Science desk
< June 3	<< May \| June \| Jul >>	June 5 >

Welcome to the Wikipedia Science Reference Desk 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 on one of the current reference desk pages.

June 4

Electromotive Force and Potential Difference?

I am slightly confused what is the difference between electromotive force and potential difference. From what I currently understand it seems like emf is a theoretical value assuming no internal resistance within a battery while potential difference is the actual, pratical value. Is this correct? 24.125.56.9 (talk) —Preceding comment was added at 00:44, 4 June 2008 (UTC)[reply]

You've already looked at Electromotive force#Electromotive force and voltage difference, right? Also note that at potential difference, it has been suggested that this article be merged with voltage. Are you asking about the difference between emf and voltage? The main thing I'm getting out of these articles is that the word "force" in emf is a misnomer. --arkuat (talk) 06:23, 4 June 2008 (UTC)[reply]

There is no real difference other than semantic convention. The emf phrase is usually applied to the voltage of a generator and the pd phrase is usually applied to the voltage across a load. However, this can be relative, the load can be a supply to something else so whether a particular item is a load or a source can be a matter of point of view. Arkuat is correct that emf is a misnomer and is therefore discouraged. Voltage is neither force nor pressure (another common analogy). It is potential energy (per unit charge). SpinningSpark 13:12, 4 June 2008 (UTC)[reply]

Electromotive force is the voltage (or energy per unit charge) transferred from the power source to the charge carriers (electrons or ions) in a conductor. Potential difference is the voltage transferred from the charge carriers to the load. -steved

mental health

explain the practicle knowledge of the principles, concepts, and methodology in the field of mental health in order. Think of yourself being a mental health couselor. —Preceding unsigned comment added by 76.114.167.213 (talk) 01:11, 4 June 2008 (UTC)[reply]

Do your own homework. Think of yourself being a student learning the material instead of a freeloader cheating on-line. DMacks (talk) 01:16, 4 June 2008 (UTC)[reply]

That seems like ~~practicle~~ practical advice ;-) --hydnjo talk 01:54, 4 June 2008 (UTC)[reply]

Sound ~~cousel~~ counsel too. Clarityfiend (talk) 02:06, 4 June 2008 (UTC)[reply]

Mental health - Mental health professional - Social worker - Psychology - Psychiatry. Damn, I really thought it was a question about the meeting of particle physics and psychology. So disappointed. 200.127.59.151 (talk) 15:15, 4 June 2008 (UTC)[reply]

ears

Do your ears get bigger as you age? It seems like elderly people have abnormally large ears. —Preceding unsigned comment added by 75.169.24.1 (talk) 02:07, 4 June 2008 (UTC)[reply]

This study suggests yes, though it is not an ironclad correlation between ear size and age. --98.217.8.46 (talk) 03:26, 4 June 2008 (UTC)[reply]

Yahoo answers[1] is inconclusive but madsci[2] discusses it with a yes in there as well. Sometimes it's only apparent (the flesh-and-hair loss effect) and sometimes it's measurable. Hair apparently falls off the head only to reappear in the nose and ears. Julia Rossi (talk) 03:31, 4 June 2008 (UTC)[reply]

Can you plug a 115 volt appliance into a 110 volt outlet?

I'm trying to determine if I can plug a 115 volt appliance into a 110 volt outlet. You know, whether or not that would actually work without anything blowing up. I found an answer to a similar question on Wikianswers, but it didn't really help at all. Digger3000 (talk) 02:41, 4 June 2008 (UTC)[reply]

In North America, household outlet voltages of 110/115/120V are used interchangeably (see this FAQ). According to that link, appliances are generally designed to operate at 115 +/- 10%, so you should be just fine. Cheers, St3vo (talk) 02:54, 4 June 2008 (UTC)[reply]

That's right. They just call them those different numbers and there's no telling what the actual voltage is going to be on any given day. It'll be higher closer to the power plant, too. The power companies don't regulate that very strictly, but they do keep the 60 cycles pretty tight. Our article Mains_electricity#Voltage_levels says "In the United States and Canada, national standards specify that the nominal voltage at the source should be 120 V and allow a range of 114 to 126 V (-5% to +5%)." Also see Mains_electricity#Voltage_regulation. --Milkbreath (talk) 04:04, 4 June 2008 (UTC)[reply]

Thomas Edison started out with 100 volts in New York City supplied from the Pearl Street Plant in 1882. He decided to stress the insulation slightly more to achieve the transfer of greater power and the voltage level was raised to 110 volts. A couple of decades later, the nominal supply voltage became 120 volts, again to aupply more power via the same conductors. 120 volts AC is a nominal voltage in North America for many utilities at the transformer terminals. By the time the voltage has dropped through the service conductors and the wiring in the customer's premesis, it may be down to 110 volts at the actual motor terminals, representing the same real life situation. Utility commissions in many U.S. states allow the utility voltage to drop from the nominal 120 volts to 114 volts (a 5 % decrease) for 1 minute. A 115 volt (nominal) motor supplied with 120 volts would generally operate satisfactorily while drawing lower current. As with all Wikipedia Reerence Desk answers, this is provided for information only and may not be relied on as a substitute for professional advice from a licensed professional. No liability whatsoever is assumed. Edison (talk) 06:02, 4 June 2008 (UTC)[reply]

Animal behaviour

I want to know some facts about social hierarchy among animals.

Which animals other than Homo sapiens have social hierarchy?

I have read the article on Gorilla. The Gorilla#Behavior section of that article does not have much information about their group life. The only information given in the article is:

Silverbacks are the strong, dominant troop leaders. Each typically leads a troop (group size ranges from 5 to 30) and is in the center of the troop's attention, making all the decisions, mediating conflicts, determining the movements of the group, leading the others to feeding sites and taking responsibility for the safety and well-being of the troop.

- - How the leader of a gorilla group is chosen?
  - If the existing leader of a group of Gorilla dies, then who will be the next leader and what is the selection procedure?
  - If any member of a gorilla group denies the order of the troop leader, then what will be the result?

