Wikipedia:Reference desk/Archives/Science/2010 June 8

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June 8

Sparrows are Lousy Parents

There was a sparrow nest under an air conditioner I was moving, and, feeling benevolent, I relocated the chicks to another location. They are now in a young cherry tree close to the original nest, but the original nest was—if I may criticize another species' instinctual skills—a shoddy piece of garbage, and it fell apart. So, I used an abandoned nest built by, probably another species of bird—a bird with some pride in its craft.

Okay, not too promising, I know. Even less promising—the derelict sparrow parents have proceeded to rebuild their (dirty, probably soon to be disease/mite ridden) nest under the air conditioner—and, I imagine, all of this in lieu of tending to their old kids.

I'm (A) interested in what's going on here; (B) interested in what I can do to maybe spark a family reunion; and (C) if B is not possible, interested in maybe considering a humane way to divert the chicks' slow and painful route to becoming a gross meditation on death...

Thanks. Alfonse Stompanato (talk) 00:15, 8 June 2010 (UTC)

Whenever you touch baby birds, especially if you move them, there is a high chance of the parents rejecting them (I'm not really sure why - possibly because they aren't sure the chicks are theirs). I don't think there is much you can do now. You can take the chicks to a vet and get them put down, but that's about it (I would just let nature take its course now - it's always possible the parents will return to them, but it seems unlikely - they seem to be planning a second attempt, which suggests they think their first lot of chicks are dead). Really, you should have moved the air conditioner either before the eggs were laid or after the chicks had left the nest. Unfortunately, I think you've killed those chicks. --Tango (talk) 00:57, 8 June 2010 (UTC)

Actually, the whole "if you touch a baby bird, the mom will reject it" is a bit of an old wives tale. ([1] [2] [3], and others by Googling "touch baby bird") This seems like something we would have an article on. The recommendation *is* to leave them alone, but that's because falling out of the nest is normal. However, if you do touch/move them, you definitely don't have to "put them down". -- 174.24.195.56 (talk) 02:20, 8 June 2010 (UTC)

And just by the way "sparrows are lousy parents" is a conclusion you only jump to if you unnecessarily anthropomorphize the situation. Their option of efficiently "trying again" is no doubt a great strategy for a species that doesn't spend 9 months gestating their young. They only take 3 or 4 weeks to hatch some young, so loosing one lot of eggs is obviously not as big a set back for a species that can lay and hatch potentially every few months, as opposed to only once a year. I can think of several valid critiques of human breeding strategies from a sparrow's point of view. Vespine (talk) 05:52, 8 June 2010 (UTC)

Sparrows (like many birds) are position dependent for parenting - they build a nest, and tend their children by returning to that position and feeding the chicks that are there. This is perfectly adequate for most small birds, whose parenting responsibilities might last a handful of weeks until the chicks learn to fly (and it has pros and cons - the parent does not waste time searching for missing chicks which were most likely victims of predators, but are also vulnerable to parasitic birds like cuckoos and cowbirds, who lay their eggs in other birds' nests). Birds generally have poor senses of smell, so they don't smell human scent, but they are attentive to their nests, and will notice if people spend an inordinate amount of time around them (and may not return to a disturbed nest on the assumption that the chicks - again - were victims of predation). --Ludwigs2 06:19, 8 June 2010 (UTC)

As I said, it is moving them that is more of a problem than touching them. If you move them and the parents start building a new nest, then those chicks are going to die. It was possible (if you didn't move them too far) than the parents would find them and continue to care for them, but that clearly hasn't happened in this case. --Tango (talk) 16:40, 8 June 2010 (UTC)

Well, the OP could take the chicks to one of those wildlife rescue places, if they take that species (and are not all like 'meh, there's millions of those - nowt we can do', which does happen) or failing that, attempt to raise the chicks himself (if legal where he is, of course - may not be), which is not easy at all (understatement!) with small, fragile, altricial birds like sparrows. I do agree with Tango that it doesn't look good for these particular nestlings, however. --Kurt Shaped Box (talk) 06:44, 8 June 2010 (UTC)

According to the Bible, ostriches are cruel parents. (http://multilingualbible.com/job/39-16.htm; context in verses 13–17)

-- Wavelength (talk) 07:00, 8 June 2010 (UTC)

"Sparrows are Lousy Parents" WTF!? there are millions of them, they must be one of the most successful parents. 86.4.183.90 (talk) 07:45, 8 June 2010 (UTC)

There are millions of salmon too, and all they do is lay eggs and die. Googlemeister (talk) 13:13, 8 June 2010 (UTC)

Why not try returning the chicks to their original nest location, using a few twigs to prop up the nest if need be, to see if the parents care for them again? The sparrows would be working by instinct rather than thinking. 92.28.243.59 (talk) 10:30, 8 June 2010 (UTC)

You might as well give that a try. However, the babies are probably inside another bird's tummy by now; unwatched chicks are an easy snack for crows. Chicks also need almost constant feeding; a day or so could be enough to starve them, depending on their size. Matt Deres (talk) 13:52, 8 June 2010 (UTC)

They'll probably die (if they haven't already) of cold without their parents. It takes a while before the little ones develop the ability to regulate their own body temperatures. --Kurt Shaped Box (talk) 16:49, 8 June 2010 (UTC)

I remember watching a television nature program in which the first turtle hatchlings from a new brood were awkwardly crawling along the beach to reach the sea. Some well-meaning humans picked them up and placed them in the water. Then they realized their error. By means of some kind of signal, the other members of the brood were notified that the first ones had reached the sea, and they also came forth, only to be preyed upon by birds who had been circling above. Apparently, those first hatchlings ventured forth as a test group to decide whether the others should follow. I tried to find a reference for this behavior of turtles, but I was unsuccessful, both on Wikipedia and on the rest of World Wide Web. However, I found http://theviewspaper.net/tinkering-with-nature-the-man-made-threats/. -- Wavelength (talk) 14:01, 8 June 2010 (UTC)

