Wikipedia:Reference desk/Archives/Science/2010 April 28

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April 28

Molecular Electronics

I'm a physics undergrad who's starting to appraise his options for a research career, and one field in particular that seemed interesting was molecular electronics. There seems to be elements of both physics and chemistry involved (which I don't mind), but I was wondering if a physics degree would properly prepare me for research in this area. I'm betting that an undergrad program won't matter all that much in the long run anyways, but what should I be looking into for graduate school? Also, while I don't mind chemistry I much prefer physics, so I need to know if such research can be more physics-based than chemistry-based. In other words, will I end up being a chemist or a physicist? Thanks. 173.179.59.66 (talk) 00:41, 28 April 2010 (UTC)

You are right in terms of your undergrad degree being somewhat irrelevent here. Any degree in the hard sciences (Chem, Physics, Bio) or engineering would probably set you up just fine for a graduate program in molecular electronics. What you need to do for grad school is find a professor somewhere in the country who is working in the field you want to work in, and contact them directly, letting them know you are interested in the field. In the sciences, grad school is all about what lab you are working in, and networking with the professor you will be working under is much more important than the school itself. As an undergraduate, things like extracurricular activities, campus life, geography, appearance of the campus, location, dorms, etc. etc. are all important aspects of choosing a school. For a terminal degree (Masters or PhD), its ALL about the program you are interested in. So if you find a well-respected researcher who is working in your field of interest, you should seek him out and ask him if he has any openings in his lab; what sort of work he does, how to go about getting in there. That will make getting into the school much easier. --Jayron32 02:50, 28 April 2010 (UTC)

Warm Sector

All I need to know is the definition of a Warm Sector for a lab titled "Frontal Weather." 74.76.183.139 (talk) 01:26, 28 April 2010 (UTC)

See Air mass and Weather front. A warm sector would simply by the warmer of two air masses that meet at a front. If the cold air is pushing the warm air out of the way, the front is called a cold front. If the warm air is pushing the cold air out of the way, the front is called a warm front. --Jayron32 02:45, 28 April 2010 (UTC)

Usually, the warm sector of a frontal system in the Northern Hemisphere is in its southeast quadrant. ~AH1^(TCU) 23:05, 28 April 2010 (UTC)

Chemistry: Si face and re face

I read the article Si face but I still don't understand how to distinguish a si-face from a re-face. Please explain what they are. —Preceding unsigned comment added by 70.68.120.162 (talk • contribs) 01:46, April 28, 2010

They "are" a formal way of describing the two faces of a flat location (atom in a molecule), defined by the position the things attached to that atom. Consider your right hand: looking at the palm, the fingers in order thumb-first-middle-ring-pinky go around in a counterclockwise direction; looking at the back of your hand, those same fingers in that same order go around in the other (clockwise) direction. The terms "si" and "re" are a way of identifying which face of your flat hand you are looking at, based on clockwise-vs-counterclockwise direction of the things attached. The "order" is the atomic masses of the atoms attached to the one being analyzed. The "direction" is still clockwise (called "re") or counterclockwise (called "si"). DMacks (talk) 06:30, 28 April 2010 (UTC)

Are cars and planes Faraday cages?

If yes, why are we able to use the cell-phone in them? (I assume that a Faraday cage would block a cell-phone wave). If not, why do they protect against a lightning? One possible answer that comes to my mind is that they are good enough to protect us against a lighting, but not good enough to block the cell-phone. Right?--Mr.K. (talk) 11:37, 28 April 2010 (UTC)

Whether a Faraday cage blocks a cell phone signal depends (mainly) in the thickness of the walls and their conductivity. Lightning however, is a discharge which takes to path of least resistance. Here is a photo of a lightning resistant soft-top: [1]--Aspro (talk) 11:55, 28 April 2010 (UTC)

It's also a matter of frequencies - cellphones are up in the GigaHertz range - lighting is basically DC. SteveBaker (talk) 12:08, 28 April 2010 (UTC)

Lightning is an impulse-like burst, and has energy content at most frequencies. There is usually more energy at very low frequency, below 10 kHz, but there is also very strong RF in the VHF and even some energy in the gigahertz range. Lightning is also large and powerful enough to have very nonlinear frequency behavior and is known to couple energy and particles into the ionosphere and magnetosphere. The fact that it doesn't harm people inside airplanes is due the skin effect, not because the plane is (or is not) a Faraday cage. You can be certain that the radio signals can be detected from inside the plane - so it's not effectively shielding all energy. Here is a beautiful video of a lightning research aircraft, the audio includes RF signals detected inside the plane used to analyze the video footage. This video focuses on transient luminous events, which are rare atmospheric/ionospheric electromagnetic phenomena related to lightning. Nimur (talk) 18:07, 28 April 2010 (UTC)

The cell phone signals come in through the windows, which are big holes in the metal screen. Graeme Bartlett (talk) 12:11, 28 April 2010 (UTC)

The newer aircraft made from non-conducting composite material will need thin metal meshes and foil to be included in construction for lightning protection. However, with a cell phone's 800 MHz to 900 MHz frequency (equals wave length of ≈ 33 cm) and with so many gaps in protection it is unlikely that they will block cell phone signals either.--Aspro (talk) 12:17, 28 April 2010 (UTC)

