Wikipedia:Reference desk/Archives/Science/2006 June 18

Humanities Science Mathematics Computing/IT Language Miscellaneous Archives

The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions at one of the pages linked to above.

< June 17 Science desk archive June 19 >

Old Alcohol

I inherited a stock of alcohol in sealed bottles - over 30 to 40 years old. Is it safe to be drinking that? —Preceding unsigned comment added by 69.118.234.15 (talk • contribs) 21:14, 17 June 2006

In the case of wine, quite possibly, although it may have passed its best. Whisky (and whiskey) may be OK to drink too, but you may want to re-ask this question at the science reference desk, as they may be more able to help answer your question. EvocativeIntrigue _{TALK | EMAIL} 21:40, 17 June 2006 (UTC)

Moved from the Miscellaneous section by vibo56 ^talk.

If it's brandy in your bottles, then it will probably be very good indeed. --Kurt Shaped Box 00:26, 18 June 2006 (UTC)

The alcohol you are referring to is ethanol, right? Otherwise, you probably wouldn't want to drink it :-) ...

If it is wine or anything stronger, I think it would be safe to taste it. And if the taste's ok, I think it would be safe to drink it. But to be on the safe side, wait a couple of days until other contributors have had their say! --vibo56 ^talk 00:19, 18 June 2006 (UTC)

Or send another contributor the alcohol and see if they survive after a few days. --M1ss1ontomars2k4 ^{(T | C | @)} 00:20, 18 June 2006 (UTC)

And if they die, the traditional rule for food-tasters applies. They get a cemetery or a crematorium named after them. (lol). JackofOz 00:35, 18 June 2006 (UTC)

Well, depending on what sort of beverage we are talking about, volunteers shouldn't be that hard to find... :-) --vibo56 ^talk 00:42, 18 June 2006 (UTC)

The thing is, if the yeast which creates the alcohol is still in there, it can take the alcohol and further convert it to Ethyl Aldehyde, and then to Acetic Acid (vinegar). Usually the yeast is removed to prevent his from happening, and with high content spirits the alcohol content can get to toxic levels for the yeast.

My guess is that it would be safe, but like was said above, it could just taste awful. —Mets501 (talk) 02:29, 18 June 2006 (UTC)

Well, you shouldn't rule out the thought of selling them. Since they are so old, you might get a good deal if you can -prove- that they are 30 to 40 years old. --Proficient 14:40, 18 June 2006 (UTC)

Even better, drink it, buy something cheap to refill the bottles, then sell it as well. Black Carrot 21:52, 18 June 2006 (UTC)

My budgerigar's eyelids

This is something that I first noticed years ago, with my very first pet budgie but completely forgot about until I read all the budgie-related questions on here. Is there any particular reason that when a budgie blinks, its bottom eyelid moves up to meet the top, as opposed to the top eyelid moving down to meet the bottom, as in humans? Is there any particular advantage to this configuration, or is it just a case of two very different species evolving from two very different evolutionary lines and arriving at different solutions for the same problem? --Kurt Shaped Box 00:50, 18 June 2006 (UTC)

Are you sure this isn't a third, inner eyelid you are seeing, in addition to the normal eyelids ? Cats have this, too, and I assume it's useful for removing debris (like fur, in the case of a cat) from the eyeball. StuRat 23:51, 18 June 2006 (UTC)

Na. It's definitely his bottom eyelid - I've been sat watching him for the past ten minutes. When he blinks, the bottom lid moves up to meet the top one. Go figure. --Kurt Shaped Box 11:25, 19 June 2006 (UTC)

Although there may be an advantage, I would chalk it up to the vagaries of evolution. --Ginkgo100 ^{talk · contribs} 20:07, 21 June 2006 (UTC)

Perhaps there is pressure from predation that pushed evolution in this direction. I'm thinking they may have a better view of predators from above with this arrangement. Are all birds eyelids like this, I wonder? —Bradley 22:36, 22 June 2006 (UTC)

How does my Electric toothbrush recharge itself?

I've got a Braun toothbrush which has a solid plastic casing. I recharge the toothbrush by placing it on a small recharging unit that also has a solid plastic casing. The unit is plugged into the mains, but how does the toothbrush recharge when there are no metal contact points on the charger or the toothbrush?