Regarding Chimpanzee, is there social hierarchy among chimps? What is the role of violence among chimpanzees? Are they attack one another or conflicts between one group and another, if there is violence then what is the reason behind the violence and what is the usual result of such violence? Otolemur crassicaudatus (talk) 06:39, 4 June 2008 (UTC)[reply]

Start from Ethology and then follow the links at the bottom. Dominance hierarchy(pecking order) and Alpha (biology) would probably also be of interest to you. Mountain Gorilla has a bit more on social structure. For Chimpanzee the answer depends on what species Common Chimpanzee is different from Bonobo.76.111.32.200 (talk) 07:00, 4 June 2008 (UTC)[reply]

Lots of questions. I'll have a go at the first. Almost all social animals have hierarchies, and that means a lot of mammals including chimps and gorillas. Perhaps the most rigid social hierarchies in mammals are among the Naked mole rats and Damaraland Mole Rats - the only two mammals that are know to display eusociality. Rockpocket 07:05, 4 June 2008 (UTC)[reply]

I carefully read the article Mountain Gorilla. The Mountain_Gorilla#Social_structure section answers to one of my question that if the existing group leader dies, then "the family group may be severely disrupted. Unless he leaves behind a male descendant capable of taking over his position, the group will either split up or be taken over in its entirety by an unrelated male. When a new silverback takes control of a family group, he may kill all of the infants of the dead silverback". This section also clearly states A typical group contains: one silverback, who is the group's undisputed leader. Here the fact I still do not understand that what will be fate of a group member if he/she denies any order of the troop leader? Will he/she be expelled from group or anything other? Otolemur crassicaudatus (talk) 07:20, 4 June 2008 (UTC)[reply]

Animals don't tend to order one another around. The dominant animal will typically do what he wants do do (which is generally eat, be groomed, and mate). If the other males stay out of his way and do not interfere with him then they will be fine. If they do, then they will likely be attacked until they submit. If they don't submit one of three things will happen: they may be chased away from the social group, they may be killed or the may usurp the dominant animal (who will either submit, be chased away or be killed). Rockpocket 07:29, 4 June 2008 (UTC)[reply]

I cut the skin on my knee

Yesterday night, I fell from my bicycle and cut the skin on my knee, for about an inch long, on the tar road. I washed it in Dettol and put on a Band-Aid. I removed the Band-Aid just now.

How come the skin got cut but my pants has no damage?

Why does it look white under the skin on the knee? It looks reddish under the skin on other parts of the body, right?

What is this translucent gel that has formed a thin film on the wound?

--Masatran (talk) 08:33, 4 June 2008 (UTC)[reply]

The fabric on your pants is stronger than the skin on your knee? I suspect the 'whiteness' is because your knee doesn't have much by way of muscle between it and the knee-cap, whereas on other parts of the body you do. I think the gel is white-blood cells. Sorry not much use i'm sure someone in the know will correct/answer more accurately in time. 194.221.133.226 (talk) 08:49, 4 June 2008 (UTC)[reply]

Sounds more like a scrape than a cut. The fact that your jeans held up is probably due to the fact that there are lots of tiny sharp edged pebbles in the road surface. They work like sandpaper. The sharp edges poked through tiny holes in your jeans and then cut lots of tiny little holes in your skin. The translucent film are white blood cells and a couple of other things your body uses to heal the wound. The white skin can have 2 reasons: Under the bandaid the skin can not "breathe" and is kept moist. The effects are the same as staying in the pool or tub too long. The second is that the blood supply is disrupted, compared to healthy skin, the body is also supplying more white blood cells in proportion to red to the site of the injury. --76.111.32.200 (talk) 09:26, 4 June 2008 (UTC)[reply]

(It's amazing how much questions and answers can resemble medical advice without people harrumphing about the Ref Desk rules.)Edison (talk) 21:48, 4 June 2008 (UTC)[reply]

Metadiscussion is best confined to the talk page. --Milkbreath (talk) 23:01, 4 June 2008 (UTC)[reply]

There is a difference between answering a question about human biology and medical advice - it's a little difficult to tell the difference sometimes, so we err on the side of caution, but I think this case is well within the realms of human biology, not medical advice, since all that's been offered is an explanation for an observation that took place after treatment was complete, no suggests about future treatment have been offered. --Tango (talk) 14:53, 5 June 2008 (UTC)[reply]

Huh? If you have an itch and scratch it too much, the skin will be covered with white marks. This is probably due to the surface of the skin being cut, without yet bleeding, swelling, and reddning, and the white cut mark on your knee is likely similar. Hope this helps. Thanks. ~A H 1^(TCU) 23:56, 5 June 2008 (UTC)[reply]

Parachute for rock climbing

Would it help if rock climbers kept a parachute? Perhaps it would slow them down if they had a fall? --Masatran (talk) 09:03, 4 June 2008 (UTC)[reply]

I think that it is not feasible. First the parachute will not have enough room to deploy should the climber. Second, it will be torn by the jagged rocks of the cliff.--Lenticel ^(talk) 09:18, 4 June 2008 (UTC)[reply]

See BASE jumping. You would need a significant amount of expertise to pull it off, I imagine, but it could work. --Tango (talk) 12:07, 4 June 2008 (UTC)[reply]

Most of the time they use ropes and such tools instead to secure themselves. More reliable than a parachute and works at any height. Regards, CycloneNimrod ^talk?_contribs? 12:49, 4 June 2008 (UTC)[reply]

Rock climbing is rarely done on overhanging cliffs. More often, it's done on vertical or near-vertical cliffs, and if you fall on one of those, your parachute won't have room to open -- it'll get tangled and torn by scraping against the cliff. --Carnildo (talk) 21:24, 4 June 2008 (UTC)[reply]

Quantum mechanics and wave functions

QM states that prior to observation, nothing can be said about a physical system other than a probability function which seems to be definable to a degree by assumptions about the system's elements. With observation a system's probability wave function will collapse into a precise quantity which is observable by the means of measuring the device applied. – taken from Reality#Quantum physical views of reality.

Does this imply that, prior to the appearance of living beings capable of observing, the entire universe was in a state of quantum superposition? Does this mean that the far side of Pluto, which is not being observed, is in a combination of all the possible states? And finally, if I enclosed myself in a dark steel box, more or less like Schrödinger's cat, would I instantly experiment superposition too? -- Leptictidium (mt) 10:20, 4 June 2008 (UTC)[reply]

I don't think there is any real agreement on what "observe" means in that context. Collapsing wave functions doesn't really appear in the theory, it's just tacked on after the fact to explain why we do actually observe fixed outcomes to experiments. Different people have different ideas about how it actually works. Someone else can probably explain what the major interpretations are better than I can. --Tango (talk) 12:10, 4 June 2008 (UTC)[reply]

I think the whole universe is in a state of superposition whether it is observed or not! Proper Interval Locality —Preceding unsigned comment added by WROBO (talk • contribs) 12:48, 4 June 2008 (UTC)[reply]

Can other animals or even plants not observe? Imagine Reason (talk) 14:49, 4 June 2008 (UTC)[reply]

In quantum mechanics, the word "observe" doesn't mean what you think it does. Anything that interacts with a system can observe it: a human, a bacterium, an atom, a photon, anything. --Carnildo (talk) 21:31, 4 June 2008 (UTC)[reply]

So why is the superposition of the cat preserved if the bateria in the box, the atoms, and the cat can all observe and collapse the wavefunction? (I have the sneaking suspicion that I may be missing something). Ζρς ι'β' ^¡hábleme! 12:49, 5 June 2008 (UTC)[reply]

Hello everyone!

