News and Discussions > History & Trivia

100cm2

(1/2) > >>

mostlyharmless:
Where did the standard of 100cm2 come from and how long have we been using it?

X-Nuke:

Well, at the risk of showing how little I know, I'll go with it being roughly equal to the size of a dollar bill (and makes the math easier too) and in use since the 1940s.

Bill

Motown homey:
I remember that they told me in ELT "C" school that there were three criteria: 1) It's easy to do - two fingers on a smear dragged 16 to 18 inches (usually in an "S" pattern).  2) Dragging a filter paper smear much further tends to deteriorate the smear and you start to lose sample.  3) It's a nice round number.

Adam Grundleger:
If I remember correctly, in ELT school they taught us it was large enough for a representative sample but small enough that the swipe would not come apart.  I wouldn't doubt the round number is for radcon math.  The limits are also written to 100sqcm, though I'm sure that's based on the sample size. 

SloGlo:
bean a factor of tenn, it makes alla math sew much easier.  peek oh curies work best two.  gist axe enny buddy dat went threw oral boards.   ;)

Navigation

[0] Message Index

[#] Next page