Guest post by Bill DiPuccio, Science Teacher
Let’s face it, high school science videos can be boring and ineffective. I like my science with a twist of comic exaggeration. So I decided to produce a video with enough humor to keep the students awake, and enough depth to challenge them intellectually.
This 30 minute video on the Greenhouse Effect is the prototype for a possible new series: “Bill Scientific” (I gave it a personal imprint to infuse some warmth and presence). Unlike introductory videos which attempt to cover a broad field of knowledge in a short time, the goal of this prospective series is to drill down into specific, but pivotal, topics in the physical and earth sciences.
Rather than just spooning out information, each program would be designed around experiments (the simpler the better) that can be used to illuminate and verify crucial scientific principles. Students will see science in action and gain a better grasp of the empirical basis for scientific theories.
Of course, future programs will depend on the response from students, educators, and scientists, as well as securing funding. The “Greenhouse Effect” was shot and produced on amateur equipment and software. Despite these limitations, I believe the final product faithfully conveys the intent of series.
P.S. If you like the video, pass it on!
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Mydogsgotnonose writes: “… put a plug between the two systems …”
Ah, but the only way to “plug” the IR would be to put some sort of “IR block” between the sky and your measuring device. That would indeed stop the IR, but now you can no longer claim to be measuring the IR from the sky.
> Spartacus says: http://en.wikipedia.org/wiki/Greenhouse_effect#Real_greenhouses… Greenhouse gases do not re-rediate some of the energy back towards the surface since the molecules do not have any infinite common orientation that forces the re-emitted radiation only to the surface. Radiation is re-emmited in all directions…
Errm, your logic and/or reading comprehension has failed you. The GHG’s do indeed (a) radiate some of the energy back to the surface, but as you so wisely observe, they (b) radiate in all directions. these two statements are not contradictory. Indeed, as the wiki article states “The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions”. Thats, ermm, the first sentence, so I can see how you might easily have missed it.
Perhaps less obviously, since the atmosphere is approximately 2-D (its 10k high but 10000k wide, so to speak) you don’t need to think of “all directions” but only up-and-down.
> near the surface it’s because CO2 is more concentrated here
As Mydogsgotnonose observes, this is wrong. There is more WV near the sfc, perhaps that is what you were thinking of. In fact, due to saturation, the GHE is less important near the surface, not more so.
Hi Tj: clever but I’m not falling for it. I’m a process engineer and for the emissivity of sand with non-forced convection, you need about 100 deg C before radiative flux > convective flux.
The ‘sky’ is an impedance to IR transmission to space. The way you measure its temperature is to use a pyrometer which, by blocking IR energy from the opposite direction, reveals the S-B radiative flux with no opposing flux.
‘Back radiation’ from a colder atmosphere cannot create heat energy at the earth’s surface, To claim this is to claim the existence of a ‘Perpetual Motion Machine of the 2nd Kind’, in thermodynamic terms.
Climate science is dead until it acknowledges its major mistakes. Hansenkoism is dead. Trenberthism may evolve by the missing ‘0.9 W/m^2’, for 18 months maximum.
Mydogsgotononose, almost everything in the atmosphere is more concentrated near the surface, including CO2. The CO2 concentration it’s indeed more constant than water vapour with altitude but all the gases get more rarified with the variation of the pressure gradient. Concentration remains approximately the same but everything follows more or less the PV=nRT variables. The “absolute amount” (not the concentration) of CO2 gas reduces with altitude because atmosphere pressure drops. If you see the patterns of the distribution of CO2 from satellite readings, you will se that the “it is well mixed” its a myth or more a misconception. It’s neither well mixed horizontally nor vertically. There are even more differences between the earth’s hemispheres for instance. I guarantee you you will not get the same absolute amount of CO2 near the earth’s surface or 4000km above your head. Most plants know that too…
See density and pressure profiles from connolley’s favourite wikireference:
http://upload.wikimedia.org/wikipedia/commons/9/9d/Comparison_US_standard_atmosphere_1962.svg
I agree that water vapour, duo to the physical properties of water, drops more rapidly than CO2, but every gas gets more scarce with altitude.
_Jim says:
“7. Should a particular frequency EM field pass by a resonant molecule, the molecule, like a resonant dipole antenna will ‘pick up’ (the field will induce into the molecule) energy from the passing field .. refer to 1. above. “
Are you denying the particle theory of light? There has never been a better proven theory than the particle theory of light … except of course the electromagnetic theory … although it does have a few problems when anything gets moved … which is why we stitched it all together like a torn bit of rags with relativity. But of course, when none of that worked we pretended we could explain it with that new theory called Quantum physics.
