Wikipedia:Reference desk/Archives/Science/2006 August 21

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Photosynthesis limit

Everybody knows plants make photosynthesis during the light time hours. In the nights, the plants "breath" oxygene as the rest of the animals do. I always wondered what happend between day and night. There is a light point in which the plant is not doing any kind of biological proccess, neither taking co2 nor oxygene? Can a plant change from doing the first thing into the other just in a second? It is possible that a part of a plant is making photosynthesis while the other is taking oxygene? (Sorry for the badspelling, I am not used to English and thank you for you help!)

Actually, the plant is always doing respiration, which is the metabolism of sugars, which as you say uses oxygen and releases CO2 and water. The plant always needs a supply of energy to maintain itself (homeostasis) and grow, and respiration is the mechanism by which it releases stored energy for use. You are also correct that photosynthesis only happens during periods of exposure to light, as photosynthesis requires light to synthesize sugars. I believe that photosynthesis rates vary proportionally to the variation in light. Since both of these processes occur on the cellular level, it is certainly possible that one part of the plant is photosynthesizing while another is not, but all living parts of the plant are always respiring (taking in oxygen) to some degree. For instance the roots of the plant do not photosynthesize, but they do respire. I hope that helps. And don't worry about your english - it's better than most questions around here! --Bmk 00:16, 21 August 2006 (UTC)

Thank you for your complete answer, sounds logical. When both processes can happen simultaneously, then is not so complicated. I think my teacher didn't emphasized on that. Good work!

Glad to be of help :) and thanks for replying - it gets discouraging to throw answers into a void that doesn't answer back. --Bmk 00:48, 22 August 2006 (UTC)

working with dams for dummies (and choosing to build them in the first place!)

Hello,

after some consideration I thought it might still be best to post this in the "Science" reference desk.

Dams are often considered vital for supplying a nation with (fresh) water. Suppose I have a country and a huge river runs through it. Let us take China and the Yangtze for instance. When I finish the dam and I close the gates, no water comes out. So the river behind it swells up and becomes a lake. I have to watch out and close my dam in time so it doesn't get destroyed! But now what? If my lake is stable in height, that means there goes just as much water through the dam as passed at that point before I ever built the dam? I'm not supplying my country with any more cubic meters per day, am I?

A good portion of the water that was flowing down the river originally ends up flowing to houses and farms, now, via pipes, with, perhaps, only a trickle going down the river. The Colorado River, for example, used to flow to the ocean via Mexico, but, due to the Hoover Dam, now has such a small trickle that it evaporates in Mexico before reaching the ocean. StuRat 03:12, 21 August 2006 (UTC)

Yeah those Mexicans must be getting pretty dry by now!--Light current 03:16, 21 August 2006 (UTC)

Yeah but you have a big reserve of water you can use even if its not raining! Also you are actually capturing all the water that falls in the catchment area. Previously you were propably collecting only a fraction of it.--Light current 23:19, 20 August 2006 (UTC)

Hmm, would it be that much of a difference. It the lake filled up in a gorge, wouldn't most of the rainfall have ended up in the original river as well? Good point though. But for the rest, it seems all I am doing is preparing myself for some fluctuations in my needs for water. But in the end the amount of cubic meters I receive each year is pretty much the same.Evilbu 01:01, 21 August 2006 (UTC)

Yes. You cant get any more water than falls as rain over the country. But you can store it in times of plenty, release it it times of drought and stop it going to waste in the sea. Hence the usefulness of the dam.--Light current 01:07, 21 August 2006 (UTC)

A second advantage is that you are preventing some of the water from dropping to the original height. This higher water has more gravitational potential energy, which may be used to deliver the water. In layman's terms, the water is now high enough to flow thru pipes up near the top of the new lake, whereas before the water could only flow through pipes near the top of the river. Also, don't forget that as much as helping with water distribution, dams are also about generating electricity using hydroelectric turbines. StuRat 03:12, 21 August 2006 (UTC)

A second question :

Yesterday I saw a British documentary about the Euphrates, and they visited the (well protected!) Ataturk dam. They said that this dam allowed Turkey to control the political behavior of Syria and Iraq. Well how exactly? If the lake behind the dam has been filled, can they really make any threats? For how many days would they be able to cut off the river without destroying their own dam or flooding valuable things alongside their own lake?

Maybe they could divert the water to their own lands. Or maybe they only need to stop the water for a couple of days. THat wouldnt burst the dam. --Light current 23:36, 20 August 2006 (UTC)

Would that impress their opponents that much, if it was only for a few days? One thing they could do is throw tons of poison in the Euphrates near the border with Syria. But I think the United Nations will immediately impose sanctions then.Evilbu 01:01, 21 August 2006 (UTC)

OK a week. How thirsty are you gonna get in a week?--Light current 01:07, 21 August 2006 (UTC)

They might very well be able to divert the entire flow into the river to some other location, perhaps even the Mediterranean Sea. Their farmers could also water all their crops more than the usual amount (but not so much as to kill them). This would be especially effective in the dry season, where there may be hardly any flow into the river to begin with. In the rainy season, however, they might not have much of an option of cutting off the water supply, but could make the flow very uneven, which would mess with boats trying to sail on the river. StuRat 03:20, 21 August 2006 (UTC)

A third question :

how bad would be the consequence of destroying such a dam? Would the flood generated by such an act be of significance in Syria and Iraq too?

THe flood would be a dam big one! (obvious - I know)--Light current 23:19, 20 August 2006 (UTC)

Yes I agree, but if you consider how the Euphrates first goes through Syria, I find it hard to believe it would still cause major flooding in cities like Basra. Or would it?Evilbu 01:01, 21 August 2006 (UTC)

I know my questions may sound a bit weird. Please try to give me an answer though. Thanks! Evilbu 22:01, 20 August 2006 (UTC)

That would depend on the geography and how full the river was to start with. If it was already at flood stage, and the river was in a deep canyon over the entire length, there would be no place for the additional water to go but further down the river. If, on the other hand, the river was low, then it could absorb a great volume of water before hitting flood stage. Also, if the land was quite flat, the water would spread out over a large area and be absorbed into the soil by flooding near the dam, and thus not flood much further downstream. StuRat 03:27, 21 August 2006 (UTC)

The British did this during WW2 in Germany using a specifically designed secret weapon. There was a well-known film made about it called The Dam Busters. The bomber crews were very brave - despite about half of them being killed, as far as I recall, the rest of them still continued cooly with the mission. There was another dam that could have been busted, but it was considered too much of a suicide mission to order people to undertake it.

Elbe and Mohne dams I think.--Light current 02:31, 22 August 2006 (UTC)

Stopping my chickens fighting?