I think you'll find that some cell phone frequencies are 900 MHz, not 900 Hz. And not all are, especially in countries other than the USA, where some of us live. --Phil Holmes (talk) 15:05, 28 April 2010 (UTC)

Thanks --Aspro (talk) 15:42, 28 April 2010 (UTC)

Nathan Stubblefield's wireless portable telephones used 900 Hz among other audio frequencies, circa 1902. As for cell phones and Faraday cages, I put my cel inside a microwave oven (turned off) and it rang when I called it. Ditto for an oven and even for a stainless steel pot with the lid on, and a sheet metal mailbox. The only thing that prevented it receiving the call was an old castiron Dutch oven (relatively thick metal). The cel towers must transmit quite a strong signal. Strangely, it does not get a signal in my basement. Edison (talk) 03:52, 29 April 2010 (UTC)

Has anyone mentioned Lightning rod? Pretty good article actually, even has a section on aircraft. Vespine (talk) 23:12, 28 April 2010 (UTC)

EM colours

Looking at this informative diagram, I was wondering about certain crustaceans (shrimps) that can see the UV spectrum (or animals that can see IR) and what colours they can actually see. Then I had a random but intriguing thought - if we could see sound, what colour(s) would it be? How/why did the mechanisms of animals adapt to see higher/lower frequency EM and why can't any animal see sound? Sandman30s (talk) 13:35, 28 April 2010 (UTC)

Animals cannot see sound because sound is MUCH lower in frequency than light. It's like asking why no animal can hear light either. The question if we could see sound, what colour(s) would it be? is meaningless; we could never see sound, and even if we could it would be impossible to describe with the very limited color selection humans have. 99.137.221.37 (talk) 13:42, 28 April 2010 (UTC)

Well, we need to define "see". If we mean perceive sound using eyes, then that's just nonsense, it's not what eyes do. If we mean get information using sound equivalent to that we get from light, then echolocation does something very close to that in some species (eg. bats). There is no concept of colour, though, since it is an active process - the sound is emitted by the animal, so the animal controls the frequency. --Tango (talk) 14:23, 28 April 2010 (UTC)

We don't really have words for the "Colors" you'd see if your vision used different primaries than human vision, if that's what you're asking. APL (talk) 14:07, 28 April 2010 (UTC)

There's a reason that color is the go-to example for the philosophical concept of qualia -- the important characteristic of red, green, and blue is that they are different from each other, nothing more. Philosophers will then argue about whether there is some kind of "essential redness", or if red can be completely described as "the color between 630 and 740mm in wavelength, associated with blood, fire trucks, and stop lights, etc."

Qualia haven't (and pretty much can't) be proved to exist, so questions about "what would it be like to see color differently" are philosophical ones. If you want some fun reading in the area, see philosophical zombie, and try to decide if p-zombies are impossible, possible but non-existent, or everywhere! Paul (Stansifer) 14:15, 28 April 2010 (UTC)

Second question first: It has been proposed by some scientist that bats may perceive their received echoes as visual impressions and in colour, but that's not proven yet. I will leave out people with Sound -colour-synesthesia fascinating as it is. However, to answer your question, it would be better to ask about the advantages of the visual spectrum for our sight and the evolution advantage that favoured it. Basically its down to frequency and the biological limitations of the two sensing organs. The retina evolved from part of the neurone network of the brain. It has many light sensitive nerve endings onto which the image of the external world can be focused. Or put it a different way: it can detect spacial separation of points to form a mental image. Whereas the ear evolved from part of the jaw and other bits of the anatomy into the organ it is today but each ear can only register one scale of frequencies. The two ears can detect differences in loudness and phase. But very often one has to turn one's head to determine the direction of the noise source. Now, this has a limitation that can be understood a little by understanding Information theory. Sound ( in air, S.T.P.) has a narrow bandwidth. Other noise sources easily swamp the 'useful' ( and sometime life preserving) information in such a system. Eyes, don't have that problem. Bats have mitigated this shortfall to some small extent and enough to hunt by, by using higher frequencies, which in effect increases the usable bandwidth well above ours. We evolved ( or so I'm told ) on the ancient, open, savannah. In this environment, it is useful to have astute discrimination for the phase shift of lower frequencies, as made by animals that wanted to eat out ancestors. It is also useful for hunting, as the phase shift give good spacial information as to location of our other hunting companions. It has been suggested that we evolved our ability to run efficiently for extended periods because that way we could run our quarry to exhaustion. The ability to hear as we do, is well suited to this type of pursuit. So, the answer is that visual sight gives animals an evolutionary advantage, which sound alone would not.--Aspro (talk) 15:11, 28 April 2010 (UTC)

"We evolved ( or so I'm told ) on the ancient, open, savannah." Not to get off-topic, but it's pretty strongly believed that this is outdated bunk. You won't find it discussed in the positive in a modern work on paleobiology. The problem is that people don't want to accept the aquatic ape hypothesis and there isn't really an alternative. Notice how our article human evolution completely avoids mentioning the conditions in which early humans evolved, even though it discusses tool use and the different theories as to whether humans evolved in one place or several. It never says humans evolved on the plains, but it also does not confront and correct this belief. That's pretty much the state of the discipline at the moment. 86.178.225.111 (talk) 19:41, 1 May 2010 (UTC)