Psychonaut3000 01:44, 18 June 2006 (UTC)

Assuming you have't missed the metal contacts I'd assume through electromagnetic induction. A coil of wire with an oscillating (AC possibly highfrequency) current in it would induce an oscillating electric current in a pickup located inside the tootbrush. This could be used to charge a battery. Sorry I can't find a good page to explain the process..HappyVR 01:54, 18 June 2006 (UTC)

Yes as described here. Also the early models of implanted artificial pacemakers used this method of recharging its batteries. --hydnjo talk 12:08, 18 June 2006 (UTC)

You can test this by dangling a small piece of steel inside the charging socket: the metal ferrule on a pencil works well, as should a small screwdriver. If you can feel a vibration, it uses magnetic induction. --Serie 20:06, 19 June 2006 (UTC)

HIV Transfer

If I have a small cut on my penis, and I am getting a blowjob from someone that has HIV or AIDS, will I get HIV? I was reading an article and it mentioned that the HIV virus is in saliva also, thanks

There is risk, but it does not guarantee infection. Any body fluid exchange can carry the virus, but the operative word is CAN, not for certian. Also consider that the virus is fairly fragile, and does not survive very long outside the body. I would strongly reccomend you get yourself checked, this virus is pretty ugly once it gets a hold of you.

See #HIV. Conscious 05:07, 18 June 2006 (UTC)

You shouldn't risk it. --Proficient 14:47, 18 June 2006 (UTC)

Regardless of the cut, you shouldn't risk it. Black Carrot 21:50, 18 June 2006 (UTC)

And you should shave more carefully. - Nunh-huh 11:24, 19 June 2006 (UTC)

PNG graphics transparency

I've noticed that some PNG graphics on Wikipedia that are shown with a transparent background within the article actually have a blueish background. Here's an example:

In the article PNG this same image has a transparent background.

Why does this happen? How do I make the background display as transparent?--Anakata 02:15, 18 June 2006 (UTC)

Internet Explorer cannot handle transparant PNG images, and often displays them (on Wikipedia) with a blue background. You could try using Mozilla Firefox; that will fix the problem. —Mets501 (talk) 02:24, 18 June 2006 (UTC)

I recommend Firefox as well, but here's a fix for MSIE users who can't switch: Wikipedia:Tools#Internet_Explorer_alpha_transparency. It isn't failsafe, though, so beware. --Kjoonlee 12:41, 18 June 2006 (UTC)

IE will handle transparency in PNGs, but only as one bit transparency (i.e. transparent or opaque), IE has no support for optional alpha channels, thus remains within the PNG spec. The PNGs are broken if they don't include the transparency map with an alpha channel, as far as the spec says. For what it's worth, IE7 seems to handle non-conformant PNGs much better than IE6 did and, of course, FireFox attempts to handle even extremely poorly formed PNGs (which may be a security flaw as libpng comes under attack) Wayne Hardman

Can you explain me the types of sugar?

I want to know everything about types of sugar like table sugar,milk sugar,starch sugar and fruit sugar. Please help me with this topic.--59.144.254.49 03:41, 18 June 2006 (UTC)

See sugar and carbohydrate. They will certainly point you to sucrose, lactose, amylose, and fructose, the sugars to which you may be referring. Cheers, David Iberri (talk) 03:45, 18 June 2006 (UTC)

Web based file sharing

I've recently been asked by an online group in which I'm active if I could establish some sort of web-based file sharing tool... Pictures, audio files, and possible applications. There are several groupware packages that incorporate some type of upload/download for members but, along with that functionality, one is bombarded with features that are not, in this case, needed.

Is there a web-based file sharing package (for linux?) that might work for this group? I've read through File sharing but the article is concerned mostly with P2P stuff. Thanks so much for any guidance you guys (and gals) might be able to provide! --Chiacomo ^talk 04:45, 18 June 2006 (UTC)

Have you considered an FTP server? –Mysid^(t) 07:52, 18 June 2006 (UTC)

I usually use FTP for large person to person transfers. However in this case, it sounds to me like given that there are a fair number of participants so I wonder if something like a members only Direct Connect server. Chiacomo, I would suggest you read up on copyright law however. You could be held responsible if people misuse your server to distribute copyrighted audio files and applications without permission from the copyright holder. Nil Einne 15:15, 21 June 2006 (UTC)

MILF!