Got given some new chickens today and I put them in the compound with the rest. The old cockerel started fighting with the new one almost straight away and I had to seperate them (hens get on fine). How do I stop them fighting?—Preceding unsigned comment added by 84.65.136.27 (talk • contribs)

• Just wondering, but since this is the 3rd or 4th chicken related question that's popped up in the last few days, what exactly do you do with your chickens? Are they for eggs, or meat, or entertainment? Where do you keep them? what do you feed them? etc..--71.247.125.144 00:56, 21 August 2006 (UTC)
  • At least nobody's trying to breed seagull bagels. User:Zoe|(talk) 16:22, 21 August 2006 (UTC)

Please do not mention *****ls. Youll get StuRat all excited again. We dont want that again! 8-(--Light current 16:25, 21 August 2006 (UTC)

Why do you have 2 cocks? One cock should be enough for anyone. 8-|--Light current 01:27, 21 August 2006 (UTC)

Im not surprised really. The old cock is defending his territory against the interloper.You'ld do the same! He doesnt mind his harem being extended but he doesnt want to share them with another cock. Would you?--Light current 02:54, 21 August 2006 (UTC)

So, to summarize, you've got to keep the two cocks separated. If that's too hard, I'd sell one, or maybe eat one. :-) StuRat 03:00, 21 August 2006 (UTC)

There is a funny comment here StuRat. Im sure you know what it is , so Im not going to say it 8-)--Light current 03:21, 21 August 2006 (UTC)

Yes, with a setup like that, it would to difficult to avoid making a nasty pun, even if I wanted to. :-) StuRat 04:55, 21 August 2006 (UTC)

You mean you dont want to. You cannot be serious!--Light current 12:52, 21 August 2006 (UTC)

So my solution would be to have two separate flocks, with one cock each. THen there should be no jealousy! (Hey sounds like marriage guidance here!)--Light current 03:02, 21 August 2006 (UTC)

You're obviously not a farmer? Cockerels can't get along together. You need to have them seperated somehow, or they'll fight to the death. — [Mac Davis] (talk)

(Just like some wikipedians!)--Light current 14:35, 21 August 2006 (UTC)

Are you dosing your old cock with Viagra?Edison 15:10, 21 August 2006 (UTC)

Oh dear! some one just couldnt resist it could they StuRat? 8-)--Light current 15:42, 21 August 2006 (UTC)

I'm just surprised people didn't say "rooster." The original question was about cockerels, after all. ;) --Kjoonlee 16:19, 21 August 2006 (UTC)

Cockerel in UK. Maybe rooster in US.--Light current 16:23, 21 August 2006 (UTC)

Physics (waves)

Will a wave of given energy (e.g., an x-ray) travel equally through a thick piece of, say, wood and a thin piece of, say, lead, if there were the same number of atoms impeding its progress in both cases? BenC7 03:08, 21 August 2006 (UTC)

Depends on the size of the atoms I wood think. But I dont want to lead you in the wrong direction8-). So wait for other answers!--Light current 03:13, 21 August 2006 (UTC)

No. I don't know what else to say; solid-state physics is complicated. Melchoir 03:35, 21 August 2006 (UTC)

No, all atoms are not the same. Some are much more massive than others, some are ionized, some have complete electron shells, others do not. All these factors cause some atoms to block more of certain types of radiation than others. StuRat 04:52, 21 August 2006 (UTC)

Jeez guys, I never thought I would be the local physics guy when the normal guys were out. The transparency of an object is based on the atomic spacing Ben: The periodic potential well generated by the crystalline structure gives rise to electronic band-gaps. Essentially, band-gaps represent energies in which the electrons in the valence electrons will not be excited to a higher state. In crystalline metals and most semiconductors, light in the visible range will excite these electrons so this energy will be dissipated before it passes through the material. In some common crystalline insulators, the atoms have a larger atomic spacing which gives rise to a larger band gap. The band gap of such materials requires a larger energy than provided by visible light in order for electron excitation to take place. Therefore, the light passes through the material without interaction. — [Mac Davis] (talk)

So whats the answer? 8-)--Light current 14:28, 21 August 2006 (UTC)

You can get the ansower yourself - without getting into complicated physics. Just use visible radiation - light. Put some snow (or shaved ice) in a glass dish and observe the darkness of the shadow. Then melt it and repeat. — Sebastian (talk) 15:58, 21 August 2006 (UTC)

Good answer, Sebastian. Indeed, solid-state physics is quite complicated, and many many interactions need to be considered beyond just the "number of atoms." So, the answer is no. Nimur 19:44, 21 August 2006 (UTC)

Exercise/Immune system

I don't know exactly where I got the idea from, but it is my understanding that exercise helps the body's immune system. How? A reasonably detailed explanation would be good. BenC7 03:09, 21 August 2006 (UTC)

It can relieve stress, which is known to depress the immune system. StuRat 04:48, 21 August 2006 (UTC)

General good health (proper foods and exercise) will give a boost to the immune system. --Zeizmic 11:46, 21 August 2006 (UTC)

Exercise will help the immune system up to a point. People who exercise too much (and it has to be quite a bit) can experience a decrease in immune system function. IIRC one of the main points is that regular exercise, especially if it results in decreased inter-whatever fat (fat surrounding the organs) improves liver function, and since the liver is 'da bomb' as far as chemical regulation is concerned (it secretes, moderates or breaks down most of the body's chemicals) improved liver function = improved immune system function. Another thing that improves liver function is increased blood flow. That's what I remember anyway. Anchoress 11:56, 21 August 2006 (UTC)

Spinning wheels

I watched and noticed several things about the observation of certain spinning / objects in motion... I noticed that if they're moving fast enough, they seem like they're not moving at all or moving in the opposite direction they're spinning (i.e. wheels on a car). Why does this happen? Obviously the wheel is not spinning at / close to / faster than the speed of light! Thanks for feeding my knowledge! --Agester 03:20, 21 August 2006 (UTC)

Stroboscope--Light current 03:24, 21 August 2006 (UTC)

Street lights typically flicker, causing this effect. StuRat 04:46, 21 August 2006 (UTC)

How do you explain the effect seen in daylight? The sun surely does not have a specific strobe rate... --Jmeden2000 15:28, 21 August 2006 (UTC)

Sunlight that varies due to fence posts, etc., can also flicker on a moving car. StuRat 15:58, 21 August 2006 (UTC)

Do you see it in daylight? I havent--Light current 15:40, 21 August 2006 (UTC)

Pffft... It's called Aliasing. See also, Wagon-wheel effect Eh-Steve 16:54, 27 August 2006 (UTC)

Do lightning strikes on water kill fish ?

this is a little off topic but just wondering about a old kind pondering question. "If lightning strikes the ocean. How come all the fish don't die?" It's probably been answered before but i can't seem to find the answer. --Agester 04:05, 21 August 2006 (UTC)

I'm just guessing, but... A lightning strike on the ocean probably only draws current across the surface of the water, where you would expect charge to build up. And even if it draws current through the bulk of the water, that current wouldn't have any particular reason to pass through fish any more than the saltwater surrounding them. Melchoir 04:32, 21 August 2006 (UTC)

And where does the current go if its only on the surface of the water?--Light current 12:37, 21 August 2006 (UTC)

Perhaps I should have made my tenses clearer: A lightning strike on the ocean probably only draws current across the surface of the water, where you would expect charge to have built up. Melchoir 14:47, 21 August 2006 (UTC)

I would fully expect it to kill fish in the immediate area of the strike, but then the charge would rapidly dissipate so that fish even a few meters away should be safe. StuRat 04:42, 21 August 2006 (UTC)

Do lightning strikes on earth kill worms? Well then....--Shantavira 08:43, 21 August 2006 (UTC)

Um, I don't know. Do they? —Bromskloss 09:24, 21 August 2006 (UTC)

(after edit conflict) Do they? DirkvdM 09:31, 21 August 2006 (UTC)

THe currents in the ground near the strike are bound to kill if not fry (MMMM-- fried worms) worms in the vicinity.--Light current 12:45, 21 August 2006 (UTC)

I wish more conflicts were like that – all parties involved agree! ;-) —Bromskloss 09:51, 21 August 2006 (UTC)