If you could see sounds, you would have a seismic image or a sonogram. Sound does not have a color. It has a power spectrum, and can be described as many frequency components, each with their own amplitude and phase. In some ways, this is similar to optics, insofar as light also can be described with a frequency spectrum; both phenomena are waves; but the similarities end there. The type of waves are dramatically different; the scales (of both energy and wavelength) are dramatically different; and therefore, the transducers that can convert the physical effect into usable information are very different (microphones and ears, versus cameras and eyes). If you feel like redefining the word "color" to be equivalent to "frequency", you may consider any frequency-spectrum to contain "color" - but that's a matter of word-choice. In practice, when we generate images using non-visible sources of information, we typically create false color images, where the color in the graph indicates some other property (most often, amplitude, and not frequency). But we can create false color images using any parameter along the color axis. For example, hyperspectral images "compress" many non-visible wavelength spectral channels into the set of printable, visible colors. Nimur (talk) 18:26, 28 April 2010 (UTC)

A peculiar colourisation of Chopin (video) Cuddlyable3 (talk) 19:19, 28 April 2010 (UTC)

Thanks for the varied answers and fascinating links! Sandman30s (talk) 14:57, 29 April 2010 (UTC)

Dream Recall

I've tried everything to improve my dream recall. I kept a dream diary, I interrupted the sleep cycle during rem sleep etc, I followed all the guides for dream recall and none of it works. So I was wondering, are there any scientifically proven methods that improve the recollection of memories from dreams? 82.43.89.71 (talk) 14:15, 28 April 2010 (UTC)

I can't see why any scientist would see a need to do a review of the techniques, much less try to develop a protocol. The main use of a dream diary appear to be for indulging in the pastime (or art) of pseudo-psychotherapy dream interpretation. In these modern times (i.e. post Jung, etc), the phenomena known as dreaming is now thought by scientists to serve as a means to consolidate memory. Any 'high emotional' periods from one's past would naturally feature from time to time as links get made from the current day's events but this doesn't mean that they have any meaningful significance (or so I am informed). This seem reasonable to me, as I've known (2 or 3 if you include their spouse ) people get very intrigued by dream interpretation and spent time (after getting their doctorate) to studying it professionally, they all eventual come to the conclusion that it is bunkum. I know this is not a very useful answer but it might save you searching in vain for some scientific work that probably does not exist --Aspro (talk) 18:14, 28 April 2010 (UTC)

I may be wrong here, but it seems that the OP is asking about simply improving his ability to remember his dreams rather than interpret them-- for which things like keeping a "dream diary" can be quite helpful. AlexHOUSE (talk) 18:20, 28 April 2010 (UTC)

His asking is their any scientific proven methods and I'm suggesting probably not and explaining why. Isn't some answer better than non?--Aspro (talk) 18:26, 28 April 2010 (UTC)

Absolutely. Although there's nothing I can find in our articles on oneirology that would suggest scientists are actively plugging away at how to remember your dreams. OP: you might find more tips for dream recall by searching for methods for lucid dreaming-- a field with a little more scientific research put into it. AlexHOUSE (talk) 18:33, 28 April 2010 (UTC)

I don't see how the OP could interrupt their own REM sleep. An effective technique is having an observer wake the subject and record their dream account immediately.Cuddlyable3 (talk) 19:08, 28 April 2010 (UTC)

Alarm clock and notepad? AlexHOUSE (talk) 19:19, 28 April 2010 (UTC)

Bzzzzzz! Oh what a horrible noise, I must reach out and press the button to stop it. Now what was it I should do, oh yes, I have to write down stuff. So here is my notebook. It reminds me of other notebooks. Yawn. Is this pencil sharp enough? Right, how shall I phrase what I was dreaming about? Uh, what the **** was I dreaming about anyway? It was probably something silly anyway. This is not working! Cuddlyable3 (talk) 10:14, 29 April 2010 (UTC)

Alan McGlashan, author of “The Savage and BeautIful Country” said the best way to encourage the Dreaming Mind to facilitate recall of dreams is to respect it and them. Keeping a dream diary would definitely help. Also eating lobsters. Kittybrewster ☎ 20:38, 28 April 2010 (UTC)

Lobsters? Is there some chemical in lobsters that helps remembering dreams? 82.43.89.71 (talk) 20:45, 28 April 2010 (UTC)

No. Eating lobsters increases the likelihood of having dreams. Kittybrewster ☎ 20:26, 29 April 2010 (UTC)

What exactly is in lobsters that has that effect? 82.43.89.71 (talk) 20:31, 29 April 2010 (UTC)

Does it matter? It could be a chemical, a hope, an expectation or faith. Kittybrewster ☎ 20:45, 29 April 2010 (UTC)

Of course it matters. I want to know why eating lobsters would increase the likelihood of having dreams. References would be nice (this is the reference desk after all) 82.43.89.71 (talk) 21:40, 29 April 2010 (UTC)

Sorry if I wasn't clear with my question. I am indeed trying to remember my dreams more clearly, as currently I have extreme difficulty remembering anything from my dreams. I do understand that scientists aren't actively working on ways to improve dream recall, but I just wondered if there had been any discoveries at all that might improve remembering dreams. Perhaps a chemical that is known to improve dream recollection or something? 82.43.89.71 (talk) 20:45, 28 April 2010 (UTC)

