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Silent-Hunter

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No, it's not! I don't know how it works exactly. There did used to be radioactive glow in the dark hands for alarm clocks. But they stopped doing that decades ago.
 

ZXDunny

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I'm pretty sure it's photoluminescence.

Back in the day when the first glow in the dark treatments were used, clock faces did indeed use radioactive elements to achieve the glow. No kidding. There was a US kid who collected them, extracted the materials and built his own reactor in his garden shed using them, before he started sourcing better (pure) elements.
 

matzesu

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I have the E-Book from Marie Curie about Radioactive causes disease from Project Gutenberg on my Kindle,
Mybe is should read this before I get my Pyra..
 

Silent-Hunter

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Back in the day when the first glow in the dark treatments were used, clock faces did indeed use radioactive elements to achieve the glow. No kidding. There was a US kid who collected them, extracted the materials and built his own reactor in his garden shed using them, before he started sourcing better (pure) elements.
I thought he used smoke detectors?
 

rygD

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I have a radium clock (didn't know it was until after I bought it and saw it glowing).
 

levi

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I have a watch from some time in the 1960s that is labelled as containing 'Tritium'. If it did originally contain the radioactive gas I can't tell, so now it just has phosphorescent hands and hour indicators which glow for a time as you go from a brightly lit room out in the nighttime (or after you turn out the lights going to bed). I guess they might have originally been energised by particle emission from the gas which has long since escaped (despite it claiming to be 'super waterproof 200' but I guess even tritium atoms are smaller than water molecules with their oxygen wings). But after less than a minute the luminance fades, so I know it's not still radioactive, if it ever was.
 

Kuro

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I have a watch from some time in the 1960s that is labelled as containing 'Tritium'. If it did originally contain the radioactive gas I can't tell, so now it just has phosphorescent hands and hour indicators which glow for a time as you go from a brightly lit room out in the nighttime (or after you turn out the lights going to bed). I guess they might have originally been energised by particle emission from the gas which has long since escaped (despite it claiming to be 'super waterproof 200' but I guess even tritium atoms are smaller than water molecules with their oxygen wings). But after less than a minute the luminance fades, so I know it's not still radioactive, if it ever was.

Tritium usually does not escape as it is stored inside small tubes that fit in the hands of the watch and the hour indicators. It does decay with time and as it has a half life of around 10 years so it halves the brightness every so often, meaning that your watch would be emitting a glow now that is 30 to 60 times dimmer than when it was brand new.

If tritium was stored free within the watch, 1 it would be prohibitively expensive and 2 it would not last has long as tritium is still hydrogen (even though its heavier hydrogen) it would escape very easily from a watch.
 

T.T.

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I have a watch from some time in the 1960s that is labelled as containing 'Tritium'. If it did originally contain the radioactive gas I can't tell, so now it just has phosphorescent hands and hour indicators which glow for a time as you go from a brightly lit room out in the nighttime (or after you turn out the lights going to bed). I guess they might have originally been energised by particle emission from the gas which has long since escaped (despite it claiming to be 'super waterproof 200' but I guess even tritium atoms are smaller than water molecules with their oxygen wings). But after less than a minute the luminance fades, so I know it's not still radioactive, if it ever was.

Old watch hands were originally radium based if I remember correctly.
 

levi

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If it did have an radium in and that was radium 226, that should not have half decayed yet, but my testing shows that the hands luminescence disappears at about the same time as the other indicators. I suspect it's just a plain phosphorescent watch and the 'Tritium' marker was just some trading mark from back then.
 

D32_bobjob

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If it did have an radium in and that was radium 226, that should not have half decayed yet, but my testing shows that the hands luminescence disappears at about the same time as the other indicators. I suspect it's just a plain phosphorescent watch and the 'Tritium' marker was just some trading mark from back then.

Tritium is not a trademark. Tritium is hydrogen(H3 or T) with 2 protons, which makes it radioactive. The gas has probably escaped through the seals(nothing can seal hydrogen completely) or while changing the battery(properly needs to be refueled before closing the case).
 

Criticalmass

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EricB

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Although it uses the battery to trigger a recation, there was Indiglow that was pretty nice and bright. But now i have an Oled watch. No need glow in the dark for it anymore. For the Pyra it would be very cool though.
 
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