Why is it that some teenage boys/young men are attracted exclusively to women in their 40s? Is there a scientific/evolutionary explanation for this? In terms of reproduction, this would seem to be counterproductive (without trying to sound too veterinary, women of that age are past their prime when it comes to breeding). --84.65.31.248 05:48, 18 June 2006 (UTC)

I'm not sure what you mean by "exclusively". I doubt young/men boys are alone in their lust for women in their 40s (one would think their husbands might also have a sexual interest in them). Nor are 40 year old women the only object of teenage boys desire (otherwise teenage girls wouldn't have many boyfriends). That notwithstanding, its an interesting question. From a psychosexual point of view, one could argue that teenage boys are experiencing the junction between cutting their ties to the primary female in their life (their mother) and experiencing sexual feelings for the first time towards another woman. Thus an older woman can fulfil both their need for a caring, maternal relationship and a sexual relationship. That someone could fulfil both roles could manifest as a strong sexual attraction in a young males. I'm sure Freud would having something to say about that. Rockpocket 08:05, 18 June 2006 (UTC)

Maybe I'm misremembering my youth, but I seem to recall that teenage boys lust after anything with two legs and a pulse. That said, Rockpocket is probably on to something with his reference to Freud. There are also undoubtedly teenage boys who find that most girls their own age are immature, just like (many more) teenage girls find boys their own age immature. --Robert Merkel 11:37, 18 June 2006 (UTC)

I think big tits have something to do with it?HappyVR 13:17, 18 June 2006 (UTC)

Well, make a decision. Do you think that or do you not? ;) My opinion more or less echoes theirs, without the Freudian part. Evolution probably has little to do with it. Black Carrot 21:48, 18 June 2006 (UTC)

On the question of evolution, it may have something to do with the female reproductive peak much later in life (I think 35yrs. is typically cited,) so perhaps the male evolutionary response is to seek out those females most likely to bear children?

The thing about the sexual peak at 35 doesn't jive with evolutionary/reproductive success theories, because women begin to lose fertility in their late 20s or early 30s. A much more documented phenomenon is of older men seeking out women in their early 20s, because these women are more fertile. At 35, the risk is much higher for pregnancy complications and birth defects. My pet ideas:

1) When (straight) teenage boys first become attracted to women, some of them might find themselves more attracted to "unobtainable women" such as celebrities, models, and older women, because there isn't any real chance of having to interact with them. They can avoid the fear of being rejected or humiliated, because they're obviously not going to hit on (or get hit on by) their friend's mom.

2) Teenage girls are just as nervous/self-conscious as teenage boys, while older women are generally much more confident and comfortable with their sexuality. Confidence is a huge turn-on for most people. TheSPY 15:07, 19 June 2006 (UTC)

Oedipus complex, anyone? --M1ss1ontomars2k4 ^{(T | C | @)} 05:02, 20 June 2006 (UTC)

Some people are weird, some people like older partners, some younger, some much younger, some too young, but those people go to jail. Philc _T^E_C^I 22:23, 20 June 2006 (UTC)

I agree with others that the exclusively part is a bit dubious. I'm sure there are some who are exclusively but my expectation is that most visitors of sites like MILF are not exclusively attracted to older women but can find older women a turn on in some circumstances. I suspect a number of the suggestions are part of the reason (freudian issues, confidence etc). I also expect experience has something to do with it. There is the expectation that older women are more 'sexually experienced' which many may find a turn on. There is also likely a vast difference between the average personality of a teenage female and a significantly older partner. I'm not talking about experience or confidence here but I would assume an older women, especially one that is interested in a romantic relationship with a teenage boy is far less liekly to have hang ups about sexual intercourse and is not going to make the kind of financial and social demans that a teenage girl would. All in all, I guess what I'm saying is it's a rather complicated question and there is no one reason Nil Einne 15:11, 21 June 2006 (UTC)

Diffusion and Osmosis

What does "concentration gradient" and "chemical potential" mean in the context of diffusion?

I am often confused by the idea of "diffusion". THe following is my idea of what's diffusion?

"The dispersion of random moving particles from high concentration to low concentration"

For the definition of osmosis:

"The diffusion of water from low concentration to high concentration"

Please correct any wrong ideas thank you!

