Re: Our 'humiliating' mistakes.

[Leigh Palmer <palmer@sfu.ca>]

> > P.P.S. Oh, I remember something else:   The entire earth is only a few
> > farads, isn't it?
>
> The capacitance of a conducting sphere (against the sphere at infinity)
> is equal to its radius. The radius of Earth is about 6378 km which is
> about 0.6 farad, since one cm is about one pF.

Looks like I'm out about three orders of magnitude. Now I get 600
microfarads. I think that "few farads" may pertain to the capacitance
of the surface-ionosphere capacitor.

An error of the same sort as mine was made once by Farrington Daniels,
a Chemistry Professor at the University of Wisconsin. Just before a
freshman lecture Daniels did a calculation which indicated to him that
the metabolic heat required to melt thirty grams of ice would offset
3000 Calories of dietary intake. He made the mistake of blurting out
his discovery to the class, at which point a student respectfully
inquired about the possibility that Daniels had confused calories and
Calories. Of course he had; the requirement was to eat thirty
kilograms of ice per day, not thirty grams. Put in that way it is
apparent that three orders of magnitude is a lot.

Remember what Everett Dirksen said.

Leigh