Maybe some dreams just don't want to be remembered. Try to record the dreams when you can remember them clearly, and when you can't then record all the details you do remember before they fade away. ~AH1^(TCU) 23:04, 28 April 2010 (UTC)

Richard Feynman at one time had an interest in recording his dreams, didn't he? 86.21.204.137 (talk) 19:26, 29 April 2010 (UTC)

He sure did. I've recorded my dreams too, and it seems to work pretty well for remembering them (at least better than when I don't). But the OP has already tried this, and it's not working out, so he's asking if there's anything else he can try. Buddy431 (talk) 20:10, 29 April 2010 (UTC)

My suggestion to the OP would be, if he/she has a vivid dream that's worth remembering, he/she should make a conscious effort to wake up, and then write it down ASAP. I don't know how well it'll work for him/her, but it works for me (I've ended up with quite a few good song lyrics this way, not to mention an idea for my first novel -- though when I have dreams with new songs in them, I tend to awaken on my own). FWiW 76.103.104.108 (talk) 06:07, 30 April 2010 (UTC)

Ambient construction

My son is working through a college report on string theory and asked me for help in understanding some key concepts one of which is "ambient construction". I consulted the wiki page as I had no idea what it meant.

I read: "In conformal geometry, the ambient construction refers to a construction of Charles Fefferman and Robin Graham[1] for which a conformal manifold of dimension n is realized (ambiently) as the boundary of a certain Poincaré manifold, or alternatively as the celestial sphere of a certain pseudo-Riemannian manifold."

and I am now more confused then ever. Can someone please explain this to me at a level most adults would understand? TheFutureAwaits (talk) 14:26, 28 April 2010 (UTC)

Not really, no. It is very technical. I've studied quite a lot of topology and even I would have to look up some of those terms (I've never come across the phrase "celestial sphere" in this context). String theory involves a lot of topology. If you don't have the necessary background, you won't be able to understand the more technical areas of the subject. If you want to try and understand it, you should start with manifold, but don't expect it to be quick or easy. Your son should probably ask someone that already knows about the subject (classmates, lecturers, tutors). --Tango (talk) 14:47, 28 April 2010 (UTC)

"Poincaré manifold" means hyperbolic space in this context. The boundary of hyperbolic space (at infinity) is a circle/sphere (it's the boundary of the Poincaré disk model). There's no natural notion of distance on the boundary, because everything is at infinity, but angles and distance ratios make sense: the geometry of the boundary is conformal. You need hyperbolic space, rather than Euclidean space, for this because the conformal boundary of Euclidean space is just a single point (the north pole of the Riemann sphere in the two-dimensional case). "Pseudo-Riemannian manifold" means "curved spacetime as found in general relativity", but in this case they're probably talking about some very specific curved spacetime, like Minkowski space or anti de Sitter space. "Celestial sphere" means the boundary at infinity of the future (or past) light cone at some point in that spacetime (it doesn't matter which point if the spacetime is symmetric enough). The celestial sphere of n+1 dimensional Minkowski spacetime is the same as the boundary of n dimensional hyperbolic space. This isn't exactly "at a level most adults would understand", but maybe it will help somewhat. -- BenRG (talk) 21:42, 28 April 2010 (UTC)

Actually I think that does clear things up a bit. Essentially it's a particular type of model that enables establishing boundries in what would otherwise be infinite space. I still don't get what that would imply but at least I get the basic meaning. TheFutureAwaits (talk) 23:00, 28 April 2010 (UTC)

Ions

Why Hg₂²⁺ is called Mercury(I)?--Mikespedia is on Wikipedia! 14:36, 28 April 2010 (UTC)

It is an example of Stock nomenclature. The Roman numeral in mercury(I) indicates the oxidation state of each mercury atom, whereas the 2+ superscript in Hg₂²⁺ denotes the total charge of the compound ion. TenOfAllTrades(talk) 14:42, 28 April 2010 (UTC)

The symbol Hg is Latinized Greek: hydrargyrum, from "hydr-" meaning watery or runny and "argyros" meaning silver. See the article Mercury (element). Cuddlyable3 (talk) 18:52, 28 April 2010 (UTC)

Since the mercury ion contains two atoms and has a total charge of 2+, each atom has a charge of 1+, making it mercury(i).--98.221.179.18 (talk) 19:21, 28 April 2010 (UTC)

Mercury(I) is also a weird case because it dimerizes. Unlike most metal ions, which are happy to live by themselves, the Mercury(I) ion forms a dimer, much like the neutral Halogens to (hence chlorine gas = Cl₂.) There are reasons for this, but if you are just at the state of learning how oxidation numbers work in your education, you can just take it as a "weird" case. If you are interested in more details on this, Mercury polycations discusses it. --Jayron32 20:46, 28 April 2010 (UTC)

help me please (eating heroin rabbits)

I must be knowing any effect or dangers that would be coming if someone (not being me!) were to be ingesting 5 heroin filled game rabbits. please be helping. This is urgent! —Preceding unsigned comment added by TalipTaste (talk • contribs) 16:02, 28 April 2010 (UTC)