Concentration gradient is the rate of change in the concentration of a substance along a given direction. In the context of diffusion, say you have a region of high concentration of a substance and a region of low concentration of the substance. As you move from the region of high concentration to the region of low concentration, the concentration changes gradually. Concentration gradient in this context is a measure of how rapidly the concentration changes as you move from one region to another.

In osmosis, you have one or more dissolved substances (solutes) dissolved in a solvent (of which water is a common example). Osmosis is the diffusion of solvent across a semi-permeable barrier from a region of low solute concentration to a region of high solute concentration. Osmoisis is a form of diffusion. (In the definition of osmosis you gave, "concentration" is that of the solute(s), NOT of the solvent)--72.78.101.61 12:52, 18 June 2006 (UTC)

Why does the particles MUST move from high to low concentraiton?

The net movement of particles from a region of high concentration to a region of low concentration is the result of the movement of many individual particles. For simplicity, imagine that there is a (real or imaginary) boundary separating the two regions and assume that particles are equally free to cross the boundary in either direction. In order for a particle to cross from side A of the boundary to side B, there first needs to be a particle on side A (near the boundary). If there's a higher concentration of particles on side A (than side B), probability dictates that the expected number of crossings from side A to side B is higher than in the reverse direction. Note that the net flow of particles is a statistical average. Particles cross the boundary in both directions. It's just that there are more crossings in one direction than in the other.--72.78.101.61 14:50, 18 June 2006 (UTC)

They don't have to, its perfectly possible that they don't atoms molecules are constantly moving about, they go wherever, but it is more likely that they will go to a lower concentration. Philc _T^E_C^I 22:21, 20 June 2006 (UTC)

Case in e-mail addresses

I've looked at the e-mail address article, but it doesn't seem to be clear on whether upper-case and lower-case letters are treated as different characters in e-mail addresses. Either they are or someone doesn't want to talk to me- which is it? Henry^Flower 08:16, 18 June 2006 (UTC)

It depends on the software which receives and routes the e-mail. There are many different software solutions for this, and some will distinguish between upper and lower case in addresses. However, upper and lower case unaccented Latin characters should not be significant in the domain name (that is, the part after the @ sign) according to the rules of DNS; however it remains possible that some e-mail software will still care. For this reason, best practice in reproducing an e-mail address is to use exactly the case originally given. Notinasnaid 08:32, 18 June 2006 (UTC)

Thanks! I'll try some permutations. Henry^Flower 08:35, 18 June 2006 (UTC)

Also, some web-based email services like Gmail and Hotmail force all usernames to be lower-case, which helps. But with email addresses residing with ISPs, their policies all vary. -- Daverocks (talk) 12:35, 18 June 2006 (UTC)

See e-mail address. The local part of the address is case-sensitive, the domain name is case-insensitive. However, not all e-mail software properly implements RFC 2821. Gdr 19:09, 18 June 2006 (UTC)

Actually my reading is that it must be treated as case sensitive but use of case sensitivity is discouraged. I would guess this means there is nothing wrong with the common practice whereby case is preserved but ignored. I.E. BillG@.... is treated as the same thing as billg@. Personally, I know my ISP and most other ISPs have done likewise (i.e. ignored case). Nil Einne 14:19, 21 June 2006 (UTC)

Health

What can cause a cancerous tumore of the brain?

Try the article on brain tumor and google. Weregerbil 11:21, 18 June 2006 (UTC)

Reading too many Wikipedia articles is the cause. :-) StuRat 23:44, 18 June 2006 (UTC)

Few things are associated directely with brain tumors. First of all, other cancers are responsible for methastesis to the brain (lung cancer is common on that). Other things to consider are radiation and some genetic disorders. neurofibromatosis, tuberous sclerosis, multiple endocrine neoplasia (type I), and retinoblastoma, increase the predilection to develop CNS tumors. But the majority of cases have no direct explanation. They arise from single cell mutations simply by chance. Did I answer your question?--Elrafael 07:13, 25 June 2006 (UTC)

drugs

1.What are the functions of drugs? 2.What are the helpful and harmful benefits of drugs to people?

