<<Disclaimer: Verify this information before applying it to your situation.>>
 
In <[log in to unmask]>, on 01/14/97
   at 11:29 PM, Bill Elkus <[log in to unmask]> said:
 
>>Phil Sheard <[log in to unmask]> said:
 
>>>...I have
>>>weighed a number of small objects to give you some sense of perspective
>>on >these small amounts. Remember, in that discussion, 100mg of gluten
>>per day
 
>>>1 grain of white rice, uncooked, weighed 20mg
 
>> depending on your point of
>>view) of the acceptability of daily consumption somewhere between 10 and
>>100 mg per day.
 
I did this a while back when black specks showed up in that delicious
yellow corn meal from Arrowhead that makes such good hot cereal. (Those
particles are actually from the base of the corn kernel --called tips,
pronounced teeps so no need to estimate mass but I did anyway.)  I avoided
weighing by measuring diameter and guessed that a density of water (1
gram/cm3) was close enough. Weight = density x volume.
 
Consider this an approximate result, likely good within a factor of two or
so.  (More on the misleading terms "safe" and "risk" some other day. Any
poison doesn't become suddenly safe below some level or dangerous above
that level.)
 
Justifying the density guess: density of fats is less than that of water,
some proteins are denser.
 
       1 mg.       1.4 mm diameter sphere
      10 mg.       3.0 mm diameter sphere
     100 mg.       6.3 mm diameter sphere
 
All these small amounts are easily visible (look at an everyday ruler with
mm. markings). Useful when you can see contamination particles in a
product.
 
(If you're puzzled at how slowly the diameter changes with mass,  volume
depends on the product of three lengths. Double + a little a diameter and
volume and mass go up by 10 (and conversly  for halving).)
 
Results consistent with Phil's measurements. Don't eats M&Ms but suspect
they're denser than water from handling them once.
 
                                         Kemp Randolph
                                         Long Island
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