If you think it's urgent, call the emergency services - the operator will at least be able to tell you if it's an emergency or not. Heroin#Effects. I imagine the actual quantity of heroin would need to be known. We can't give medical advice, by the way. Vimescarrot (talk) 17:01, 28 April 2010 (UTC)

Also, see gluttony if you have in fact eaten 5 rabbits in a short time. Googlemeister (talk) 19:03, 28 April 2010 (UTC)

And protein poisoning. AlexHOUSE (talk) 19:08, 28 April 2010 (UTC)

Also, rabbit starvation. ~AH1^(TCU) 23:01, 28 April 2010 (UTC)

(Same thing.)AlexHOUSE (talk) 23:05, 28 April 2010 (UTC)

Also, see troll —Preceding unsigned comment added by 86.4.186.107 (talk) 07:56, 29 April 2010 (UTC)

Foiled again. AlexHOUSE (talk) 17:32, 29 April 2010 (UTC)

Naming of a species

The new British moth is named after its discoverer.[2] I thought he was supposed to name it after something other than himself, according to conventions. Imagine Reason (talk) 17:33, 28 April 2010 (UTC)

I think you've misparsed the article. Nowhere does it say HE named it after himself - to quote the article - "In January this year, the moth was officially recognised in the journal Zookeys as a new species, named Ectoedemia heckfordi after its discoverer." - implying it was named in his honour by a third party. Exxolon (talk) 18:21, 28 April 2010 (UTC)

As I understood it, the person who discovers a species gets to name it. Why didn't it happen in this case? Imagine Reason (talk) 13:54, 29 April 2010 (UTC)

The article is poorly written. The discoverer is sometimes referred to as an amateur naturalist and sometimes as a biologist. In theory that's certainly possible, but sure sounds weird. Anyway, it only says he was the discoverer, not the person who described it scientifically, which is who would have provided the name. You see this sometimes in dinosaur circles - some kid finds the bones and "discovers" the dino, but it's a professional palaeontologist who actually does the write up and determines whether it's a new species or not. The kid (or whoever) often gets his/her name worked into the species name. For example, see here. Matt Deres (talk) 16:18, 29 April 2010 (UTC)

Mass to energy conversion

If One could efficiently (100%) convert mass to energy and v.v., how much mass could you get out of the energy stored in a AA battery? How much mass could a 1GW nuclear reactor produce in an hour? Googlemeister (talk) 19:37, 28 April 2010 (UTC)

E = mc**2, and this page says an AA battery has at most 11050 joules of energy, so:

11050 J = m * c**2
11050 J / c**2 = m
11050 kg*m**2/s**2 / (3*10**8 m/s)**2 = m
11050 kg / 3*10**8 = ~0.00000000000012277778 kg

Similar math applies for the reactor case. --Sean 20:18, 28 April 2010 (UTC)

That would be about the mass of a few hundred bacteria. That's a lot more than I'd have guessed.

11000 / (3x10⁸)² = 1.1x10⁴ / 9x10¹⁶ = 1.2x10^-13kg.

SteveBaker (talk) 00:55, 29 April 2010 (UTC)

According to [3], an AA battery contains 1kJ. If we plug that into E=mc², we get a mass of 1000/c²=1.1*10^-14kg. 1 gigawatt-hour is 3.6*10¹²J, or 40 milligrams. --Tango (talk) 20:17, 28 April 2010 (UTC)

If you compress a mass of 6*10^11 kg to within its Schwarzschild radius of 8.9*10^(-16) meters, you'll get a micro black hole that will emit about 1 GW of power in the form of Hawking radiation (at a temeperature of about 200 billon K). Then, as Tango has calculated, it will only lose 40 milligrams per hour, which is 1 kg per 2.85 years. So, we would have plenty of energy and no headaches about what to do with waste! :) Count Iblis (talk) 22:05, 28 April 2010 (UTC)

Now all we have to do is figure out where can we get one of those. Dauto (talk) 23:14, 28 April 2010 (UTC)

Well, that and how we're going to stop it falling through the floor and bouncing back and forth through the earth from now until doomsday. Sure, you can charge it up and hold it in a suitable electric field - but you need to be really careful...one tiny "oopsie" and you're in deep poop! SteveBaker (talk) 00:55, 29 April 2010 (UTC)

Yes, one has to be careful with these things! One could perhaps put such a micro black hole in orbit around the Earth. Count Iblis (talk) 02:18, 29 April 2010 (UTC)

See The Hole Man. Ariel. (talk) 02:40, 29 April 2010 (UTC)

Is it normal for men to have a noticeably reducing libido at the age of 50.