Try the article on drugs and the articles on medication and recreational drugs linked therein. Also google is your friend. After doing some research on your own please ask specific questions on anything you can't find on Wikipeda and the net. Weregerbil 11:23, 18 June 2006 (UTC)

Some of them make you better if you take the right amount. Some of them make you sick if you take the wrong amount. --Kurt Shaped Box 11:30, 18 June 2006 (UTC)

I'd say they all make you better if you take the right amount, and make you sick if you take the wrong amount. In some cases the right amount would be "none", but in the words of ... hell, I don't even know ... "Of course too much is bad for you - that's what too much means!" Confusing Manifestation 09:30, 19 June 2006 (UTC)

Drugs are like fire: Used correctly fire can save your life by allowing you to cook your food so you won't starve and keep you warm so you won't freeze. Used incorrectly fire can kill you. Same goes for drugs. Used correctly they can prevent a disease from killing you. Used incorrectly they themselves can kill you. My best advice: see your doctor and ask him or her if you require any special drugs to survive or improve your quality of life. If not, tell him or her whatever drugs you are taking and ask him or her whether your level of intake has the possibility of harming your health. We all use drugs. Whether it's a cup of coffee or an aspirin or a glass of wine. Usually this type of drug intake is relatively harmless. Yet if you're considering something radical like some sort of illicit drug, beware, these drugs aren't illegal simply because the government wants to control our minds, but because they have the potential to cause serious harm to one's body. Just like fire... Loomis 22:42, 25 June 2006 (UTC)

Turkish spider

Does anyone know what kind of spider this is? I took these pictures in southern Turkey, near the village of Aglasun. Many thanks, pjd 11:50, 18 June 2006 (UTC)

I'm no expert, but the head reminds me of windscorpions. --Kjoonlee 13:26, 18 June 2006 (UTC)

Many thanks Kjoonlee, I just read the article and you are probably right. The eyes on top of the head, the pincer 'jaws' and the long pedipalps 'giving the appearance of two extra legs' all point to a windscorpion. pjd 14:20, 18 June 2006 (UTC)

biology question.

Potato plants bear seeds and flowers yet they never grow from their seeds.Why?--59.144.242.244 12:19, 18 June 2006 (UTC)

Some varieties of potato produce seed, some don't. The ones that do can be grown from seed. It's just that they germinate slowly, the plant grows smaller, and produces less harvest than potatos grown from tubers (the tuber has all that easy-to-use energy that gives young plants a jump start on life.) So commercial production starts from tubers. Potatos are occasionally grown from seed by researchers when they try to produce new varieties by cross pollination. Weregerbil 13:07, 18 June 2006 (UTC)

Non-microwavable security devices

OK, so i've just been to the supermarket and bought some razor blades. They come fully equipped with a sticker saying: "This product contains a non-microwavable security device". Presumably this is some kind of RFID tag. My questions are:

1) Is a RFID tag any more or less microwavable than a razor blade? The razor blades don't come with a 'Don't put me in the microwave' warning.

2) Why would you want to microwave a packet of razor blades anyway (unless you were into making sparks?)

--Chris 12:53, 18 June 2006 (UTC)

Presumably that's a safety warning against attempts to destroy any RFID tags embedded in the product by "cooking" the product in a microwave.---72.78.101.61 13:09, 18 June 2006 (UTC)

It sounds like a dare to me!

It's probably a standard label placed on a number of items, some of which happen to already have metal components. Black Carrot 21:44, 18 June 2006 (UTC)

I think the point of the warning is that you should not microwave it, not that microwaving would have no effect. Hence not a dare, but a warning of possible sparks—i.e., this packaging contains hidden metal. —Bradley 23:29, 19 June 2006 (UTC)

razor blades are no fun. you should try putting light bulbs in the microwave. that's fun! (serious) VdSV9•♫ 01:33, 20 June 2006 (UTC)

They've actually covered this in the Feedback column of the New Scientist - why would you want to microwave razor blades!? Or an RFID tag, for that matter? --Jrothwell 16:39, 20 June 2006 (UTC)

• it';s just a suggested guidline, like when they tell you your signature is horrifyingly long, it's just a guidline to change it--Bee(y)^Ti 01:48, 21 June 2006 (UTC)