Considering my profile, I might be one of the least qualified persons to comment upon this. But, reading the italicized quoted paragraph gives me an impression that it is to be taken in perspective of Heisenberg's uncertainty principle, which implies that there are certain coupled physical quantities, say position and momentum of a particle that cannot both be determined with absolute certainty (this I'm saying with the risk of talking to real experts). To determine the position (the meaning of observation in the said paragraph) of any particle one will have to "bombard" it with at least one photon. And, the time it takes to return would tell you the position, but the catch is in the process, the photon would have altered the original momentum by an uncertain quantity, so again we become ignorant of the "exact" momentum possessed.

One might think that if a particle is absolutely stationary, then, and if we determine it's position, then we'd be able to determine both (momentum and position accurately), again the above argument would apply, and most importantly, quantum mechanics does not allow for a particle to have zero energy. It has to have at least 1/2h.v² amount of energy (where "h" is the Planck's constant, "v" is actually mu, and stands for certain frequency [loosely put, the frequency at which the particle "oscillates" and does not loose energy in the process]). This energy is known as the "zero point energy". The explanation I gave of the uncertainty principle is kind of crude (qualitative). There are other more complex explanations (like the "particle-in-the-box" example) that also account for certain phenomena like the tunneling effect used in electron microscopes (loosely put, the probability for an electron to exist outside as well as within the walls of a tunnel are both greater than zero!).

One more thing that I'd like to point out is that as quantum mechanics stands today, it is only to account for phenomena occurring at the subatomic scale, not at scales as large as a planet. Even a "small" particle like the a bacterium would be too complex and large to explain. That's why scientists are trying hard to find a unified field theory for a physics that could explain phenomena at subatomic scale as well as really huge bodies like the galaxies in the Universe. It is may be in this context that the Strings theory might come in handy.

Because, of the above mentioned uncertainty, we talk of wave function, which some what corresponds to the concept of trajectory in classical mechanics, which is a cumulative description of a particle's momentum (mass, direction, speed), and of course position at all points in time. Wave function if properly solved can yield the energy possessed by a body (kinetic+potential energy, of which the actual potential energy is again indeterminate), and the probability of a particle existing at a particular position in the coordinate system. So much for the uncertainty principle!

My ideas are greatly based on a book by Peter W. Atkins called "Physical chemistry" that I'd read more than 6 years back, and a program presented on the "Discovery channel" based on a book by Brian Greene called "The elegant Universe" with the same name.

If (the probability of which is very high) my ideas are misdirected, please do let me know. I find these topics very interesting.

Hope my comments would be of some help. Regards.

—KetanPanchal^taLK

Nu (ν) not mu (μ) is frequency. Mu is the notation for micro. I (am not sure but) think a wavefunction is a combination of all possible quantum states of a system. Thus, a wavefunction describes the superposition of all quantum states of a particle. When the particle is observed, the wavefunction "collapses" and becomes a definite state. The probability of collapsing into any of the possible states is described by the wavefunction.Caution: These ideas may, too, be misdirected. This is content from a few months ago obtained from Wikipedia via memory. If any of my statements are misguided, please kindly point them out. Ζρς ι'β' ^¡hábleme! 02:37, 6 June 2008 (UTC)[reply]

Perhaps as a physicist in training I can add a little something. Short answer: Your question shows a common flaw in how people receive quantum mechanics. Its all about scale.

The wavefunction is said to contain all the information there is about a quantum particle. The square of the wavefunction is the probability density that tells you the probability that a particle is in any given place. The wave function is determined by the boundary conditions which are defined by its surroundings (see the particle in a box for the easiest to understand example).

When something is 'observed' its wavefunction collapses to a Dirac delta function and it takes on a definite value for that period of time until it begins to time evolve again. The important thing to understand about probability density is that it applies for an ensemble of particles, not one particle by itself. If you have a wavefunction that allows for states 1 and 0, and you measure a particle to be in state 1. It is in state 1 for you to be able to measure that it is in state 1 (its an obvious thing that needs to be said). Its state is known (this is not meant to imply that its momentum/position are simultaneously known, commutator relationships still apply). If you were to take an identical particle and put it in the situation again, you might get 1, you might get 0. The relative probability of getting either of those is based on the probability density of the particle.

All that said, this applies ONLY for quantum particles. It does not apply for cats or as stated above, even bacteria. Or (often) even atoms. These objects are just too large for quantum effects to be observable. Atoms are kind of a gray area in that we CAN make predictions using quantum mechanics, but only if we break the atom down into its components, the electron cloud and the nucleus. But the atom considered as a unit will not typically follow the rules of quantum mechanics.

So yes, one could theoretically say that the far side of Pluto is in a state of quantum uncertainty. But above a certain scale, quantum effects are very difficult to observe and you'll more often find statistical mechanics or thermodynamics or Newton calling the shots. This inability to scale quantum up to an arbitrary scale is, as said above, the goal of a Grand Unified Theory, but we're not there yet. EagleFalconn (talk) 13:52, 6 June 2008 (UTC)[reply]

Hi! Thanks, EagleFalconn. I could follow your reply, but only partially so (no doubt, it "Q-U-A-N-T-U-M" physics!). Well, what I particularly didn't understand was the meaning of the term "quantum states". What are the parameters (like wave function, position, energy, spin, momentum or oscillatory frequency are included)? As I had said, I'm very unrelated to the field, but after I'd completed replying, I realized the concept that was being discussed had somehow never come to my attention during (whatever little) exposure I've had of quantum physics, that's why I probably tried to mould the situation in terms of uncertainty. Thanks in advance. Regards. —KetanPanchal^taLK 05:41, 7 June 2008 (UTC)[reply]

A quantum state is the case of having a wavefunction. If you change the wave function, you change the state (Disclaimer: Technically, you only change the state if you change the probability density, but its not a distinction that its strictly necessary just yet). From the wave function, everything you mentioned (position, energy, spin etc) is derived. Well, more accurately, given the parameters of the Hamiltonian which are based on the potential energy in the region the wave function is determined, which contains all the information about a particle. It is completely accurate to say that a wave function is defined by its boundary conditions, not the other way around, and the particle in a box that I mentioned earlier is an excellent example of this. EagleFalconn (talk) 13:50, 9 June 2008 (UTC)[reply]

Vehicle Fuel Economy declines by 10% for every mile per hour over 60 mph. Is this true?

Common knowledge or media has told me that for every increase in speed by 1 MPH, over the speed of 60MPH, fuel economy declines by 10%. This would result in a fuel economy loss of 50%, from say 15 MPG to 7.5 MPG by driving at 65 MPH. (5mph X 10% for each MPH= 50%. This cannot be true. What is the truth? Steve in canada. —Preceding unsigned comment added by 142.179.218.64 (talk) 13:02, 4 June 2008 (UTC)[reply]

Here's a question to answer your question. Say something costs $100. A store charges a 50% markup on the price. Later, when the store is going out of business, they have a 50% off sale. How much does it cost now? sho y 13:49, 4 June 2008 (UTC)[reply]

Obviously the 10% rule of thumb as described above can't be literally true, otherwise your fuel tank would instantly empty itself when you hit 70MPH. (I have myself driven over 70MPH and can report that my fuel consumption did not suddenly divide by zero.)

