Wikipedia:Reference desk/Archives/Science/2013 March 7

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March 7

could you compare a hot air balloon with a plane and helicopter?

Let's say we want something to get to 10,000 feet from ground while expending as little energy as possible. Three ways of doing it are: the something is a plane. The something is a helicopter. The something is a hot-air balloon. All of these require energy to get up to their heights. Can you give me an idea of how these energies compare? (for the same weight). I would think that the hot-air version is least efficient as you are basically heating a huge volume of air. But then again you only do it ONCE and then just "float" up. Whereas the other two require continual energy even to just maintain level flight. Still, how do these three compare in terms of total energy required to lift to 5000 feet from ground? 91.120.48.242 (talk) 07:46, 7 March 2013 (UTC)

I think the answer will depend on whether "for the same weight" means "for the same total weight" or "for the same payload". Lifting the total weight of a small plane or helicopter using a hot air balloon sounds quite inefficient (hand waving theoretical justification: considered as a heat engine, the operating temperature of the balloon is lower than the plane or helipcopter engine so its theoretical maximum efficiency is lower). But for the same payload (say five people), the balloon could be more efficent because it has no heavy engines/wings/rotors. Gandalf61 (talk) 09:19, 7 March 2013 (UTC)

Could you be a bit more precise or explain your reasoning further? In particular I don't understand your argument about "the operating temperature of the balloon is lower than the plane or helipcopter engine so its theoretical maximum efficiency is lower". What does the plane or helicopter have in its favor?

Also, is there some theoretical argument to be made about kinetic energy here? I can imagine some kind of theoretical proof that heating the air around an object and encapsulating it is guaranteed to be the most efficient use of those joules of power. On the other hand, I can imagine that there is a theoretical argument to be made based on air resistance (how lift is generated). Any ideas? 91.120.48.242 (talk) 10:20, 7 March 2013 (UTC)

See heat engine, fuel economy in aircraft, aerodynamic drag and drag coefficient. I don't think there is going to be a clear cut answer. If this is a homework question then the point of it is probably to see how many different arguments and variable factors you can come up with, to show that you understand the complexities that may lie behind an apparently simple question. Gandalf61 (talk)

The wiki article suggests a hot air balloon will mass 3.5 tonnes for 5 passengers. That surprised me. So perhaps you could do your calculations based on 5 people as a payload. FWIW the helicopter will almost certainly be the worst possible choice, and I have a suspicion that rather expensive aircraft might be the best. Greglocock (talk) 22:41, 7 March 2013 (UTC)

The answer (not one of the choices given) is almost certainly the glider. It needs a tow to get off the ground, but after that there is no energy expenditure at all. It only relies on the pilot's ability to find suitable thermals to get to height. SpinningSpark 23:11, 7 March 2013 (UTC)

I strongly disagree. You're conveniently ignoring the energy cost of towing the glider to an altitude high enough to be able to reach the first thermal before it hits the ground again. That's most definitely not a zero energy cost! The (powered) airplane, the helicopter and the hot-air balloon can (and will) benefit from those very same thermals. As a practical issue, navigating the hot air balloon to get to where they are might not be possible...and a high speed fixed wing aircraft might have trouble staying inside the thermal - but a powered airplane could be designed to be just as good at catching thermals as the glider, yet get into the air more efficiently than your gliders' towing system can.

Location matters though. If you were starting the experiment near to the base of a 10,000 foot tall mountain - on the side where the wind is blowing gently up-slope - then a hang-glider could probably make it to the top without a tow, using slope-lift and truly zero energy. But if you're on a flat, featureless, windless, uniform surface (hence no thermals and no slope-lift) then your best bet is probably the fixed wing aircraft. If you're on a flat surface and there is plenty of wind - then maybe a kite is what you need?