Firefox problem

Hello. I am trying to download Google's notebook, and I keep getting this darn porblem about it not letting me install the software. Then, below the address bar, it sasys "Software installation is currently disables. Click Edit Options... to enable it and try again." I then added "tools.google.com" to the allow list, but it still doesn't let me download it. I followed all of the instructions on the page that helps you, but to no avail. Any ideas? Thanks a lot. Iolakana|^(talk) 16:22, 18 June 2006 (UTC)

it's unlikely, but could be a profile problem. Try removing your Firefox profile and starting again (it'll remove all your cache/bookmarks, though). Heres how; Close all Firefox windows and make sure the firefox process is stopped. Assuming you're using windows go Start -> Run "Firefox.exe -Profilemanager" (if you're not running Windows you can use the same option through command etc), delete your current profile, then create a new one, then restart Firefox. There's a chance that might fix it as it could be due to some mismatching. I suggest you try this as a last resort only though. -Benbread 21:55, 18 June 2006 (UTC)

You might have set your security options to disable all software installs, no matter what the website. --M1ss1ontomars2k4 ^{(T | C | @)} 05:00, 20 June 2006 (UTC)

You mean Google SketchUp? I am not aware of a notebook. — The Mac Davis] ⌇☢ ญƛ. 03:34, 21 June 2006 (UTC)

Scientific Reviews

Why do scientists write reviews and how long does it take?

What types of reviews are you talking about? Book reviews, article reviews, peer review? (Movie reviews?) The one type of review which is most associated with scientists is the peer review, take a look at our article on that. As for how long it takes, surely it depends on the subject matter and the scientist. --Fastfission 18:22, 18 June 2006 (UTC)

In my mind the sort of review most associated with scientists is a review article. Research articles describe results from a particular experiment or a set of experiments. Review articles, on the other hand, describe the results from a set of research articles, attempting to unify various results with a simpler explanation, usually trying to argue that the various results support the author's personal theories. How long it takes depends on a lot of things: how well the author knows the literature, the intended length of the review/amoung of content to be included, number of authors writing the review, number of hours per day spent writing, etc, so it's hard to give a good answer. Hope that helps. 128.197.81.181 18:39, 18 June 2006 (UTC)

Yeah, I was referring to review articles (cf. movie reviews!) Who funds the scientist writing a review article? --Username132 (talk) 20:59, 18 June 2006 (UTC)

I'm pretty sure whomever is funding the person's work is funding any review articles the scientist writes as well. Unlike actual experiments which can require specific funding for equipment, lab workers, chemicals, etc., writing a review paper really only requires time, so there isn't really a need to request extra funding. 65.96.221.107 22:59, 18 June 2006 (UTC)

I have written a number of reviews in my time and, in my experience, they can take anything from 10 hours to 50 hours of work depending on length and how much i know about the relevent primary literature off hand. I often get a student or post-doc to write a draft first, so that cuts down on my time. In most cases there is no payment for writing the review (though occasionally there may be a token fee paid if it is an invited review) so my time is paid for off research or core grants. Though, as is the case with most scientists, grant, review and paper writing tends to happen on your own time (at weekends and evenings). Rockpocket 02:49, 19 June 2006 (UTC)

Scientific reviewers are almost always benevolent, unpaid. It's considered 'part of the job': you review papers for others, and expect others to return the favor, although this is done anonymously, so you never know who comments on your own work. In addition to the factors already listed, the total time it takes to get the reviews back also depends on the willingness of the Editor responsible for the publication to chase reviewers, on the professionalism of the reviewer(s), on the efficiency of the secretarial assistants, etc. Sometimes, the preparation of a special issue on a particular topic may lead to further delays in the review process if the Editor insists in synchronizing the handling of a number of papers, or if multiple papers are sent to the same reviewer(s). For the most responsive journals, you may expect to hear about your paper in a matter of one to a few months. In the worst cases, you may have to wait for a year or more. --Michel M Verstraete 23:37, 19 June 2006 (UTC)

CSS DIV issue

I've been trying to make a workmanlike image map using primarily CSS. After scouring Google for examples of how to do this, I've ended up with what seems to be a relatively basic approach. It almost works...

