Changed to OT, as getting somewhat off EE.

>When I was at school there was a box of radioactive sources
>in the physics lab.  During one meeting of the Electronics
>Society we got this out (lead-lined box with pieces of Uranium,
>Strontium, Radium, etc) along with a geiger-counter.  It had
>dire warnings and a set of tweezers for handling the t-shaped
>holders the tiny pieces were mounted in, but when we found that
>at least two kids' watches were over ten times as radioactive
>as any of the samples we dispensed with the tweezers!

I went to the Open University Open day last year, and they had various
samples of radio active minerals and a Geiger counter on one stand. Some guy
was playing with the Geiger Counter, pointing it at the various minerals,
and observing the count. I told him to point it at his watch, which he did,
and much to his astonishment the counter hit something like 20 times the
count of any of the minerals.

>Interestingly, I recently went to a museum that had most of a
>"Horsa" WWII glider, and you could go into the main part of the
>fuselage, but the cockpit was roped off.  I asked why and was
>told that (1) they didn't want anyone damaging the instrument
>panel or controls - it's quite cramped in there and (2) Health
>and Safety wouldn't let anyone within 3 feet of the instuments
>because of the luminescent dots on them!

When I worked at the DSIR in NZ they were doing a mortar ranging calculator
as a project, and to illuminate the display has some little glass vials
filled with a tritium based radio active source IIRC, that caused a
fluorescent coating on the inside of the tube to glow pale green. Apparently
these are only available to the military because of the radio active content
...

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