I suspect that a rocket would be the best option. According to rocket engine, chemical rockets can be 60% efficient...that's better than either jet or piston engines. Also, a fixed-wing aircraft has massive drag due to those big wings - the rocket can be designed to be almost any shape you like - so it can be aerodynamically optimal. Fixed-wing aircraft have to travel quickly in the horizontal direction in order to get enough lift to gain altitude - so they need to spend more time getting to altitude than the rocket does - and therefore they expend more energy overcoming drag and gravity.

Calculating "energy costs" is tricky though. An airplane is re-usable, but the rocket probably isn't...so do we include the construction costs into the calculation? If we don't then we can use a hydrogen balloon...the hydrogen "cost" is a part of the construction cost - but if that's not included then this technology can do the job at zero energy cost. Sadly, you either have to throw away some of the hydrogen at altitude in order to get back down again - or you have to expend energy in some other way to get back down...so unless this is a one-shot mission, then that's another consideration.

Without tighter rules, this debate can get silly. Suppose we put the payload onto a large spring so it's flung into the air with enough speed to get to 10,000 feet. The energy cost is now that of compressing the spring. We can do that using a very slow, highly geared solar powered motor that takes an entire year to slowly compress the spring. If the glider is allowed to get "free energy" from thermals, then my spring launcher can certainly get "free energy" from sunlight. What's more, since my payload is the only thing I have to get to 10,000 feet - I don't have to waste energy launching some kind of vehicle along with it. For some payloads, this makes a lot of sense.

SteveBaker (talk) 13:59, 8 March 2013 (UTC)

A good glider pilot can make use of the thermal rising from a plowed field. That won't get you much height, but it can you enough to get somewhere else. I'm not saying you can get to 10,000 feet from a low height in every circumstance, but an experienced pilot has at least a possibility of doing it, even starting from a flat landscape. SpinningSpark 18:54, 8 March 2013 (UTC)

OP here. Thanks for the response guys :) You guys went off in your own direction, which is fine and interesting, but actually only prompted by my "topic-setting" sentence which seemed general. The rest of my comment mentioned in specific the three things I was interested in comparing the theoretical energy requirements of: a hot-air balloon, an airplane, and a helicopter. Perhaps we can add that the hot-air balloon is assumed to be inflated by ambient-temperature air at ground. So while of course a helium balloon can get there for "free", and so can a glider riding thermals, what I'm really interested in is helicopter and airplane craft "powered" by an engine versus using those joules simply to heat a balloon. I agree that perhaps there are no clear-cut or theoretical arguments to be made here. I was hoping some argument about air density at different temperatures, versus a coefficient of friction argument about air, could be combined to come to a theoretical proof that of the three proposed things we are comparing, one has a better theoretical limit. 86.101.32.82 (talk) 11:55, 9 March 2013 (UTC)

Mean from a wavefunction

Thanks for your help with the previous question. Now I would like to prove this identity:

$\int _{-\infty }^{\infty }p|{\tilde {\Psi }}(p)|^{2}dp=\int _{-\infty }^{\infty }\Psi ^{*}(x)(-ih{\frac {\partial }{\partial x}})\Psi (x)dx$

Working

$\int _{-\infty }^{\infty }p|{\tilde {\Psi }}(p)|^{2}dp$

$=\int _{-\infty }^{\infty }p\left|{\frac {1}{\sqrt {2\pi h}}}\int _{-\infty }^{\infty }\Psi (x)e^{-ipx/h}dx\right|^{2}dp$

$=\int _{-\infty }^{\infty }p{\frac {1}{2\pi h}}\left|\int _{-\infty }^{\infty }\Psi (x)e^{-ipx/h}dx\right|^{2}dp$

$=\int _{-\infty }^{\infty }p{\frac {1}{2\pi h}}\left(\int _{-\infty }^{\infty }\Psi (x)e^{-ipx/h}dx\right)\left(\int _{-\infty }^{\infty }\Psi (x)e^{-ipx/h}dx\right)^{*}dp$