Basically, I have a menu image with a number of places to click on little links to other pages. The basic CSS behind it is as follows:

#headermenu { background: url("header-menu.jpg") no-repeat right; background-color: #000000; height: 25px; width: 100%; } 

#headermenu .aboutbtn { 
	border: 1px solid red;
	position: relative; 
	left: 440px; 
	width: 51px; 
	top: 2px; 
	height: 18px;
}

#headermenu .archivebtn { 
	border: 1px solid red;
	position: relative; 
	top: -18px; 
	left: 518px; 
	width: 66px; 
	height: 18px;
}

#headermenu .linksbtn { 
	border: 1px solid red;
	position: relative; 
	top: -38px; 
	left: 613px; 
	width: 48px; 
	height: 18px;
}

#headermenu .contactbtn { 
	border: 1px solid red;
	position: relative; 
	top: -58px; 
	left: 689px; 
	width: 64px; 
	height: 18px;
}

Pretty straightforward, yes? (I know it would be more straightforward if the positions were "absolute" but that doesn't work with the arrangement I have). The little red borders are just there so I can see where the links are set for at the moment.

The HTML which uses this looks like so:

<div id="headermenu">
	<a href="about"><div class="aboutbtn"></div ></a>
	<a href="archive"><div class="archivebtn"></div></a>
	<a href="links"><div class="linksbtn"></div></a>
	<a href="contact"><div class="contactbtn"></div></a>
</div>

Now this all comes up perfectly on the screen. The menu image is there, the links are in the right place, they do what they are supposed to do.

Except that the entire menu image itself is also a link, and goes to wherever the first button is set to go. This is not what I want it to do, nor is it what it seems to me that it should do (I haven't told the entire headermenu to be a link, just the div inside it... right?).

What could be causing this? It happens in all browsers I try it on. I find it perplexing because I can't see why it thinks it should do this, much less how to prevent it from doing it. --Fastfission 18:31, 18 June 2006 (UTC)

The HTML 4.01 Transitional DTD says: <!ELEMENT A - - (%inline;)* -(A) -- anchor --> I don't think you're allowed to put <div> inside <a>, because <div> is a block-level element, not an inline-level element. --Kjoonlee 18:54, 18 June 2006 (UTC)

Have you tried using <span>, the inline equivalent of <div>? --Kjoonlee 18:57, 18 June 2006 (UTC)

Turning the <div class="aboutbtn"> into <span class="aboutbtn"> made it so that the links don't appear at all. :-( CSS sometimes makes me sad... --Fastfission 19:02, 18 June 2006 (UTC)

Oops. I didn't expect that.

<div id="headermenu">
        <a href="about.htm"><img src="about.png" alt="about" class="aboutbtn"></a>
        <a href="archive.htm"><img src="archive.png" alt="archive" class="archivebtn"></a>
        <a href="links.htm"><img src="links.png" alt="links" class="linksbtn"></a>
        <a href="contact.htm"><img src="contact.png" alt="contact" class="contactbtn"></a>
</div>

How does this work? You need something inside the anchor if you want to click it. --Kjoonlee 05:02, 19 June 2006 (UTC)

Well, I could try that as a last resort, but it's not at all what I'm trying to do (I was trying to make an imagemap, i.e. links positioned in regions on an image)... --Fastfission 13:56, 19 June 2006 (UTC)

Here's something else that drives me bonkers. If I use SPAN and make the positions ABSOLUTE, then it works. However it won't (unsurprisingly) stay "glued" to the menu image (If I resize the window, they are not in sync at all). If I make the positions RELATIVE then the links don't show up at all. What the heck? --Fastfission 14:37, 19 June 2006 (UTC)

OK, I got it to work with the original code, more or less. A lot of my troubles were stemming from the fact that I termined by curly bracket on the line before the CSS posted here with a semicolon (habit), which apparently made all hell break loose. But once I removed that semicolon, it works fine. Sigh... --Fastfission 15:08, 19 June 2006 (UTC)

Blade Sharpening

In the film 'the colour purple', there is a lady that sharpens a razor on what appears to be a leather strap. How is a leather strap able to sharpen a metal razor and is this method still applicable to modern-day blades? --Username132 (talk) 20:54, 18 June 2006 (UTC)

You might be interested in our articles at straight razor and strop. — Lomn | Talk 21:27, 18 June 2006 (UTC)

On the other hand, you might not. Neither one answers your question. - Nunh-huh 23:44, 18 June 2006 (UTC)

