Post the Experiment

[jc456]

I haven't the faintest idea. You'd have to ask Frank.

Nppe, you tagged it.

 

[Crick]

While we're here, have you tried asking anyone to explain to you what Watts per Square Meter means?

 

[jc456]

While we're here, have you tried asking anyone to explain to you what Watts per Square Meter means?

Relevance?

 

[Crick]

You might be able to stop complaining that graphs scaled in percent radiance don't contain information regarding thermal.

 

[jc456]

You might be able to stop complaining that graphs scaled in percent radiance don't contain information regarding thermal.

But they don't. They are only a statistical point. No thermal at all.

 

[Crick]

What is a "statistical point"?

 

[jc456]

What is a "statistical point"?

Look it up
BTW, You need to provide a reference point.

It then provides a reference to what the point signifies. Called temperature

 

[Crick]

The reference point would be 100% of the incoming solar radiance.

 

[Crick]

What is a "statistical point"?

Look it up

I checked two encyclopedias and six dictionaries. There were no listings in any of them for "statistical point".

 

[jc456]

What is a "statistical point"?

Look it up

I checked two encyclopedias and six dictionaries. There were no listings in any of them for "statistical point".

I knew you were lacking in logic try statistical then see what it says the word is ... An adjective. Heard of that ? The point is a data point on a graph for this use. Put them together and what do you get, a comparison data point. Not thermal at all.

 

[jc456]

The reference point would be 100% of the incoming solar radiance.

So it isn't a measure of temperature?

 

[Billy_Bob]

You might be able to stop complaining that graphs scaled in percent radiance don't contain information regarding thermal.

Because they do not. Watts/Meter^2 is a term designed to measure energy. Joules is the definition of that energy's ability to perform work and create heat in relation to its mass and composition.

It is really ignorant to point at people and make fun of them when you dont even understand what it is your talking about.

 

[Billy_Bob]

The reference point would be 100% of the incoming solar radiance.

You really dont have a clue about how or where it is measured do you..

 

[Wuwei]

Getting back to the OP, all that Herr Koch and Tyndall did was show that the CO2 was very good at blocking some IR. Neither knew that the absorption was due to elastic collisions of photons tuned to the vibration modes of the GHGs.

The Myth Busters experiment was not not realistic, but not for the reason you said. The percentage of CO2 they used was too low. If you consider the CO2 in the atmosphere at 400 ppm there is a bit of mass of it above us. The total weight of air above us is about 14.7 lb per sq in. The molar mass of CO2 is about 1.5 times the molar mass of air. So the CO2 part of it above us would be .0004 x 1.5 x 14.7 lb. = .009 pounds per in^2.

The weight of a cubic foot of air is .0807 lbs. The Myth Busters used a 3 foot box. If you do the arithmetic you will find the weight of a 36x1x1 section of air is .0017 lb. Since the Myth Busters used 7.23% CO2, the mass in that same section would be .0017 x 1.5 x .0723 = .000184 lbs. That is quite a bit lower than the .009 lb per in^2 that is in the atmosphere.

In fact it is easy to calculate that at 7.23% CO2 the Myth Busters used what is equivalent to 544 feet of atmosphere rather than the dozens of miles. Furthermore, to be more accurate the sides of the boxes should have been more insulated and the front of the boxes should have been close to absolute zero temperature. But that would be way too expensive.

The one thing that was under their control that they did not do was to shine the bright light from above and have the dark background at the bottom of the box. The convection part of the experiment was all wrong. What happened in their experiment is that as the black background at the rear of the experiment warmed, the heat would rise parallel to the background and allow colder air to replace it from below. On earth thermal convection is perpendicular to the earth. My guess is that the eddy currents of thermal convection in the Myth Busters setup would have been much stronger than perpendicular eddy currents like those on earth.

In summary I think the Myth Buster experiment was an understatement of the actual heating compared to conditions found on earth. No, they did not tell us how much effect an additional 120 ppm would have, but it was interesting it what it did show. I don't think it would be possible to design a definitive experiment confined in a lab.

 

[IanC]

Getting back to the OP, all that Herr Koch and Tyndall did was show that the CO2 was very good at blocking some IR. Neither knew that the absorption was due to elastic collisions of photons tuned to the vibration modes of the GHGs.

The Myth Busters experiment was not not realistic, but not for the reason you said. The percentage of CO2 they used was too low. If you consider the CO2 in the atmosphere at 400 ppm there is a bit of mass of it above us. The total weight of air above us is about 14.7 lb per sq in. The molar mass of CO2 is about 1.5 times the molar mass of air. So the CO2 part of it above us would be .0004 x 1.5 x 14.7 lb. = .009 pounds per in^2.

The weight of a cubic foot of air is .0807 lbs. The Myth Busters used a 3 foot box. If you do the arithmetic you will find the weight of a 36x1x1 section of air is .0017 lb. Since the Myth Busters used 7.23% CO2, the mass in that same section would be .0017 x 1.5 x .0723 = .000184 lbs. That is quite a bit lower than the .009 lb per in^2 that is in the atmosphere.

In fact it is easy to calculate that at 7.23% CO2 the Myth Busters used what is equivalent to 544 feet of atmosphere rather than the dozens of miles. Furthermore, to be more accurate the sides of the boxes should have been more insulated and the front of the boxes should have been close to absolute zero temperature. But that would be way too expensive.

