global warming?

Question

if i trap CO2 gas between two panes of glass under sunlight, with a space between the ground, will the temperature be higher than two other panes of glass without CO2 gas trapped between them?

Answer 1

I think that there is a fundamental problem with the experiment. The glass will have a far more efficient greenhouse effect than the trapped CO2, making any small difference hard to measure. This is the reason that car interiors get hot when in the sun, it allows the radiation in but then traps the heat trying to escape (greenhouse effect).

The other problem is that CO2 by itself doesn't contribute that much to the greenhouse effect. It is a secondary effect of the CO2 that causes the main temperature increase. What happens is the CO2 causes a small temperature increase. This allows the atmosphere to retain more water and it is the increase in water that causes most of the greenhouse temperature increase.

What I would suggest is to try some other material that will not absorb in the infrared (can't think of one at the moment, but thin PE may be okay, it will absorb in the infrared but less than most other readily available materials). Make this material as thin as possible add the CO2, I would suggest as dry ice, and a small container of water.

Edit:
The IR transmission is clear in a lot of the IR as indicated in the diagram by gcnp58, but this is misleading. Unfortunately the greenhouse effect is based on transmision at the 8-12 micron range (outside the range of the graph). In this region SiO2 and CO2 absorbs very strongly. (Source: Handbook of chemistry and physics and the weather makers by Tim Flannery).

There is a reason why glass is not used to sample infrared spectra, it interferes with the longer infrared wavelengths

Answer 2

This is a misinterpretation of how the greenhouse effect works and the experiment you propose has no relation to the atmospheric greenhouse effect. First off, glass doesn't transmit longwave infrared so there would be nothing going through the panes of glass that would interact radiatively with the CO2 trapped inside. So any longwave radiation gets stopped at the surface, and if there isn't a lot of longwave radiation, then other processes will take over the temperature, mainly sensible heat fluxes. This is why the teach observed that the temperature went down inside the panes. There was some convective cooling of the glass going on.

The atmospheric greenhouse effect works by trapping outgoing longwave infrared radiation and reradiating part of that radiant energy back towards the ground. In order to set up an accurate experiment demonstrating the greenhouse effect, you would need a radiant heat source generating longwave infrared radiation with a set power output. Say perhaps a 100 W heater in an aluminum plate. Then, you would measure the equilibrium temperature of that plate with a non-radiatively active atmosphere (something like argon) above it (except you would have to stop convective transfer of heat, which will affect your measurements (there is no good way to do this)). Then, you would put an atmosphere of CO2 above the plate instead of argon and measure the temperature. What you would find is that the temperature of the plate would increase because a small part of the outgoing longwave radiative flux is now coming back and heating the plate a little. So the plate's temperature has to rise to support a larger outgoing radiative flux. But keep in mind that no partition in this system could be made of glass, since it won't transmit longwave infrared. You would need to use something like Saran wrap, which does transmit IR, or something really exotic like NaCl plates, pure silicon (cuts off around 8 microns), germanium (better than silicon), or something really exotic like zinc selenide.

Except that thought experiment won't really work since the radiant flux captured by a small volume of CO2 isn't large enough to generate a measurable change in the temperature of the plate. But in principle, the above description is how you would demonstrate the atmospheric greenhouse effect. Thinking that trapping CO2 between plates of glass represents an accurate model of the atmospheric greenhouse effect is naive and incorrect.

Answer 3

I think a better experiment would be:

Measure the temperatures inside two glass containers on a sunny day, one with a CO2 mixture and one with no CO2 in the mixture. But remember, the CO2 does not interact with the incoming sunlight, it is only the IR energy radiated from surface matter that is heated by the sunlight. So to do your experiment it would be better to place the two containers in front of an electric heater.

Answer 4

Yes. But it would be small if the area of the glass was small. And the glass itself would need to be transparent to infrared radiation to avoid the effect of the glass swamping out the effect of the CO2. The ground beneath each glass would need to be a uniform surface of some type. Outdoors, stopping the wind from messing things up without creating an actual glass greenhouse would be tricky. So it would probably need to be done indoors, using full spectrum lights to represent the Sun.

It could be done, but, doing it on a small scale requires a careful scientific experiment. There are many opportunities for error.

Answer 5

The glass blocks IR too. They call CO2 a greenhouse gas because it does the same thing in the atmosphere that the glass does in a greenhouse. It blocks IR light. So the glass alone does as good a job as the glass and CO2.

Answer 6

No, never it can be measured, (since it would be infinitely small to measure as right up to the atomic scale) to confirm a result to confirm the fact that the trapped millions of tons of CO2 in our atmosphere stops the reflective sunlight energy to leave the Earth, energizing and warming the planet to 4 to 5 deg Celsius in a period of one century! This warming has the chance of doubling and trebling or more depends on the rate of emission increase of CO2 compounded with other gaseous effect of CFCs to deplete the Ozone and to allow more Ultra violet rays to enter earth for warming to eventually create a worldwide disaster of overnight destruction of all coastal cities taking a toll of a hundred million peoples life too, is not ruled out!

Answer 7

The students of a local high school performed this experiment and the co2 filled space actually showed a lower temperature.

Answer 8

no the volume would be too small to make a difference.

Answer 9

yes