Need info on greenhouse effect in a greenhouse (not global warming)

Beverly Erlebacher bae at cs.toronto.edu
Fri Mar 5 14:58:26 EST 1999


In article <01be6651$57349300$1f899cd1 at default>,
Stephen M Jankalski <CEREOID at prodigy.net> wrote:
>
>Could anyone provide me with an explanation of the physics of the
>greenhouse effect as it occurs in an actual greenhouse? Is there a website
>somewhere illustrating this?
>
>Most of the information on the net about the greenhouse effect actually
>pertains to global warming. That is not what I am looking for. None of it
>explains in detail the actual origin of the term as it pertains to
>greenhouses or physics of how solar radiation is transformed as it passes
>through glass.

Different materials may be transparent to different frequencies of light.
Glass is transparent to visible light, but much less so to infrared.  So
the sun shines into the greenhouse, materials inside absorb the energy
and become warm, then re-radiate it as infrared, which is mostly reflected
back from the glass, so the greenhouse continues to warm up beyond the
outdoor temperature.

"Greenhouse gases" in the atmosphere, such as CO2 and methane, have the
same kind of effect, reflecting infrared back to the earth.

Btw, not all transparent materials act like glass in this regard.  The
possibility exists to make sheets of diamond using vapor deposition 
techniques.  This material would be transparent to both visible and IR
light, just the thing for car windows in warm climates. :-)




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