Check out the graph at page 4-23 of this report for a rough idea of how this goes. Obviously it will be somewhat different depending on the vehicle. APL (talk) 14:01, 4 June 2008 (UTC)[reply]

Minus 10% and then minus another 10% isn't the same as minusing 20% - pick a starting number and try it. --Tango (talk) 14:24, 4 June 2008 (UTC)[reply]

But even taking compounding into account, a 10% drop per 1 mph increase in speed would mean that fuel economy at 70 mph was only 35% of its value at 60 mph - which is clearly not correct. The rate of drop off in fuel economy in the source given by APL above is much smaller than this - only 1% to 2% per mph. Gandalf61 (talk) 14:37, 4 June 2008 (UTC)[reply]

It massively depends on the engine and gearbox of the car, too. Different cars are optimised for different speeds, a car with a fairly low-ratio gearbox designed for city driving does lose efficiency quite quickly at high speeds, but a car designed for it generally gets its best mileage at 70-80mph. ~ mazca ^talk 14:27, 4 June 2008 (UTC)[reply]

That number surprises me. I thought cars typically saw their most efficient speeds in more like the 30-50 mph range. Where did you read about cars that are most efficient at 70-80? Air resistance becomes way more significant with higher speeds- there's not really any getting around that. Friday (talk) 15:34, 4 June 2008 (UTC)[reply]

Yeah. I can see an engine producing peak power in that range, but not peak fuel efficiency for the overall system. — Lomn 18:27, 4 June 2008 (UTC)[reply]

The Union of Concerned Scientists guy here says you lose 1% for every mph over 55 (not 10% for every mph over 55) (You have to love the sidebar poll - On a 65mph speed limit road, how slow would you go to save gas? Most common answer - 70!) Rmhermen (talk) 15:46, 4 June 2008 (UTC)[reply]

At high speed efficiency is governed mostly by wind resistance, which goes up proportional to the square of the velocity. So, its not linear at al, and depends a lot on the aerodynamic efficiency of the vehicle. Perhaps it is 10% between 60 and 70, but it will be more than that between 70 and 80. We used to (try to) enforce a 55 mph speed limit in the USA just because of the really large fuel savings that would accrue if people stuck to that limit. I really think we need to go back to that, and make speeding tickets a priority revenue source for the states for a few years. --BenBurch (talk) 19:54, 4 June 2008 (UTC)[reply]

That was one of the stupidiest laws we ever had. I lived in a hilly area at the time, which results in cars gaining speed going down the hills and losing speed when they went back up. But once they put that absurdly low speed limit in place, we either had to come to a stop at the top of the hills or ride the brakes down the hill to keep it under 55. This wasted fuel, time, and brake pads. Another unintended consequence is that slower cars stay on the roads longer for a given trip, resulting in more cars on the road at any given time, which requires additional lanes to prevent gridlock. StuRat (talk) 04:01, 6 June 2008 (UTC)[reply]

Obviously they'd never heard of engine braking if they were riding the brakes down hills. Even an automatic gearbox has a low gear selector override for just such an occasion. Exxolon (talk) 21:07, 8 June 2008 (UTC)[reply]

Most Americans have automatics. You can switch to nuetral or a lower gear on long hills, but it's just not practical to constantly switch gears going over a series of short hills. Changing gears that often distracts from driving and you can miss and put it in reverse if you don't watch the gear selector, which means taking your eyes off the road. StuRat (talk) 22:07, 10 June 2008 (UTC)[reply]

Why aren't pygmies considered a separate species or sub-species of Homo Sapiens?

For example, the Pygmy Hippopotamus is considered a separate species from the Hippopotamus. The Pygmy Blue Whale is considered a separate sub-species of Blue Whale. And there are many other examples. So why aren't human pygmies considered a different species or sub-species of Homo Sapiens? Is it because of political reasons or because of actual scientific reasons? ScienceApe (talk) 13:25, 4 June 2008 (UTC)[reply]

See Race (classification of human beings)#Race as subspecies. --Elliskev 15:07, 4 June 2008 (UTC)[reply]

Good link. In general the meanings of the terms "race" and "subspecies", while vague, mean something pretty similar. So to answer the original question - yes, you probably could call pygmies a subspecies, just as you could call Caucasians, or Maoris, or Koreans a subspecies. In general, though, I think the term "race" is used because it sounds more neutral. To me "subspecies of human" gives an implication of "subhuman" which is obviously worth avoiding politically. ~ mazca ^talk 16:58, 4 June 2008 (UTC)[reply]

You seem to be hung up on the term "pygmy". It is not a scientific term, neither when applied to hippos, whales, or humans. It is a name that just means "smaller". It does not denote whether anything labeled it is a different species or sub-species. Membership in a species is determined by a number of factors—no human groups have ever been found who were not of the same species. There has been a long discussion over whether it makes sense to consider human races forms of subspecies or variations, but in there the apparently static appearances of the races is quite deceptive, they are just probabilistic clusters of traits that on aggregate seem to be biologically real but have no distinct genetic basis (other than being said probabilistic clusters of traits—people from X area have a higher chance of having certain traits than people from Y area that is distant), and much of what we consider to be the differences are very superficial and are colored by social cues. --98.217.8.46 (talk) 15:30, 4 June 2008 (UTC)[reply]

Well, 98..., you have just described subspecies quite well (people from X area have a higher chance of having certain traits than people from Y area that is distant) in your attempt to prove the opposite. This is part of the problem of defining subspecies for any organism. Rmhermen (talk) 15:54, 4 June 2008 (UTC)[reply]

In my understanding of it, the definition of subspecies is considerably more complicated than that, and it is in those complexities that the whole problem of race as a subspecies falls apart. Human racial traits are clinal, which goes against the categorization of subspecies fairly strongly.--98.217.8.46 (talk) 17:39, 4 June 2008 (UTC)[reply]

And how do the African Pygmies not fall into the definition of a subspecies exactly? —Preceding unsigned comment added by ScienceApe (talk • contribs) 18:31, 4 June 2008 (UTC)[reply]

As yet another example of why not to get hung up on the name: the African pygmies were only called such as early as the 1860s[3], after the categorization of the Pygmy Hippos (1840s). This loose application of similar names to African peoples is tres' 19th-century, and it's interesting to note that the man who was responsible for giving a full description of the Pygmy Hippos to science was none other than notorious scientific racist Samuel George Morton. While I doubt Morton had anything to do with apply the term "Pygmy" to people, it's worth noting that he did think that human races were distinct species (despite the obvious evidence of ability to interbreed), and used it as a way to justify all sorts of things like Slavery. So just to reiterate: "is it because of political reasons or because of actual scientific reasons?" is not exactly the right question; questions about race and biology have long been both. --98.217.8.46 (talk) 15:40, 4 June 2008 (UTC)[reply]