Consider that for any species to maintain a stable population, each breeding pair over their lifetime must on average raise only two offspring that themselves successfully breed; otherwise the population will increase. Different species use different strategies to achieve this, as Vespine touched on above: see r/K selection theory. —Preceding unsigned comment added by 87.81.230.195 (talk) 15:22, 8 June 2010 (UTC)

Actually, it works even better if the males are "time shared" Googlemeister (talk) 15:47, 8 June 2010 (UTC)

It's my personal theory that it's easier for people to (probably unconsciously) pass moral judgements on the behaviour of somewhat 'cute' animals than it is for say, insects or fish - whose breeding strategies may not be dissimilar, yet as species are harder to empathize with, or even view as conscious entities in the first place. --Kurt Shaped Box (talk) 16:49, 8 June 2010 (UTC)

According to the Bible, the ancient Israelites were counseled not to take the mother bird from a nest, but they were allowed to take the young ones. (http://multilingualbible.com/deuteronomy/22-6.htm; http://multilingualbible.com/deuteronomy/22-7.htm)

-- Wavelength (talk) 15:54, 8 June 2010 (UTC)

According to the Bible, God is mindful of sparrows. (Matthew 10:29–31; Luke 12:6, 7) -- Wavelength (talk) 16:10, 8 June 2010 (UTC)

And according to the Bible there is a giant fairy who lives in the sky, so it's not a great reference really. The Science refdesk is probably not a good place to spout the Bible. 144.32.126.11 (talk) 21:51, 8 June 2010 (UTC)

You can see what others have said about the Bible. (http://www.why-the-bible.com/) -- Wavelength (talk) 22:58, 9 June 2010 (UTC)

And if any of it pertained to fledging sparrows, a serious respondent would have linked to it in this question. Why are you wasting people's time with this? Matt Deres (talk) 11:41, 10 June 2010 (UTC)

God bothering trolls, you see something new every day. 86.26.225.3 (talk) 19:35, 10 June 2010 (UTC)

See Wildlife rehabilitation and the external links. -- Wavelength (talk) 16:13, 8 June 2010 (UTC)

NFPA 704

Are there any chemicals which are 4 in all three areas? --75.25.103.109 (talk) 01:09, 8 June 2010 (UTC)

The "best" I can find is nitroglycerine at 3-3-4. Nitrogen triiodide seems like a good bet since it's extremely explosive, but I can't find a link showing the NFPA rating for it. 75.157.57.12 (talk) 01:50, 8 June 2010 (UTC)

tert-Butyl hydroperoxide is 4/4/4 and also "OX" special-hazard for added fun. DMacks (talk) 02:38, 8 June 2010 (UTC)

I can't find the code for Peroxyacetyl nitrate but there must be some 5's in there..87.102.17.246 (talk) 05:37, 8 June 2010 (UTC)

Bretherick's Handbook of Reactive Chemical Hazards (aka Boy's big book of blowing buddies to bits) is your friend.87.102.17.246 (talk) 05:54, 8 June 2010 (UTC)

I think you'll like this blog. In particular the category I linked to. Chlorine trifluoride is still my favorite from that list. Ariel. (talk) 06:04, 8 June 2010 (UTC)

I'm confused why tert-Butyl hydroperoxide has a 4 for Flammability since our article seems to suggest you need a flashpoint below 23 degrees C for that. Does either article require clarification? The NFPA 704 official standard [4] doesn't appear to be available for free. Nil Einne (talk) 11:07, 8 June 2010 (UTC)

[5] seems like a reliable publisher and says 4/4/4. However its linked PDF (in the "CHRIS Code") says 1/4/, and also says flashpoint is 100 °F (= 38 °C, vs the 43 °C listed in our article). [6] also says it's 1/4/4. [7] says 3/2/2, specifically talking about 70% aqueous solution--seems sensible that diluting would reduce flammability and reactivity (i.e., consistent with /4/4) but not that it would raise heath hazard (so more consistent with 4/ than with 1/). Sheesh! DMacks (talk) 14:40, 8 June 2010 (UTC)

Bicycles and biomechanics...

Bicycles are famous for being such a sterling example of design through experimentation - it took decades for people to understand what made bicycles work, and how best to design them. And yet, the pedal motion remains a perfect circle whereas whether walking or running, the path traveled by the human foot is elliptical.

Has any research been done on what sort of path (circular, ovoid, etc) is most efficient for the legs? For the sake of the question, let's ignore the obvious design difficulties presented by an elliptical pedaling system. I'm just interested in what using our legs at optimum efficiency looks like... 218.25.32.210 (talk) 02:08, 8 June 2010 (UTC)

Well, no one has had a go yet so I'll just have a wild guess, the regular circular pedal path might only deviate from the "perfect optimal" path by a few centimeters. Trying to make an efficient elliptical pedaling "system" would probably add weight and complexity that would outweigh (literally and figuratively) the few % improvement you might get from the slightly better pedal action. Vespine (talk) 05:39, 8 June 2010 (UTC)

A piston action would, I suspect, be slightly more efficient from a human muscle point of view, but the legs deliver power on the downstroke of the circle, so the advantage would be small. I would be surprised if variations on design have not been tried, but perhaps the loss in power in converting the force to drive the chain outweighs the gain from a longer straighter leg-stroke. Can anyone find any research? Dbfirs 08:29, 8 June 2010 (UTC)

Try search "bicycle crank mechanism" - many results many of which are patents. Here's one example [8] 87.102.17.246 (talk) 08:52, 8 June 2010 (UTC)

On a similar line elliptic and ovoid drives have been produced eg search "elliptical bicycle crank"

I've no idea if any of these are any good or just 'bright ideas'. These are mostly designs to eliminate dead spots, haven't found a straight stroke mechanism yet. But they (the other types) definately exist - no problem buying them if you want them.

closer? Treadle bicycle - like walking up stairs - possibly makes more sense. 87.102.17.246 (talk) 09:08, 8 June 2010 (UTC)

I know there's been some sparse theoretical work on the bicycle "shimmy" from physicists (my friend actually did her senior project on this) which would need to take into account many biomechanical mechanisms - see a nice overview. SamuelRiv (talk) 16:35, 8 June 2010 (UTC)

how does water eat thru polyurethane thou?