Some of my colleagues of a similar age still shout "phwar" when a teenage girl walks past our window. I find I'm thinking "she's younger than my daughter" and only feeling fatherly thoughts. One guy said "what would you like to do if you had a night out with her" when one walked past. Of course I said "cor just imagine", but I was really thinking that if I would probably just treat her like my daughter and take her to the Pizza hut and talk about how her careers going! Is this normal for someone in their early fifties? —Preceding unsigned comment added by 88.107.183.51 (talk) 20:07, 28 April 2010 (UTC)

Congrats, you're one of the few non-perverts in the world. :-) But seriously, male libido starts decreasing from around 18, hence the popularity of Viagra. StuRat (talk) 20:17, 28 April 2010 (UTC)

Yes. You have a daughter and therefore a different reference point. Very healthy and much more grown up. Kittybrewster ☎ 20:20, 28 April 2010 (UTC)

Your colleagues may be doing exactly the same thing you are are just saying it because they thing it's what they should say. --Tango (talk) 20:22, 28 April 2010 (UTC)

As another guy in his 50's (without the daughter) - I doubt it's a matter of libido so much as a matter of maturity and respect. I suspect that (assuming you're otherwise unattached) you'd have no trouble getting sexually interested in an attractive person with the right attributes whom you met under reasonable circumstances. I too don't see the attraction in young women encountered at random like that. Like the majority of people of that age, I find them mostly superficial and uninteresting after not much time spent with them. But reduced libido is another matter entirely. Don't confuse selectivity with disinterest. But all of that bravado from younger guys definitely gets tiresome - and I'm pretty damned sure it doesn't do much for the ladies either. Those of us who have been around the block a few times can more easily tell what's just bullshit and what's not. So don't sweat it...go out and buy yourself a brand new convertible...a red one...with turbo...it's time! :-) SteveBaker (talk) 23:14, 28 April 2010 (UTC)

An old adage says something like (for men's sexual prowess) "Age 20:Triweekly. Age 40: Try weekly. Age 60: Try weakly." If there's any compensation for the decreased libido, it is said to be that 60 year old women look far hotter to a 60 year old man than they do to a 20 or 40 year old man, while 20 and 40 year old women still look hot. Edison (talk) 03:35, 29 April 2010 (UTC)

"I'd rather have two girls at 21 each, than one girl at 42." -- W.C. Fields (singing) ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:49, 30 April 2010 (UTC)

But would a 60-year-old man still look hot to a 40-year-old woman? 76.103.104.108 (talk) 06:10, 30 April 2010 (UTC)

If he has enough money. Those babes don't hang around Hugh Hefner because of his looks, you know. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:49, 30 April 2010 (UTC)

Is the OP aware that his expletive "cor" is derived from "cor blimy", itself derived from "God blind me (if I tell a lie)"? This list can help linguistically challenged Americans.Cuddlyable3 (talk) 10:00, 29 April 2010 (UTC)

Chromate formation

Can chromates be formed by reaction of chromium(III) oxide with a hypochlorite. When I react a chemical (formed by the neutralization using ammonia of Nichrome previously dissolved in acid) with sodium hypochlorite, a yellow solution is formed. How could you tell whether it was iron(III) chloride or sodium chromate? I duplicated this reaction with a chromium-containing stainless steel screw and it formed the yellow color too. --Chemicalinterest (talk) 20:41, 28 April 2010 (UTC)

Add thiosulfate to the solution. If Iron(III) is present you will form the blood-red Thiocyanatoiron(III) complex ion. If Iron(III) isn't present, the yellow is probably from Chromate or Dichromate. --Jayron32 20:55, 28 April 2010 (UTC)

ED: I screwed up. You should add thiocyanate to the solution. My bad. --Jayron32 01:59, 29 April 2010 (UTC)

Unfortunately I do not have thiosulfate or thiocyanate. --Chemicalinterest (talk) 21:13, 28 April 2010 (UTC)

These are the reactions: 2 Ni + 2 Cr + 10 HCl → 2 NiCl₂ + 2 CrCl₃ + 5 H₂ | NiCl₂ + CrCl₃ + 5 NH₄OH → Ni(OH)₂ + Cr(OH)₃ + 5 NH₄Cl | 2 Ni(OH)₂ + 2 Cr(OH)₃ + 4 NaClO + 4 NaOH → 2 Na₂CrO₄ + 4 NaCl + 7 H₂O + Ni₂O₃ --Chemicalinterest (talk) 21:24, 28 April 2010 (UTC)

Iron(III) is a major Lewis acid (in addition to being an oxidant). I don't know as much tests but I am sure there are plenty. Cr(VI) prefers to oxidise over any Lewis acid ability, I think. Also Fe3+ forms many insoluble complexes ... whereas I believe Cr(VI) compounds tend to be more water-soluble. John Riemann Soong (talk) 22:29, 28 April 2010 (UTC)

Btw, Iron(III) chromate forms an insoluble salt. If you didn't observe this, well you probably don't have both ions in there. I would test with some copper (II) chloride (will precipitate copper chromate), sodium sulfide (will precipitate FeS), etc. Your reaction might have just worked because iron(III) hydroxide is very insoluble in water. John Riemann Soong (talk) 22:45, 28 April 2010 (UTC)

Adding a source of phosphate will also precipitate any Fe(III). (Try not to add it in the form of phosphoric acid...monoprotonated or free phosphate is preferred...) John Riemann Soong (talk) 22:51, 28 April 2010 (UTC)

I did react it with ascorbic acid, a reducing agent, and the color faded, but the Fe(III) could have been reduced too. I wonder if alkali would work. --Chemicalinterest (talk) 12:53, 29 April 2010 (UTC)

Alkali/base wouldn't reduce Fe(III) normally (you would be forming N-oxide, peroxyacid, O2, etc. depending on base used). But OH- would precipitate Fe(III). How much excess NaOH did you add? John Riemann Soong (talk) 15:19, 29 April 2010 (UTC)

