As readers may know, Dr. Roy Spencer and I have had a long running disagreement with the group known as “Principia Scientific International” aka the Sky Dragon Slayers after the title of their book. While I think these people mean well, they tend to ignore real world measurements in favor of self-deduced science. They claim on their web page that “the Greenhouse gas effect is bogus” and thus ignore many measurements of IR absorptivity in the atmosphere which show that it is indeed a real effect. Rational climate skeptics acknowledge that the greenhouse effect exists and functions in Earth’s atmosphere, but that an accelerated greenhouse effect due to increased CO2 emissions doesn’t rise to the level of alarm being portrayed. Yes, there’s an effect, but as recent climate sensitivity studies show, it isn’t as problematic as it is made out to be.
I don’t plan to get into that issue in this thread, as this is an hands-on experiment showing one of the thermal premises of the “slayers” in action to prove or disprove it. Most of what that group does is to spin sciencey sounding theories and pal reviewed papers by a mysterious members-only peer review system, and I have yet to any one of them try to do anything at an experimental/empirical measurement level to back up the sort of claims they make.
What started the recent row was an essay by Dr. Spencer titled Time for the Slayers to Put Up or Shut Up, which I followed on with: The Spencer Challenge to Slayers/Principia.
In their response to Dr. Spencer, they made this essay…
…and in that response was this curious graphic from Dr. Alan Siddons:
To be honest, I laughed when I saw this, because for all their claims to be “experts” on thermodynamics while telling the world that “back radiation” has no effect, this is a clear-cut case of them not knowing what they are talking about when it comes to heat -vs- visible light. Clearly, you can indeed reflect/re-emit a portion of the visible and infrared energy back to the light bulb, energy which would have been lost to the dark surroundings. There is no “extra” energy per se, just a spatial redistribution of energy (a greenhouse atmosphere has higher temperatures near the surface, but lower temperatures at high altitudes). They also seem to fail to understand how a mirror actually works, bold mine:
“Does shining a flashlight at a mirror so that all the radiation comes back to the flashlight make the flashlight shine brighter?”
While the emissivity of a glass mirror is high, no mirror reflects 100%, and mirrors of course are not lossless, so it will also absorb some Visible and IR in addition to reflecting/re-emitting some of it back. You can see this loss of energy in the FLIR camera in the video just before the mirror is removed at about 16:30.
I put their claim of “a light bulb facing a mirror does not heat up” to the experimental test.
I did several spot experiments at home over the last couple of weeks to investigate the issue empirically (since talk is cheap), and to make sure it was repeatable, while discussing the design and results with Dr. Spencer. The first two designs of the experiment had weaknesses that I was not happy with, and so it has take time to devise an experiment in a way that was fully comprehensive and uninterrupted from start to finish. For example, in my first iteration, the experiment was shot from the side (similar to the diagram), but required rotating the bulb mount assembly away from the mirror to get the temperature of the bulb surface. This wasn’t always repeatable to get the same spot on the bulb surface and it introduced variances. Another problem was that standard household bulbs had odd temperature gradients across their surface due to the way the filament is placed. The flood lamp was much more repeatable at its center. Repeatability is important, because I want others to be able to replicate this experiment without significant variances due to the equipment and how it is setup.
After ensuring the experiment works, and is repeatable/replicable, and that the control run without a mirror performed as expected, today in this WUWT-TV segment, I present the entire experiment uninterrupted as one long video. It is almost 21 minutes long, but I had no choice, because at least 16 minutes of it were required to be non interrupted to show the experiment in progress. I didn’t want anyone to be able make silly claims that the experiment was faked that there were video edits going on to change the results, such as Al Gore did in his Climate 101 video.
In my case, I did some graphic overlays to illustrate points and data, but there was no discontinuity edits of the video or audio from start to finish.
Here’s the experiment equipment list and procedure.
Equipment:
- FLIR BCAM portable infrared camera
- 65 watt incandescent flood lamp (used due to mostly flat center target surface)
- clamp on ceramic lamp base and metal electrical base/stand
- small glass wall mirror from K-Mart
- video camera to record the event
Procedure:
- Setup equipment in similar fashion to Alan Siddons figure 3 above, using stands and clamps to allow for correct height and continuous recording of FLIR camera image and a timer image.