As I understand it (i.e., in my limited understanding), strops aren't very good at sharpening, but they're good enough that it can stretch out the time needed between "real" sharpenings. If you think of the use of a razor, the thinnest parts have a tendency to "fold over" back in the opposite direction of the razor's use. This "folding over" makes the edge less keen. A few strokes on the strop helps reverse this and tide you over until the razor can be resharpened with a more efficient tool. - Nunh-huh 23:48, 18 June 2006 (UTC)

Leather strops are used with an abrasive polish (absorbed by the leather). - Nunh-huh 03:29, 19 June 2006 (UTC)

To explain his folding in a different way is that every knife, whether serrated or not, has thousands of little tiny teeth on the blade. Each time you cut, the knife's teeth ribbons bend to the sides. When you sharpen, you try and bend the teeth ribbons back all pointing the same way. — The Mac Davis] ⌇☢ ญƛ.

I don't remember that part of the movie (i barely remember seeing it at all.) But, any good Boy Scout knows that an essential part of knife sharpening (for wood carving purposes, at least) is use of a 'slipstick' which is essentially a piece of leather bound to a small plank of wood. It is used after the knife has been sharpened on a stone, to break away the fine edge on the blade left from the stone.

What!!! you can't be using a slipstick for sharpening!!! — The Mac Davis] ⌇☢ ญƛ. 03:31, 21 June 2006 (UTC)

Static On My Person

If my skin is non-conductive at low voltages then how does touching an earthed object with one hand remove static from my entire body? --Username132 (talk) 22:18, 18 June 2006 (UTC)

For one thing, "static" is the same as high voltage. Second, your skin isn't non-conductive. Instead, skin is both a bad insulator 'and' a bad conductor. It's full of moisture, particularly salt water, and is backed up by very wet and salty meat. In other words, it's a resistor. Touch your finger to the leads of an ohmmeter, and you'll see a reading somewhere between thousands of ohms and hundreds of thousand of ohms. If your skin was made of metal, then it would only take a few nanoseconds in order to discharge your entire body by touching Ground. Instead it takes many microseconds: it's still almost "instant," yet it's much slower than what metal would do. --Wjbeaty 22:32, 18 June 2006 (UTC)

So what sort of features of a person would mean they would have a very high/very low resistance? I have a friend who can literally touch one finger to a wire and then touch another finger (on his other hand) to the other and of a wire and be able to complete the circuit, on voltages < 9v! We call him the human wire... -Benbread 22:42, 18 June 2006 (UTC)

I am a person with a low (electrical) resistance. This is becasue I sweat profusely on the palms (and feet). When I touch the leads of the ohmmeter, I registered the lowest resistance in my class (I don't remember how much). Even though I don't sweat all over my body, I suppose that the sweat on my palms makes a very good contact with the leads, thus allowing electric current to pass easily. The worst part was that I frequently got small electric shocks from the bare wires of the 5V circuits we used to build in our electronics labs. I even used to feel the tingle if I put my fingers across a conducting diode (~ 0.7V). It is a different issue that many of my friends didn't believe me. -- Wikicheng 04:14, 19 June 2006 (UTC)

This is the same thing the E-meter does in Scientology. The conduction at the surface, i.e. how much you're sweating, is very important in the total resistance, which is how the E-meter does a good job of measuring stress. (or engrams I guess, depending on your beliefs). I believe one of the measurements of a polygraph may operate on a similar principle. moink 07:18, 19 June 2006 (UTC)

Please help me identify this insect

Unknown insect

I found this very odd insect in my parents house, they live on the north south end of Vancouver Island in Sidney, British Columbia.

I have never seen such an insect around here before and was wondering if anybody could identify it. It is about 1 inch long and was sitting high on a wall near the ceiling. HighInBC 23:42, 18 June 2006 (UTC)

Check the Weevil article. Since Sidney is on the ferry route there is a good chance it hitched a ride. Very common in the US. ...IMHO (Talk) 06:52, 19 June 2006 (UTC)

Just as an aside, Sidney is nowhere near the North end of Vancouver Island. It's at the North tip of a small peninsula near the South of the island. moink 07:15, 19 June 2006 (UTC)

Oops, I got the words mixed up. Thanks for the info! HighInBC 12:32, 19 June 2006 (UTC)