Water filters, urine, and beer

Dave Long dl@silcom.com
Mon, 15 Apr 2002 10:53:42 -0700

> > The Waterworks can filter 0.2 micron particles.
> Well, IIRC, a carbon atom is about an angstrom (0.0001 micron) across.
> I think urea molecules are considerably larger than salt ions, on the
> order of five or ten angstroms across.

So, if the urea molecule is
Ronald Reagan, and a C atom
is the laptop on which his
web browser is running, the
Waterworks will filter out
particles about the size of



> [Urea] was synthesised in 1828 by Friedrich Wohler and was the first
> organic compound to be synthesised from inorganic starting materials.
> It was found when Wohler attempted to synthesis ammonium cyanate, to
> continue a study of cyanates which he had be carrying out for several
> years. On treating silver cyanate with ammonium chloride solution he
> obtained a white crystalline material which proved identical to urea
> obtained from urine.
> This discovery prompted Wohler to write triumphantly to Berzelius:
> "I must tell you that I can make urea without the use of kidneys,
> either man or dog."


(with apologies to Knox, Berkeley,
and Gell-Mann)

On Quantum Decoherence:

There was a young man who said, "God
Must think it exceedingly odd
    If he finds this cat
    Is still where its at
When there's no one about in the Quad."

Dear Sir:
    Your astonishment's odd:
*I* am always about in the Quad.
    And that's why that cat
    Is classically "at",
Since observed by
        Yours faithfully,