$=\int _{-\infty }^{\infty }p{\frac {1}{2\pi h}}\left(\int _{-\infty }^{\infty }\Psi (x)e^{-ipx/h}dx\right)\left(\int _{-\infty }^{\infty }\Psi ^{*}(x)e^{ipx/h}dx\right)dp$

$=\int _{-\infty }^{\infty }p{\frac {1}{2\pi h}}\left(\int _{-\infty }^{\infty }\int _{-\infty }^{\infty }\Psi (x)\Psi ^{*}(y)e^{-ip(x-y)/h}dxdy\right)dp$

$={\frac {1}{2\pi h}}\int _{-\infty }^{\infty }\int _{-\infty }^{\infty }\int _{-\infty }^{\infty }p\Psi (x)\Psi ^{*}(y)e^{-ip(x-y)/h}dpdxdy$

But, the inner integral does not converge ! ! !

150.203.115.98 (talk) 10:46, 7 March 2013 (UTC)

Shouldn't this be at Wikipedia:Reference desk/Mathematics? --Guy Macon (talk) 12:10, 7 March 2013 (UTC)

That inner integral is the Dirac delta function; if you want a more rigorous derivation that avoids invoking the delta function, you have to use (and prove) the fact that transforming to momentum space and back is a unitary tranform. In general:

<psi|A|psi> = <psi|U-dagger U|A|U-dagger U|psi>

for U some arbitrary unitary transform. U-dagger denotes the Hermitian conjugate (which is equal to the inverse of U because U is unitary). Then the state |psi> transformed under U is |psi'>= U|psi>, and thus <psi'| = <psi|U-dagger, and the transformed operator A is

A' = U|A|U-dagger, so we indeed have:

<psi|A|psi> = <psi'|A'|psi'>

In your problem the momentum operator p = -ihbar d/dx is diagonal in the momentum representation, so you can take it out of the Dirac brakets. Count Iblis (talk) 12:58, 7 March 2013 (UTC)

How is the inner integral a dirac delta function? 150.203.115.98 (talk) 13:49, 7 March 2013 (UTC)

It's the derivative of the Dirac delta; to see this, differentiate the integral identity for the Dirac delta w.r.t. its argument. Count Iblis (talk) 15:44, 7 March 2013 (UTC)

Are you sure? I thought $\delta (y-x)={\frac {1}{2\pi }}\int _{-\infty }^{\infty }e^{ip(y-x)}dp$. This one is ${\frac {1}{2\pi }}\int _{-\infty }^{\infty }pe^{ip(y-x)}dp$. 150.203.115.98 (talk) 16:10, 7 March 2013 (UTC)

Yes, the derivative of the delta. So, if you put z = x-y and differentiate both sides w.r.t. z, and move the derivative under the integration sign, you'll get a factor p in the integrand as a result fo taking that derivative. Count Iblis (talk) 16:30, 7 March 2013 (UTC)

And then you would have to make a integration by parts to move the derivative over to one of the PSI functions and finally use the delta function to get rid of one of the outside integrations completing the desired proof. The only thing to keep in mind is that some of the steps of this proof need to be further explained (if you care for mathematical rigor), specially the reversal of the order os derivative and integration mentioned by the Count in his last post. A rigorous proof requires special treatment for the delta function because it is not a normal kind of function. Dauto (talk) 17:17, 7 March 2013 (UTC)

Hydrogen solubility in copper

What is the hydrogen solubility in alpha-copper at 100 kPa and 25 °C? Values should be stable up to 50 MPa. Plasmic Physics (talk) 12:32, 7 March 2013 (UTC)

Growth between 18 and 24

Do any significant changes or growth occur between 18 and 24 years of age? Most people can't tell the age differences in this age group. — Preceding unsigned comment added by Clover345 (talk • contribs) 13:05, 7 March 2013 (UTC)

