Posted on 12/03/2007 11:09:35 AM PST by kathsua
I was rereading the essay by Dr, Gerhard Gerlich and Ralf D. Tscheuschner and found this account of an experiment R.W. Wood conducted in 1909 that disproved the claim about greenhouses being hotter because they trapped radiation.
<<I have always felt some doubt as to whether this action played any very large part in the elevation of temperature. It appeared much more probable that the part played by the glass was the prevention of the escape of the warm air heated by the ground within the enclosure. If we open the doors of a greenhouse on a cold windy day, the trapping of radiation appears to lose much of its efficacy. As a matter of fact I am of the opinon that a greenhouse made of a glass transparent to waves of every possible length would show a temperature nearly, if not quite, as high as that observed in a glass house. The transparent screen allows the solar radiation to warm the ground, and the ground in turn warms the air, but only the limited amount within the enclosure. In the "open", the ground is continually brought into contact with cold air by convection currents.
To test the matter I constructed two enclosures of dead black cardboard, one covered with a glass plate, the other with a plate of rock-salt of equal thickness. The bulb of a thermometer was inserted in each enclosure and the whole packed in cotton, with the exception of the transparent plates which were exposed. When exposed to sunlight the temperature rose gradually to 65 C, the enclosure covered with the salt plate keeping a little ahead of the other, owing to the fact that transmitted the longer waves from the Sun, which were stopped by the glass. In order to eliminate this action the sunlight was first passed through a glass plate.
There was now scarcely a difference of one degree between the temperatures of the two enclosures. The maximum temperature reached was about 55 C. From what we know about the distribution of energy in the spectrum of the radiation emitted by a body at 55 C, it is clear that the rock-salt plate is capable of transmitting practically all of it,while the glass plate stops it entirely. This shows us that the loss of temperature of the ground by radiation is very small in comparison to the loss by convection. in other words that we gain very little from the circumstance that the radiation is trapped.
Is it therefore necessary to pay attention to trapped radiation in deducing the temperature of a planet as affected by its atmosphere? The solar rays penetrate the atmosphere. warm the ground which in turn warms the atmosphere by contact and by convection currents. The heat received is thus stored up in the atmosphere, remaining there on account of the very low radiating power of a gas. It seems to me very doubtful if the atmosphere is warmed to any great extent by absorbing the radiation from the ground even under the most favorable conditions.>>>>
Originally published in the Philosophical magazine , 1909, vol 17, p319-320.
Here’s an answer:
http://www.tennessean.com/apps/pbcs.dll/article?AID=/20071202/COLUMNIST0130/712020382/1007/OPINION
This is ridiculous. The greenhouse effect is a natural atmospheric phenomena recognized for over a century, and it’s as real as gravity. Al Gore didn’t invent it. It’s a vital thing - without it, earth would have an average global temperature of 0 degrees F. It is the reason Venus is a hellish, sweltering place. You can test it with an infrared thermocam and a tube full of CO2 - the CO2 will block out and absorb heat. The politics of global warming are another matter, but don’t try and deny a basic fact of science.
If you want to bring global warming crashing to the ground, disprove the link between greenhouse gases and warming.
I never could see how gas could store that much energy anyway.
What are you doing waving your “science” around? Don’t you know physical processes vary according to the political climate?
>>I never could see how gas could store that much energy anyway.<<
It doesn’t STORE the energy!
exactly.
Yes, it does.
Thank you for the voice of reason. I honestly couldn’t believe what I was reading in this article.
“a tube full of CO2...”
Maybe. But try comparing a tube with a concentration of, say, 250 ppm of C02 with another containing 350 ppm.
That, to me, is the real issue.
How does it block out and absorb heat at the same time?
Seems like it was a poor choice of words. Trap would be more apt.
[How does it block out and absorb heat at the same time?]
When eneergy impinges on a surface it is either passed, blocked (absorbed) or reflected. Or a combination but all must be accounted for. It is that nasty conservation of energy thingy.
BBC: 50 years on: The Keeling Curve legacy - ( CO2 -- Global Warming?)
I'm sure its proximity to the giant heat radiating fireball in the sky has nothing to do with it.
Remember the DUmmie who did an experiment with a some lighter fluid and steel mesh that “disproved” the “official story” of the 9/11 attacks?
Gases are composed of atoms that contain kinetic energy. This energy is not lost, but merely redistributed among other atoms during collisions (law of conservation of energy)... Also, energy exists between electron shell states of the atom (potential energy)...
If you want to live above the CO2 on Venus you’ll have to go up to about 50,000 meters in the sulphur clouds where the pressure is only one bar and the temperature about 70F.
Bring your own ladder and oxygen supply as they have no rentals.
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