Right. That’s why it lets it in. Why doesn’t it let it all back out? Because the radiation outward isn’t visible light, it’s much lower frequency radiated heat, which the CO2 absorbs.
Thus my suggestion to use black construction paper. Visible light passes through the glass and through the CO2-containing air, strikes the black paper and is radiated back outward as heat. Some of this heat gets absorbed by CO2. Some gets reflected back by the glass? Perhaps – but we have a control for that.
I’d also add a 4th jar, filled by breathing air into it using a tube, and allowed to reach equilibrium with all the jars in the dark, before putting in sunlight. We couldn’t measure the amount of CO2, but we could see if increasing the CO2 content makes a notable difference.
Then we’d see the effect of water in the presence of a GHG, and we’d also see a difference based on additional GHG. Gee, add a 5th jar, with breath but no glass of water. Then we can control for two independent variables, and expect to see a synergistic effect when using both.
[BTW, after a moment’s thought, I realize my objection to glass (heat bouncing off it and not entering) is silly, or greenhouses wouldn’t work. I need to think before hitting that “post” button!]
BTW, above I said ‘high school’ but it’s targeted for elementary and middle school.
At the end, the author says he believes the theory but wanted to address the authenticity of the two presenters (Gore, Nye).
I think I’m gonna have to get myself some jars and thermometers!