how does water eat thru polyurethane thou? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 03:32, 8 June 2010 (UTC)
(Copied from above re "hard wood floors"--220.101 (talk) ^Contribs 04:04, 8 June 2010 (UTC))

What is "thou"? --Chemicalinterest (talk) 11:02, 8 June 2010 (UTC)

"though" ?? (as it's a follow-up to an earlier question) Ghmyrtle (talk) 11:30, 8 June 2010 (UTC)

Maybe it's Hey, thou! Tell me how water eateth thru polyurethane, or I shall cudgel thee until thou shouldst talk! --Trovatore (talk) 02:50, 10 June 2010 (UTC)

I would think that it is a network of fibers that can break the surface tension of water. Then the spaces between the fibers are filled with water. --Chemicalinterest (talk) 11:36, 8 June 2010 (UTC)

It sounds like they have coated the wood floor with polyurethane. That should stop water getting through but the water might go through cracks or the polyurethane might be worn. Floors which used a lot like community halls need to be stripped and resealed every couple of years. Aluminium oxide is often put into the mix to make the surface more hard wearing. Anyway you should mop up spilt water rather than leave it lying on the floor. Dmcq (talk) 13:38, 8 June 2010 (UTC)

A proposed mechanism:

• Water attacks the carbonyl and forms a tetrahedral intermediate
• The intermediate collapses back into polyurethane -- only now the water is expelled on the other side of the polyurethane layer. Rinse and repeat for however thick the polyurethane is. John Riemann Soong (talk) 19:37, 8 June 2010 (UTC)

Nope, polyurethane is completely waterproof -- they even use it in boat hulls! So the water must be soaking through gaps or cracks in the plastic. 67.170.215.166 (talk) 02:45, 10 June 2010 (UTC)

titanium

how come titanium is sometimes dull and sometimes shiny? like this titanium bowl below is dull but iv seen shiny titanium too. if its just metallic titanium shouldent it only have one finish?

http://www.rei.com/product/720286

--Alexsmith44 (talk) 04:51, 8 June 2010 (UTC)

That's probably been shot peened to give it a non-polished finish (or another process - it may not have been shot peened)

Same thing goes with steel - you can have polished steel or brushed steel or other finishes.87.102.17.246 (talk) 05:26, 8 June 2010 (UTC)

In fact, by anodizing titanium to produce oxide layers of different thickness one can produce quite an amazing variety of coloured finishes. This is how the "pale gold" titanium cladding for the Guggenheim Museum Bilbao was produced. An explanation of how to achieve this practically is here [9]. Equisetum (talk | email | contributions) 10:14, 8 June 2010 (UTC)

so isint it a coating not a real metal? —Preceding unsigned comment added by Alexsmith44 (talk • contribs) 10:52, 8 June 2010 (UTC)

Yes it is a coating of oxides upon the titanium surface, but the strength of the underlying metal isn't compromised. --Chemicalinterest (talk) 11:01, 8 June 2010 (UTC)

Assuming of course that the thickness of the oxide coating is small in comparison with the thickness of the remaining titanium. That would probably only be a factor if you a very thin piece of titanium, like paper thin. Googlemeister (talk) 13:08, 8 June 2010 (UTC)

color of elements

how does elements got there colors? whats there at atomic level to give them color?What abo't compounds and mixtures? --Myownid420 (talk) 05:15, 8 June 2010 (UTC)

This has been asked many times in the past, the answer is "it varies". There is no single quick and simple answer. Our article on Color goes into quite a bit of detail, have a read of that and come back if you have any specific questions. Vespine (talk) 05:33, 8 June 2010 (UTC)

I don't see why color is produced, only that it is produced. --Chemicalinterest (talk) 11:40, 8 June 2010 (UTC)

Light from the sun (or a light bulb or whatever) hits the surface of the object. Some of that light is reflected back to your eyes - that is what you see. The "color" that the object has is a function of what frequencies of light it reflects - and what it absorbs. The graph (at right) shows how (for example) Gold...the red curve...reflects almost all of the light that's above 500nm. If you look at the spectrum in the second picture - you'll see that the colors above 500nm are reds, oranges and yellows. That's why gold looks orangy-yellow. On that same graph, you can see that the blue curve for aluminium is almost flat - it reflects nearly all light equally - so it's a white/silver looking color. The brown curve (for silver) shows that it doesn't reflect colors below about 300nm - but that's up in the ultra-violet somewhere - so silver also looks pretty much white/silvery because it reflects all VISIBLE light (although not all INVISIBLE light).

So the question boils down to "Why do some materials absorb some frequencies of light and not others?"

The reason materials reflect one set of frequencies and absorb others is very complex. It depends on things like crystal structure, particle sizes, quantum effects...all sorts of deeply complex matters...all interacting with each other in complex ways. I can offer you our articles on Discrete dipole approximation, Electric polarizability, Clausius–Mossotti relation, Mie theory, Rayleigh scattering and such - but I fear it wouldn't help you to understand this any better.

For some simple materials - like gasses - the size of the particles (molecules), the distance between them and the speed of light within them (which affects the refractive index) can be used to calculate the colors they reflect - but for more complex situations, it's just too complicated. This simplest case is explained by Rayleigh scattering - and to understand that, you have to get into the math. For solid materials, it's much more complicated.

Honestly, this final step in the story is beyond my ability to provide an approachable explanation...and it's not often I have to say that!

SteveBaker (talk) 20:52, 8 June 2010 (UTC)

thanx for answers, once even i also thought of some absorption and reflection theory, but another question arose.

Question

how do transparent compound behaves? i mean they are also made of elements like water so what they absorb and reflect--Myownid420 (talk) 02:53, 9 June 2010 (UTC).

