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

http://www.bbc.co.uk/h2g2/guide/A586668

This is something for the more pedantic - whom I was afraid the original Laser entry (also in the PR somewhere) would not be precise enough.

Also, it is quite dry, but in a common understandable form - I hope.

Probably Typo-infested - please point them out.

If there's the need for discussion, I'll be glad to talk things out.

Happy nitpicking,

HELL

Hell,

imho both laser Entries are good an a valuable addition to the Guide, but I think you should combine them to one single Entry. Each of them is somehow lacking what the other one offers. What do you think about that?

Jeremy

Wouldn't that be too long?

I mean, for the folks who don't really want to know exactly how it works, but want to know what kinds of lasers there are the Laser entry is enough and quite complete.

For the most pedantic folks, or the ones who just want to know how it works this one is good enough.

Hmmm.. What would be the problem leaving them separate?

I honestly just wanted to write the general one... But then I realized that with scientific stuff people tend to get nitpicky... For that reason I added this one separately.

I think it's OK to leave them apart. But if many other people think it's best to merge them... why not?

I am open to more suggestions.

HELL

I understand what you mean, Hell, and there would be good reasons to keep tham seperated. But it is one of the rules of the Guide not to have more than one edited Entry for each topic. This means that if someone searches the Guide for a Laser Entry they can expect that this Entry contains everything that the Guide knows about lasers.

From that viewpoint it would be better to combine them. Let's assume that 10% of the readers would miss the scientific stuff if you left it away. Another 10% of the readers would be annoyed of the scientific stuff if you took it in. The broad majority of the readers would probably understand at least much enough of the scientific stuff to have fun reading the combined Entry.

I'm afraid that one of the Entries would lose the race for the Front Page. It would be a shame if one of them had to be dropped due to the One-Entry-per-topic-rule. Instead of gambling one which one would win and which one would lose, combine them and you'll definitely have a winner.

It's up to you, of course, but what I said before is my sincere recommendation.

Jeremy

I don't seethat the two entries fall foul of the one entry per subject rule, as they cover different subjects. This one covers "how lasers work - a technical explanation", whereas the other covers what type of lasers exist, and how lasers are used. not the same subject at all. I think you should go and have a think about how you are interpreting that rule.

Thanks xyroth, that's sort of what I was thinking too. I would not want to overload any of the entries.

Of course both entries are tightly related, but there have been other cases where a 'same topic' was subdivided into separate entries (e.g. The Periodic Table' and the 'History of the Periodic Table')

And even if they are tightly related they cover different aspects. One person looking for Lasers will probably find both entries (and some more, e.g. laser surgery, tattoo removal...) listed in the 'serch Results'. The titles are clear what to expect from the contents. One person looking for the working mechanism will find it here, one person looking for general stuff (and briefly how it works) will find it in the other one. Apart from that I think both entries could as well stand alone.

You must understand that I will - of course - be on the side of having both entries separate (also because it will be some lots of work for me to do if everybody decides they should be merged - I'd do it, but first I'd like to discuss it.)

Let us see what other people think.

What about the contents per se? Is it OK? To earnest? Typos?

See you around,

HELL

Hi Hell - typos yes. Quite a few Too many for me to bother pointing them all out to be honest. We usually like to suggest running it through a spell checker for this sort of thing.
In my personal opinion though I wouldn't worry too much - a subeditor has to sheck the spelling anyway.

Content - very good. Well explained. I have one slight criticism but guess you left this out because it might become impenetrable to the layman.
You can't simply get a laser by heating anything up. You need a population inversion to get stimulated emission to cascade like this (ie. dominate absorbtion and spontaneous emission).
Explaining a population inversion might start to get tricky though. I leave this to your opinion.

For that reason I must say I prefer the other article but both are good and should end up in the edited guide.

I see no problem with there being two articles.

Orcus

You see Orcus... I also like the other one best - This one is sort of a by-product, as mentioned. Eventually I even thought about discarding this one... But it got better and better, and after a while I thought: "Well, why not?"... So here it is - infested with typos (I am so sorry, but my English is deteriorating fast) and perhaps too dry.

And yes, I left the population inversion thing out intentionally. That only makes sense along with Einstein's rate-equations. And as far as the mechanism is concerned you don't need the inversion to explain it. The population inversion is then 'merely' the basic trick to *get* to the stimulated emmission.... And adding to that: Most lasers are 4 level-systems (or 3 level but almost never 2 levels - with a virtual one in between), so you do not REALLY have a thermodynamic population inversion. Anyways... That could get way out of scope.

I'll think about a more didactic way of explaining this tonight.

Bye, thanks for your valuable attention.

HELL

Hell,

if you decide to keep both Entries separated, that's absolutely fine for me. It was just my personal point of view that something like

"LASER - How they work and how they are used"

would have been an excellent combined Entry. Your reasons for not combining them are understandable, although I do not share them.

Anyhow, good luck for both Entries!

Jeremy

Hello everybody...

Somehow I think I managed to squeeze some 'population inversion' in, without having to get very far into theory, without mentioning rate-equations and - what's best - without modifying the text too much... (Since this entry was aimed at the pedantic, it would be pointless to omit population inversion after all. - Drats... I could have anticipated that.)

Then I found (and eliminated) some of the typos, hope it's better now.

Thanks for your comments,

HELL

PS. St. Jeremy: Thanks for your suggestions, I actually considered melting them both... It's just that this entry has less quality than the original 'laser' entry - it is, as I mentioned before, a by-product - and it would probably overload the 'laser' entry. - Thanks anyway.

Hmmm... No one read it? Or no comments?

Anyways, the changes've been done. I think it's better with the 'population iversion' bit I have added.

Greetings,

HELL

Oh sorry I didn't post - must have forgotten after reading it before.

I'll just say

Orcus

Just quickly skimmed this Entry, and I loved it Good going The only thing I feel is missing (or maybe I missed something - I did just skim it......) is how the photon passing through the medium stimulates the release of another photon, without being absorbed? Did I just miss something? Anyhoo, this should have no bother with Peer Review Well, until later....
BCNU - Crescent

Exactly for that reason you need population inversion.

Isn't that clear? (I'm going to lunch now, but I'll have a glimpse at that later)

HELL

Editorial Note: This conversation has been moved from 'Peer Review' to 'How a laser works'.

This thread has been moved out of the Peer Review Forum because your entry has now been recommended for the Edited Guide.

You can find out what will happen to your entry here: http://www.h2g2.com/SubEditors-Process

Congratulations!

Yiepiiieee

Oh just in time... Uff...

I have added a prenthesis that explicitly explains the problem. It goes something like this:

Need more excited molecules than relaxed ones (otherwise the photon will be absorbed and not used to stimulate emission).

I think this is a lot better that way. Thanks for pointing that out, Crescent.

HELL

Hell

Hey Orcus... Did YOU pickit?

That has to be the quickest response to an acceptance I have seen