From: jmc@SAIL.Stanford.EDU (John McCarthy)
Subject: Re: Radioactivity and Superstition; was: Re: Are Your Light Bulbs Radioactive?
Reply-To: jmc@cs.Stanford.EDU
Organization: Computer Science Department, Stanford University
	<1992Sep2.172549.29172@ornl.gov>
	<1992Sep3.025004.20771@u.washington.edu>
Date: 2 Sep 92 20:39:26

In article <1992Sep3.025004.20771@u.washington.edu> whit@milton.u.washington.edu (John Whitmore) writes:

   In article <1992Sep2.172549.29172@ornl.gov> de5@ORNL.GOV (Dave Sill) writes:
   >In article <1992Aug29.000626.16080@u.washington.edu>, whit@milton.u.washington.edu (John Whitmore) writes:
   >>In article <l9ns6oINNmol@utkcs2.cs.utk.edu> de5@ORNL.GOV (Dave Sill) writes:
   >>
	   <talking about the things kids might eat>
   >>>Few of which are radioactive, since most folks don't have concentrated sources
   >>>laying around their house...unless they have smoke detectors or compact
   >>>flourescents. ... Radioactivity *is* a different kind of threat than most
   >>>parents are used to dealing with. 

   >>	This is not true; ALL organic foods are radioactive (carbon-14,
   >>remember?), and potassium contains 0.01% of K-40... so an eight-year-old
   >>child (just about hammer-wielding age) has a 'safe and adequate'
   >>recommended dietary intake of circa 1 gram of potassium per day...
   >>which comes to about two microcuries.

   >Which of my statements is not true?  Do you consider organic foods
   >concentrated sources of radioactivity?
	   Basically, you can't call a compact fluorescent lamp's
   initiator a 'concentrated radioactive source'.  The initiator is
   no more radioactive than a bite of banana.

	   I know of quite a few household items that have natural
   radioactivity which is large compared to that of compact fluorescent
   bulbs.  International standard 'radiation warning' symbols are
   not present on those bulbs, because they are NOT HAZARDOUS
   radiation sources.  There is no hazard here to be discussed.
   The radiation is comparable to (or less than) natural sources.

	   What, exactly, is the reason for that label?  I'm mystified.
   The reason for the radioactive materials is to initiate the arc
   in the discharge lamp; if you leave the source out, the bulb
   requires a 'starter' circuit (expensive and/or unreliable).

	   John Whitmore

I'll bet that the radioactivity label is required when any substance
is added *because* of its radioactivity.  The radioactivity in the
smoke detector is added because it ionizes some of the air, or
possibly smoke particles, in a tiny air gap inside the detector.

Jym Dyer complains about the concentration, but the total possible
exposure is surely more relevant.  If someone will supply me with
the previously posted data about the amount of radioactivity, I'll
try to do a calculation and decide whether to offer to eat the
radioactive part for a reasonable payment, e.g. $10,000 for every
day it reduces my life expectancy.  Am I allowed to encapsulate
the active element in something that protects me from its chemical
neighborhood?
--
John McCarthy, Computer Science Department, Stanford, CA 94305
*
He who refuses to do arithmetic is doomed to talk nonsense.

Newsgroups: sci.physics,sci.environment,misc.consumers