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Author Topic: Can we demonstrate the greenhouse effect experimentally?  (Read 3863 times)

John Blinke

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John Blinke asked the Naked Scientists:

I would like to see a "kitchen science" experiment that demonstrates the greenhouse effect produced by carbon dioxide. It should be fairly easy, I think, to set up a container of low pressure CO2 next to a container of dry N2 -- both under a sun lamp. One would hope the container with CO2 would heat up more. 

John Blinke
Rochester, Michigan U.S.A.

What do you think?
« Last Edit: 12/02/2011 04:30:03 by _system »


Offline CliffordK

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Can we demonstrate the greenhouse effect experimentally?
« Reply #1 on: 12/02/2011 08:32:40 »
I think you could make such an experimental setup quite easily.

Perhaps in fishtanks, or in glass carboys.  The Carboy would be easier to seal.  I would consider adding sand or some other heat absorber into the bottom.

I don't know why you would want to use pure Nitrogen over using "Air".  Water, of course, is a wildcard, and it would be easy to get more water in the air tank than in the CO2 tank.

The "Greenhouse Effect", of course, is the allowing visible light to pass through a substance, be absorbed by the "crust", then blocking & diffusing the radiation of IR light back towards the source.

The lower atmosphere, the Troposphere, represents a 14km thick "column" of gas, which is made up of about 78% Nitrogen, 21% Oxygen, and 0.04% Carbon Dioxide (and other gases including water vapor & water mist).

On top of the Troposphere, is the Stratosphere for an additional 36km, as well as additional layers. 

Can a Carboy full of CO2, or half-full of CO2 adequately simulate a 14km column of very low density CO2 in a primarily N2, O2, atmosphere, including water (vapor&mist), and other compounds?

Keep in mind that the vapor, mist, and even small crystalline forms of water don't necessarily all act the same.

0.03% to 0.04% CO2 doesn't sound like a lot, but the theories indicate that it is adequate to absorb essentially 100% of the IR light in the

The top of your system should be uninsulated to allow the passage of IR heat.

You will have to decide if you wish to insulate the sides of the system (as any "column" of air is always surrounded by other identical columns).  If using a carboy (or any other tank for that matter), you can choose any appropriate (clear) side for the top.

You know, as far as the dry CO2 vs moist air question...  in at least one setup, I might just add some standing water.

Your temperature measurements should be in either the heat absorber, or just above it.

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Can we demonstrate the greenhouse effect experimentally?
« Reply #2 on: 12/02/2011 16:58:59 »


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