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Now pay attention class.

Anyone who already knows the answer can keep quiet, and no googling, I just want to hear of theories as to why it happens.

Q: If reds fade first as you descend, followed by orange, yellow etc, why do flourescent colours still show as orange at 30m+ without artificial light.

A Green for the most inventive reply [no matter how surreal], and a green for the closest to the real answer.

Homework in by 1700 Monday.
 

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Thats MISTER Blue Boots to you....
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Yes you may go to the toilet...


My theory is that the flourescent colours have paid more tax and bribes to the colour fairies that live in the depths, and as a result the fairies have allowed their colour to shine through instead of dimming them as they do with the regular colours which are stingy and won't pay their tax on time. :)
 

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ratcliffe said:
Yes you may go to the toilet...


My theory is that the flourescent colours have paid more tax and bribes to the colour fairies that live in the depths, and as a result the fairies have allowed their colour to shine through instead of dimming them as they do with the regular colours which are stingy and won't pay their tax on time. :)
id say you were the one talking.... :D
 

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Thats MISTER Blue Boots to you....
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:D now, now - lol

refers the honourable reikimaster to my sig :teeth:
 

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...
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Me.....Me...oh, please sir .....me!!!!!!:teeth: :teeth: :teeth:

How about because they produce the light by a chemical reaction rather than reflecting/absorbing daylight....?????

Do I win the cash?:money: :money: :money:

David.
 

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For the dives where one helicopter isn't enough
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IIRC, its not a chemical reaction per se, but down to the fact that they absorb light in one wavelength and then release in a different wavelength.


Of course, I could be talking a load of .....


Simon
 

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Going down and loving it
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Freeflow said:
Now pay attention class.

Anyone who already knows the answer can keep quiet, and no googling, I just want to hear of theories as to why it happens.

Q: If reds fade first as you descend, followed by orange, yellow etc, why do flourescent colours still show as orange at 30m+ without artificial light.

A Green for the most inventive reply [no matter how surreal], and a green for the closest to the real answer.
I new my years studying chemistry would pay off.

Flourescent is produced when a outer shell electron absorbs a photon and is exsited into a higher shell breifly. It then falls back to its original shell releasing a photon of energy. The photon is of the same wavelength as that absorbed and so gives a bright colour.

Want to know about phosphourescent too?
 

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If red is the first to dissapear then it would follow that Ultra Viloet is the last, being the other end of the spectrum. It's UV that causes things to fluoresce (sp?) so that's why they still work at depth.

Danny (looking forward to more greenies)
 

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Going down and loving it
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DannyB said:
If red is the first to dissapear then it would follow that Ultra Viloet is the last, being the other end of the spectrum. It's UV that causes things to fluoresce (sp?) so that's why they still work at depth.
It's not just UV that makes things flouresce. Are you thinking of black lights in night clubs that make white things glow. This is becasue of the soap powder having flourescents put in them to make your whites whiter then white. Over time you get a build up of these and the loose their flourescent properties to make your whites look gray.

To floursece a photon of energy that is equail to the energy needed to promote an electron into a hight orbit is absorbed by the electron. The energy is then used to move it up into this higher orbit where it stays for a split second before falling back into it's starting orbit. When it does this it emmites the photon out again. So if you look at something flouresent it will absorb the light that hits. This light can be any wavelenght so long as the photons it is made up from are for the exact energy needed for the electron promotion. The electron falls back down and release this energy again as light. So if you look at it, the light you see will be richer in the abrosbed released photon, and so the colour in that wavelenght will seem bright and to glow.


P.S. where is my green blob :)
 

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Hmmm
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It's because the flourenscent light is sensitive to the narcosis that your fins give off at depth .... sur.
 

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I think tihs has a lot more to do with the Dude. Now, if any of you have seen him, you will notice that he likes to decorate himself in any number of ridiculous colours (some flourescent, I'd like to add) in a most non-technical fashion.

We were openly ridiculed as a group by some C-Card waving tourists in Cyprus because of his gaudy dress, either that or that hottie was waving at me, but it's unlikely when you have to dive with your Dad all the time.

Now, another thing you will notice, Mr Dude has a new box. I'm not talking abut a coffin, he's not ready for that just yet, but a bright Fisher Price yellow one. Now I don't know what particular feature of these boxes causes it, but they seem to glow, usually as their users float off into the ether (this may have been narcosis, but have you noticed how their buoyancy is always worse than KISS divers? ;) ) - in order to prevent this it is required that the colours used by the Dude are brighter than those of us mere mortals using sensibly coloured equipment. Someone has to catch the old codger before he floats off through all that deco and forgets who he is and how he got here.

Now the flourescence I am told is similar to spidey-sense, or whatever it was that Spiderman had, and in line with all sons believing their dads are superheroes (until a certain age, when they realise they're just old gits who a girl could beat in an arm wrestle) I believe this to be The Dude's superpower.

I am led to believe that the colours glow brighter when the Dude pisses himself, which happens regularly. So regularly in fact, he has taken to wearing nappies. Sometimes on land too.

That is my truth. Can I have a green for being offensive towards my dad? I'll kick him when I next see him as well if you want. Only gently though, it could kill him.

Digs.
 

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Has it been Tango'd
 

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Getting Grumpy, Old and Twisted
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Fluorescence is the emission of light from a material during illumination by radiation of a higher frequency.
Higher frequency energy is converted by fluorescent material into a lower frequency emission. Hence UV illumination always appears as a lower frequency emission such as green or blue-green.
In water UV penetrates the depths and will still energise a fluorescent material.:tongue:
 

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You can get different wavelengths emitted by fluorescence than the wavelength of light absorbed. All to do with our friend quantum mechanics!

UV = short wavelength = lots of energy

Red = long wavelength = not much energy

Absorption of a photon of UV (or violet or blue as these are still this end of the EM spec) kicks (excites) an electron into a higher energy orbital (energy difference equal to energy of photon). In fluorescence this then dexcites back to it's original state by emiting a photon of energy equal to the energy gap.

It can go back to it's original energy level via several steps, so there may be phtons of lower energy (and hence longer wavelength) emitted. Hence the molecules in the fluorescent dye can absorb light of one (shorter) wavelength and re-emit a longer wavelength.

It's a Friday night and I'm writing about quantum mechanics. I really need a life (or to go diving).

Oh (yes I get sadder) in phosphorescence the absorbed photon i s not re-emitted instantaneously e.g. glow-in-the-dark stars.

I'll go now and play perplexcity.......
 

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Death Once Had a Near Harlequin Experience...
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Jesus guys, don't you know the answer to this, the most elementary of questions...?

Oh, OK, sitting comfortably...?

Here goes... You descend yeah...? colours fade yeah...? But what happens at 30-40 metres...? Yeah, you get narked out of yer box and all of a suddent certain colours become vibrant again.

So, there ya have it, in a nutshell :D Get Narked, see in TechnoColour...!
 
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Discussion Starter #20 (Edited)
Settle down in class.

Right, marks as follows:

Greens to Ratcliffe , Jen [B+] Harlequin [B-]

The following people are to see me after school for obviously NOT reading the whole of the homework question:

Luddite [twice], DannyB, Frankie Price, all of whom had a correct answer. However Sphyrna Lewini tops the lot as the smart arse, good explanation, but the wavelength x the quantum energy equals a constant, which you could have mentioned for 10/10. You have either a red or a green, once the waveform has collapsed we will find out. And what WAS the name of Schrodinger cat?

Freeflow said:
Anyone who already knows the answer can keep quiet, and no googling, I just want to hear of theories as to why it happens.
Digger has answered a question, but I'm not quite sure which one.
 
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