It's a similar deal. If you want the full picture: Some frequencies of light pass through the material with some attenuation - some are reflected - others are absorbed - others are sub-surface-scattered within the material (think about how materials like milk and human skin look) - and some frequencies are actually emitted by the material (think about something that's "Red hot" - glowing by its own light). The color you see is (technically) the sum of all of those things - and also depends on the frequencies present in the incoming light. All of those things are super-complicated to describe at the level of atoms. You also have to think beyond the visible spectrum. Some materials are transparent to infra-red light - while being opaque to visible light...and vice-versa. We have a coating on our windows which is supposed to reflect infra-red light - thereby keeping the house cool in summer and warm in winter...however, the glass seems almost perfectly transparent in the visible light spectrum. SteveBaker (talk) 04:02, 9 June 2010 (UTC)

Fox mauling baby - motivation?

Was the fox attempting to eat the baby, or motivated by something else? --78.148.138.14 (talk) 11:41, 8 June 2010 (UTC)

From what I've read [10], there is no previous authenticated attack of the sort that is described, but the article has some suggestions as to why it might have happened. Mikenorton (talk) 11:47, 8 June 2010 (UTC)

[11] too --BozMo talk 11:47, 8 June 2010 (UTC)

What is the incidence of rabies in the area? A rabid fox will approach people and act aggressively. The expert's confidence that "Foxes do not attack people" stands in sharp contrast to the mother's eyewitness report. Or maybe a cat or a German shepard attacked the babies and the fox innocently wandered in to see what was the matter. The "expert" trying to blame the victims was pretty amazing. Edison (talk) 14:08, 8 June 2010 (UTC)

I can't see any suggestion of "blaming the victims" in the linked article, Edison. What part are you thus interpreting? 87.81.230.195 (talk) 15:09, 8 June 2010 (UTC)

No rabies in the UK, apart from in bats (the attack happened in London). Mikenorton (talk) 14:13, 8 June 2010 (UTC)

So can foxes not catch rabies from bats? I know people can. Googlemeister (talk) 15:45, 8 June 2010 (UTC)

Humans only rarely catch rabies from bats, the last case in the UK was a bat handler who got bitten while moving a bat in 2002; according to this [12] the prevalence of rabies in bats in the UK is actually very low and this is the European bat Lyssavirus, not the classical rabies strain as found in dogs etc. Mikenorton (talk) 16:52, 8 June 2010 (UTC)

As Mike says, no rabies. People in the UK have been living around foxes for a long time, and nothing like this is ever recorded as having happened before, although they have been known to attack lambs and kids. It seems reasonable that an investigation would look into what else could have caused the same apparent effect before concluding that something had happened for the first time ever. 86.164.69.239 (talk) 14:40, 8 June 2010 (UTC)

A fox's natural instinct is to bite and kill any small animal that is vulnerable, and once it starts to kill, it tends to continue until all such creatures have been killed. I'm surprised that the fox thought the babies were small enough to be victims, but something must have made it realise that they were vulnerable and wouldn't retaliate. A wolf or a large wild cat would have behaved in a similar way. Wild animals can be dangerous. Dbfirs 15:13, 8 June 2010 (UTC)

A number of experts have identified that this behaviour was very unusual for a fox. They are by nature not confrontational animals and tend towards very small animals or carrion. As with most wild animals they tend to bugger off at speed rather than attack. A baby is significantly bigger than most of what a fox would attack.

The mother has already identified that she didn't see what happened at the beginning of the event, she saw what had already happened. So there is no indication of why the fox did what it did.

There are a number of things that could have caused it to happen, but it's very unusual behaviour.

ALR (talk) 15:22, 8 June 2010 (UTC)

I agree that it is unusual behaviour for a fox to attack a baby, but anyone who has seen the incredible carnage that a single fox can cause in a hen-house knows that a fox in a killing frenzy is not exactly timid. Perhaps this fox had recently killed a new-born lamb and the cry of the babies sounded similar to that of the lamb and so triggered similar behaviour. Dbfirs 16:21, 8 June 2010 (UTC)

A newborn lamb? In East London in June? 86.164.69.239 (talk) 00:19, 9 June 2010 (UTC)

Yes, It occurred to me after I had written the suggestion that the place and time were not quite appropriate for lambs, but perhaps some other small animals - foxes love kittens! Dbfirs 07:26, 9 June 2010 (UTC)

Notwithstanding the issue about suggesting a lamb :) I'd find that unlikely. Part of the issue with the behaviour in chicken coops is a loss of control, as well as a defensive response with all the chickens around as well. Despite what's said it's not a spite issue but a fairly normal response in a target rich environment. They eat their fill, and take some away to hoard, but they also leave a lot of dead chickens around.

My thought is that it's been confident enough to explore, perhaps jumped into the cot, staartled one or both children who've started crying. That would be enough to startle the fox, particularly if it's got tangled in bedclothes or something. I'd assess it as a defensive reaction rather than a raitonal thought process about where to find food.

ALR (talk) 10:30, 9 June 2010 (UTC)

This isn't necessarily a question of whether the fox was trying to eat the baby; it could have just been spooked by a sudden cry or something similar. Foxes are very easy to spook. Regards, --—Cyclonenim | Chat  16:46, 8 June 2010 (UTC)

Reports I've read there have been precisely TWO recorded incidents in recent years, this one and one in 2002. To put it into perspective there are THREE THOUSAND people injured by dogs in the UK per year[13] - while some of those injuries are accidental it really makes an idiocy of the 'kill the fox vermin' brigade. The danger is your family pet, not the urban fox. Exxolon ([[User talk:Exxolon|talk]]) 17:14, 8 June 2010 (UTC)

It doesn't seem that implausible - if the fox happened on the baby and decides to sniff it to figure what's going on - then the baby grabs tail and/or ears (as they do with friendly dogs) - then it wouldn't be surprising if that triggered a defensive attack. SteveBaker (talk) 20:02, 8 June 2010 (UTC)

er...both kids Steve? 86.4.183.90 (talk) 21:40, 8 June 2010 (UTC)

The kids were sleeping in the same cot, weren't they? If one did something to scare the fox, the fox would probably attack both. --Tango (talk) 00:41, 9 June 2010 (UTC)