Which … says that everything is waves. No, No! … not those old fashioned waves travelling through the ether … no new fashioned waves travelling through a new fashioned ether of time-space. Which really isn’t an ether at all because time space isn’t something its nothing.
And now that everything is completely clear, the argument is over, the science is settled and the theory of light is provable and predictable:
It means we have completely testable science. We can prove the theory is true because we can explain why it doesn’t work when it is supposed to be a wave … because we have the excuse its a particle. And, we can explain why it doesn’t work when it supposed to behave like a particle …by using the excuse that its really a wave.
And we wonder why climate “scientists” think they can make predictions … and if they don’t work they just adjust the causations to include a few added bits and after the experiment is over “prove” they were right because they can swap the theory to suit whatever the result turns out to be.
Isn’t that hilarious!
http://upload.wikimedia.org/wikipedia/commons/9/9d/Comparison_US_standard_atmosphere_1962.svg
If you see from those graphics, the density of the atmosphere drops almost 1kg/m3 from the surface until the Tropopause. Thats a huge amount of less gas re-emmiting radiation, including CO2. This is one of the biggest misconceptions among those that are trying to find hotspots within altitude 😉
Sorry, in one of my last comments, i wanted to write “I guarantee you you will not get the same absolute amount of CO2 near the earth’s surface or 4000 meters (AND NOT KM) above your head.
PS. If you like the video, pass it on!
I’d like to pass it on to Michael Mann, Al Gore, Phil Jones …..
Re my above comments ridiculing the wave-particle theory.
Let me put this in a way most people here will understand. (And just pray the climate “scientists” don’t get any ideas!)
Let us suppose that a climate “scientist” proposes the “drought-flood” theory of climate. This theory says that sometimes the climate behaves to give floods, sometimes drought. We don’t know why or when but it just does. They then offer it to be tested. Asked what they think the climate will do, they say: “I think flood”, there is a drought … is the theory disproven, no! This is because it was behaving like a flood event and not a drought event.
Let us now suggest we create a few more particles (sorry modes of behaviour). Let’s call them the heat-cool particle … sorry event, the flood-drought, the wind-calm … I think you may understand where I’m going.
E.g. the theory predicts the warming of the climate from 1970-2000, then (for reasons they do not need to explain) the other nature of the beast is uncovered and instead of being a heat-event the theory “predicts” (or post-dicts) the cooling event.
The theory is entirely “scientific” like wave particle. It explain everything: there is not a flood, drought, heat-wave, freeze that is not consistent with the theory. Yet strangely it predicts nothing.
First –
Maximum radiative transfer of energy between two non contiguous bodies occurs in a vacuum.
Interposing any matter at all between the bodies reduces the amount of energy received by both.
Where one body is warmer than the other, reducing the efficiency of the energy transfer between the two will not cause the cooler body to increase its temperature above that which is achieved at maximum efficiency.
“Back radiation” is merely cultist obfuscation, attempting to ascribe magical properties to something which exists naturally, and is a property of all bodies above absolute zero – ie all bodies. Every body above absolute zero emits electromagnetic radiation – freezing cold, boiling hot – no exceptions.
Second.
The Earth has obviously cooled since its creation some time ago, if, indeed it was originally a molten blob.
Because it is still a large molten blob, surrounded by a thin solid (or “frozen”) crust, the Earth’s temperature gradient proceeds from the hot inside to the cooler surface. Until the the Earth reaches a point where it has a uniform temperature throughout, it has obviously not finished cooling.
Any calculations purporting to show that the Earth “should have” a temperature of x, are nonsense. The Earth’s surface is at the temperature it has reached as it cooled from several thousand degrees initially.
Third.
Any person claiming to have calculated an “average surface temperature” for the Earth is pulling your leg. Ask what the figure is for say, 0300 UTC on 1/1/2012, and you will find that the figure given comes with caveat or two – a particular refuge is to quote something like 95% certainty. In other words, one chance in twenty that the figure is wrong. Not to mention the fact that whatever is purportedly measured is most certainly not the surface – usually near surface, over land. Not even that over the ocean, which covers most of the planet.
Anyone claiming to measure “global warming” is delusional. They can’t even define the surface that they claim to be measuring. Is it the top of the soil? The top of the rain forest canopy, or the top of the humus beneath it? Maybe the froth on the ocean wave, or the solid water in the trough, a split second later. Does it all “average out,” perhaps? If you believe that, I have a nice bridge you might be interested in buying.