That French word is properly très, in case you're interested; no apostrophe. —Tamfang (talk) 21:04, 4 June 2008 (UTC)[reply]

Possibly due to a relatively recent Population bottleneck approx 70,000 years ago (the cause is speculated to be the Toba catastrophe theory ), the human species is very similar genetically, more so than other animals with such a large population. This means on genetic grounds it is unlikely that any subsection of the human species will be genetically different enough to be regarded as a subspecies. Due to anthropomorphic bias we tend to regard differences in humans as more noticeable than differences in other animals. I.e. Most people find it far easier to tell the difference between 2 people than 2 snails. GameKeeper (talk) 19:52, 4 June 2008 (UTC)[reply]

Gigantic dogs and tiny dogs vary by a greater ratio in mass than larger and smaller races of humans, but the dogs are certainly of one species. Size and color do not necessarily imply speciation. Edison (talk) 21:44, 4 June 2008 (UTC)[reply]

Yes they are the same species, but they are regarded as different breeds, which means a domesticated subspecies. ScienceApe (talk) 23:40, 4 June 2008 (UTC)[reply]

Hi. Of course, there are claims that creatures such as Bigfoot and Orang pendek are seperate species of the Homo genus, but this has not yet been proven. Thanks. ~A H 1^(TCU) 22:34, 4 June 2008 (UTC)[reply]

Hi everyone! Hope am not adding to the confusion. Yes, of course apart from the fact that the "pygmy" in pygmy hippopotamus and pygmy whale are adjectives given to an originally "DIFFERENT" species, whereas "Pygmy" as applied to the human "race" is more like the original noun, another thing to consider is a relatively practical criterion for considering a group of animals as one species—that being they can successfully and naturally reproduce among themselves. So, this criterion would definitely apply to Pygmies as well as other named races. Regards. —KetanPanchal^taLK 17:11, 7 June 2008 (UTC)[reply]

Well, if that is so, the atomic family is a species ;-). Seriously, Pygmies are, of course, compatible with other groups of humans, and hence form a common species with them. --Stephan Schulz (talk) 17:28, 7 June 2008 (UTC)[reply]

The pygmy blue whale is not a different species. It is a different sub-species, akin to a race. ScienceApe (talk) 19:01, 8 June 2008 (UTC)[reply]

Baby seagulls

Can baby seagulls swim soon after hatching, like ducklings can? —Preceding unsigned comment added by 90.242.27.201 (talk) 14:00, 4 June 2008 (UTC)[reply]

Ducks generally nest on or very near the water, so it's quite necessary for ducklings to swim very early on. Conversely, seagulls generally nest on cliffs and crags a fair distance from the water and the chicks stay in the nest for longer, so I don't think it's likely that the babies need to swim soon after hatching. My guess would be that they gain swimming capabilities about the time they fledge and fly out of the nest, because they are unlikely to encounter the water much before then. I'm not sure, though. ~ mazca ^talk 14:40, 4 June 2008 (UTC)[reply]

If the nest is near water, gull chicks do sometimes swim (well, it's really more like splashing around and paddling a bit) in the days before they fledge, once most of their feathers have grown through. Newly hatched babies seldom leave the safety of snuggling beneath the mother gull (though if they try to scramble out of the nest, she picks them up and puts them back under anyway), though they can run within hours of hatching if the need arises. --Kurt Shaped Box (talk) 20:38, 4 June 2008 (UTC)[reply]

Escaping from a falling plane that is going to crash

I was on a plane the other day and I always wondered that if a plane is going to crash, yet I am still high enough in the air to parachute down, would I survive? How would you survive, if it is possible? I know now that there are security restrictions on actually bring a parachute pack with you on the plane nowadays. But, if you could, what would you bring so that you can literally jump out of a jumbo jet and survive? Also what part of the plane would have to jump from to survive? --Vincebosma (talk) 15:10, 4 June 2008 (UTC)[reply]

Certainly you could do it with a pressure suit and parachute, because Joseph Kittinger did it from over 100,000 feet. But I don't know what altitude you can safely jump from with a parachute but without a pressure suit. Vesna Vulović survived a fall from 33,000 feet with no suit or parachute, but that's rare. This site says you can jump from near 30,000 feet with just a parachute and an oxygen bottle, but I don't know how reliable it is. --Allen (talk) 15:56, 4 June 2008 (UTC)[reply]

With an airliner, there's also a very real question of how you're going to safely bail out. D. B. Cooper exited his craft via a tail hatch, but that's an uncommon feature these days, and present-day exits (forward hatches, over-wing windows) aren't designed to let an occupant jump while avoiding wings and engines. — Lomn 16:33, 4 June 2008 (UTC)[reply]

In fact, the Boeing 727 tail hatch that Cooper used was modified after the hijacking and a number of similar events, to keep the hatch locked in flight so no one could do that again (see Cooper vane). --Anonymous, 20:57 UTC, June 4, 2008.

It is not known for certain whether D.B. Cooper survived or not, but it is believed that he did not. 69.140.152.55 (talk) 22:08, 5 June 2008 (UTC)[reply]

Furthermore, if you're high enough (like 35,000 feet or so), and you have only the clothing you normally wear on an airliner plus a parachute, you're probably more at risk of freezing to death (or at least suffering severe frostbite, losing limbs, ears, nose, etc.) if you did get out safely. ~Amatulić (talk) 17:24, 4 June 2008 (UTC)[reply]

Finally, there is the issue of getting out of the plane. Passengers are not allowed to open the hatches - even if the plane is crashing. So, you'll have to fight your way through the flight crew as well as all passengers that think you are trying to blow up the plane somehow by opening a hatch in flight. -- kainaw ™ 18:32, 4 June 2008 (UTC)[reply]

Well, if the plane is already crashing -- that is to say, in a clear dive towards the ground -- I doubt anyone is going to be all that concerned about someone trying to blow up the plane or even paying all that much attention to individual passengers (though it's certainly true that navigating your way to a hatch in the ensuing chaos is likely to be challenging). But the real problem is that you literally cannot open the doors of a modern airliner while in flight, at least not if it's properly intact, because the pressure within the airplane cabin is greater than the air pressure outside. The doors in airliners have to be pulled inwards, towards the cabin, before they can be opened, but because the air inside the cabin is pushing against the door, it can't be done -- it'd take far more strength than any human or even several humans possesses to do it. (According to this Straight Dope article, in order to open an inward-opening hatch on the plane, you'd need to exert the equivalent of a metric ton of pressure on the door to yank it open.) Still, for the sake of argument... if we were to assume that the plane was low enough (but not too low), broke up in flight and you were to get out of through the new hole in the fuselage while wearing a parachute... well, with some luck, sure, you could survive, provided you didn't get hit by a piece of the fuselage or anything and kept your head. Still, I wouldn't like to bet on it. -- Captain Disdain (talk) 20:04, 4 June 2008 (UTC)[reply]