We've had a previous instance of a similar question here. Have a look at the links there and get back to us if you need further. --TammyMoet (talk) 13:12, 7 March 2013 (UTC)

−

thanks. Do you think these statistics change though. Most people think that young people looked older 20 years ago. Why is this? Clover345 (talk) 13:36, 7 March 2013 (UTC)

Well, we know that the onset of puberty has shifted (at least in developed countries) over the last 200 years, and we know that average human height changes with respect to environmental conditions and the like, so yes, these statistics can certainly change. As for "people looking older": that's highly subjective and speculative, and I doubt we can verify it, much less meaningfully extrapolate to "why". — Lomn 14:14, 7 March 2013 (UTC)

“Most people think that young people looked older 20 years ago.” I think every generation has this perception. Looking through my family photograph albums, people clearly tend to stay with the clothes, hairstyles and social etiquette they became accustomed to in their younger years – thus that style become thought of as looking mature by the later generation. Actors and actresses often dress in the latest styles for the reason that it makes them (they think) look younger and use modern jargon. I've noticed on some recent American films (if you can call 1990 recent), such as the Memphis_Belle_(film), that the director and makeup artists went to lengths, to have the actors playing the air crew, appear to conform to image of modern youths of that age – to emphasis just how young the original crew of the Memphis Bell really were. It is more striking when you look at World War II RAF officers with their short-back-and-side haircuts, neatly trimmed moustaches and panache for voicing understatements. So it is not really a perception of 'older in age' but recognition of older cultural values. --Aspro (talk) 15:06, 7 March 2013 (UTC)

There are real differences though which may make new generations look relatively younger. Decreased tobacco, alcohol, and other drug use, decreased time working as youths/increased time spent in school, decreased time in the sun, higher sunscreen use, decreased manual labour, better hygiene, and better diets, can all increase youthfulness. I think many of these things are working to make newer generations appear younger, minus those who use tanning beds to an extreme and those who are overweight. 70.48.212.115 (talk) 16:01, 8 March 2013 (UTC)

Unfortunately the answer offered to that September question is astonishingly bad. The answerer clearly did not know what he was talking about and did not read the relevant article: puberty clearly says there is a relationship between timing of puberty and completion of growth because both are dependent on several years of estrogen and androgen. Aspro is closer than Lomn to answering this current question, in the sense that perception of age of young adults is more influenced by clothing and hairstyles than by actual earlier pubertal onset. The degree of earlier puberty in this century is much smaller than popularly supposed. The late changes of puberty have not changed as much as the early changes. Surveys of boys and girls suggest menarche is occurring perhaps 3 mos earlier now than in the late 1960s, but thelarche may be occurring as much as 1-2 years earlier. The nature of the widening gap in uncertain; one possible explanation is that the early changes come from environmental estrogens and are not true puberty, which has been only slightly hastened. The phenomenon in boys is even smaller. Progression and timing of late stages of puberty do not seem to have changed much in the last 50 years. On average maximum adult height is reached at average ages of about 15 and 18 y for girls and boys (wide individual variation of course). The outward changes of facial appearance in late teens and early twenties that serve as age cues to us involve thickening of the skin, recession of the frontal hairline, slight thinning of the hair in both sexes, but increasing facial hair, especially in men. Men's beards continue to get heavier throughout this period-- but again with large inter-ethnic and inter-individual variation. Men also continue to have some increase in shoulder musculature and width in late teens as height growth is finishing. Acne often improves. But all of these changes have been far smaller over the last century than the changes of hairstyle and dress and I vote with aspro that our questioner's impression was entirely based on those features. alteripse (talk) 16:21, 7 March 2013 (UTC)

Plane lens?