It wouldnt be a conflict then would it! 8-)--Light current 15:38, 21 August 2006 (UTC)

To clarify the above answwers (and to ckeck if I got this right): Lightning tries to follow the path of least resistance. If you're standing in a field the water in your body will conduct the current more easily than the surrounding air, so all of the current is concentrated in you. In water, it will spread evenly in all directions (unless it sticks to the surface - why would that be?), meaning in all three dimensions, so over twice as large a distance the power will have been reduced to 1/8 (there must be a clearer way to say this). And the fish may even repel it because its skin will conduct it less easily than the water. By the way, lightning isn't necessarily lethal. Some people have survived it, though they did not remain unaffected (the brains work differntly). DirkvdM 09:31, 21 August 2006 (UTC)

Not necessarily! Lightning makes its own path by generating ions in the air. Its impossible to predict the exact path of a lightning strike. (Bolt from the blue)--Light current 12:45, 21 August 2006 (UTC)

Slight correction: Most of an electrical discharge follows the path of least resistance, true, but some also follows other paths. And since a good portion of the discharge changes to heat in a material with significant resistance, those items tend to have more damage, even if they carried less of the discharge. As for twice the distance meaning power is reduced to 1/8th, that would be described as "power varies with the inverse cube of the distance". StuRat 15:42, 21 August 2006 (UTC)

I was asking for a clearer way to put it - for the uninitiated. DirkvdM 19:09, 21 August 2006 (UTC)

The last time I took my kids to the swimming pool, there was a rumble of thunder and the lifeguards made everyone get out of the water. Were all those wet kids standing outside the pool in more danger than they would have been in the pool? --Ed (Edgar181) 12:01, 21 August 2006 (UTC)

Pools conduct electricity much better than the ground, so tend to attract lightning strikes. And anyone in the pool is likely to be killed or seriously injured by the strike. StuRat 15:53, 21 August 2006 (UTC)

Sorry Stu thats just not true. If you have a ref, Ill reconsider my view!--Light current 03:23, 22 August 2006 (UTC)

This site says to stay away from pools during a thunderstorm, as has every other site I've seen on this topic: [1]. StuRat 06:30, 23 August 2006 (UTC)

Yes I think they were. They were certainly higher (and therfore at more risk) unless the life guards made them all lie down. I mean, if youre out side, the best place is a hole in the ground (preferably with a lid on it)-- you dont wand to send up any streamers (--Light current 12:25, 21 August 2006 (UTC)

THe best place really would have been under the water! Just a slight problem breathing--Light current 12:48, 21 August 2006 (UTC)

Most outdoor pools should have some form of shelter (changerooms). Standard practice is to wait 20 min. after the last thunder rumble. --Zeizmic 13:58, 21 August 2006 (UTC)

Yeah but it should be totally enclosed and preferably made of conducting material. see Faraday cage--Light current 14:11, 21 August 2006 (UTC)

If the current indeed follows the surface of th water, then swimming at the surface would not be a good idea. But if the lightning strikes the ground, it apparently also follows the surface, so it is not a good idea to lie down. The best position would be to squat (with your head down I believe)- minimising both your height and the surface in contact with the ground. Lightning#Lightning_safety doesn't seem to say anything on this, which should really be fixed. DirkvdM 19:09, 21 August 2006 (UTC)

But you are only looking at the chances of surviving, assuming that a lightning strike is inevitable, and not looking at how to avoid being hit at all. It you are flat on the ground, far from water or trees, it's quite unlikely that you will be struck. The lightning will instead strike a higher point (tree) or better conductor (water). StuRat 19:19, 21 August 2006 (UTC)

If you are attractive to lightning and draw a strike- then you are probably dead. The point of crouching down is to make you less likely to send up leaders in response to the high electric field present.--Light current 23:53, 21 August 2006 (UTC)

If only I weren't so attractive. DirkvdM 05:27, 22 August 2006 (UTC)

Yeah, that's why I wear silver mail whenever I go outside. Well, that and the land sharks. Melchoir 05:37, 22 August 2006 (UTC)

Ahh yes. You mean an equipotential suit? THe only problem here is that if you do attract a stroke of lightning, the suit will vaporise and leave you quite hot and bothered.--Light current 21:14, 28 August 2006 (UTC)

Relative Humidity

Can Relative Humidity be higher than 100%?

By definition, the answer is "no". StuRat 15:35, 21 August 2006 (UTC)

Relative humidity discusses the question. Weregerbil 09:48, 21 August 2006 (UTC)

Ooo I dont know tho. What about supersaturated solutions?--Light current 02:37, 22 August 2006 (UTC)

Article in National Geographic, IIRC, shows supercooled air at 400% in calm at Antartica. Also supersaturated sea water unfrozen well below 0% C.

Identify a spider

Dear fellow Wikipedians,
A few days ago, I found a spider in my basement. Sometime between yesterday and today, it laid eggs and started to weave a cocoon for the eggs. I would ask for your help in identifying the spider. Since I do not want to post pictures here, these are links to pictures of the spider:

From above, with flash
From above, without flash, cocoon visible
From below, without flash, cocoon visible
Showing the structure of the net

As you can see, the netweb is highly irregular. The spider is about 5 by 10 millimeters large (without legs), I would estimate the legs to span about 20-30 millimeters. I am located in a town close to Vienna in Austria.

Thank you, --Florian Prischl 10:44, 21 August 2006 (UTC)

It does not lok like a Brown Recluse or Black Widow. Edison 15:05, 21 August 2006 (UTC)

By "net", do you mean web, or is this the spider that weaves a net and tosses it on it's prey ? StuRat 15:30, 21 August 2006 (UTC)

Yes, I was talking about the spider's web. That was a translation error, I'm sorry. --Florian Prischl 12:55, 28 August 2006 (UTC)

Have you seen http://www.boingboing.net/2006/07/24/online_bug_identific.html ? I'm not sure the sites identify arachnids, but you never know. --Kjoonlee 16:15, 21 August 2006 (UTC)

That's great! I'll see what they can do. Thank you! --Florian Prischl 12:55, 28 August 2006 (UTC)

The striped pattern on the legs reminds me of an orb-weaver spider... BenC7 00:50, 22 August 2006 (UTC)

You are right, in that "my" spider looks similar to an orb-weaver. The problem is that there areabout 2800 species of orb-weavers... I found this bit from the article interesting: "Some "orb-weavers" do not build webs at all. Members of the genera Mastophora in the Americas, Cladomelea in Africa and Ordgarius in Australia produce sticky globules, which contain a pheromone analog. The globule is hung from a silken thread dangled by the spider from its front legs. The pheromone analog attracts male moths of only a few species. These get stuck on the globule and are reeled in to be eaten." Maybe this is the yellow thing I saw, and not a cocoon for eggs? --Florian Prischl 12:55, 28 August 2006 (UTC)

Steatoda. Hard to say if it's Steatoda grossa or Steatoda triangulosa. From the markings and the fact it was already quiet large (grossa seems to get less vivid markings when they get old), I'd bet triangulosa. Not that uncommon, though they're usually quite good at not attracting attention.

Thank you for all your replies! --Florian Prischl 12:55, 28 August 2006 (UTC)

Information about, or proper name of, circular magnetic keys as used on tills and (less commonly) shared doors.

Does anybody have any information about the type of "key" consisting of a round metal disc that's pressed against a reader? In the UK they're commonly used on relatively high-tech tills/cash-registers (especially in bars) to "log in" the person about to use the device. The disc is usually attached to the end of a short plastic tag and carried on some kind of lanyard.