The problem is some people are thinking of foxes as ravenous beasts, when in fact they're usually timid scavengers. If they have the option to run, they take it. If the fox was looking in the cot for food as the babies were sleeping and was thus unaware of them, if they suddenly start crying or pulling on the foxes fur that's going to be a pretty big shock to the fox. I wouldn't be surprised if it decided to attack. Regards, --—Cyclonenim | Chat  17:03, 9 June 2010 (UTC)

As an interesting aside, I grew up in Malaysia but read quite a lot of British books including Dick King-Smith and others with animals in them; and in general of course many British books include foxes. It was only a few years ago in my early twenties that I realised foxes are actually fairly small, I had always thought they were about the size of a medium dog or slightly smaller then a wolf rather then generally not that much bigger then a cat that they are. Nil Einne (talk) 18:41, 9 June 2010 (UTC)

Do you have unusually large cats & dogs in Malaysia? I agree, much smaller than a wolf though, and the bushy tail makes them look bigger than they actually are. Some species of fox look quite dainty, but a mature well-fed British dog-fox can weigh up to 20 pounds (less than the weight of the babies that were attacked) with a length up to three feet and looks like a fairly large dog. Dbfirs 21:07, 9 June 2010 (UTC)

What was the one in 2002, and do you have a link? Because the reports I've seen have talked about only two previous cases, and both times it turned out not to be a fox attack. 86.164.69.239 (talk) 22:24, 9 June 2010 (UTC)

Annihilation

Would an antiproton and a neutron(or a proton and a antinutron) annihilate if they collided?Diwakark86 (talk) 13:12, 8 June 2010 (UTC)

Yes, and it would produce a shower of mesons. Dauto (talk) 16:01, 8 June 2010 (UTC)

But sometimes, ever-so briefly (unless moving reeeeaaally fast), they will form an exotic molecule called positronium, before eventually quantum-tunneling through this metastable state and annihilating. SamuelRiv (talk) 16:38, 8 June 2010 (UTC)

The positronium is a bound state of an electron and a positron. Dauto (talk) 19:12, 8 June 2010 (UTC)

Protonium is the antiproton exotic atom. Graeme Bartlett (talk) 21:31, 8 June 2010 (UTC)

Thanks guys, I've been making dumb mistakes like that all week. SamuelRiv (talk) 00:20, 9 June 2010 (UTC)

Hexamminecobalt(III) ion

What is the color of the aforementioned ion in aqueous solution? --Chemicalinterest (talk) 14:25, 8 June 2010 (UTC)

Yellow here 87.102.13.111 (talk) 14:40, 8 June 2010 (UTC)

As you see on my user page, I wanted to form the ion, but I needed a color to identify it. As of this minute I am drying the black cobalt(III) oxide powder that I filtered. --Chemicalinterest (talk) 14:48, 8 June 2010 (UTC)

Usually described as "golden-brown", but I guess "yellow" would be valid for dilute solutions. Good luck tying to prepare it from cobalt(III) oxide! It's usually easier to start from a solution of a cobalt(II) salt, add ammonia and let it oxidize in air. Physchim62 (talk) 15:03, 8 June 2010 (UTC)

The link above says "In fact the hexaamminecobalt(III) ion is yellow! What you see is a mixture of this ion and various other cobalt(III) ions involving ligand exchange reactions with both water molecules and negative ions present in the solution" - I can't actually confirm this - maybe someone else can check.87.102.13.111 (talk) 15:46, 8 June 2010 (UTC)

My source says "orange" (without any qualifiers) and gives a peak absorbence at 475 nm (in the blue region of the spectrum). On the other hand, I do know that one of the ammonia ligands is relatively labile, and so it makes sense that some of it would be replaced by water or other negative ions. My same source says that aquapentaaminecobalt(III) is red, and has a peak absorbence of 495 nm (blue-green). I suppose if the pure hexaamine complex is yellow, adding a little red aqua pentaamine complex might make it appear orange. Buddy431 (talk) 16:06, 8 June 2010 (UTC)

(edit conflict with 87.102) This is a common exercise for freshmen chemistry students. If you have access to scientific literature, there are a plethora of articles about this and closely related syntheses. This, for example, is from the Journal of Chemical Education and outlines this exact synthesis, along with some other pentaamine cobalt(III) compounds. Yeah, getting it from the oxide is going to be hard. Usually Cobalt(II) chloride is dumped in an ammonia solution, and then oxidized with air or hydrogen peroxide. Note that during oxidation, one of the ammonia ligands may be replaced by water. It's not too hard to knock off the water to put an ammonia back on, or any other ligand for that matter (I made the chloride and nitrite pentaamine complexes, if I recall correctly). Buddy431 (talk) 15:56, 8 June 2010 (UTC)

I didn't know wiki had an article on it: . --Chemicalinterest (talk) 16:26, 8 June 2010 (UTC)

I reacted the cobalt oxide with hydrochloric acid to get a light brown solution, which was reduced by ascorbic acid to a pink Co²⁺ solution. Is that brown solution some type of higher chloride? --Chemicalinterest (talk) 16:15, 8 June 2010 (UTC)

Almost certainly - note the stability of "CoCl₃" is debatable, it probably doesn't exist as a binary solid.. There's a brief mention at Cobalt(II) chloride (had to remove some WP:OR)

What the solution was I don't know - it would have to be some sort of cobalt(III) / chloride complex - but more details than that I cannot give. A lot depends on the mole ratio of HCl to Co, as well as the Cl- concentration. amongst other factors. 87.102.13.111 (talk) 17:00, 8 June 2010 (UTC)

Did you make the cobaltic oxide yourself? - just wondering if it was totally free from impurities? 87.102.13.111 (talk) 17:08, 8 June 2010 (UTC)

I reacted cobalt chloride from a chemistry set (looked pure) with household bleach. --Chemicalinterest (talk) 20:12, 8 June 2010 (UTC)

Lots of HCl to small bit of cobalt oxide. --Chemicalinterest (talk) 20:12, 8 June 2010 (UTC)

I was wondering if you had tried to make it from Hexamminecobalt(III) chloride + base + boiling as described here [14] - if there was any ammonia left in the solid it could have confused the colour a bit.87.102.13.111 (talk) 20:42, 8 June 2010 (UTC)

Clay

How can rip Aluminum Oxide ( Al2O3 ) from clay, and the chemical formula for the question of what is clay? —Preceding unsigned comment added by אנונימי גבר (talk • contribs) 15:14, 8 June 2010 (UTC)

As far as I know it is practically impossilble to get aluminium oxide from clay.

