undergoes hydrochory, the dispersal of seeds by water. They're all legitimate English words. Maybe someone should start an article at Hydrochory. —Keenan Pepper 04:15, 24 June 2006 (UTC)

They all come from the Greek ὕδωρ, "water", and χωρειν, "spread". —Keenan Pepper 04:24, 24 June 2006 (UTC)