h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

http://www.bbc.co.uk/h2g2/guide/A546077

Please discuss this entry,

Cheers,

HELL

You have been extremely busy Hell, nice one

Your last link (to photovoltaic devices doesn't work).

I'll check that out too..

Now it workx. (41 instead of 11) isn't that nasty...

Excellent entry. I couldn't find room for improvement.

Short of writing a text book, this seems reasonably complete to me.

Incidently, when I was in high school, I discovered a way of illustrating the lobe angles of electron orbitals using wire frames and 'soap' films. If you have never done so or seen the experiment, try making a wire cube with a handle from one corner. Dip the cube into a fairly strong dish detergent solution (or use commercial bubble solution) and remove it. Then, exclaim loudly and run to show your friends. (Warning: Your mother is likely to be more sympathetic.) Then start wiring up the edges of other regular solid shapes.

This article, COULD go with your Periodic Table article, but it doesn't belong there.

Barton

Its just a really minor quibble, but in the first paragraph your article says " elctrons do not move in random orbits around the nucleus, but much rather in defined regions called 'orbitals' "

(just noticed typo in elctrons, but thats not my point)

As I always understood it, the electrons do move randomly, and the orbitals are in fact just the regions around a nucleus where it is most probable that the electrons will be, as calculated from the probability density function, the square of the wave function.

Dont mention wavefunctions obviously (they are far too complicated ), but maybe something like "electrons move in random orbitals around the nucleus, mostly within regions called 'orbitals', which are defined as where an electron is most likely to be, and which resemble..." would be more accurate, and not too confusing.

If I am just being too nit picky, tell me to go away, and I will, as all these articles altogether are brilliant, and you deserve s for your efforts, not pins in your sides .

vp

*Gets super nitipicky*

Isn't the probablitly density function derived from the wavefunction multiplied by its complex conjugate?

*ducks *

Hmm, well ok yes - brackets anyone?

= 1
Normalised so probability of finding electron somewhere in space is 1.
where is the wave function.

But that is somewhat beyond scope of article, and not too far off being beyond scope of my understanding of Dirac notation, so if you really want to discuss expectation values and the like, then feel free to write an article on them


Then I can sit back and learn something maybe

Thank you vp. Of coure you are right. Modifications comming up.

Thank you, and please stay.

HELL

Thats much better , very nice indeed.

Reading continues....

Whoops a daisy, typos :

1)How to Fill Shells and Orbitals with Electrons section:

2nd paragraph:... Electrons will tend to move in a shell as close as possible to the >>>nucleous<<< and in an orbital with a shape as simple as possible...



2)And what is that good for? section:
1st line: For >>>exapmle<<<:


There are a few too many commas as well I think, but I guess the editors will pick up on that anyway.

vp

Darn...

The exaplme has been correcdet.

And about the commas.... I not native. I not speaks tongue of English. Sorry... The SubEds will have to straighten that out for me.

Gaudite,

HELL

, well if I hadn't already been to your page and found brazilian connection I would never have guessed - everyone writing english has a tendency to use too many commas, because when you read something out loud, you have to insert gaps in your speech to give people a chance to understand. It always takes me a good bit of self editing to ever be truly happy with my commas, and at the end of the day, it just doesnt matter .

Superb entry!
With chemistry exams next week, that's my revision done!
I think you may be missing a closing bracket on about the third line from the end of the article with "-To generate colourful light in neon, xenon or mercury-lamps (cf. emmission lines" I think it should be ending with "(cf. emmission lines)".

Kenrick

Here are a few awkward areas I have taken notes on:

clever concoctings resulted -- the word would be 'concoctions'

defined as where an electron is most likely to be -- awkward, perhaps 'where an electron will be mos of the time.' But, talking about where an electron is, is bound to be awkward.

These orbitals have a defined shape -- the orbitals have defined shapes (plural), but the shapes are not defined so much as recognized, so I might rephrase as 'obitals have distinct shapes' (No, I would not draw the distinctions between shapes and volumes, enough is enough)

are classified according to their shape, with a -- note the addition of the comma

... All of those orbitals arrange forming shells, which are also numerated (and letter-coded) -- use 'numbered' not 'numerated' (the word you were thinking of is 'enumerate' which means to count) and tbe phrasing you have used is foreign, try 'All of these orbitals group themselves in shells which also have number and letter codes'

The consequence of many concoctings is, that there are certain defined orbitals, in which the electrons can move, and that only two electrons (kind of spinning in opposite directions) can occupy one orbital at a time (also known as the Pauli-principle). -- 'Concoction' is a peculiar, some what contrived, word and shouldn't be used to often in on context. I think you really mean 'arragement' here, so I suggest. 'The consequence of these arrangements is that there are only certain defined orbitals in which the electrons can move. Onlt two electrons (each having a quality called 'spin' but which has noting to do with spinning) can canoccupy one orbital at a time (also known as the Pauli Exclusion Principle).' This last I changed because that is how that principle is known in English physics texts.(at least, that's how it *was* known back in the ice ages when I was studying this stuff.)