- Focus FLIR on flat front surface of 65 watt bulb
- Start video camera to record experiment, simultaneously start digital timer
- Apply AC electrical power to 65 watt bulb
- Note FLIR temperature of bulb center surface at intervals, record that data.
- Run until equilibrium temperature is reached, which I defined would be when temperature no longer increases after a period of about 60 seconds, note that temperature, note how long that takes with timer. Record that data.
- Leaving all equipment in place and operating, place mirror perpendicular to 65 watt bulb surface, at about 3 inches away to fit scale of Alan Siddons Figure 3. This will obscure surface of bulb from FLIR camera but is required so that distance/position between bulb and FLIR is not changed, which could result in altered readings.
- Continue experiment.
- Show with video camera how equipment remains in place.
- Wait for the same amount of time as previous equilibrium temperature took to reach.
- Remove mirror, note on the FLIR camera what the surface temperature of the 65 watt light bulb is at that time.
Premise of the experiment:
If the temperature recorded by the FLIR camera is the same after the mirror has been left in place for the amount of time that it took to reach equilibrium temperature, then the Principia/Slayers claim is true.
If the temperature has risen, it falsifies their premise that “a light bulb facing a mirror does not heat up”.
Video of the experiment (with conclusion) :
Note that this is not a big budget production (it was done in the dining room of my home) so I apologize for less than perfect audio quality. BTW, the clothes iron I used as a prop was not turned on, which is plainly evident in the FLIR image. It just so happend that the tabletop ironing board and iron worked out well to position the mirror…. and I had no budget beyond a few dollars for light bulbs and lamp bases. Where’s that big oil check when we need it? /sarc
Plotted temperature data:
[Note: per a suggestion in comments, this graph was updated to show the data after the “mirror added” as dashed line, since only one datapoint (228F) was measured. – Anthony]
Supplemental information:
In a PDF file here: Slayers_lightbulb_experiment
- Temperature data recorded from the experiment to reach equilibrium temperature
- Graph of the data recorded from the experiment showing data including after removal of mirror.
- I also ran a separate control experiment for 2x of the tested equilibrium temperature time to see if bulb can reach same temperature without mirror. I’m satisfied that the experiment is properly functioning.
I have another experiment planned for part 2 that will test another claim that the Principia/Slayers routinely make. I’ll have that in a few days.
UPDATE: In the claim by Joe Postma at Principia where they stated a couple of days ago that we’d “cut and run” (obviously not, just taking our time to be careful) Alan Siddons makes this claim:
As PSI’s Alan Siddons laments:
“All of us on our side have researched and deeply pondered the actual principles of radiative heat transfer. On the other side, however, the “experts” we argue with, like Spencer, Lindzen, Monckton, Watts, just insist that a body’s radiant energy can be doubled by directing that energy back to it — even though the simplest of experiments will shows that this is false.
I’ve never made a doubling claim like that, nor am I aware that any of the others named have claimed a doubling, only that some energy will be returned, as I have just proven in the “simplest” mirror experiment postulated by Siddons.
I have to think these folks aren’t operating with a full understanding of what the physical basis is when I read things like this. This is an excerpt of this comment left in the thread below by Joe Olson where he confuses a microbolometer with doppler radar:
“Remote read IR thermometers are also used to ‘explain’ this back-radiation warming effect. These instruments work be sending out an IR signal and measuring the shift in the returned signal. ” (bold mine -A)
No, sorry, you are 100% wrong. it is a passive sensing device. No active signal is emitted.
FIGURE 1. One pixel in a microbolometer array. An infrared-absorbing surface is elevated above the substrate and thermally isolated from adjacent pixels. Low mass increases the temperature change from heat absorption. Read-out circuits typically are in the base layer, which may be coated with a reflective material to reflect transmitted IR and increase absorption of the pixel. http://www.laserfocusworld.com/articles/print/volume-48/issue-04/features/microbolometer-arrays-enable-uncooled-infrared-camera.html
Gosh, I didn’t think your misunderstanding of an IR bolometer was that distorted. No wonder you guys make the sort of way out claims you do.