Hi. Remember however, that if you parachute into a thunderstorm, you are unlikely to survive. The only person ever to survive this was Lt. Col. William Rankin, who apparently does not have an article yet so I'll try and create one later. Hope this helps. Thanks. ~A H 1^(TCU) 22:27, 4 June 2008 (UTC)[reply]

You might like reading this amusing and practical guide. --Sean 22:46, 5 June 2008 (UTC)[reply]

Electric Motors

Domestic electric fans

How it works with a rotor where no electricity is supplied ?
What is the function of a capacitor attached to the fan?Practically it boosts the efficiency of the motor.
Since a generator is the reverse of a motor, it should be possible to generate current from a domestic AC exhaust fan by keeping it exposed to air flow. In that case the current so generated will be AC or DC? What will be the function of the capacitor of a motor in case the same is used as a generator?
It is mentioned that aluminium winding is more efficient than copper. But I have never seen aluminium winding wires being used by professionals. Rather copper wire is seen used by them, Why? —Preceding unsigned comment added by Santoshkumardessai (talk • contribs) 15:31, 4 June 2008 (UTC)[reply]

To get you started, you could read things like electric motor, electric generator and aluminum wiring. Friday (talk) 15:37, 4 June 2008 (UTC)[reply]

Induction motor will also be appropriate for learning about the type of motor used in most mains-powered fans.

Atlant (talk) 19:37, 4 June 2008 (UTC)[reply]

The aluminum wiring article linked to by Friday is concerned with grid and building wiring. Aluminum started to become popular in the 1960s when the then Rhodesia led by Ian Smith was under international sanctions. At the time, Rhodesia was the worlds major source of copper and prices went through the roof, even getting into the same bracket as silver at one time. Not sure if this is the same reason for aluminums use in motor windings though, the OP mentioned improved efficiency. Perhaps there is a weight saving, but it is certainly not a very common thing to do. SpinningSpark 20:12, 4 June 2008 (UTC)[reply]

At first blush it would seem like a fan motor should generate electricity when the wind spins it. But from childhood experimenting with one, my impression is that it does not have a functioning field current adequate to produce much output voltage. External excitation might be needed in addition to high speed rotation of the shaft. There is also the fact that when powered it spins far faster than is likely to be achieved when you attempt to make it a generator from normal amounts of air flow. Edison (talk) 21:37, 4 June 2008 (UTC)[reply]

We do have an all-too-brief article on Induction generators. And yes, they need an external source of electrical power to begin working, although with the right load impedance they'll keep themselves powered-up after that. Essentially, just as an induction motor converts electrical power to mechanical power as the rotor slips backwards against the rotating field, an induction generator converts mechanical power to electrical power as the rotor slips forwards against the rotating field.

Atlant (talk) 11:24, 5 June 2008 (UTC)[reply]

I'm speculating here on motor windings, but since aluminum has much less power density than copper, I'm thinking that the windings would have to be that much bigger, therefore a less-efficient motor would result. The weight saving is only a factor in starting the motor, not in running it, and the cost saving in materials would be offset by the larger motor casing and reduced motor efficiency. Franamax (talk) 22:52, 4 June 2008 (UTC)[reply]

This motor manufacturer would appear to agree with you on the efficiency issue. SpinningSpark 01:55, 5 June 2008 (UTC)[reply]

Ants smell

Here's a thought I have: if we could shrink to the size of an ant, so that the ant was as big as a dog to us, what would it smell like? I know that ants have pheremones, but I'm not sure if these are something a human would smell. Would the ant smell like dirt, since it lives in the dirt? Would it be really stinky? I also heard somewhere that some ants grow fungus. Jonathan ^talk 17:04, 4 June 2008 (UTC)[reply]

I guess a giant ant (OK, a regular ant where we were tiny) would smell like a whole mess of normal ants do to us at our present size. Formic acid seems to pretty much override any other smell. --Milkbreath (talk) 17:18, 4 June 2008 (UTC)[reply]

If you retained your human sense of smell, you likely wouldn't ever pick up on the pheromones anyway. ~Amatulić (talk) 17:20, 4 June 2008 (UTC)[reply]

Surely the ant would still be releasing the same amount of pheromone and your nose would be the same sensitivity it is now I would have thought (assuming your cells are shrunk with you) so i'm pretty sure it'd be no different. Regards, CycloneNimrod ^talk?_contribs? 18:13, 4 June 2008 (UTC)[reply]

So humans can't smell pheromones? That's what I was wondering Jonathan ^talk 16:01, 5 June 2008 (UTC)[reply]

Humans can smell some animal pheromones. For example, (±)-2-sec-butyl-4,5-dihydrothiazole and 6-hydroxy-6-methyl-3-heptanone are both mouse pheromones. They also have a distinct smell. However, while we humans have the ability to detect the odors of pheromones via our olfactory epithelium, we do not have the ability to detect the active pheromones themselves (because we don't have a vomeronasal organ). Rockpocket 20:18, 5 June 2008 (UTC)[reply]

The fungus growing ants are the Leafcutter ants SpinningSpark 19:56, 4 June 2008 (UTC)[reply]

Yeah, I definately agree, they would probably smell about the same that a whole bunch of ants do at normal size :) Do some ants really smell like formic acid? I live with pavement ants and I never notice any formic acid smell. Jonathan ^talk 16:01, 5 June 2008 (UTC)[reply]

Make yourself an ant farm. We used to just dig up an anthill, dump it all in an old pickle jar, and wrap it in black construction paper. Let them get situated and take a whiff. --Milkbreath (talk) 16:28, 5 June 2008 (UTC)[reply]

According to the formic acid article, "As early as the 15th century, some alchemists and naturalists were aware that ant hills gave off an acidic vapor." D0762 (talk) 16:52, 5 June 2008 (UTC)[reply]

Not all ants produce formic acid but plenty do, it does have a very distinct whiff that a human can easily smell by sniffing a suitable nest (without miniaturization!) . I have occasionally detected the smell of a nest before actually seeing it. As to whether a human could detect the ant pheromones, that is a tough one. I am sure certain ones would be detectable but millions of years as a eusocial animal which communicates with pheromones means that ant's pheromones are likely extremely subtle . I would expect these subtleties to avoid even a shrunk person GameKeeper (talk) 22:44, 5 June 2008 (UTC)[reply]

I don't see what difference size would make at all. Smell is based on two things: the composition of the air and the receptors an organism has. If you shrink, you aren't changing either of these factors: your nose is the same albeit smaller, and the composition of the air would stay the same. Maybe the difference would be that you were closer to the ground, where ants lay pheromone trails? But I mean, you could just as easily get on your hands and knees and sniff. --Shaggorama (talk) 15:24, 7 June 2008 (UTC)[reply]

Lidocaine and a couple of other questions

I work in a hospital and onje day I was in the prep room next to the building exit and there was a 100mg in 5ml vial of lidocaine sitting. How dangerous would that have been had it been taken, what could it to if injected intravenously, rubbed topically etc? There was also a 200mg in 10ml of acetylcysteine. Same question applies.

