Newsgroups: sci.astro,alt.sci.planetary,alt.astronomy
From: henry@spsystems.net (Henry Spencer)
Subject: Re: NASA Experiment Lays Groundwork For 'Living Off The Land' On Mars
Date: Sat, 27 Mar 1999 19:00:29 GMT

In article <36fb9530.1582856@news.apk.net>, Parallax <parallax@apk.net> wrote:
>>...When carbon dioxide is fed to this unit, the
>>zirconia cell "cracks" the carbon dioxide into carbon monoxide and
>>oxygen...
>
>What amazes me is that, after hundreds of years of technological
>development and study, we have finally duplicated the function of the
>leaf, albeit 1,320 degrees hotter, made out of much more expensive
>materials, and with a lot more trouble.

Alas, not correct.  Plants do not crack carbon dioxide at all; they crack
water, and react the hydrogen with the CO2 to produce the complex organic
materials (carbohydrates etc.) that they need.  The oxygen they emit comes
from the water, not from the CO2 -- if memory serves, this was one of the
first discoveries made with radioisotope tracers.
--
The good old days                   |  Henry Spencer   henry@spsystems.net
weren't.                            |      (aka henry@zoo.toronto.edu)

Newsgroups: sci.astro,alt.sci.planetary,alt.astronomy
From: henry@spsystems.net (Henry Spencer)
Subject: Re: NASA Experiment Lays Groundwork For 'Living Off The Land' On Mars
Date: Tue, 30 Mar 1999 05:06:07 GMT

In article <36FFBE79.A3B83B7A@hyperbole.com>,
Derek Dexheimer  <derekd@hyperbole.com> wrote:
>Plants use water instead of C02 for their famous chemistry? Really? Then
>the science taught to just about every middle school kid in America is
>wrong, and has been for a while...

Not exactly *wrong*, just oversimplified.  When you're trying to get the
basic idea across, often you will lie a bit about the fine points to avoid
complicating the explanation.  Probably quite a few of the things those
kids are learning are only approximately true.  (The one real flaw of the
textbooks and teachers is that they don't *warn* the students about that
often enough or loudly enough.)

If you want another example, remember that bit in chemistry about how
elements combine only in integer ratios of atoms?  Not true.  Oh, it's
*usually* true, and it's a basic organizing principle of chemistry, but
there are weird exceptions.  For example, the Ti/O ratio in TiO is
nominally 1, but can vary continuously from 0.75 to 1.45 depending on
conditions of preparation.  (How?  For example, you can get a titanium
shortage if some of the Ti is present as Ti+++ rather than Ti++.)

>How long ago was this discovered?

As others have already noted, this was discovered over half a century ago,
and any discussion of photosynthesis that goes into any detail will
mention it.
--
The good old days                   |  Henry Spencer   henry@spsystems.net
weren't.                            |      (aka henry@zoo.toronto.edu)