What I want to know is how these devices work. They're usually referred to as "magnetic keys", but they can clearly carry a certain amount of information (which member of the bar staff is using the till, at least) so there's more than a simple magnet in there. Are they perhaps some variant of RFID, and if so why does one have to press them quite accurately onto the reader?

If you don't know these details, at least the correct term for the device so that I can search for more myself would be useful.

Thanks. PeteVerdon 12:58, 21 August 2006 (UTC)

I don't know much about them, but they seem similar to the key cards we used at one workplace. They were the size and shape of credit cards and made of plastic, but would open doors when waved in front of a reader. The common wisdom was that they contained "a chip," and it was known that if you bent one, it was ruined. --Ginkgo100 ^{talk · e@} 13:16, 21 August 2006 (UTC)

That sounds like a straightforward RFID proximity card, as used at my University (my workplace uses cards with both mag stripe and chip-with-physical-contacts, for different purposes). I know how they work, more or less - and find the implications of [this article] very interesting - which is why I wondered in the question if the "magnetic" discs are actually some kind of RFID. But I'd like to know for sure. PeteVerdon 14:13, 21 August 2006 (UTC) {NB Edit conflict with below}

RFID keys (keycards, reader cards, pass cards, pass IDs... there's a million names) work at a rangs based on the reader. In an area where you want it to pick up the RFID from a distance, the reader has more power. If you don't want a cashier to accidently trigger a register (till) just by walking past the counter, it is turned down. See RFID for a lot of information about how they work. You should focus on the passive (unpowered) version as I seriously doubt your RFID keys are powered. --Kainaw ^(talk) 13:46, 21 August 2006 (UTC)

So they're just standard RFID tags in a metal button, with the exciter coil in the reader turned down so low that they have to be touching? I suppose that makes sense. PeteVerdon 14:17, 21 August 2006 (UTC)

If they have to be pressed against the reader, then they could be the "1-wire" or "i-Button" devices from Dallas/Maxim. [2] These are serial ID devices packaged in a housing that looks like a watch battery or coin cell, and work by metallic contact with the reader. "1-wire" is just a marketing term - they have two contacts just like a normal coin cell. --Heron 14:39, 21 August 2006 (UTC)

Is this Akbil is an instance? These are used on public transport in Istanbul for paying the fare; you have to "refill" them (at paying stations) when the balance is low. At the very least they need an internal memory like EEPROM, and a protocol for reading from and writing to it. --Lambiam^Talk 01:53, 22 August 2006 (UTC)

Hairs standing up when frightened: evolution

Do the hairs of humans really stand up when they are frightened? If so, how could proponents of ID explain this? God with a sense of humor?

Hedgehogs (which evolutionarily predate almost every mammal) stand their spines up when frightened. They are rather useless for defense when they lay flat. That hereditary anomoly appears again in felines, which raise the hairs on their back - assumably to make them appear larger. I'm sure you can find it showing up again and again throughout mammals - so it shouldn't be surprising that humans have the same reaction. As for "does it happen?" - it is more related to the "chilling" factor of being scared and not the fear factor. When humans get cold, the hair stands up also. --Kainaw ^(talk) 13:49, 21 August 2006 (UTC)

Cats puff for two reasons. 1. They do it when confronting a possible predator to make their body appear bigger. They will also often turn sideways at the same time for the same reason. 2. They do it when it gets cold to trap more air in their fur, though this fluffing is not to the same extreme as in the other situation, so it is less often noticed. Obviously both of these behaviours have reproductive advantages that worked, otherwise they wouldn't be retained. Human erector pili muscles are really vestigal (though functional), but most likely had the same functions orginally. As for the ID people who knows. Maybe they'd just say that you shouldn't question the designs of an almighty deity. I'd be interested in how they explain it away though. pschemp | talk 15:53, 21 August 2006 (UTC)

Pilomotor erection, aka gooseflesh. Left over from when we had fur. No IDea how Intelligen Design proponents would explain it away. Edison 15:08, 21 August 2006 (UTC)

Somehow I doubt that many ID people would be hanging around this part of Wikipedia, but if there are, feel free to answer. Ooh wait, maybe that's our natural God detector system. When God speaks to you, the hair on your body stands up! ;) pschemp | talk 16:00, 21 August 2006 (UTC)

Hair standing up when it's cold makes sense for most mammals because it thickens the fur. Humans are out of luck here because of our puny bodily hair. If there is some connection between cold and fear, then that might explain it. When you get a fright you may feel 'a shiver running down your spine' and I recall my skin reacting just like it would to cold when I had a fright. I don't know why there would be such a link, though. DirkvdM 19:24, 21 August 2006 (UTC)

Darwin himself devoted a lot of discussion to this in his The Expresion of the Emotions in Man and Animals—check out the section on "erection of hair" in this link if you're curious what he thought about it. --Fastfission 19:43, 21 August 2006 (UTC)

Attaching multiple speakers to my amplifier

In my external PC speakers there is a small, cheap amplifier. If I connect a couple of box speakers to the wires coming out of this, I get fairly good sound from them. Can I just keep adding speakers? Will the volume continue to increase as I add more speakers? The amplifier is powered from the mains, so there should be no power issue, but maybe there wont be enough voltage?

No, you can't keep adding more speakers, the amp won't be able to drive the speakers if you put to many, and it will be quieter and sound quality will go down. Keep in mind more does not equal better for speakers. — [Mac Davis] (talk)

No. I wouldnt do that. You must make sure the total impedance of the loudspeakers you attach is greater than the minimum reqired by the amplifier, or you could destroy the output stage of the amp. Look at the handbook. It may tell you the nominal impedance there. I wouldnt go any lower than this by adding extra speakers.--Light current 13:57, 21 August 2006 (UTC)

Mabye there will be too much current, for you amplifier. As you may have seen, amplifiers are often marked with a minimum input impedance the speakers need to have. The thing is that the amplifier will put out a certain voltage, and if the impedance of the speaker is too low, the current will be so high that it can harm the amplifier. So, if your amplifier says that 4 Ω is the minimum impedance and you connect two 4-Ω speakers in parallel, the amplifier will see only 2 Ω, and the current will be twice as high as the maximum. (I used to do this when I was younger, btw. I was lucky, nothing broke.) Connecting them in series works fine on the other hand. That only increases the impedance. —Bromskloss 14:03, 21 August 2006 (UTC)

Agree with Bromskloss. He has put it more clearly than I did.--Light current 14:41, 21 August 2006 (UTC)

Is it just me, or did we say the same thing thrice with increasing complexity? — [Mac Davis] (talk)

Yes we did--Light current 16:55, 21 August 2006 (UTC)

It appears to me that throughout several consecutive posts the same point was being made, however with increasing attention to details. Could it really be that I am the sole person to have had this awakening, implying that less credibility should be ascribed to my observation? —Bromskloss 19:51, 21 August 2006 (UTC)

No. Or on the other hand , yes.--Light current 00:46, 22 August 2006 (UTC)

Thanks for all your replies!

