RE: Bq soon

["Neil, David M" <neildm@id.doe.gov>]

I think part of the acceptance problem may be in perception.  As Sandy mentioned, a Curie is "oversized" (most measurements end up as milli- or micro-), but a Becquerel is "undersized" (notwithstanding it IS a natural unitary measure).  This means that reported quantities are typically in megaBequerels - and J.Q. Public does understand that mega- means "a lot of", whether or not the precise multiplier is understood.  This means that a quantity that was reported as microCuries (micro- ? no big deal) is now reported as megaBequerels (mega- ? we're all gonna die! :-P).



The comment below on Grays and Sieverts reflects this also. The qualitative change between Rads/Roentgens and Grays/Sieverts is less than for Curies and Becquerels.  



Similar logic seems to apply to other unit conversions - a liter is a reasonable quantity to drink, a meter of cloth is a reasonable amount to hold up.  This may also apply to the inertia in adopting Centigrade/Celsius in everyday measure - in Fahrenheit, 100 is darn hot weather, and 0 is real cold; whereas in Celsius, 0 is just chilly, and hot weather is around 37.  100 is not directly perceivable, just a physical constant.  (As a side note, 100 Fahrenheit was supposed to be human core body temperature - seems he was running a mild fever the day he calibrated his new instrument ;-D )



So, while I disagree that "Perception is reality", the old saw that "Man is the measure of all things" has some application in perception.



Dave Neil



-----Original Message-----

From: Graham Roger Stevenson [mailto:Graham.Stevenson@cern.ch]

Sent: Tuesday, April 08, 2003 2:43 AM

To: William V Lipton

Cc: Faillace, Ernie; Michael G. Stabin; radsafe@list.vanderbilt.edu

Subject: Re: Bq soon





Greetings!



A few comments on SI units may help to calm personal fears - it is not at

all as bad as you think it might be!



<SNIP>

Becquerels for ever! but I still have some regrets about the passing of the

millirem.  The innate danger levels are still there though in the new system.

Sieverts and Grays are lethal, millisieverts are nasty, microsieverts don't

count unless there are lots of them and who cares about nanosieverts!



Graham

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