Wikipedia:Reference desk/Archives/Science/2011 August 2

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August 2

Identifying YAG crystals

How can I tell a YAG crystal from a diamond ? I tried using a ruby for a scratch test, but couldn't get either to scratch the other. 68.79.93.3 (talk) 01:22, 2 August 2011 (UTC)

Ruby (corundum) should scratch YAG, and should be scratched by diamond. YAG can also be distinguished by its lower refractive index (1.83, versus 2.42 for diamond), higher density (4.56 g/cc, versus 3.52 for diamond), and different cut: [1], [2], [3].

You seem to be stumbling across a inordinately large number of gemstones that need to be identified. (Not a bad problem to have I suppose.) Perhaps you need to start some sort of relationship with a jeweler? APL (talk) 08:11, 2 August 2011 (UTC)

Perhaps the same gemstones, but the OP still hasn't identified whether they are diamonds because of the failure of the scratch test and a lack of trust in any external party to verify they are diamonds Nil Einne (talk) 01:48, 3 August 2011 (UTC)

subatomic particles

Where can I find a list of subatomic particles that result at different energies of proton collision? --DeeperQA (talk) 09:00, 2 August 2011 (UTC)

See list of particles. Dauto (talk) 15:45, 2 August 2011 (UTC)

subatomic shells

Is there a discussion anywhere regarding the possibility of the subatomic particles existing as clouds or in shells within the proton, like the electrons fill shells external to the atom? --DeeperQA (talk) 09:42, 2 August 2011 (UTC)

Usually the internal structure of protons is modeled by form factors. Dauto (talk) 13:48, 2 August 2011 (UTC)

See nuclear shell model. Oops, sorry, misread. Wnt (talk) 14:33, 2 August 2011 (UTC)

The internal structure of nucleons like protons and neutrons is not well understood beyond the "quark and gluon sea" level. We don't have solid, well accepted models for the organization of quarks, with well defined geometries, the same way we do for the electron cloud. There are some models, but none has gained widespread acceptance. See Nucleon#Models. --Jayron32 16:54, 2 August 2011 (UTC)

Wow. That "chiral bag model" sounds very interesting, but the puny weapons of my mind cannot dent its neutronium armor. How does the baryon number, or quark fields, become a matter of topology and how would they cancel each other out? Wnt (talk) 17:02, 2 August 2011 (UTC)

Zinc chloride solution

What is the zinc contend in 65% zinc chloride solution — Preceding unsigned comment added by 41.29.251.155 (talk) 12:03, 2 August 2011 (UTC)

Need more info:

1) What's the solvent ?

2) Is that 65% by mass ?

3) In what form do you want the zinc content ? Also in mass ? 68.79.93.3 (talk) 13:17, 2 August 2011 (UTC)

% by volume, mass or amount? If by mass, then zinc makes up 64.85% the total zinc chloride mass, meaning that of the 65% zinc chloride solution, only 64.85% is zinc. To get the final mass percentage multiply the percentages together: 42.15%. Plasmic Physics (talk) 13:21, 2 August 2011 (UTC)

Which animal in burrow?

In rural south east England recently, I was walking along a broad strip of rough grass adjacent to a field, with some light scrub on the other side. I saw a burrow about an inch in diameter, and a circular bare patch of a few inches diameter around the burrow, which was a little off centre. Does anyone know what animal the burrow may have been made by? 2.97.215.11 (talk) 15:04, 2 August 2011 (UTC)

Do they have chipmunks in England? The article says they are native to N. America and Asia; but perhaps they are an invasive species? --Jayron32 16:48, 2 August 2011 (UTC)

I'm fairly sure (being actively interested in out-of-place animals) that chipmunks have not yet been identified as an invasive species in SE England, though there's no telling if some idiot has released one or more into the wild very recently. However, there are other more likely candidates.

My immediate thought was a weasel, whose burrow entrances, as you will see from that article, are typically this size. Other possibilities are a wood mouse or yellow-necked mouse (aka field mouse), a vole (in the European, not North American, sense), or even a solitary bee or solitary wasp (I'm assuming if it had been the entrance to a communal bee or wasp nest, you'd have seen some of its denizens).

The ever reliable Sun says that chipmunks are already here[4]. Alansplodge (talk) 22:23, 2 August 2011 (UTC)

Doh! How could I have missed an announcement in such a scholarly and reputable scientific journal :-) ? {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 22:32, 2 August 2011 (UTC)

[Later] Ok, a perhaps more reliable report from a Dr Toni Bunnell of the University of Hull via The Independent, though I note that Dr Bunnell is also a practitioner of Reiki and has investigated healing by laying-on of hands, which suggests a less-than-complete focus on wildlife studies. {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 23:04, 2 August 2011 (UTC)

More knowledgeable UK naturalists may have further suggestions, but probably more clues are needed for a definitive identification - any chance of making some follow-up observations? {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 19:57, 2 August 2011 (UTC)

What follow-up observations would you like? 2.97.215.11 (talk) 22:57, 2 August 2011 (UTC)

Finding droppings or other perhaps-related debris in the burrow's vicinity; traces of fur around or near its edges; prints in the earth and trackways in vegetation; observations to eliminate insect candidates (taking due regard to appropriate times of year)? You might also consult staff at a nearby town museum for local information and advice about local wildlife, or seek out local naturalist societies: in the latter cases, photographs would be useful, as they can show relevant details of micro-topography that we (given the wide possibilities) have not thought to ask and you might not have noticed or be easily able to describe, but that would be meaningful to experts (of which, let me stress, I am not one). {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 23:19, 2 August 2011 (UTC)