Live well and prosper!
Mike Flynn
Mr. Scientific, or may I call you Bill, check out your humor with your kids’ friends. A good try… but I don’t see a donate button, because I certainly think your in the right space but professional assistance is required.
BTW I am reminded of Zeno’s paradox about the “reflected” radiation… isn’t half of that also “reflected” back to space … half of that back down and half of that back..etc.? In fact, the whole notion is entirely simplistic and childish. Some serious analysis is required before a line of computer code is written…. and I mean serious, not just building on further models and hearsay.
In fact, I think climatologists should just shut up for a couple of thosand years until they have a reliable series of
temperaturesenergy balances.Mydogsgotnonose says: April 27, 2012 at 4:05 pm
“Hi Tj: clever but I’m not falling for it. I’m a process engineer and for the emissivity of sand with non-forced convection, you need about 100 deg C before radiative flux > convective flux.”
Ah, but now you are talking magnitudes of various processes rather than the existence, in principle, of a process. I don’t doubt that in many situations, conduction and/or convection are more important than IR photons for transferring thermal energy. But just because something is small does not make it “imaginary”.
The vast majority of energy in the atmosphere near the surface is transferred from molecule to molecule through collisional exchange rather than emission of photon radiation.
The energy represented by an average IR photon emitted from a hot rock at noon spends time in billions of different atmospheric molecules (99.999% transmitted through collision) before it makes its way to 10 kms high where it starts to have 50% chance of actually being emitted as a photon and making its way directly to space.
Real physics is different than the greenhouse effect explanation. The energy takes a lot of time to make its way back to space and it spends that time in billions of different molecules. It is not “in and out”.
An average 1 sq metre rock on a beach in the tropics receives 2.5 X10^21 solar photons from the Sun each second at noon and emits 1.5 X10^22 IR photons per second at noon. How many of those photons are intercepted by CO2? How many of those interceptions result in a back-radiated photon to the surface? It is a tiny, tiny, tiny fraction compare to the 1.5 X10^22 photons emitted per second. The rock is more likely to receive the energy back after a Nitrogen molecule collides with it and then re-collides with it putting the energy back into a molecule on he surface of the rock.
Climate science is still based on the way we understood physics in the 1896 when Arrhenius did his infamous work. The quantum world is much different.
ozzieostrich says: April 27, 2012 at 5:15 pm
First –
Maximum radiative transfer of energy between two non contiguous bodies occurs in a vacuum.
True, so the maximum transfer between earth’s surface and space occurs with no atmosphere in between. By adding at atmosphere, we reduce the transfer to space. This in turn means the surface must get warmer until it once again radiates enough energy to space to balance the incoming sunlight.
“Second.
The Earth’s surface is at the temperature it has reached as it cooled from several thousand degrees initially. “
No, if the only process involved was the earth cooling by radiation, it would have cooled much more much faster. Estimates put the geothermal heat flux at ~ 0.1 W/m^2. Even if this is off by a factor of 100 and the flux is really 10 W/m^2, this is way smaller than the incoming 340 W/m^2 of sunlight.
“Third.
Any person claiming to have calculated an “average surface temperature” for the Earth is pulling your leg. Ask what the figure is for say, 0300 UTC on 1/1/2012, and you will find that the figure given comes with caveat or two …
This is true. That is one reason people often talk about “changes in temperature” or “temperature anomalies”. It is often quite possible to measure changes quite accurately even when the actual values are not known. For example, I can measure two resistors with the same cheap DMM. Even if the readings are 100.0 Ohms +/- 5 Ohms and 100.5 Ohms +/- 5 Ohms, I know the second resistor is about 0.5 Ohms more, even thought that is less than the uncertainty in either measurement.
If I measure 1000’s of temperatures, it is quite possible to see that they have gone up an average of 0.4 C from one day to the next, even without worrying about what the “average temperature” might represent, and even if the thermometers are only calibrated to +/- 0.5 C.
Tim
Robert of Ottawa says:
April 27, 2012 at 6:02 pm
“…isn’t half of that also ‘reflected’ back to space … half of that back down and half of that back..etc.?”