A microbolometer is a specific type of bolometer used as a detector in a thermal camera. It is a grid of vanadium oxide or amorphous silicon heat sensors atop a corresponding grid of silicon. Infrared radiation from a specific range of wavelengths strikes the vanadium oxide and changes its electrical resistance. This resistance change is measured and processed into temperatures which can be represented graphically. Source: http://en.wikipedia.org/wiki/Microbolometer
You should really quit while you can Joe, you are making a fool of yourself when you make such claims that are so easily disproved. – Anthony
UPDATE3: The Principia/Slayers group has posted a hilarious rebuttal here:
http://principia-scientific.org/supportnews/latest-news/210-why-did-anthony-watts-pull-a-bait-and-switch.html
Per my suggestion, they have also enabled comments. You can go discuss it all there. – Anthony
Even simple CCD-based cameras are sensitive to near (shortwave) IR; I have a black and white camera CCD camera that is most sensitive to near (or shortwave) IR as emitted by LED IR emitters (iluminators.)
Perhaps some do, but these are NOT thermal imagers in the FLIR class utilizing cooled image plane sensors or linear arrays and a suitable back and forth scanning mirror system (in lieu of an X by Y thermal image plane sensor).
Of course not.
You had a simple ‘toy’ camera and display ‘system’ that ‘saw’ near (shortwave) IR as output by an illuminator, utilizing wavelengths that were just outside the normal range of human and animal sight, IOW, our eyeballs do not respond to those wavelengths. Also, objects close in temperature as normal room temperature do not emit much IR at the short wavelengths your toy operated at, so it saw NOTHING.
No.
They DO NOT ‘send a[n] IR signal, measure the reflection’. No!
That’s NOT how they operate.
They operate using exotic optics and ‘thermal’ sensors at the end of those optics to sense the LWIR emitted BY OBJECTS and THEIR FEATURES which they are aimed at.
No
That’s NOT how they operate.
Word salad; makes no reference to Electro-Magnetic wave ‘capture’ (or EM wave interaction with CO2’s moving/vibrating dipole-moment ‘charges’) which is the mechanism at play with CO2 and various wavelengths to which CO2 is responsive (‘resonant’) in its various vibratory or ‘resonant’ modes.
That looks to be an actual LW (longwave) thermal IR ‘camera’ probably using a cooled thermal “image plane” (or imager) to detect LW IR emergy as emitted by objects which are at ‘room temperature’ (and vicinity).
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Joseph A Olson says: “Actually, my rather expensive, 1995 first generation “Night Owl Infrared Rifle Scope” was vastly superior to a $60 IR toy, but was returned for full refund when it could not amplify ambient IR to any useable level …”
They are two different devices. Your “Night Owl Infrared Rifle Scope” wasn’t a Infrared (IR / thermal) scope but a Night Vision scope. Night Owl products are night vision imagers; which are meant to intensify visible (and near-visible) light reflected off an object. From Night Owl manual: “Light (like moonlight or starlight) coming into the device from the direction of the object is gathered by the objective lens and focused onto the Image Intensifier Tube. The front of the Image Intensifier Tube contains a photocathode which converts light into electrons.”
What a IR (thermal) Scope does from FLIR’s web page: “FLIRs make pictures from heat, not visible light. Heat (also called infrared, or thermal, energy) and light are both parts of the electromagnetic spectrum, but a camera that can detect visible light won’t see thermal energy, and vice versa. Thermal cameras detect more than just heat though; they detect tiny differences in heat – as small as 0.01°C – and display them as shades of grey in black and white TV video.”
To clarify this: A Night Vision scope needs some weak visible light source to see a human. A FLIR scope can detect that human without any light source. For example: A FLIR scope can show a human’s foot prints (albeit rough pattern) after a human has walked through a carpeted area if done within a few seconds (longer with high-end models). A Night Vision scope simply can not.
Thus – No surprise you had to return Night Owl scope, you were trying to use it to do something it was not capable of doing. If you think your Night Owl scope was “rather expensive” at $250-$500, then you are in for sticker shock if you try to purchase a IR (thermal) scope, being their basic starting prices are $8,500.