Clay can be various minerals - it's a (wet) mixture of various Aluminosilicates (and sometimes silicates) of small particle size.

Some of the minerals commonly making up clay are listed at Clay#Grouping.87.102.13.111 (talk) 15:58, 8 June 2010 (UTC)

Aluminosilicate clays are the largest source of aluminum, but they are very difficult to extract aluminum from. Bauxite, although rarer, is used as an aluminum ore. --Chemicalinterest (talk) 16:12, 8 June 2010 (UTC)

Perhaps extract it from chemical reactions involving alum? ~AH1^(TCU) 02:09, 10 June 2010 (UTC)

You can extract aluminum from kaolin clay by converting it to aluminum trichloride. FWiW 67.170.215.166 (talk) 02:49, 10 June 2010 (UTC)

Sapphire Windows

I noticed in media releases for Alon, that it is repeatedly compared to sapphire. I have never (to my knowledge) seen a sapphire window. Do sapphire windows exist? What is the common usage for one? -- kainaw™ 15:38, 8 June 2010 (UTC)

SapphireWindow.com helpfully lists some of the benefits; they appear to be strong and scratch-resistant, and are used in spaceflight applications. -- Coneslayer (talk) 15:42, 8 June 2010 (UTC)

Sapphire 'glass' is more common (and cheap) than you might think. Sapphire says it's used in barcode scanner windows. It's also used in watch glasses (scratch resistant glass) - eg just an example There's scientific applications as well. 87.102.13.111 (talk) 16:02, 8 June 2010 (UTC)

Even my (£50) casio watch has sapphire glass. - Just looks like glass.87.102.13.111 (talk) 16:03, 8 June 2010 (UTC)

Cool. I had no idea sapphire glass was so common that nobody really discusses it. I just checked and my watch has sapphire glass. My phone also has a sapphire glass cover over the camera lens. Wish the touchscreen had one too. I broke the last touchscreen trying to get it to recognize my presses. -- kainaw™ 17:46, 8 June 2010 (UTC)

Perhaps you already know this but if your phone has a capacitive touch screen then pushing harder most likely doesn't help Nil Einne (talk) 19:22, 8 June 2010 (UTC)

It should be pointed out the sapphire is actually aluminium oxide, AKA alumina. Ariel. (talk) 21:02, 8 June 2010 (UTC)

Or even Corundum - in fact the uses are mentioned at Corundum#synthetic corundum.87.102.13.111 (talk) 21:54, 8 June 2010 (UTC)

Yep, it's handy stuff; scientists love it. In addition to its much greater strength and scratch resistance, it is also transparent across a wider range of wavelengths (well out into the ultraviolet and the infrared) than ordinary glass, plus it can take much higher temperatures. In really unpleasant chemical environments, it's far superior to glass — sapphire windows aren't even etched by fluorine gas: [15].

Industrial sapphire is also used for non-transparent applications where its extreme toughness is an asset. Analytical chemists and biochemists will usually find little sapphire pistons inside the high-pressure solvent pumps of their HPLC apparatus. (These pumps need to deliver small volumes of liquid – milliliters per minute – at extremely constant flow rates and at pressures up to a few thousand pounds per square inch.) TenOfAllTrades(talk) 12:54, 9 June 2010 (UTC)

anyone familiar with saccharides and gold nanorod aggregation?

I'm trying to search for promising surfactants to use for saccharide-treated gold nanorods. We want to use smaller rods because they require less surfactant and are thus less cytotoxic (if we use cationic surfactant like polyethylenimine) and to promote cell entry, but as they get smaller aggregation increases (i.e. gold nanorods form bigger ones via metallic bonding). Currently PEI-treated rods like to get stuck on the surface of the cell of the rods are too big.

(We need them to be rods because of their special anisotropic properties useful for microscopy.)

Any suggestions maybe for a saccharide that would promote entry and prevent aggregation? We currently use sulfide linkages between the Au and the ligands, and while we haven't performed any diagnostic tests, would displacement of these sulfide linkages be necessary for aggregation? Would using something like in this paper be better? (but adapted to saccharides?) John Riemann Soong (talk) 16:05, 8 June 2010 (UTC)

Electrical Doubt Clarifying

Why the birds are not shocking when it is on the a distribution line? If you know the answer please send the answer to this mail <Email address removed> —Preceding unsigned comment added by 117.200.27.105 (talk) 16:33, 8 June 2010 (UTC)

Hi, we don't respond to queries by email so I've deleted your address. Brammers (talk/c) 16:38, 8 June 2010 (UTC)

You'll find a lot of good information on this amazing resource. Regards, --—Cyclonenim | Chat  16:47, 8 June 2010 (UTC)

It's because the current can't flow them to anywhere else. Linesmen occasionally work on live wires directly. CS Miller (talk) 16:51, 8 June 2010 (UTC)

Don't some chemicals in your body have reduction potentials? If there was a way for the sweat on your skin to send back ions along the wire...or deenergised electrons....I mean, when electricity makes your muscles spasm, there is a voltage drop, right? John Riemann Soong (talk) 18:22, 8 June 2010 (UTC)

One previous reference-desk thread. Deor (talk) 18:49, 8 June 2010 (UTC)

That previous discussion covered a lot of other sub-questions - here is the meat of it: The electricity has two paths it can take - the short path down an inch or so of copper wire - or the longer path: up one leg of the bird, past it's "naughty bits" and back down the other leg. The amount of current that flows down each path is inversely proportional to the resistance. Since nice thick copper wire has very little resistance - and birds have (relatively) high resistance, a huge amount of current flows down the wire - and very little of it flows through the bird. BUT that amount isn't zero! The bird is indeed being very slightly electrocuted...but the current flow, even with a soaking wet bird on a very high voltage wire is so slight that it doesn't seem to harm them. SteveBaker (talk) 19:53, 8 June 2010 (UTC)