Very close, but not exactly. At the surface there is a 50/50 chance of a photon being radiated toward the surface or toward space. But the part of the atmosphere that does most of the radiating is above 10 km altitude. Therefore, an emitted photon has a greater than 50/50 chance of being emitted toward space, due to the altitude and the curvature of the earth. So no matter how many billions of re-emissions occur, the net effect is the same: there is more than a 50/50 chance of a photon ending up in space than on the planet, and the odds rise with altitude.
That is why William Connolley tries to reinforce that argument when he says: “since the atmosphere is approximately 2-D (its 10k high but 10000k wide, so to speak) you don’t need to think of ‘all directions’ but only up-and-down.”
“Only up and down” is an attempt to eliminate the ‘more up than down’ scenario. Can’t have that, can we? Because then it might be possible that CO2 has a net cooling effect.
Bill says “How many of those photons are intercepted by CO2? How many of those interceptions result in a back-radiated photon to the surface? It is a tiny, tiny, tiny fraction compare to the 1.5 X10^22 photons emitted per second. “
First, how many of those photons would return with NO greenhouse gases? None!
So we are already at least a BIT ahead of the game.
As for the amount of energy returned, you can “look” up with a cheap IR thermometer (which brings us back to the top post!) and easily measure the “back-radiated” photons. Sure it is typically less than the upward IR from the ground (ie the thermometer reads a lower temperature when aimed at the sky). Much of this is from clouds; some is from H20 vapor; some is from CO2. I would not consider the amount “a tiny, tiny, tiny fraction”.
“The rock is more likely to receive the energy back after a Nitrogen molecule collides with it … “
Except that the nitrogen molecules are about the same temperature as the rock, so on average they neither add nor remove energy much energy. (The “17 W/m^2 Thermals” would mean the surface is, on average loosing energy from collisions with the air, not receiving energy.)
Smokey says:
April 27, 2012 at 6:45 pm
“Only up and down” is an attempt to eliminate the ‘more up than down’ scenario. Can’t have that, can we? Because then it might be possible that CO2 has a net cooling effect.
=========================================================
A net cooling effect is possible, but rather for a different reason: the “greenhouse gasses” block some IR coming from the Sun, this must contribute to cooling. This is a dirty little secret of the warmists.
@tjfolkerts
In response to your comments.
First
By adding an atmosphere, we reduce the radiative transfer between the Sun and the Earth, and vice versa. No ifs, buts, or maybes. This means that the surface of the Earth gets cooler – it is receiving less radiation. Pretending that the atmosphere blocks EMR unidirectionally might be convenient, but is not true. However, if someone can demonstrate experimentally that you can cause a body to become warmer by wrapping it in CO2 (or anything else that is not warmer than the body in question,) I will change my thinking.
Second.
Your response does not make much sense to me. The Earth was molten. It is not now. No ifs, buts, or maybes. Apart from emitting EMR, how would you suggest it cooled? Obviously, (I would think it’s obvious,) the output from the Sun was insufficient to prevent the Earth cooling to where it is now. You can estimate all you like, but it doesn’t change the reality that the Earth has cooled, all by itself. Facts are facts.
Third.
I notice you use your own caveats. This is normal for people who believe in the ability of gases to create warmth out of nothing by some magical process of “one way insulation”. You say ” . . . it is often quite possible . . .” Another characteristic of believers is to use inappropriate analogies. Rather engage in a probably pointless discussion about cheap DMMs, etc, I would merely point out that you assume absolute repeatability, but then add the caveat ” . . . is about . . .” after your statement “. . . I know . . .”
Your assumptions about making thousands of measurements etc., would would carry far more weight if you actually did it, and were than prepared to defend your assumptions relating to how you defined the surface etc.
There is no “greenhouse warming effect” due to CO2 or anything else. Insulators do not warm (or cool) objects in and of themselves – the “blanket effect” does not lead to a rise in temperature, in spite of Mike Mann and Chris Colose. So, sorry, the only source of man made warming is the heat generated by the activities of man. For example –
1. Burn a tree. The action oxidises carbon, creating heat and carbon dioxide.
1. Stay alive. You have oxidised carbon within your cells, creating heat and carbon dioxide.
Creating carbon dioxide by means of combining oxygen and carbon is exothermic, resulting in heat. Go one further, create lots of heat by thermonuclear means – say in a nuclear powered submarine or power station. Lots of heat without carbon dioxide generation. Man creates heat. No ifs, buts or maybes. No caveats to be seen.
Heat cannot be trapped. The perfect insulator does not exist, and all objects above absolute zero emit EMR. No ifs buts or maybes. Given long enough, all matter in the Universe will become isothermal – an assumption shared by much smarter and well educated people than me. Without additional energy input, the earth will continue to cool – slowly and remorselessly
If you want to believe the myth of CO2 greenhouse warming, be my guest.