Can a "lens" be plane, meaning not being curved at all? 117.227.203.61 (talk) 13:28, 7 March 2013 (UTC)

You might be interested in fresnel lens. They are flat at the gross scale, but have tiny ridges at the fine scale. SemanticMantis (talk) 13:34, 7 March 2013 (UTC)

not being curved at all? 117.227.203.61 (talk) 13:38, 7 March 2013 (UTC)

Well, a Fresnel lens can either have the individual segments be curved ([1]) or flat ([2]). The curved segment version focuses more clearly, but the flat segmented kind has application where you don't need a clear image, such as focusing sunlight for solar energy. StuRat (talk) 15:25, 7 March 2013 (UTC)

If the material has a uniform refractive index throughout the plane, no, that can't be a lens. 131.251.133.27 (talk) 14:10, 7 March 2013 (UTC)

then what it is called? — Preceding unsigned comment added by 59.161.101.17 (talk) 14:26, 7 March 2013 (UTC)

Ah, a window? TenOfAllTrades(talk) 14:32, 7 March 2013 (UTC)

If the faces are plane but non-parallel, it will be a prism. If they are it may be called a plate (as in plate glass and photographic plate). Note that TOAT's suggestion of 'window' is not (I presume) whimsical - apertures sealed by flat glass (or other materials) in scientific instruments may also be called windows: one that springs to mind is the mica window used in the designs of Geiger Counters I was taught about in school (which are probably now obsolescent, like myself). {The poster formerly known as 87.81.230.195} 212.95.237.92 (talk) 14:41, 7 March 2013 (UTC)

Mica windowed Geiger Counters are not obsolescent, in fact I have one sitting behind me in my lab as I write this (used for contamination monitoring during and after biological radiolabeling experiments). Equisetum (talk | contributions) 16:42, 7 March 2013 (UTC)

Though if you're allowed to vary the material composition (specifically, its refractive index) across the plane, then you can build GRIN devices (see gradient-index optics). TenOfAllTrades(talk) 14:34, 7 March 2013 (UTC)

There's also a pinhole lens, which can be a planar material with a small hole. Note that they reduce the brightness of the object considerably, so are most useful for focusing bright objects, like the Sun, or with time exposures. StuRat (talk) 16:16, 7 March 2013 (UTC)

There are also plain lenses made of a material with negative refraction index. Ruslik_Zero 18:52, 7 March 2013 (UTC)

Isn't space itself curved? Aren't all so-called straight or plane objects intrinsically curved? -- Jack of Oz ^[Talk] 23:05, 7 March 2013 (UTC)

See Geodesic and Geodesics in general relativity for the concept of straight lines in curved spacetime. --Carnildo (talk) 00:37, 8 March 2013 (UTC)

See gravitational lens. SpinningSpark 06:51, 8 March 2013 (UTC)

Russian MBT Designs

It is known that Russian tanks are smaller and have a less area exposed to fire , but does that make a big difficulty for opponents to hit it ? in other words does it worth to exhaust the tank crew for this reason ? — Preceding unsigned comment added by Tank Designer (talk • contribs) 15:18, 7 March 2013 (UTC)

Yes and no. The T-90 is about a foot lower than the M1 Abrams, but their guns are roughly the same distance below turret top. So in the open, the T-90 presents a slightly smaller target. In a hull-down position, this distinction in height doesn't matter, though the T-90 turret is also somewhat smaller. Our article there further notes that US tanks can typically depress their main gun farther than Russian designs, which results in the Russian design potentially exposing more of the tank body (particularly if using a natural slope). For aerial threats, the two tanks have roughly the same size.