Headlights changing colour

I was driving at night the other day, and an expensive car behind me had its headlights on. I noticed that the headlights were turning blue, and then back to white pretty randomly. When the car stopped, the lights would stay white the whole time. Is this caused by the wavelengths of the light being compressed by the moving car, or does the car have some kind of coloured, flashing headlights. They were really annoying. --liquidGhoul 14:07, 21 August 2006 (UTC)

If it was caused by relativistic effects arising from the speed difference between the cars, I'm sure that other driver has a hefty speeding ticket waiting for them somewhere! ;-) That is, no, the movement is not the reason. Actually, you are reasoning correctly, but it takes a much higher speed for the effect to be visible like that. —Bromskloss 14:11, 21 August 2006 (UTC)

It is definitely NOT "caused by the wavelengths of the light being compressed by the moving car". That only happens to a noticeable extent at relativistic speeds. My guess(es):

1. This effect is caused by varying angles the headlights are making with your mirrors.
2. This effect is caused by varying voltages applied to the headlamps by the electrical system of the car in question.

Rangek 14:13, 21 August 2006 (UTC)

My guess is that the light is only truly white on the optical axis of the lamp. Off axis you get artifacts of the lamp emission. Why this should be I cant say.--Light current 14:18, 21 August 2006 (UTC)

Wouldn't that be a design flaw? It was a Volvo! --liquidGhoul 14:21, 21 August 2006 (UTC)

Yes. I would think so, but it may just be a side effect of the efficient design--Light current 14:26, 21 August 2006 (UTC)

I would guess that car had two sets of headlights, one being high intensity discharge mercury vapor lamps (blue high beams), and the other being normal halogen lamps (white standard lights). Either they were turning their high beams on and off, or both the high beams and normal lights were on, and the different angles of the two lights cause you to see a different color depending on the bumps in the road, which change that car's angle relative to you. StuRat 15:12, 21 August 2006 (UTC)

Or two different lamps as you describe in the same reflector housing. THat would do it!--Light current 15:22, 21 August 2006 (UTC)

I don't know about that, there was quite a bit of traffic and it is illegal to have high beams on. I think I would have noticed too, it is very bright when someone has their high beams on right behind you. --liquidGhoul 15:16, 21 August 2006 (UTC)

I will second the color-changes-with-angle theory. HID lights can be very intense and it's for the best that they aren't full brightness for the entire beam width. Why they (volvo?) chose to have the lights shift color this way is debatable, but they would probably tell you something like 'the color temperature of fringe areas is best skewed toward blue since it makes it easier for your eyes to pick up distant objects', or some such marketingspeak. Bottom line is, it was probably cheaper to use an optic that faded toward blue to dim the edges of the beam. --Jmeden2000 15:23, 21 August 2006 (UTC)

In some communities certain high-intensity blue-tinted lights (such as xenon, though mercury vapour may be popular too, I'm not sure) are popular in sports cars (which are often blue on the inside, and under the skirt, too), even though they illegal, and the more blue-ish, the more illegal (and easy to spot) they are. Some of the most expensive car modifications allow the lights to be easily switched back to plain ol' halogen from the dashboard, presumably whenever a cop passes by. The xenon lights I've seen are not known to last very long either, so it makes sense to use them only in very groovy situations.  freshofftheufoΓΛĿЌ  06:38, 22 August 2006 (UTC)

The blue tint is caused by a sort of prism effect of the light bending around the bezel which limits the illuminated area. The blue photons bend around this very sharp and straight bezel at a different angle (and with a greater angular area) than do other wavelengths, and as a result, blue is the dominant color around the border. The reason the bulbs seem to change color is because you and the car behind you are going over bumps, putting you at different places in the beam's angle at different times.Tuckerekcut 00:41, 24 August 2006 (UTC)

LOL @ "blue photons". When you find a plaid photon, send me a pic. :-) StuRat 05:50, 30 August 2006 (UTC)

WIKI "Methane Gas" article is DANGEROUSLY UN-Scientific & MISLEADING

Moved post to talk:methane

Yay, caps lock. :-/ —Bromskloss 19:41, 21 August 2006 (UTC)

He cant help shouting!--Light current 00:48, 22 August 2006 (UTC)

a little knowledge is dangerous... Xcomradex 08:02, 22 August 2006 (UTC)

Night sky

Are all of the stars seen without a telescope within our galaxy? ike9898 16:25, 21 August 2006 (UTC)

• Yes, they are. Stars in orther galaxies are way too far away to be seen with any but the most powerful of telescopes. In fact, from our perspective here on earth, the closest galaxy, the Andromeda Galaxy, is barely visible to the naked eye, and only its dense center can be seen by the naked eye at all. – ClockworkSoul 16:39, 21 August 2006 (UTC)

• To clarify the previous response, you can't see individual stars in other galaxies without a telescope (although there may be an occasional exception for a supernova), but you can see stars from another galaxy "collectively", as a galaxy, without the aid of a telescope. StuRat 16:54, 21 August 2006 (UTC)

(after edit conflict) Well, since the visible part of a galaxy is composed primarily of stars, if you can see the galaxy, you are seeing the stars. But I would agree that only stars within our galaxy can be distinguished as individual stars. You might (or might not) be further interested to know that according to the "acuity" section of the article on the eye, the average human can resolve distances of about .93 mm at a distance of 1 meter, which is a ratio of about 1:1000. Therefore, if ${\frac {Distancebetweenneighboringstars}{Distancetostarsfromobserver}}<0.001$ then the stars cannot be resolved. The nearest galaxy, as Clockwork said, is the Andromeda galaxy, at about 2.5 million light years away. Since neighboring stars tend to be on the order of a lightyear apart at the closest, that's a ratio of 1:2500000, far smaller than the visual acuity of the human eye. By this measure, some of the stars across the galactic disk of our galaxy, at around 80,000 ly away, are also probably indistinguishable (not taking into acount the decreasing density of stars at the galactic rim), but the nearer ones, on the order of 1000 ly away, should be distinguishable (note that just because neighboring stars are indistinguishable by the naked eye doesn't mean that they are invisible - just that you can't tell them apart). Wow, that was way more long winded than I intended. Sorry! --Bmk 16:57, 21 August 2006 (UTC)

• I have had a few people with good eyesight claim that they can see individual stars in the Large Magellanic Cloud under good conditions. Personally, I find this difficult to believe and I've never been to the southern hemisphere to check it out for myself. --Nebular110 17:28, 21 August 2006 (UTC)

Just a possible guess - Your friend could be seeing several stars, and thinking it was only one. --Bmk 17:43, 21 August 2006 (UTC)

Itraconazole

Why in the United Kingdom, if an intravenous preparation of itraconazole is needed, an alternative antifungal drug is recommended? Thanks very much. --208.65.245.193

Sounds like a medical homework question. Is it?--Light current 16:57, 21 August 2006 (UTC)

Cos we aint got any itraconazole in the UK?--Light current 16:58, 21 August 2006 (UTC)

Eeep. Even medical-students come to Wikipedia for homework help? I fear for the state of our children's healthcare system! Nimur 19:52, 21 August 2006 (UTC)

RE: Not because I doubt Wikipedia's accuracy; I'm just afraid of lazy doctors. Nimur 19:53, 21 August 2006 (UTC)

Maybe all those medical questions we keep getting are really from stumped doctors. :-) StuRat 21:18, 21 August 2006 (UTC)

Itraconazole is an inhbitor of Cytochrome P450s, including CYP3A4, the major drug-metabolizing enzyme in humans. I guess itraconazole is fine for topical application, but you want to minimize systemic exposure or you will have all kinds of interesting (and adverse) drug-drug interactions and hepatotoxicity. Ignoramibus 01:54, 22 August 2006 (UTC)

