[time-nuts] Atomic Clocks: It is important that they keep good time, Part 1

[Kiwi Geoff]

Steve Allen wrote:
> I remember my mom's wind-up travel clock glowing brightly.  50 years
> later there is nothing.  I brought it into the lab just to check that
> it is still radioactive (wouldn't want to have lost that radium
> somewhere).  It's the zinc sulfide crystals, the radiation damages
> them and they stop producing light.

Steve, another example of that happening, is in this video by Fran
Blanche, where she tests the clock face of an old radio-clock, showing
that it no longer "glows in the dark" but the radio-active source is
never the less still there !

I have set the start to be at the 15 minute mark, to save watching the
whole mailbag!

https://www.youtube.com/watch?v=0J3cu67SBZY#t=15m

Regards, Geoff (NZ)