Frank wrote:
On 3/23/2010 8:13 PM, Don Klipstein wrote:

In , Frank wrote:

On 3/23/2010 12:36 PM, Dave Liquorice wrote:

On Tue, 23 Mar 2010 15:57:02 +0000, Mike Barnes wrote:

The clock I bought recently has some kind of fluorescent paint that
glows green for a short while after the light goes out, but not long
enough to be of much use.


The non-radioactive paints need "charging up" with decent light, kept
in room with the curtains closed or only brief artifical light source
they are dim. The best way to charge up these paints is with a UV
light source, say a bank note light or one for making the invisible
security pens visible.

There are still radio active glow in the dark things in the market.
Mostly emergency signs and the like, they use tritium IIRC rather
than radium.

There are alarm clocks with tritium dials. Did not google far but they
look pricey:

http://www.gemday.com/item0817.htm

Beta particles from nuclear decay are harmless.


Not completely. Bad if source is ingested, bad if source is
inhaled in
form of anything that sticks in lungs or is absorbed into the body from
lungs. OK if in a closed container and low energy, as is the case with
tritium.

Yes but unlikely and does not compare to the old radium dials that
caused cancer to the women painting them on.

That probably wouldn't have happened as much is the ladies weren't in
the habit of "pointing" the brushes with their lips.

(Or so I've read.)

Jeff


--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10e12 furlongs per fortnight.