The question we need to know to give an appropriate answer is" "recommended" by who? Some "recommendations" are based on cost analysis rather than medical benefit. All IV antifungals have advantages and disadvantages, but they uniformly inhibit cytochrome oxidase (as do many useful drugs). Itraconazole is not even the prime offender. It's more easily tolerated than amphotericin, but more expensive (but less expensive if you calculate associated costs, including decreased hospital stay). Lipid amphotericin formulations are better tolerated but more expensive. Patterns of fungal resistance might also be the basis of the recommendation, but you'd have to know who's doing the recommending to say. There are so many different considerations (presense or absence of neutropenia in the patient, prior treatment with antifungal agents, etc.) that it's difficult to believe that a blanket recommendation has much validity. - Nunh-huh 18:26, 22 August 2006 (UTC)

Memory Loss in Mental Illness

Relative has been diagnosed with a thought disorder, doctors vary on schizophrenia or bipolar but are not sure of precise diagnosis, this has been going on for almost two years with multiple "events-psychotic breaks". The latest symptom though is profound memory loss, the depth of which is concerning to his Psychiatrist and Psychologist. Has bot MRI's and EEG's are "normal", blood work is normal too. The memory loss includes some "semantic" loss like "who is the president" and long term "episodic" memory loss like not know where he went to school or if graduated and things that he did for a full year 5 years ago. short term loss is even worse, intra-week and intra-conversation is very poor. Only thing we're being asked to pursue in neuropsch testing which am pursuing. When you experince something like this you want a practitioner to say "seen dozens of these" but so far I've not found such a person. The person lives independently but can't hold a job due to memory issues but also has complete lack of insight to his illness, i.e. "what memory problem". He has been on meds but has refused them AGAIN. Suggestions to pursue are welcome.

Findjcr 16:57, 21 August 2006 (UTC)

Sorry to hear that. Tried amnesia?--Light current 17:02, 21 August 2006 (UTC)

• Have you tired alzheimer's? sometimes that can get confused with certian types of schizophrenia (^{I think})--71.247.125.144 17:18, 21 August 2006 (UTC)

(I am not a clinical psychologist or medical doctor) I'm surprised to hear that he has a normal EEG and MRI (presumably structural) but is having episodic memory loss, though you do say it's pretty recent so it might mean his hippocampus hasn't degenerated sufficiently for a loss of volume to show up. The "short-term memory" loss coupled with the episodic memory loss going back a few years suggests to me some sort of medial temporal lobe damage which is causing the "short-term memory" loss as a side-effect. That shouldn't cause much or any semantic memory problems though, which suggests a more global problem, perhaps schizophrenia, indeed. Personally I wouldn't assume it was bipolar disorder or Alzheimer's, unless he is very old, because semantic memory problems shouldn't be too bad in those cases unless his dementia is very bad (I think). Epilepsy comes to mind if the semantic memory impairments come and go, but that should be detectable in the EEG. Regarding his living situation, it sounds tough. To get him to take his medication you could always try bringing him a meal once a day with the medicine hidden in it or something. I hope things get better for you all. digfarenough (talk) 22:50, 21 August 2006 (UTC)

I'm also very sorry your relative is experiencing this. I won't waste time speculating on what it is (like Dfe I'm not an MD, and like Dfe all the things I'd guess at seem to have been ruled out by the normal scans), so I'll just say that I have several close friends/family/associates who are severely mentally ill (same diagnoses; schizo-affective disorder, bi-polar, paranoid schizophrenia, fast-cycling bi-polar with paranoid delusions... blah blah blah... it seems like maybe the old labels don't really fit anymore), and none of them seem to have similar memory problems, I'm afraid. The two who have the most profound 'breaks from reality', one in her early thirties and the other around 60, do sometimes fail to remember the worst episodes of their illnesses, and I'd say that overall their memories can have 'blanks', but truthfully (and un-educatedly) I attribute that to the fact that they have not pursued any course of treatment. All the people I know who are carefully caring for their illness (whether it's through conventional phrarmacology, therapy, or natural treatments) don't have any memory problems. Is your relative getting treatment? Is it possible that the treatment is causing the memory loss? Or that conversely the proper treatment might mitigate the problem? I don't think I helped but I wish you well. Anchoress 09:43, 23 August 2006 (UTC)

Valentin Glushko's mystery killer rockets

In the BBC docu-drama series Space Race, (which is accurate to records of the time) there is a part of the story line where Valentin Glushko, tests a new rocket engine in the labs, and it performs well, and all of the people working with it have to be in suits similar to chemical warfare suits (fully covered in thick yellow plastic, with gas masks), and it is mentioned that the fuels are so toxic that on inhilation they imediately begin to dissolve the victims lungs (accomponied by a shot of a rather ill looking russian worker removing his mask and promptly coughing up a liquid that is presumably his lungs). Later in the same episode they are testing it on a launcher vehicle and an electrical fault triggers the launchers second stage, which promptly incenerates the top of the first stage, and ignites several hundred tonnes worth of highly toxic rocket fuel. Many are caught and die, even those who had time to run, are caught as the tarmac melts and traps them. Promptly Glusuhko recieves a cut in funding for killing a large portion of the USSRs top scientists and "top-brass", who decided not to retreat to a safe distance when prompted.

There is no mention of an event like this in the Valentin Glushko article, and I dont know where else to look.

So, two questions;

1. What were the fuels, I looked about and found that Tripropellant rocket mentions the use of a combination of lithium, hydrogen, and fluorine, could this account for the "lung melting" effects? are there any other records of this event?
2. What are the enviromental "fallout" effects of an event like this, once the fuels have been identified, how dangerous would the site have been due to the fuels everywhere after the fire had been tamed, and how long would it be dangerous, and what effects on local flora and fauna would there be, long and short term?

Thank you. Philc _T^E_C^I 17:57, 21 August 2006 (UTC)

It looks to me like hydrogen fluoride and lithium fluoride may be the reaction products. Hydrogen fluoride is really, really nasty stuff (as is fluorine gas itself), but "lung melting" sounds like an exaggeration to me. Nevertheless, I can't image the sheer stupidity of being anywhere near a rocket filled with fluorine or a source of large amounts of hydrogen fluoride. --Ed (Edgar181) 18:25, 21 August 2006 (UTC)

Hydrogen peroxide was also used. In it's pure form, it's pretty nasty stuff. The stuff you buy in a store is mostly water with only a tiny portion of hydrogen peroxide. StuRat 18:58, 21 August 2006 (UTC)

it will likely be tetrafluorohydrazine. very nasty stuff, used as an oxidiser. or it could be nitrogen trifluoride, a related compound. both will spit out all sorts of nasties upon reaction with fuel (either the intended fuel, or your flesh), such as hydrogen fluoride, which would certainly produce the effects you describe. Xcomradex 08:00, 22 August 2006 (UTC)

This sounds similar to the Nedelin catastrophe but that involved a different rocket designer. For more one the fuels Glushko preferred, see N1 rocket. Rmhermen 18:52, 22 August 2006 (UTC)

Cheers, It appears the fuel he demanded use of was unsymmetrical dimethylhydrazine and nitrogen tetroxide. Philc _T^E_C^I 22:20, 22 August 2006 (UTC)

Hermaphrodite

My friend said hermaphrodite is having both parts, male and female, which it is; so what is the term used when a species has absoloutely no male nor female parts? Thank you. 81.131.76.34 18:48, 21 August 2006 (UTC)

That would be asexual reproduction. Many plants are asexual. StuRat 18:53, 21 August 2006 (UTC)