The one thing that was under their control that they did not do was to shine the bright light from above and have the dark background at the bottom of the box. The convection part of the experiment was all wrong. What happened in their experiment is that as the black background at the rear of the experiment warmed, the heat would rise parallel to the background and allow colder air to replace it from below. On earth thermal convection is perpendicular to the earth. My guess is that the eddy currents of thermal convection in the Myth Busters setup would have been much stronger than perpendicular eddy currents like those on earth.

In summary I think the Myth Buster experiment was an understatement of the actual heating compared to conditions found on earth. No, they did not tell us how much effect an additional 120 ppm would have, but it was interesting it what it did show. I don't think it would be possible to design a definitive experiment confined in a lab.

hahahahaha. one of the more eclectic descriptions of the MythBusters experiment that I have heard. dont forget that the control would also have to have a massively increased CO2 density by your method.

 

[Billy_Bob]

Getting back to the OP, all that Herr Koch and Tyndall did was show that the CO2 was very good at blocking some IR. Neither knew that the absorption was due to elastic collisions of photons tuned to the vibration modes of the GHGs.

The Myth Busters experiment was not not realistic, but not for the reason you said. The percentage of CO2 they used was too low. If you consider the CO2 in the atmosphere at 400 ppm there is a bit of mass of it above us. The total weight of air above us is about 14.7 lb per sq in. The molar mass of CO2 is about 1.5 times the molar mass of air. So the CO2 part of it above us would be .0004 x 1.5 x 14.7 lb. = .009 pounds per in^2.

The weight of a cubic foot of air is .0807 lbs. The Myth Busters used a 3 foot box. If you do the arithmetic you will find the weight of a 36x1x1 section of air is .0017 lb. Since the Myth Busters used 7.23% CO2, the mass in that same section would be .0017 x 1.5 x .0723 = .000184 lbs. That is quite a bit lower than the .009 lb per in^2 that is in the atmosphere.

In fact it is easy to calculate that at 7.23% CO2 the Myth Busters used what is equivalent to 544 feet of atmosphere rather than the dozens of miles. Furthermore, to be more accurate the sides of the boxes should have been more insulated and the front of the boxes should have been close to absolute zero temperature. But that would be way too expensive.

The one thing that was under their control that they did not do was to shine the bright light from above and have the dark background at the bottom of the box. The convection part of the experiment was all wrong. What happened in their experiment is that as the black background at the rear of the experiment warmed, the heat would rise parallel to the background and allow colder air to replace it from below. On earth thermal convection is perpendicular to the earth. My guess is that the eddy currents of thermal convection in the Myth Busters setup would have been much stronger than perpendicular eddy currents like those on earth.

In summary I think the Myth Buster experiment was an understatement of the actual heating compared to conditions found on earth. No, they did not tell us how much effect an additional 120 ppm would have, but it was interesting it what it did show. I don't think it would be possible to design a definitive experiment confined in a lab.

Two major failings in your assessment...

First, The concentration is in total height of the vapor column. you would compress the amount of gas in the total column and place this in the box? They already had 7,000ppm within the box. 10,000 times greater than the current saturation.

Second, The improper heat application and lack of offsetting cold with thermal convection makes the rise they did see roughly 10 times greater than it should have been.

Both of these situations give an extreemly false (positive) upward bias. Your assessment that the experiment gave to low a temperature rise is patently false and misleading.

 

[Wuwei]

hahahahaha. one of the more eclectic descriptions of the MythBusters experiment that I have heard.

Thank you.

dont forget that the control would also have to have a massively increased CO2 density by your method.

I didn't see a clear description of the control. My assumption is that the control had no GHG at all. Basically what they showed is that the GHGs acted as a "blanket". The only physical interpretation that I could see is that the blanket is caused by back radiation, although they did not explicitly say that.

 

[Wuwei]

First, The concentration is in total height of the vapor column. you would compress the amount of gas in the total column and place this in the box? .

Of course not. A better experiment (still not ideal at all) would be to have a much longer box, but vertically oriented. If the concentration were too high inelastic interactions with the IR would confuse the result.

They already had 7,000ppm within the box. 10,000 times greater than the current saturation.

??? More like 72,000ppm which is 180 times current estimates of 400ppm.

Second, The improper heat application and lack of offsetting cold with thermal convection makes the rise they did see roughly 10 times greater than it should have been.

That doesn't make any sense. Where do you get a factor of 10? In their experiment the convection current would rise at the back and be replaced by cooler air from the bottom. The cooler air would creep across the floor front to back. The hotter air would fall from the ceiling to the floor near the front of the box. It would be a very efficient circular pattern of convection.
If the light source were at the top and the absorption at the bottom, the rising warm air and falling cool air passing each other would form a more chaotic convection path. I think that would more effectively preserve the heat at the bottom.

 

[IanC]

I dont think we can read into the MB experiment what isnt there. the controls were standard air, they added massive amounts of CO2 and methane far beyond what is naturally present.

 

[Wuwei]

I dont think we can read into the MB experiment what isnt there.

That's right. I think Billy is doing that.

the controls were standard air, they added massive amounts of CO2 and methane far beyond what is naturally present.

Yes the added GHGs were larger in percentage but smaller in total projected cross-section. So the experiment is unrealistic both ways in quantifying atmospheric physics. However I think that it does demonstrate qualitative aspects. Those who don't believe in back-radiation at all will have a hard time explaining the results unless they resort to unsubstantiated bold claims (like SSDD)