What might the actual emf (volts, millivolts, microvolts) be between the bird's feet? hydnjo (talk) 02:16, 9 June 2010 (UTC)

If we imagine the drop in emf along the distribution line is 1 volt per kilometre, and the distance between the bird's feet is 5 centimetres, the emf between the bird's feet would be 50 microvolts. But if the drop in emf is 1 volt per mile, and the distance between the bird's feet is six inches, the emf between feet is 95 microvolts. Dolphin (t) 02:28, 9 June 2010 (UTC)

Thanks for doing the math but it begs the question; what would the expected voltage drop be on multi-kilovolt transmission lines over a distance of say... birds feet? hydnjo (talk) 02:50, 9 June 2010 (UTC)

From the few places I could find information, I believe the worst case figure that the industry tolerates is around 5% drop over an entire transmission line - which would typically be over 50km. So for a 10,000 volt line, we have 10 volts per km...about ten times what Dolphin51 estimates...but even for a large bird, we're talking less than a millivolt. Another way to ask this is to ask what the resistance of a 6" long chunk of inch diameter transmission cable is...I don't think it's much! —Preceding unsigned comment added by SteveBaker (talk • contribs) 03:52, 9 June 2010

Also, I don't think birds like to perch on the high voltage transmission lines. At least I have never seen one perched on such a line. Googlemeister (talk) 13:23, 9 June 2010 (UTC)

Steve, thanks for that research :-) I didn't know where to begin :-( hydnjo (talk) 04:02, 9 June 2010 (UTC)

So, given skin resistance and all, a few millivolts of emf between the birds feet might actually be the reason that they like being there - a slight warming rather than a slight shocking. They do seem to congregate for some reason. hydnjo (talk) 04:14, 9 June 2010 (UTC)

Slight warming, yes, but caused mainly by the current flowing through the wire, not through the bird, so the bird sees the wire as a warm twig of just the right size to perch on, with lots of space for its fellow-flock-members, well-clear of any ground predators and with a clear view of any threat from the air. Dbfirs 07:20, 9 June 2010 (UTC)

Eating rotten eggs

Is it unhealthy to eat rotten eggs? Are rotten eggs also raw eggs?--Quest09 (talk) 17:26, 8 June 2010 (UTC)

In general if it smells rotten that's nature telling you not to eat it. I would guess any sort of egg: raw, scrambled, boiled etc can go rotten eventually.

See also Century egg which looks rotten, but people still eat (apparently).87.102.13.111 (talk) 17:44, 8 June 2010 (UTC)

Century eggs are delicious. It's like saying yogurt or wine is rotten. Western chauvinists! John Riemann Soong (talk) 18:09, 8 June 2010 (UTC)

Of course wine is rotten, why else would people like it? --Chemicalinterest (talk) 20:13, 8 June 2010 (UTC)

Yeah, but that's not really a 'rotten egg', is it (or is it?)? More like 'chemically preserved', IMO. I mean, you wouldn't say that a pickled egg was 'rotten', would you (or would you?)? --Kurt Shaped Box (talk) 18:48, 8 June 2010 (UTC)

The protein is denatured [16] "Production of the century egg involves chemical reactions such as denaturation of proteins, hydrolysis, deamination, decarboxylation and racemisation" - hence the ammonia and sulphur - it's not clear to me why pickled eggs are different - though they are hard boiled first.87.102.13.111 (talk) 19:15, 8 June 2010 (UTC)

Apparently hundred-year eggs are made in an alkaline medium; pickling is ordinarily in an acid medium. --Trovatore (talk) 21:02, 8 June 2010 (UTC)

Most eggs are sterile, and will not rot even if kept without refrigeration (they will keep for over a month). The danger of a rotten egg depends entirely on what made it rot. Rot usually just means it was colonized by bacteria (or fungus). Rot in and of itself is not dangerous, what is dangerous is that some bacteria will release toxins when they grow - and those toxins are what is dangerous. Other bacteria will grow inside a person, which can be dangerous (but most are not). If neither of those things happens, then it can be rotten, but edible. For example if you choose a bacteria that is safe to eat, and doesn't release anything harmful - which is exactly what fermentation is. Ariel. (talk) 20:57, 8 June 2010 (UTC)

Rhino Virus and Nanometers

Hello! Does anyone know what the human rhinovirus eats (presumably cells in person, but I'm not sure) and how many nanometers are in a centimeter (or preferably an inch). Thanks! ~ QwerpQwertus ·_Talk_·_Contribs_· 17:59, 8 June 2010 (UTC)

Viruses don't eat. From one point of view, they are not alive. They don't need to digest anything to reproduce. I suppose it's like asking the manager of a factory what he products he makes. From one POV, he doesn't make anything -- the workers do. Viruses hijack cell machinery to produce more viruses. Think of a Toyota executive walking into a Ford factory and convincing all the workers to start producing more Toyotas (to carry Toyota executives in... to walk into more factories...). Those executives don't consume any metal. The machines do.

For the virus, it would be better for the cell not to die at all -- but sometimes it's not worth the trouble to save the cell -- just explode out of the cell and infect more. Some viruses employ alternate strategies. John Riemann Soong (talk) 18:13, 8 June 2010 (UTC)

Oh, that makes sense. Thanks! ~ QwerpQwertus ·_Talk_·_Contribs_· 18:22, 8 June 2010 (UTC)

Google does unit conversions quite nicely. Paul (Stansifer) 18:42, 8 June 2010 (UTC)

1 inch = 25,400,000 nanometers, 1cm = 10,000,000 nanometers. SteveBaker (talk) 19:48, 8 June 2010 (UTC)

Molecular compexity

This [17] states (section 12.22.2) "molecular complexities" of 3,2,1.5 . Apart from the problem that I can't see the relevant link, I have no idea what is meant by this, and searching for "molecular complexity" gives various measures. eg [18] [19]

Is there a standard interpretation for this term, and if so what would it mean? 87.102.13.111 (talk) 18:46, 8 June 2010 (UTC)

The term is widely used but rarely defined. I see one PDF here that (I think) defines the term and proposes a new definition. I'm no chemist - but perhaps you can understand what it's saying? (We need an article about this!) SteveBaker (talk) 19:45, 8 June 2010 (UTC)

I'm (supposed to be) a chemist and it's news to me.. I've seen the link above but it gives values of over ten for simple molecules .. the compounds described are similar but have quoted complexities less than three.