Or being androgynous. Iolakana•T 18:56, 21 August 2006 (UTC)

StuRat, I seem to recall that all plants reproduce sexually; while some algaes and unicellular organisms are asexual, they are properly classified in Kingdom Protista. Are you sure about asexual plants? Nimur 19:55, 21 August 2006 (UTC)

Many plants reproduce mainly via asexual means, such as with rhizomes or simply dropping leaves which can then grow into full "clones" (especially some succulents), and most are able to regenerate from small pieces - some have adapted to favor this as the primary means of reproduction - sorry I can't provide any sources or good examples, but perhaps someone else can. --Bmk 21:07, 21 August 2006 (UTC)

Ah - after following my own link, I found vegetative reproduction which describes the process. Also, I guess when a single organism is hermaphroditic and it reproduces with itself, it's kind of asexual, because it doesn't introduce any new alleles to the offspring. Although it still does undergo "crossing over" during meiosis. --Bmk 21:07, 21 August 2006 (UTC)

Also check out apomixis and parthenocarpy. --Lambiam^Talk 02:09, 22 August 2006 (UTC)

The term "asexual species" is used for such species, as for example in our article Evolution of sex. --Lambiam^Talk 02:20, 22 August 2006 (UTC)

Sunbeds

I'm becoming increasingly vain and am considering using sunbeds to get a tan. Of course I've been told by everyone everywhere that this is bad for my skin's health, but I don't fully understand. What's the difference between the sun's UV radiation and a sunbed's UV? Is sunbed use only as bad as excessive natural sun-tanning or is it worse? Thanks! --87.194.21.177 20:22, 21 August 2006 (UTC)

Sunbeds traditionally used UV A radiation, but there's increasing use of UV B. UV A is classically thought of as "safer" than B but that is debatable... The World Health Organization is not a fan of sunbeds; you can read more about their stance here (check the .pdf file). -- Scientizzle 20:38, 21 August 2006 (UTC)

The sun also prematurely ages your skin, just like sunbeds, and sunburns have been linked to skin cancer. --Bmk 21:09, 21 August 2006 (UTC)

UV radiation damages your skin, and you look older faster. Sure you may look better next week, but in a few decades you're going to be a raison. I went to Arizona and observed this one time. :yuck: — [Mac Davis] (talk)

Don't sunbathe either way! Its easy to get a fake tan - either something you rub on (including something that gradually builds up) or thats sprayed on. About 25 years ago I had a deep tan from both using sun lamps and the sun, and recently I had a mole removed which was found to have pre-cancerous cells - the sort that would have developed to the worst sort of deadly skin cancer. It was only by a string of luck that a dermatologist saw it. If it wasnt for the good old National Health Service and me wanting to get my moneys worth even if its free, then it wouldnt have been spotted and in a few more years it would have killed me.

Crotch sensation - strange question a

I am wondering if anyone can explain the strange sensation that one can start but not maintain in the testes by...and here comes the hard part...explaining how to create the sensation...it's sort of a sexual sensation, just like when you're about to climax...but not yet there and not as extreme...

It feels funny in the testes sort of...damn it's not like when you flex your buttocks or anything.

Well the question is when I do it and watch my eyes in a mirror the pupil starts to dilate...is there a connection between this sensation and the brains reward system? It's really strange...the pupil dilates while I do it and then shrinks afterwards.

Is it normal to be able to 'almost' voluntary control the size of your pupils, though I have to do this crotch thing to make them grow!? Have people researched this connection? And whats up with people on drugs...they've got these huge black pupils...same connection? Overload to the reward system? And what about depressive people...do they have needle pupils? —The preceding unsigned comment was added by Azalin (talk • contribs) 21:26, August 21, 2006.

This seagull bagel's crotch is not clearly visible, but his pupils may be dilated

Its like holding back the flow when your urinating, isnt it!! I know it well! (having urinated many times in my life)--Light current 01:13, 22 August 2006 (UTC)

Can you run a quick control experiment, and see if your pupils dilate even without doing your... thing? Looking in my mirror, my pupils appear to grow as I change from soaking up all ambient light to focusing on my eyes. Maybe your... thing... is unrelated. Hyenaste ^(tell) 21:12, 21 August 2006 (UTC)

Some teachers in inner city schools also have huge black pupils. Ask them.Edison 20:52, 21 August 2006 (UTC)

Ouch. That was bad. --Bmk 21:10, 21 August 2006 (UTC)

Maybe he means something about the dim lighting conditions? Hyenaste ^(tell) 21:12, 21 August 2006 (UTC)

Can we also look forward to "Crotch sensation - strange question b" and so on up to "Crotch sensation - strange question z" ? StuRat 21:14, 21 August 2006 (UTC)

I thought he was using some library catalogue method to help keep the page in order, so really it would say "A strange question - Crotch sensation" Hyenaste ^(tell) 21:20, 21 August 2006 (UTC)

Can [[seagull bagel]]s experience this crotch sensation? Nimur 21:34, 21 August 2006 (UTC)

Do gulls have crotches? --Kurt Shaped Box 21:48, 21 August 2006 (UTC)

The gals I know have them! (Oh sorry you meant gulls)--Light current 01:55, 22 August 2006 (UTC)

Guys! Do not degrade the science desk with totally humorous answers. To answer the question, about pupils, which I am surprised hasn't been said: Yes, everybody's pupils dilate during sexual arousal, and even more when you climax. This is the reason some women use belladonna eye drops, because it dilates the pupils, and men love dilated pupils in women. Vice versa has been found to be false. Men probably like it because it is like the women is having sex. Pupils dilate presumably so you can see what is going on better, with a supercharged view. — [Mac Davis] (talk)

"People op drugs"? There's a gross overgeneralisation. Considering the wide variation of drugs, their effects can probably go either way. So ladies, make sure you take the right kind of drug if you want to turn a guy on. DirkvdM 05:46, 22 August 2006 (UTC)

You asked if there is a connection , there is a very real physical connection of nerves between these areas, try autonomic_nervous_system.

Ok...so if you can control your autonomic nervous system which you cant' unless? you're a monk...or something with balls..not...it can be done? Rise and shine...grow and...look....hmm... what's up with the donut?

Crotch sensation - strange question b

Why is it that whenever I watch something on TV that looks painful (I dunno, someone getting their finger realistically cut off in a horror movie or something), I can feel my testicles rise upwards into my abdomen slightly? --Kurt Shaped Box 21:47, 21 August 2006 (UTC)

Clearly this is a learned response, much the same way that lab-rats can be trained to salute an American flag when the Star-Spangled Banner plays in their cage. In other words, to protect your testicles, you are semi-subconsciously retracting them. Nimur 21:49, 21 August 2006 (UTC)

I just remembered - the worst sort of scenes for making my balls shrink are those that involve the removal of skin, or pulling out of finger/toenails... --Kurt Shaped Box 22:10, 21 August 2006 (UTC)

It happens to me too. — [Mac Davis] (talk)

Yeah I get that too. Perhaps its a reflex reponse trying to protect you testicles from what you are seeing on the screen!--Light current 00:04, 22 August 2006 (UTC)

Of course the more interesting question is: what do women feel in similar situations? C'mon gals-- tell us all!--Light current 00:06, 22 August 2006 (UTC)

Also see this partial (unless you want to pay for more) answer from "The Last Word" (New Scientist): [3].  --Lambiam^Talk 02:31, 22 August 2006 (UTC)

'Pop em back into your cavity'. I like it! Yes I do believe when you are really scared they can disappear--Light current 02:44, 22 August 2006 (UTC)

Look up PC muscle (pubococcygeal muscle). Trouble is, I dont know how to spell it! Looks like I spelled it right - do I get a prize?---Light current 15:39, 22 August 2006 (UTC)

Scale up a herring gull to the same height as a human...

