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Re: [Phys-l] gasoline



Panzers, and that's crazy! In 10th grade we were taught photosynthesis involved CO2 + water. I grant, one must know that a mole of C has a much greater mass than one of H. This is 17th cent. knowledge!


Jan van Helmont <http://en.wikipedia.org/wiki/Jan_van_Helmont> began the research of the process in the mid-1600s when he carefully measured the mass <http://en.wikipedia.org/wiki/Mass> of the soil used by a plant and the mass of the plant as it grew. After noticing that the soil mass changed very little, he hypothesized that the mass of the growing plant must come from the water, the only substance he added to the potted plant. This was a partially accurate hypothesis - much of the gained mass also comes from carbon dioxide as well as water. However, this was a signalling point to the idea that the bulk of a plant's biomass <http://en.wikipedia.org/wiki/Biomass> comes from the inputs of photosynthesis, not the soil itself.

missing steps

In 1796 <http://en.wikipedia.org/wiki/1796>, Jean Senebier <http://en.wikipedia.org/wiki/Jean_Senebier>, a French pastor, showed that CO2 was the "fixed" or "injured" air and that it was taken up by plants in photosynthesis. Soon afterwards, Nicolas-Théodore de Saussure <http://en.wikipedia.org/wiki/Nicolas-Th%C3%A9odore_de_Saussure> showed that the increase in mass of the plant as it grows could not be due only to uptake of CO2, but also to the incorporation of water. Thus the basic reaction by which photosynthesis is used to produce food (such as glucose) was outlined.

http://en.wikipedia.org/wiki/Photosynthesis


bc
<http://en.wikipedia.org/wiki/Amino_acids>
[edit <http://en.wikipedia.org/w/index.php?title=Photosynthesis&action=edit&section=14>]


John Clement wrote:

It was from Minds of Our Own. Incidentally there were also Harvard profs
who said the same thing, and most biology graduates that I have asked this
also said the soil.

John M. Clement
Houston, TX


Was this from "A Private Universe" or "Minds of Our Own"?

This leads to a "Fermi" problem: How much forest growth is necessary to
balance the world's production of CO2?

bc, who was surprised that there is max. only ~ 6.7% C in a sat soln. in
iron. It's a similar reason / calculation.

John M Clement wrote:


As surprising as the answer to how much CO_2 is produced, the reverse
question is just as interesting and could not be answered by most
Harvard graduates.

Given a wooden log, where did most of the mass of the log come from.

Most Harvard graduates said the soil.



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