I was wondering whether it works. I plan to try it soon. --Chemicalinterest (talk) 19:53, 29 April 2010 (UTC)

I happen to only have ammonia, so I'll make sure I do it outside or I might not be here to tell the results. :) --Chemicalinterest (talk) 19:54, 29 April 2010 (UTC)

I added 10 times its volume of ammonia and no precipitate formed. So then it is hexavalent chromium. --Chemicalinterest (talk) 20:03, 29 April 2010 (UTC)

Well the thing is that ammonia tends to form complexes, not insoluble salts. John Riemann Soong (talk) 05:20, 30 April 2010 (UTC)

Oh whoops, silly me, you were using it as a replacement for NaOH, not using NH3 to complex the Fe(III) directly. John Riemann Soong (talk) 05:21, 30 April 2010 (UTC)

Do you know why you have to put the test tube outside? When bleach is reacted with ammonia, it forms toxic chloramine gas. --Chemicalinterest (talk) 11:53, 30 April 2010 (UTC)

Did you oxidise all the metal? Interesting. I would think you would have consumed all the hypochlorite ... but maybe the equilibrium is not favourable. John Riemann Soong (talk) 22:40, 30 April 2010 (UTC)

Geology

Recently a large quantity of "river rocks" have been imported to our area to be used in landscaoing. These rocks came from somewhere in Arizona. The rocks appear to be of great variety. some are granite some basesalt etc. They vary in size from one inch to one foot. A few of them are almost perfectly round, but the top and bottom are slightly and equally convex. They are, of course, smoothed by errosion. I do not think, however, that errosion alone explaims there near perfect symmetry. I suspect that they were magma which was blowen into the air by a volcano. As they spun in the air they would have developed into a ball shape. When they struck the ground they would have been flattened like a pancake. But if such were true, one would expect one side to be flatter than the other side. Such is not the case. Can some one explain to me the origin of these beautiful rocks? Thanks, wsc—Preceding unsigned comment added by 66.27.177.28 (talk) 23:04, 28 April 2010

How about if they just got rounded off by rolling down a stream ? Perhaps one got stuck somewhere and had the top erode more, making it slightly flattened. Then, the next time the river flooded and it rolled, it settled on that flatter side (and then the opposite side eroded the same way). StuRat (talk) 23:11, 28 April 2010 (UTC)

If these have been imported in large quantities, then I think the easiest and most reliable way to find out, is to approach such a home owner with said landscape and inquire. Take a pen and paper for making notes. If your impressed with their garden rock feature, then that is likely to please the owner who may be happy to tell you the supplier, and from them you can find the rock's geological details, formation etc.--Aspro (talk) 23:30, 28 April 2010 (UTC)

Did you mean to type "If you're impressed..." ? Cuddlyable3 (talk) 09:50, 29 April 2010 (UTC)

Rock that is flung out into the air turns into light stuff like pumice, not into basalt; and granite doesn't form unless cooling is very slow. I'm not aware of any other mechanism that erosion that gives rounded rocks. Looie496 (talk) 00:19, 29 April 2010 (UTC)

It is quite possible that decorative rocks like those you describe could be artifically ground into shape. Imagine an industrial scale tumble finishing process. Astronaut (talk) 01:58, 29 April 2010 (UTC)

What's wrong with the theory that they are just perfectly normal and abundant river rocks? ok some of the rocks in that pic don't look PERFECTLY symmetrical, but some do. Vespine (talk) 05:18, 29 April 2010 (UTC)

You can get some remarkably symmetric shapes in volcanic bombs, the article has a wonderful example, but I don't think that's what is being described here. Pebbles in rivers (and on shorelines) become progressively rounded due to lots of knocking together with other pebbles (that sort of tumble finish comes free of charge and on a vast scale). They don't quite make perfect ellipsoids but they can be pretty close.[4] It's possible that someone has selected the most symmetrical from some natural examples but that seems like a lot of work to go to. Mikenorton (talk) 19:45, 29 April 2010 (UTC)

Ghost

Is ghost really exist?75.168.119.109 (talk) 23:38, 28 April 2010 (UTC)

Real ghosts on TV. Cuddlyable3 (talk) 09:47, 29 April 2010 (UTC)

Scientists are very sceptical about their existence. Wikipedia has an article about them. Ghost#Scientific_skepticism--Aspro (talk) 23:48, 28 April 2010 (UTC)

Thank You!75.168.119.109 (talk) 00:04, 29 April 2010 (UTC)

No - they don't exist. Aspro: we shouldn't sugar-coat this. I don't know of any scientists who are actually "skeptical" about ghosts. They know ghosts aren't remotely possible - period. Some might come out with some wishy-washy super-formal "we haven't yet proven that they don't exist" statements if forced into it - but nobody in the hard sciences really believes there is even a one in a billion-trillion chance that they could exist. There is absolutely zero solid evidence FOR ghosts - and against that are all of the laws of physics and biology that say they can't exist. The hypothesis that there are ghosts fails the falsifiability test. Occam's razor says the best approach is to assume that they don't exist because that assumption violates no known laws and the guess that they do exist violates many. Russell's teapot asks why you'd believe in ghosts but not the much higher chance that there is a teapot in orbit about Mars (or pink piano-playing aardvarks on the dark side of the moon - or any other crazy thing you might think up on a boring Wednesday afternoon). There are a literal infinity of things one might believe in without any evidence whatever - why pick the ghosts rather than the pink aardvarks? SteveBaker (talk) 00:05, 29 April 2010 (UTC)