Here is a picture of a common vole (Microtus arvalis) burrow, which would be one possibility. Ghmyrtle (talk) 09:44, 3 August 2011 (UTC)

Although the photo of the common vole's burrow does not have the ring of bare earth around it like the one I saw, thae article says it does mostly eat grass, so it could be what I saw. (If it lives off grass, then since grass is so abundant, why are there not millions of them swarming everywhere?) 92.29.116.165 (talk) 11:13, 3 August 2011 (UTC)

Because they are heavily predated, notably by owls. In the absence of external interference (such as unusual weather patterns, human interference with habitats, or outright killing for vermin control or hunting), the complex interactional web of predators and prey tends to remain fairly balanced, though there are sometimes cyclical variations resulting in temporary gluts of prey, followed by gluts of predators, followed by successive population crashes of prey and predators, which in the end average out. {The poster formerly known as 87.81.230.195} 90.197.66.52 (talk) 13:44, 3 August 2011 (UTC)

The significant thing is the bare ground around the burrow entrance. The grass must have been removed somehow. The inhabitant of the burrow has either eaten it, or removed it for making a nest underground. It rather suggests that the inhabitant is timid, only venturing out of the burrow the shortest distance required to get a blade of grass. So probably not a carnivore, and not a giant bee either. 92.29.116.165 (talk) 10:32, 3 August 2011 (UTC)

I vaguely recall that some solitary bees or similar insects do deliberately tidy up the soil around their nest entrances (beyond merely depositing excavated earth), but I can't offhand think of a reference to link to. In general, animals (in the widest sense) do a lot of apparently odd things for reasons that would not immediately occur to you or I, so I would caution against jumping to conclusions prematurely. This, by the way, is a weasel burrow, though unfortunately it's in bare ground (probably in the USA) rather than the more grassy situation you describe. {The poster formerly known as 87.81.230.195} 90.197.66.52 (talk) 13:56, 3 August 2011 (UTC)

I don't think any bees are big enough to need a one inch diasmeter hole. The entrances to bee hives are smaller than that. I think I recall that bees keep the entrance small to keep predators out.

The picture of the weasel burrow has given me the idea that the bare patch might have been due to excavated material, but the soil I saw looked compacted and I would have expected grass to have grown through it. 2.97.219.104 (talk) 11:39, 4 August 2011 (UTC)

Chipmunks don't denude the area surrounding their holes, but the holes are indeed only about an inch wide. The are often long enough to accommodate a good part of a broom handle. I am surprised chipmunks haven't been intentionally introduced to Britain, they would liven up the place. μηδείς (talk) 01:40, 5 August 2011 (UTC)

Tips to identify a Bird of prey in southern england?

In rural south-east england I have had brief glimses of large brown birds that I thought could be birds of prey. One was sitting on a fence post as I sped past, another passed me skimming over the heathland vegetation as if hunting.

For future reference are there any ways of identifying or making a good guess about which species they are, for when I have another brief glimse of similar birds in the future? 2.97.215.11 (talk) 15:12, 2 August 2011 (UTC)

A Red Kite perhaps? They are on the increase in southern England. Try the RSPB bird identifier page.--Shantavira|^{feed me} 15:16, 2 August 2011 (UTC)

The best guess for the first one is buzzard. But I'm more interested in being able to quickly identify birds of prey that I see in the future. 2.97.215.11 (talk) 15:39, 2 August 2011 (UTC)

After looking through the Wikipedia articles, am I correct in thinking that the birds of prey I am likely to see in south eastern Britain would be, using their common local names: falcons, kestrels, harriers, goshawks, buzzards, and sparrowhawks? Owls and the extremely rare eagles would be easy to differentiate. 2.97.215.11 (talk) 15:29, 2 August 2011 (UTC)

Buzzards are a lot bigger than one might think, and usually seen high overhead rather than flying around or perching low down. Really, just as some young prince was once told "there is no royal road to mathematics," for bird identification there is really no substitute for obtaining and studying a good field guide (those published by Collins are held in high regard, but there are others), watching appropriate nature programmes, and above all spending time outside (with the aforesaid guide) actually watching birds (or whatever - the same applies to butterflies, dragonflies, etc). {The poster formerly known as 87.81.230.195} 90.197.66.143 (talk) 20:04, 2 August 2011 (UTC)

Put simply, a large brown bird of prey sitting on a fence post in southern England is far more likely to be a common buzzard (Buteo buteo) than anything else. They are widespread - "common", in fact. Ghmyrtle (talk) 09:37, 3 August 2011 (UTC)

From the RSPB site linked to above, the frequency of British birds of prey is Sparrowhawk 40100 pairs, Buzzard 31100-44000 territories, Kestrel 36800 pairs, Hobby 2200 pairs, Peregrine 1402 pairs, Merlin 1330 pairs, Hen harrier 749 pairs, Goshawk 410 pairs, Marsh harrier 360 females. I have left out owls and eagles. So anything you see is much more likely to be a sparrowhawk, buzzard, or kestrel than anything else. 92.29.116.165 (talk) 10:47, 3 August 2011 (UTC)

Sparrowhawks and kestrels are much smaller and don't often perch on fence posts. Ghmyrtle (talk) 11:42, 4 August 2011 (UTC)