Also, there is much saline and sterile water lying around which might be confused for drugs in an admissions ward. Before I say anything to ward staff I would like to know the dangers of all these things. 92.0.228.141 (talk) 19:36, 4 June 2008 (UTC)[reply]

This is a medical question and so will not be answered here. --BenBurch (talk) 19:50, 4 June 2008 (UTC)[reply]

I want ACTUALLY asking for medical advice, I was just asking what the dangers would be of such a matter. There are many people admitted to the ward with overdoses etc and have to pass the often unattended toom to go out to smoke. I just wondered what could happen to the patient and things before I consider reporting it to staff if it isn't really a big deal 92.0.228.141 (talk) 20:00, 4 June 2008 (UTC)[reply]

Ben they're not asking for any advice, they're just curious. Well, lidocaine should give you an insight into what the drug actually is and you'll soon find little damage could be caused unless you put it somewhere it wasn't supposed to go e.g. stabbing it into someones eye. Topical application e.g. rubbing, however, wouldn't really do much harm at all.

As for acetylcysteine, again read the article first. It's used for various purposes e.g. reversing paracetamol overdoses, mucolytic therapy and also has kidney-protective uses. Insensible use of the drug therefore must have side effects, no idea what though. It also has to be stated about the possible toxicity of acetylcysteine. Read the article for more info. Regards, CycloneNimrod ^talk?_contribs? 20:23, 4 June 2008 (UTC)[reply]

Oh and don't worry about the saline or sterile water, they're not dangerous at all really. Regards, CycloneNimrod ^talk?_contribs? 20:25, 4 June 2008 (UTC)[reply]

As for lidocaine/lignocaine the amount needed to overdose (IV route) is very high. At least 9 vials of the type you specify. Topical application is harmless: it numbs you, full stop. Same goes for n-acetylcysteine, the biggest risk is that somebody will spill the drugs and slip on the wet floor. (Not as trivial a concern as it may seem). Fribbler (talk) 20:29, 4 June 2008 (UTC)[reply]

thanks for the help guys. COuldn't the lidocaine cause problems if injected? Like how far would it travel in the veins? I don't know a lot about pharmacology I#m afraid. And rubbing a vial on an area would numb it? Heh.. sounds wierd. Thanks though. What does "not dangerous at all really" in regards to the saline and water. I know they are technically harmless but what does THAT mean? 92.0.228.141 (talk) 20:40, 4 June 2008 (UTC)[reply]

Lidocaine causes trouble if injected in large quantities, as my external link explains. Water and saline are technically harmless? Translation: Don't drill a hole in your head and pour them in, don't drink 758 litres of them in one sitting, don't pour them into an electrical outlet..... :-) We just like to be careful. Everything is dangerous if misused. Fribbler (talk) 20:47, 4 June 2008 (UTC)[reply]

Wow, this has really got my inqusitiveness working. I mean how much of someone's arm/body would go numb from injecting it or rubbing it on? 92.0.228.141 (talk) 21:15, 4 June 2008 (UTC)[reply]

If it's injected subcutaneously then only a very small area is affected. Quite obviously a topical dosage will affect only the area it's applied to. As for IV, that's a little more complicated. It's all dependent upon the dosage really. Regards, CycloneNimrod ^talk?_contribs? 22:32, 4 June 2008 (UTC)[reply]

Ligno/Lidocaine is usually (but not by any means always) given with adrenaline, a vasoconstrictor that makes certain it won't travel too far to, lets say, affect the heart. Fribbler (talk) 22:49, 4 June 2008 (UTC)[reply]

True, the exception being when it's used to treat heart defects, particularly arrhythmias. Regards, CycloneNimrod ^talk?_contribs? 23:24, 4 June 2008 (UTC)[reply]

Naturally, as an antiarrhythmic, you want it to get to the heart of the matter :-) Fribbler (talk) 23:27, 4 June 2008 (UTC)[reply]

My personal feeling on this is that any unsecured materials are a concern, as they are a possible indication of carelessness on the part of the hospital staff, i.e. tomorrow it could be something more dangerous. If there is anything that could be casually stolen by someone walking by to go for a smoke, it's worth a call to the Director of Nursing, what harm will that do? Of course, they might just close the smoking area ;) Franamax (talk) 22:44, 4 June 2008 (UTC)[reply]

I couldn't agree more. Regards, CycloneNimrod ^talk?_contribs? 23:24, 4 June 2008 (UTC)[reply]

Thanks guys. I mean, as a member of staff in the prep room I see them lying about, but I don't know how accessible it would be to a patient. I am sure if the Sister on the ward had any knowledge of it it would be a different matter as she is the one who is answerable to the drugs. It's just a bit worrying. I don't know if I could say to the director as I have no idea who she is but it is something I will mention to the sister if I see it happen again. —Preceding unsigned comment added by 92.0.228.141 (talk) 18:28, 5 June 2008 (UTC)[reply]

Dust from old books

While scanning books in my denomination's archives, I've noticed that some old notebooks (the oldest of which was first used in 1893, and the newest in 1916) leave some reddish-brown (I'd guess; I'm partially redgreen colorblind) dust on the scanner and on my clothes, which is rather difficult to brush off. The dust is obviously coming off of the binding. Can anyone tell me what it is, and/or how we can handle the books so that as little as possible comes off? Nyttend (talk) 19:58, 4 June 2008 (UTC)[reply]

By the way, I don't see any publication information, but the books were used by a group of churches that were mostly located in Kansas, so I'd guess that they were bought in the area. Nyttend (talk) 20:06, 4 June 2008 (UTC)[reply]

Are the notebooks bound, wholly or in part, in leather? If so, this is probably the result of red rot. Unfortunately, nothing much can be done about it. Deor (talk) 20:21, 4 June 2008 (UTC)[reply]

The bindings seem to be leather. Thanks for the link: it seems to describe it quite well, especially the idea of the powdering and the feltlike consistency. I guess this is the reason I'm employed: we want to have the books digitized so that the records aren't lost. Nyttend (talk) 20:30, 4 June 2008 (UTC)[reply]

Just to follow up … Here's a page from the British National Archives on the problem; and here's an article by someone who claims to have a treatment. The treatment doesn't look likely to solve the underlying problem, but it may inhibit the powdering off of the leather when the volumes are handled. Deor (talk) 20:55, 4 June 2008 (UTC)[reply]

Why electricity 60Hz in some countries and 50Hz in other?