Barton

Here are a few awkward areas I have taken notes on:

clever concoctings resulted -- the word would be 'concoctions'

defined as where an electron is most likely to be -- awkward, perhaps 'where an electron will be mos of the time.' But, talking about where an electron is, is bound to be awkward.

These orbitals have a defined shape -- the orbitals have defined shapes (plural), but the shapes are not defined so much as recognized, so I might rephrase as 'obitals have distinct shapes' (No, I would not draw the distinctions between shapes and volumes, enough is enough)

are classified according to their shape, with a -- note the addition of the comma

... All of those orbitals arrange forming shells, which are also numerated (and letter-coded) -- use 'numbered' not 'numerated' (the word you were thinking of is 'enumerate' which means to count) and tbe phrasing you have used is foreign, try 'All of these orbitals group themselves in shells which also have number and letter codes'

The consequence of many concoctings is, that there are certain defined orbitals, in which the electrons can move, and that only two electrons (kind of spinning in opposite directions) can occupy one orbital at a time (also known as the Pauli-principle). -- 'Concoction' is a peculiar, some what contrived, word and shouldn't be used to often in on context. I think you really mean 'arragement' here, so I suggest. 'The consequence of these arrangements is that there are only certain defined orbitals in which the electrons can move. Onlt two electrons (each having a quality called 'spin' but which has noting to do with spinning) can canoccupy one orbital at a time (also known as the Pauli Exclusion Principle).' This last I changed because that is how that principle is known in English physics texts.(at least, that's how it *was* known back in the ice ages when I was studying this stuff.)

Barton

Hello again Barton, and thank you again (I could not go without your help.... One day I'll post an entry to PR and - for some reason - you're not going to read it: I'll be desolate.)

Your suggestions:
"where an electron is most likely to be -- awkward, perhaps 'where an electron will be mos of the time.'" Isn't that the same? I mean... Orbitals, or at least those thingies we see depicted in chemistry books, are the square of the wavefunction (which is the 'probability of finding an electron')... Trying to explain that could go very far.
Maybe it should go 'where an electron is more likely to be found'?

"The consequence of many concoctings is, [...] -- 'Concoction' is a peculiar [...] word and shouldn't be used to often in on context. I think you really mean 'arragement' here[...]" You are right. Concoction IS a peculiar word, and it SHOULDN'T be used too often. But: I do not mean arrangement. I mean: Someone brewed this quantum mechanics stuff up, and from that we tend to believe that there are electrons and orbitals and shapes and all that. The BIG problem is, that this devious theory quite well agrees with the experimental reality. If it wasn't so all of this quantum mechanics rubbish would go straight to the scientific "sin-bin"... Now this notorious brew-up (concoction) must postulate certain behaviour patterns, such as the Pauli-Exclusion-Thing, because otherwise it wouldn't fit the experiment so well. (Quantum mechanics is a very slippery piece of soap... Everytime some new effect shows up they change the boundary conditions, and -- voila' -- all is perfect. I currently writing an entry on the Einstein-Podolsky-Rosen Paradox.) Maybe there is another word for 'concoction' in that sense, that does not sound too serious? Do you know any?

As to the other things... They have been changed.

Thank you Barton.

HELL

Try fabrication, speculation, or guess. Be aware though that you probably should add a footnote to explain precisely the point you are making by the word choice. I think that the point is important and significant.

It is becoming more and more obvious to me that I need to write an article titled "The Map Is Not the Territory" discussing these very issues about labeling, science, mathematics, and, for that matter, all aspects of man's 'knowledge.'

I think I just bumped that up to the top of my list. It'll start out with a quotation from Douglas Adams about digital watches, perhaps.

Barton

Hi Barton thank you... I decided to leave it more neutral and rephrased the whole 'concoction' part, because (a) you said that you are going to do the 'dirty' part (i.e. explaining that things are not what people with Nobel prizes tell you things are...) and (b) because it would just confuse things more up I guess, after all I am trying to explain what shells are, and not how it came that we think that shells are what we think they are... Grumble... The guys that got the Nobel-Biscuit were specially lousy teachers (excluding Linus and Rick P.)

Salve,

HELL