As for the last, the Gulf War demonstrated a clear advantage for US-manned M1s with air superiority against Iraqi-manned T-72s. For the rest, I refer once again to the evidence of design philosophy: each military fields the tanks they believe best match their doctrine and probable opponents, but unless and until it comes to open warfare, anything further would be conjecture. — Lomn 16:04, 7 March 2013 (UTC)

Having talked with a Gulf War tank crew veteran, he claimed that the US advantage in tank-to-tank combat was due to their automatic targeting system, allowing US tanks to hit the target with the first shot, while Iraqi tanks averaged about 3 (for those which managed to survive that long). StuRat (talk) 18:01, 7 March 2013 (UTC)

I've read quite a bit about the Persian Gulf War (of 1991), and talked to a few veterans, and it is my opinion that the chief American advantage in tank-to-tank combat was avoiding it. From the Combined Arms Research Library, here are the memoirs of one Captain Enloe, an officer in a mechanized infantry brigade, Persian Gulf War: 2d Battalion, 18th Infantry Regiment (Mechanized), 197th Infantry Brigade. "At 280515 Feb 91, all elements were ordered to stop all movement, a temporary cease fire was immediately in effect throughout the entire theater of operations. In absolute disbelief, we came to a halt and formed into a Task Force Tactical Assembly Area." Ground operations in Desert Storm famously lasted less than one hundred hours, most of which were spent driving from formation assembly areas to to other formation assembly areas.

Our original poster may find the digital library collection full of interesting information about modern armored doctrine. Nimur (talk) 18:21, 7 March 2013 (UTC)

Thank you very much Mr. Lomn

Filter paper to concentrate interesting things for microscope viewing?

Hi Folks, I have a pretty good microscope (1000x oil immersion) but am a total amateur as a scientist. I live on the ocean and would like to see interesting things like tardigrades, nematodes, plankton, etc. I'm not that interested in things at the bacterial level. Looking at plain seawater it takes a long time to find neat stuff so I was wondering if I could run a bunch of seawater through filter paper to concentrate creatures. What kind of filter paper should I use? Maybe a coffee filter would work but I don't mind buying the real thing. Any other suggestions for easy interesting things to see? Thanks! — Preceding unsigned comment added by 72.165.55.147 (talk) 17:46, 7 March 2013 (UTC)

The problem with filters is that the critters will all be stuck in the filter, and you'd need to use more water to flush them back out. Swamp water seems to be crawling with critters, so you might try that instead of ocean water. I also suggest starting a slide on a low magnification, then finding something of interest, before zooming in to max res.StuRat (talk) 17:53, 7 March 2013 (UTC)

First, usually freshwater is used for this type of thing: there are plenty of freshwater tardigrades (and nematodes and plankton too). I've found water bears in wet moss, on the edge of ponds, etc. It's easiest to find the bigger things, of course, and tardigrades can get up to 1 mm. However, I am not sure if the reason fresh water is more common is because there are more critters to see, or if it's just more widely available...

I think your idea is worth trying. As Stu says, some critters will get caught on the filter, but if you filter e.g. 1 L and then use 0.1 L to flush them back, you'll presumably have a 10X concentration, which could make your hunting up to 10X easier. I'd start with a filter of about 0.4 mm and see how it goes from there. You could also filter out coarse debris first with a 2mm sieve. As for other interesting thing to see (in freshwater/pond scum), bdelloid rotifers, hydras and volvox are all pretty cool. In ocean water you'll probably find more (and more interesting) diatoms, though they are also in fresh water. SemanticMantis (talk) 19:19, 7 March 2013 (UTC)

I think the best way to concentrate these critter is to use patients. I may take a long time to go through a bucket full of sea water with an eye dropper drip-by-drip but that the best way IMHO. You can take advantage of sea water stratifying. Not easy close to shore, because the wave action mixes it up. However, go a little off shore and you have the photosynthesising hungry stuff in the upper surface areas and the bottom dwelling stuff ... err... on or within the bottom sediments – like nematodes . Text books should tell you their natural habitat and all you need to do is take sample from those areas. For instance, a suitably weighted metal tube, hack-sawed off like a giant hypodermic syringe, with a cord attached for retrieval, can by used to get bottom sediment samples. This hunt (a male trait) makes microscopy more satisfying then just going mindlessly through the mechanics of preparing a slide and peering down the lens. A good cook book, can also help to solve the disposal problem of most sea life that is too big to go on the microscope stage. This alone, can only add pleasure to your hobby. I’m salivating at the thought. Don't forget also, many seaweeds are edible too and they have microscopic life crawling all over them. Go down to you local Japanese delicatessen and you'll have to pay good dollars for seaweed. Collect your own and its a double win situation. Forget filter paper - unless it for coffee. --Aspro (talk) 20:06, 7 March 2013 (UTC)