You would not want to mess with this.

Fight. Human is skilled in martial arts. Ring of death. Which would win? --Kurt Shaped Box 22:28, 21 August 2006 (UTC)

• I'm going to say the Gull, I mean the thing would be a giant feathered death machine, just look at that beak--71.247.125.144 22:38, 21 August 2006 (UTC)
• Gull. For comparison, think of a life-sized goose or turkey, which is maybe only 2 or 3 feet (0.7 - 1.0 m) tall, and yet still vicious and dangerous to a human. If the gull is comparable in relative strength, AND scaled to a human's height - it's no contest. Nimur 22:45, 21 August 2006 (UTC)

I wonder though if the gull's bones would be too brittle for it's augmented size? And the gull certainly wouldn't be nearly as agile. There is a very important adaptation to scale that takes place in the body structures and material selection of organisms. For a famous example, just because ants are disproportionately strong for their size (compared to humans), an ant that had been simply scaled up to human size wouldn't even be able to stand up. I think I may have to vote human --Bmk 23:34, 21 August 2006 (UTC)

True, when scaling up, mass increases on a line of y=x³, wile bone support, which is measured in the cross section of the bone increases at y=x² (ie, every time the weight is cubed, the strength is only squared) thise goes for muscle and bone, soon it will be unable to support its own weight. Philc _T^E_C^I 18:27, 23 August 2006 (UTC)

• Human. To echo Bmk, a human is constructed for locomotion at human scales, and a gull is not. I'm no expert in aerodynamics, but I'm sure that a six-foot tall gull would be quite unable to fly. Without being able to effectively push on the air to balance, even its combat-mode hopping will be awkward. All you have to do is sidestep its jumps, knock away its legs, then go to town. Melchoir 23:47, 21 August 2006 (UTC)
• Human. If the human is Ronnie Coleman. --GTubio 14:24, 22 August 2006 (UTC)

However, a gull vs scaled-down-human fight would be uncontested in favor of the seagull bagel. We'd be like big juicy floppy fish. --Bmk 00:01, 22 August 2006 (UTC)

Yeah, a big juicy floppy fish with an Jackhammer fully-automatic 12-guage shotgun. Of course a situation is always less bloody if it is a battle of words, that can be settled with a nice cup of tea. :) — [Mac Davis] (talk)

Depends on if the human skilled in martial arts gets to bring a kwan dao! --Ginkgo100 ^{talk · e@} 03:07, 22 August 2006 (UTC)

Both if they decide not to fight. DirkvdM 05:48, 22 August 2006 (UTC)

Quality of WP:RD/S Decreasing?

Is it due to global warming and CFC emissions? Nimur 22:53, 21 August 2006 (UTC)

• I blame the exponential increase in wikipedia's seagull population--71.247.125.144 22:56, 21 August 2006 (UTC)

Not f****ing seagull again please!--Light current 23:40, 21 August 2006 (UTC)

No its my fault.--Light current 03:12, 22 August 2006 (UTC)

You're damn right. — [Mac Davis] (talk)

Well I guess they aren't masturbating, or becoming giant... or both. =o — [Mac Davis] (talk)

I've heard of some weird sexual aberrations, but fucking seagull? DirkvdM 05:51, 22 August 2006 (UTC)

I fear this thread is diverging--Light current 13:32, 22 August 2006 (UTC)

I have a wikiproject that might put your fears to rest--BagelCarr 13:37, 22 August 2006 (UTC)

I think replacing seagulls by bagels is despicable. After all they are living creatures!--Light current 15:47, 22 August 2006 (UTC)

Light Current, I removed all your changes to other people's posts, and changed your post too. Notice how irritating that is? DirkvdM 09:38, 23 August 2006 (UTC)

What changes to other peoples posts? Not guilty! Please explain--Light current 15:58, 23 August 2006 (UTC)

Occurrences of 'seagul' were crossed out and replaced by 'bagel'. I thought you had done that. If not, I apologise. DirkvdM 08:57, 24 August 2006 (UTC)

Not me . I found it quite annoying too. Probably USER:BagelCarr, but thanks for reverting them anyway.--Light current 09:28, 24 August 2006 (UTC)

Zoology

How much is the average zoologist salary? And how long do you stay in college for it?

I think both questions depend on for whom and where you work after your education. But i'm sure that wasn't very helpful. --Bmk 23:37, 21 August 2006 (UTC)

Most gull experts do not have a degree in zoology; and they do not receive a salary either, since their chief employment is volunteering on the Science Reference Desk. Nimur 00:06, 22 August 2006 (UTC)

Yes, all seagull bagel experts work here for no salary whatsoever! --Light current 00:09, 22 August 2006 (UTC)

On a serious note though. Zoologists usually get a four-year bachelor's degree in the United States. They may then work at a zoological park; perhaps they pursue veterinary graduate studies; or maybe they choose to work in agriculture, which probably has the most significant room for salary growth. There's a lot of business in agricultural economics, speculating on farm futures. Nimur 00:12, 22 August 2006 (UTC)

• What can I do with a major in Zoology? From North Carolina State University.
• In North Carolina, a four-year-Baccalaureate-degree in Zoology will earn you... $ 27,443 per year [4]
• A four-year degree in Animal Science: $ 29,917 [5].
• Comparative Career Chart including Salary info

You may consider looking at your university-of-choice to see if they have similar Career Options guides. Nimur 00:21, 22 August 2006 (UTC)

I must note that my four-year zoology degree never made me that much. In fact, the only job I have ever had that paid in that range didn't require a degree. If you want to work in a zoo or aquarium, you should be prepared to live below the poverty line, or else marry rich. If you pursue your eduction to the Ph.D. and post-doc level, however, a position at a university would pay more. --Ginkgo100 ^{talk · e@} 03:04, 22 August 2006 (UTC)

Baygulls, seagull bagels, and bagels

^{Baygulls, seagull bagels, and bagels}

So.. a pair of gulls were fighting over part of a bagel, and one of the gulls knocked it out of its grip in midair, causing the bagel to plumit to the ground, both gulls dove for the falling bagel, and after a lot of drops, near catches, and gull fighting, one of the gulls finally grabs the bagel, and gets away. But wait, just as it's escaped with bagel in tow, it deliberately drops the bagel into traffic right in front of a truck without even taking a bite.. bagel is destroyed, and neither gull gets to eat it. Was the victorious gull taunting the loser? That seems awefully mean for a gull. PS. this is a true story that has been haunting my dreams for several years now--71.247.125.144 23:06, 21 August 2006 (UTC)

OK, guys.. I think we've just about beaten this horse to death now. It's getting a little tiresome. --Fastfission 00:04, 22 August 2006 (UTC)

Who mentioned horses?--Light current 00:19, 22 August 2006 (UTC)

He did. DirkvdM 05:52, 22 August 2006 (UTC)

Horse Bagel? — [Mac Davis] (talk)

We dont have bagels over here, so these posts do not represent a worldwide view and show a certain POV (that bagels are superior to seagulls) I dispute this.--Light current 15:33, 22 August 2006 (UTC)