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Author Topic: How do glow in the dark coatings work?  (Read 2847 times)

Tim Ream

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How do glow in the dark coatings work?
« on: 12/01/2010 09:30:02 »
Tim Ream  asked the Naked Scientists:
   
Dear Naked Scientists,

Recently I bought a new chronograph watch and noticed that the glow-in-the-dark paint glowed brighter and longer with less light input.

How do the newer generations of glow-in-the-dark materials, such as on watches and trijicon night-sights, work on a molecular level?

Love the show, keep up the work!
 
Tim from California, U.S.

What do you think?
« Last Edit: 12/01/2010 09:30:02 by _system »


 

Offline Riki

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How do glow in the dark coatings work?
« Reply #1 on: 26/01/2010 22:13:11 »
Apparently the new watches use a radioactive isotope of hydrogen called tritium to make them glow.  Normally glow in the dark items need the phosphors to be charged, like using a light.  They then glow for a certain period afterwards.  The radioactive version, as in your watch, does not need an external source to charge it.

Tom Clancy also wrote an interesting book "Sum of all Fears" which details alternative uses of tritium.
 

Offline rosy

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How do glow in the dark coatings work?
« Reply #2 on: 27/01/2010 11:58:27 »
Old-style glow in the dark watches certainly used radioactive isotopes. I find it hard to believe it would be legal these days (not that an alpha emitter in a watch would be dangerous to the wearer, as long as the source is enclosed it's not, but I bet the rules are against it..). Do you have a reference for that assertion?

I would assume, infact, that the difference is just better (more energy absorbing/longer half-life) phosphors, which are molecules which are able to absorb energy from sunlight (typically in the UV part of the spectrum) and then release it slowly as lower-energy visible light.
 

Offline syhprum

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How do glow in the dark coatings work?
« Reply #3 on: 27/01/2010 14:08:25 »
As a boy (back in the thirties) I gleefully scraped some Radium type luminous paint from the dial of an old watch, I often wonder if I ingested any ?.
 

Offline yor_on

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How do glow in the dark coatings work?
« Reply #4 on: 30/01/2010 13:19:47 »
Simple test.
Close the curtains, does the sun still glows?
 

Offline syhprum

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How do glow in the dark coatings work?
« Reply #5 on: 30/01/2010 22:25:24 »
I don't think I would have ingested enough to make me glow like the frogs in the Springfield pools
 

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How do glow in the dark coatings work?
« Reply #5 on: 30/01/2010 22:25:24 »

 

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