I would suggest using patience, as using patients might be considered unethical, although you could use patients to grow some parasitic organisms into an easier to see size. :-) StuRat (talk) 03:29, 8 March 2013 (UTC)

P.S. For other interesting thing to see, go down to the landings an buy some of the stuff that comes up in the nets that are not of commercial value. Some critters that the fishermen bring in make Alien look like a loveable puppy. With a few sharp dissecting tools, there are things that would take more than a life time to explore. A good book on the microscopic dissection of marine zoology would help to give you an idea of how to slice them up for best viewing under the 'scope. These critter also often have tiny little parasites on them so inspect them carefully, as they make for good viewing too... Also, whilst you may have never seen some off these critters on the supermarket fish counter, what’s left over from your dissections are very probably edible as well. It's a crying shame that it usually only goes into cat food. --Aspro (talk) 20:39, 7 March 2013 (UTC)

Regulatory genes that account for monocot physiology

Is there some sort of regulatory gene regime like the homeobox genes in animals that accounts for differences between monocots and (eu)dicots as a suite? Or are things like parallel venation and monocotyledony separate, unrelated innovations? Thanks. μηδείς (talk) 20:40, 7 March 2013 (UTC)

I don't know. But I found this reference in the homeobox article: A Comprehensive Classification and Evolutionary Analysis of Plant Homeobox Genes. Mol Biol Evol. 2009 December; 26(12) (open access here [3]) - A quick glance leads me to believe it would answer your question, but I can't really read that stuff. SemanticMantis (talk) 20:51, 7 March 2013 (UTC)

That source basically says that analogs of the homeobox genes exist broadly in plants from algae to flowering, but it doesn't focus on flowering plants or answer the question as to whether monocot innovations are a suite of characteristics due to one regulatory system or not. μηδείς (talk) 21:03, 7 March 2013 (UTC)

Flirting

If flirting a subconscious human behaviour? Do animals do it or only humans? Clover345 (talk) 22:57, 7 March 2013 (UTC)

Flirting behavior is by definition a human behavior; it can be conscious or subconscious. For (slightly) analogous behavior in animals, see courtship display and courtship_in_animals. SemanticMantis (talk) 23:46, 7 March 2013 (UTC)

if its subconscious, is it an emotional response? — Preceding unsigned comment added by Clover345 (talk • contribs) 23:51, 7 March 2013 (UTC)

Flirting in primates does not brake down into simple conscious or sub-conscious behaviour. The opposite sex can often detect conscious willful manipulation. However, if the basic animal instinct of sexual attraction is satisfied (emotional) then the higher intellectual demands requiring compatibility come into play. In the past, when people often did not travel far from their village and and expectations were less, like-married-like. Now, in the modern age, with cheap travel... like still marry like (so they hope) – but from further afield, because they have been brought up to be more fussy. The down side is that in the US and some other countries, singletons are chasing the impossible dream. Many animals flirt as part of their courtship.--Aspro (talk) 00:41, 8 March 2013 (UTC)

For specifically subconscious flirting behavior, see Proteans. Evanh2008 ^{(talk|contribs)} 22:57, 8 March 2013 (UTC)

Psycho-acoustics

are the explanations of psycho-acoustic simulation per the Hank Risan article consistent with science in this area? --_nonsense ferret 23:33, 7 March 2013 (UTC)

Wikipedia has an article on Psychoacoustics with references. You could use that to help your research. --Jayron32 02:13, 8 March 2013 (UTC)