In the meantime, live well and prosper
Mike Flynn
Now that damned dog with no nose is pedalling his nonsense full time here too?
He won’t ever write you his equations though. That would catch him out. It’s all about how everyone else is wrong, but no actual maths/physics to back it up. With equations.
The problem is that radiation physics hasn’t really developed since the 1920s and Planck invented the photon as a throw-away concept. it isn’t real.
People are already laughing at you Doggie. But saying nonsense like this will make the laughs a lot louder.
Give us your equations that show that every particle physicist for the last 100 years is wrong. No spouting. The equations that replace the photon.
Scottish Sceptic says:
April 27, 2012 at 4:31 pm
“Isn’t that hilarious!”
That pretty funny.
tjfolkerts says:
April 27, 2012 at 6:42 pm
True, so the maximum transfer between earth’s surface and space occurs with no atmosphere in between. By adding at atmosphere, we reduce the transfer to space. This in turn means the surface must get warmer until it once again radiates enough energy to space to balance the incoming sunlight.
OK, I’ll play along. How does the surface get warmer??? This sounds to me like a Maxwell’s demon issue. If the atmosphere keeps the energy in, it must also keep the energy out (If it inhibits energy flow it must inhibit in both directions)
Why not try to show the spectral intensity graphs to their correct proportions. A lower temperature spectral intensity graphs lies completely under a higher temperature spectral intensity graph. In your case you would not even see the lower temperature graph if graphed within the higher temperature graph. There is more long wave incoming than coming from the surface and could be absorbed by water vapor and carbon dioxide before reaching the surface.
Larry
ozzieostrich
1) Certainly the atmosphere absorbs/scatters/reflects some sunlight before it reaches the earth. No one disputes that. The question then becomes how much EM radiation each way is blocked, and how that affects the temperatures. The common answer is that, given current conditions, the net effect is to warm the earth. If you have other calculations, then tell us what temperature YOU predict based on your calculations.
“if someone can demonstrate experimentally that you can cause a body to become warmer by wrapping it in CO2 (or anything else that is not warmer than the body in question,) I will change my thinking.”
It’s called “the earth”. 😉
The challenge to do this in a “laboratory experiment” is that you need
1) a warm object
2) cold walls all around
3) a thick enough layer of CO2 (or other GHG) to absorb a significant fraction of the IR.
Also, on a cold day, my fingers get much warmer by wrapping them in cooler fabric (aka “gloves”).
2. The point is that the earth has indeed cooled by radiation, but the current temperature cannot be inferred solely from the initial conditions as your statement seems to imply: “The Earth’s surface is at the temperature it has reached as it cooled from several thousand degrees initially. ” You seem to imply that the surface is ~ 288 K because that is all it would have cooled from the hot initial conditions. In fact, the surface would have cooled much further than 288 K if the sun was not keeping the earth warmed.
The current temperature is determined 99+ % by sunlight, and less than 1 % by geothermal energy.
3. I can’t speak for “people who believe in the ability of gases to create warmth out of nothing by some magical process”, because I believe in a scientifically based greenhouse effect. 😉
Certainly the “global temperature” is open to numerous questions in terms of calibration, siting issues, lack of coverage, etc. I’m just saying it is not QUITE as bad as you seem to think it is.
“Insulators do not warm (or cool) objects in and of themselves”
Very true. But they don’t have to. If I build two houses that are identical other than insulation and run the furnaces exactly the same on a winter day, the house with insulation will be warmer inside. The furnace provides the thermal energy to each house; the insulation simply makes the one furnace more effective.
Similarly, it is the sun that provides the thermal energy to the earth. The GHGs simply make the sun more effective.
Russ in Houston proposes an insightful hypothesis: “If the atmosphere keeps the energy in, it must also keep the energy out (If it inhibits energy flow it must inhibit in both directions)”
That is the crux of the greenhouse effect. The atmosphere does indeed have to inhibit the flow of photons equally in both directions. But! this applies individually to each wavelength.
* A 0.5 um green photon is block from leaving just as well as it is blocked from arriving. There just happen to be a lot more 0.5 um photons heading down than up.
* A 15 um IR photon is block from leaving just as well as it is blocked from arriving. There just happen to be a lot more 15 um photons heading up than down.
These facts allow the atmosphere to inhibit photons differently in the two directions.