Why are there different electricity frequencies? Why not fewer? Why not others (a metric 100Hz, etc)? --70.167.58.6 (talk) 20:49, 4 June 2008 (UTC)[reply]

It's the usual reason that these things arise. People and companies working in different places made different decisions; by the time it became clear that this was becoming an important business and a single worldwide standard would be desirable, existing practice in different areas was too well entrenched; and the important companies whose choices had become the local standard weren't interested in changing their products to be compatible with someone else's from another country.

Lower frequencies are more efficient with certain types of motors used on heavy equipment and allow for more efficient power transmission; higher frequencies allow transformers to be built more lightly and reduce flicker in lighting supplies. Frequencies around 50-60 Hz turned out to be a suitable tradeoff point between these issues, but there have been large installations using lower frequencies from 15 to 25 Hz for industrial or railway use, and some of them still exist. (And in some areas these frequences have been in households, too -- Toronto was converted from 25 to 60 Hz power only about 50 years ago). As to higher frequencies, 400 Hz is used (I'm not sure how commonly) in aircraft electrical systems, and 20,000 Hz on the space shuttle.

See utility frequency. --Anonymous, 21:11 UTC, June 4, 2008.

Nuclear weapons underground (forgot to give this a title, sorry)

Well, I'm stumbling through this previously unknown Wikipedia section, and I already asked this somewhere else. Apologies. This appears to be the right place. I am writing a novel, and cannot find anything to help me out. A cache of nuclear weapons, simultaneously detonated a mile undergroung would produce what effect? Keeping in mind the necessary piping, elevators, and whatnot involved in a project that far down, what could I expect on the top, in regards to blast force, nuclear fallout, earthquakes and eruptions...

Thanks!! —Preceding unsigned comment added by 12.201.115.120 (talk) 22:08, 4 June 2008 (UTC)[reply]

Underground nuclear testing should give a good start. Bear in mind that it won't be all that dramatic except for (1) the immediate area and (2) the political fallout (other places will detect the explosion via seismometers, even if calling it an "earthquake" is exaggerating). — Lomn 22:19, 4 June 2008 (UTC)[reply]

If the site was badly planned, there could be radioactive venting to the surface, which has happened in the past. Other than that, triggering a nuke right at a fault could possibly trigger a major earthquake, there's always the possibility of groundwater contamination, releasing the cap on a high-pressure natural gas reservoir. But hey, aren't you the one with the vivid imagination? ;) Franamax (talk) 22:30, 4 June 2008 (UTC)[reply]

Also, when you say an underground cache detonated simultaneously, keep in mind it has to be very, very simultaneous, a difference of milliseconds will result in the first nuke just blowing the other ones into vapour. Getting the right neutron density and critical mass is tricky business to trigger even a single nuclear detonation. Franamax (talk) 22:36, 4 June 2008 (UTC)[reply]

I agree that there would be fratricide; the first one to detonate would so disrupt others in the same room or in compartments nearby, that they would not produce a nuclear blast of any appreciable magnitude. Their high explosive components might detonate, but the additional band would be negligible in addition to the nuke. Detonating one nuke in an underground cache would be remarkably like the result of an attempt to detonate many in the cache. Not at all like a room full of conventional bombs. If the explosion vented to the atmosphere, the additional fissionable material would add to the radioactive contamination of the area. Edison (talk) 23:41, 4 June 2008 (UTC)[reply]

It is also likely that they would need to go off deliberately, it is very hard to accidentally detonate a nuclear weapon, due to the huge amounts of safeguards in them. It would be impossible to accidentally set off an entire cache. Prodego ^talk 03:20, 5 June 2008 (UTC)[reply]

I agree. A nuclear weapon is a surprisingly robust and fragile device in many ways. It is far easier to make one not work than to initiate one by accident. The explosive initiator in a warhead must detonate precisely; an outside explosion would in all likelihood impair the explosion. The first device would destroy the second, and the materials would be vaporized; if open to the atmosphere, it would create a secondary "dirty bomb" effect, but I have no idea how much. As far as earthquakes and the like: there would be a lot dependent on the structure of the earth, but I find it unlikely unless it were directly on a fault line. This plot sounds similar to that of Superman and of Space: 1999, both of which were unrealistic. --—— Gadget850 (Ed) ^talk - 10:40, 5 June 2008 (UTC)[reply]

One thing to keep in mind is that most currently fields US nukes are at most in the few hundred kilotons. That isn't all that much from a raw yield point of view (though it is considerably larger than the nukes used against Hiroshima and Nagasaki). How much is this "cache" going to have? What I'm getting at is that even if they did all go off, it would only be a few megatons in yield. I'm not sure but I believe the highest yield underground tests were conducted at Amchitka (around 5 Mt of yield in the Cannikin test). There were discussions about possibly triggering earthquakes, and it may have triggered some very light seismic activity, but nothing major.

For me the entire idea of a "cache of nuclear weapons" being stored in some deep underground vault is not very plausible. To my knowledge nuclear weapons are stored fairly on the surface in locked bunkers. If they were underground, they would not be in seismically active areas—not because of a worry that they'd trigger earthquakes, but because nuclear weapons are expensive and the risk of them being damaged by naturally occurring earthquakes would be too high. --98.217.8.46 (talk) 15:01, 5 June 2008 (UTC)[reply]

I agree with other comments that only the first nuke will detonate and destroy the others, unless they are very elaborately and intentionally timed to detonate at the same time, and even then it's questionable since there is so little room for error. Unlike nuclear test sites, the storage room sounds like it was not built to contain a detonation, as you describe elevators and piping going up to the surface. These would act as a chimmney for the rapidly expanding gas and vaporized rock. At a mile below the surface, the cache seems deep enough not to produce a crater, but you have to consider the yield of the bomb(s) and the composition of the earth above it. If it's loose enough dirt and a strong enough bomb, you could see a subsidence crater around it as the surface rock loses support from below; near the center of the crater is the chimney through which some of the ejecta managed to escape. This could go up thousands of feet, but would be much thinner than the mushroom clouds we've seen in pictures, due to the narrower orifice of the escaping gas. I'm not sure if you would see a mushroom shape to the cloud, but I don't see why not. Fletcher (talk) 18:27, 5 June 2008 (UTC)[reply]

If the fireball itself is wholly contained underground you should not get a mushroom cloud. The mushroom cloud of most nukes is caused by the rising of the heated fireball. (See mushroom cloud for full description.) If there was a significant disruption of the heated matter/gas rising then you'd get a real strange looking cloud, not a neat mushroom cloud. Look at how unpleasant the cloud can be if the bomb is hindered by something as simple as being enclosed in a ship: [4]. --98.217.8.46 (talk) 21:39, 5 June 2008 (UTC)[reply]

Good point. That was a funky looking cloud. Fletcher (talk) 14:00, 6 June 2008 (UTC)[reply]