The idea looks like a simple maths concept, I'll ask at that desk see if they spot the method.87.102.13.111 (talk) 20:00, 8 June 2010 (UTC)

I've only seen the term applied to biological molecules, particularly proteins which can be defined in complexity as primary, secondary and tertiary. I'd guess it's something similar, but the way they're wording it makes it look different. No idea! Regards, --—Cyclonenim | Chat  19:50, 8 June 2010 (UTC)

Ah! I think it might be the "augmented valence sum" AVC(1/2^d) value as described in the SteveBaker reference for just the metal atoms (I thought the Oxygens would be included too). Still confused - is the 'AVC' method common? The paper itself says that Morgan's method is the one that has been most used.87.102.13.111 (talk) 21:37, 8 June 2010 (UTC)

This sounds more and more like something we should have an article on. SteveBaker (talk) 03:37, 9 June 2010 (UTC)

Naturally Occuring Dendrimers

Are there any naturally occuring dendrimer macromolecules apart from those on gecko feet? I can't seem to find any and don't know much about the subject 144.32.126.11 (talk) 21:23, 8 June 2010 (UTC)

Whatever you find (even a sentence noting that gecko-feet are a naturally-occurring example--it's not mentioned(?), please add it to our dendrimer article. DMacks (talk) 03:47, 9 June 2010 (UTC)

Pikachurin

What does pikachurin actually do? I looked at several journal articles about it, but I can't understand any of them. --75.25.103.109 (talk) 21:50, 8 June 2010 (UTC)

As far as I can tell from our pikachurin article, it forms part of the molecular structure that mechanically attaches light receptor cells in the retina to the cells they send signals to. (I don't blame you for having a hard time making sense of it.) Looie496 (talk) 23:03, 8 June 2010 (UTC)

Cobalt(II) hydroxide solubility

Why is the solubility 3.2g/100 mL of water? I thought transition metal hydroxides were insoluble. --Chemicalinterest (talk) 22:18, 8 June 2010 (UTC)

Because the figure in Wikipedia was wrong by four orders of magnitude! Thanks for pointing out the error. Physchim62 (talk) 22:25, 8 June 2010 (UTC)

I just added the picture and it looks quite insoluble (soluble in acid though). --Chemicalinterest (talk) 22:42, 8 June 2010 (UTC)

Good, thanks for bring attention to that - there is no CoO₂ - at least not from this compound.. so I corrected that too [20] 87.102.13.111 (talk) 00:06, 9 June 2010 (UTC)

If you boil that blue Co(OH)₂ it should turn into the more stable reddish form here - can we have a picture of that too.. please.87.102.13.111 (talk) 00:35, 9 June 2010 (UTC)

I'll try to get some; I just have a limited supply of Co compounds so I cannot show a picture of a watch glass heaped with the stuff like they normally do, only a small test tube with some precipitate. --Chemicalinterest (talk) 13:51, 9 June 2010 (UTC)

Extract From Dry Ingredients?

I have for a long time wondered, how does one produce an extract from a relatively dry ingredient, i.e. almonds? I know that nuts generally contain a fair amount of oil, but I don't understand how almond extract, being a very low-viscosity liquid, can be extracted from almonds, a very solid, dry substance? Thanks! Stripey the crab (talk) 23:42, 8 June 2010 (UTC)

In our article about extracts, four methods are mentioned for extracting liquids from a variety of foodstuffs, including almonds. They are expression by fruit press, absorption through steeping in liquid (probably how almond extract is created), maceration, and distillation. Interestingly, searching almond extract turns up that almonds are 49% oils. Intelligentsium 23:58, 8 June 2010 (UTC)

Any distillation is likely to be Steam distillation.87.102.13.111 (talk) 00:13, 9 June 2010 (UTC)

For example - sunflower oil - either mashed, squashed or otherwise broken up (some oil can be extracted using presses at this point) - the remains which still contain oil will typically be mixed with hexane and warmed etc - the remaining oil dissolves in the hexane - the husks are then filtered off (these husks sometimes go to make cattle feed etc) - and the hexane evaporated to leave 'sunflower oil'.. (newer processes use supercritical carbon dioxide instead of hexane - but it's still the same principle.)

There are quite a lot of good books on google books if you want to know a lot more - searching for "XXX oil extraction" where XXX is almonds, sunflower etc should do it.87.102.13.111 (talk) 00:13, 9 June 2010 (UTC)

Depending on what is being processed the exact set up differs eg for almonds it seems to be "cold pressing" that is used, and there are additional stages to remove prussic acid from it.

Just looking at a seach for "almond oil extraction" shows methods using Carbon dioxide, steam distillation, and cold pressing. A lot depends on what the final product is used for - cold pressing is usually the prefered method for (high value/quality) food stuffs (such as walnut oil, olive oil) - but for high volume food stuffs such as sunflower there will be extractive techniques as well (hexane, CO2 etc). Steam distillation is probably the worst method since the high temperatures affect the final product.87.102.13.111 (talk) 00:22, 9 June 2010 (UTC)

Historically, essential oils (for example, for perfume or incense) were made by boiling the item in water, then skimming the oil off of the top. You can probably do that with ground almonds. If there is too little oil in the material, you add some plain oil, and the essential oil dissolves in the plain one, and then you skim off both of them together. Ariel. (talk) 01:11, 9 June 2010 (UTC)