How is it sugar coated. In science one is never absolutely dogmatic about anything. Also, accepting somebodies word on their say so alone, is stupid and foolish. Judgement, comes with practise and experience. To sort cut this process with blunt dogmatic statements is to encourage the slow acceptance of Argument from authority fallacies, which can lead to pseudo- scepticism, where what one feels should be over powers logical deduction, because the right way to think, has never been learnt properly. Scientists who are not naturally sceptical -even about their own beliefs- are not really scientists but merely highly qualified lab technicians.--Aspro (talk) 00:59, 29 April 2010 (UTC)

I agree with Steve in principle. There is a large class of "paranormal" that we can categorically discount as "absolutely untrue." Things like ghostly apparitions that take human-like form and preserve the consciousness of the individual in the form of some type of gaseous mist - well, these are just plain contrary to all kinds of laws of physics and chemistry and biology. If somebody wants to go out and concoct an extremely restricted concept of "ghost" by playing games with definitions, and putting a bunch of conditions they might be able to weasel out a bizarre definition that a scientist could say "well, unlikely, but not inconsistent with scientific fact." But any such definition of a ghost would not look like the representations of ghosts in mythology and fiction - a God of the gaps sort of approach that would leave the ghost-enthusiasts pretty dissatisfied. As we have become better able to explain the biological processes that constitute life, it has become harder and harder to justify an afterlife - especially in the form of ghostly apparitions - in any way that is even remotely scientific. Ghost ideas can persist because people are unscientific and inexact in their descriptions. "They're sort of transparent", for example. The details and descriptions are vague, but if somebody with an attention to detail and a methodical, analytic approach (ergo, a scientist) starts thinking about any particular set of observations, it becomes blisteringly clear that the cultural portrayals of ghosts are pure fiction. Follow up on the "semi-transparent ghost" - define some optical properties; measure some reflectance coefficients; measure an optical spectrum and deduce a chemical composition. Is it a solid, liquid, or gas? Where does it get its energy for locomotion, if not by conventional biological metabolism? If it is flying, is it suspended buoyantly, or is it exerting energy to hover? If it is a skeleton, how does it move its structure without musculature? Find a way to make any of these observations remotely consistent with some type of explanation. We can not, so we can categorically say that descriptions of ghosts are due to faulty observation - and are better studied by psychologists and anthropologists. A fascinating, and scientific question, is "what causes groups of people to share similar descriptions of fictional things?" The answer is a complicated melange of biological/psychological predispositions, cultural and social conditioning, confirmation bias, and so on. Nimur (talk) 08:03, 29 April 2010 (UTC)

What about a mental image that is in the form of a semi-transparent ghost? That wouldn't break the laws of science 'cause it's all in the observer's mind, right? 76.103.104.108 (talk) 06:15, 30 April 2010 (UTC)

As I said, "better studied by psychologists... ." The neurobiology of unstimulated perception is definitely fascinating, and has many unanswered questions that are open to actual scientific research. Nimur (talk) 14:41, 30 April 2010 (UTC)

You are right that scientists should always be sceptical, but I think it would be more precise to say "Scientists are confident that ghosts to do not exist, but they accept that they could be mistaken." (You don't really need to include the last part since it applies to any statement of science and is implicit in the work "scientists".) --Tango (talk) 13:34, 29 April 2010 (UTC)

I disagree, just because science has not proven something yet, does not mean it is untrue. Also, if one has experienced paranormal activity, one is more likely to beleive, even if it cant be explained by science yet. Auschwitz is a good example, there is a presence there that cannot be explained by science. But it is there, and for obvious reasons. —Preceding unsigned comment added by 62.172.59.90 (talk) 13:13, 29 April 2010 (UTC)

Science has never proven anything. Proof is a mathematical concept. You have to weigh up two possible explanations for people's paranormal experiences: 1) They are somehow mistaken about what they experienced. 2) All of science is wrong and all the accurate predictions we have made have just been luck. Both of those are entirely possible, but the former is overwhelmingly more likely. --Tango (talk) 13:34, 29 April 2010 (UTC)

Proof is indeed just a concept. There's always a very small, negligible chance that in the second something could come along to disprove your hypothesis. Probability is a better term. The probability that ghosts exist is miniscule, but many would choose to exaggerate that even further. Regards, --—Cyclonenim | Chat  16:50, 29 April 2010 (UTC)

What does "just a concept" mean? --Tango (talk) 16:59, 29 April 2010 (UTC)

Just an idea, in practicality. It may have a mathematical basis but in every day terms we use probabilities. Regards, --—Cyclonenim | Chat  01:21, 30 April 2010 (UTC)

And probabilities aren't an idea? --Tango (talk) 06:14, 30 April 2010 (UTC)

You know what I mean, don't be pedantic. "Just an idea" means it's essentially useless--you can't prove anything. Probabilities are used all the time. Regards, --—Cyclonenim | Chat  01:39, 1 May 2010 (UTC)