Picture showing difference between Night Vision vs. Tthermal (FLIR) scope: http://i3.ytimg.com/vi/rAvnMYqj2c0/hqdefault.jpg
rgbatduke says:
May 27, 2013 at 2:54 p
“Personally I think that the best way to conduct the experiment is to just put a small light bulb inside an over the counter thermos and screw down the lid.”
__________________________________________________________________________
You are right of course, but my suggestion was intended as a very minor change to the exact set-up Anthony was using. But your idea of the best-set up brought to mind a similar set-up used for an entirely different experiment. A little off topic but the following may be of interest to some here who enjoy such things.
V. A. Kishkintsev, a Russian scientist, used a similar set-up to rgb’s “best way” to demonstrate the Eotvos Effect – the dependence of the weight of a mass of gas on its temperature and latitude. He used a light bulb to heat the gas inside a sealed dewar placed inside another container on a sensitive balance to monitor the weight. As the gas heats, the gravitational attraction for the mass of the contained gas changes in the order of 1 part in 100,000 per degree.
This tiny change in weight is due to the rotation of the earth as the change in centrifugal force on east bound gas molecules does not compensate perfectly for the force change on west bound ones, as that force is a function of velocity squared rather than linear. The dewar was needed to minimize and slow the temperature change on the outer surface of the container resulting in dimensional changes, affecting the container’s buoyancy in air which also affects the weight measurement.
F. Ross says (May 27, 2013 at 4:27 pm ): “When one wants to survive in a snow storm, does one sometimes not form a small cave like chamber in order to keep warm? Have not the Inuit people used igloos in the same manner for millenia? How’s that work anyway?
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It works as a barrier between you and the air warmed by you inside and the colder air outside. The colder air outside can not reach you and cool you by conduction and convection.
25 W and lower bulbs are generally ‘vacuum’ filled … that used to be the norm anyway.
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@F. Ross:
As you surely know, like most thermal shelters, a snow house or cave acts to insulate its occupants, keeping heat in & cold out. That is, it interrupts convection. The snow is at 32 F while the air temperature outside, especially with wind chill, could be much colder.
Please excuse my Alaskan chauvinism however to point out that the Inupiat people of the Beaufort and Chukchi Seas also build igloos. While the Inuit of Canada & Greenland speak mutually intelligible dialects, Greenlanders can’t understand Inupiaq, although the languages are closely related. I don’t know, & maybe no one does, which group invented the igloo in its advanced form.
The other group of Alaskan (& Siberian) Eskimos, the Yupik of the Bering Sea, however don’t often use igloos & speak a less closely related language.
Is this the ‘house’ comedy act scheduled for 7:00 hour (locally; it’ll be 7 PM here shortly)?
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“The experiment was simple, and was designed to specifically test a suggested effect.”
Very badly designed, by someone with little understanding of the effects of thermal mass.
It has not falsified any hypothesis, nor has it proven it. Its a NON-experiment for its purpose.
Joseph A Olson says: ” The IR thermal image systems used by law enforcement and the military far exceed the $60 IR toys, which do send a IR signal,”
“$60 IR toys” do not send an IR signal and Law Enforcement / Military IR (thermal) do not send an IR signal. As Anthony correctly stated both are passive devices.
With regard to “$60 IR toys”, from WiKi – “An infrared thermometer is a thermometer which infers temperature from a portion of the thermal radiation sometimes called blackbody radiation emitted by the object being measured. They are sometimes called laser thermometers if a laser is used to help aim the thermometer, or non-contact thermometers or temperature guns, to describe the device’s ability to measure temperature from a distance.”
@ur momisugly Olaf Koenders
What is “churlish” ~ a) rude, boorish, miserly, vulgar, b) Medieval peasant
….is the Medieval premise that a single human caused parameter has a linear effect on a vast, dynamic and chaotic system that is never in equilibrium. To foist this vulgar fable requires a population with a miserly understanding of reality. Replying to some of the above, Joe Bastardi is correct, CO2 has a Specific Gravity of 1.5, more than standard air at 1.0 [assigned] and a Specific Heat of 0.8, less than standard air at 1.0 [assigned]. The en.wikipedia.org/wiki/infrared page has a greenhouse gas schematic showing 168 w/m^2 solar, 324 w/m^2 from GHE, so some folks, at one time believed in this magic doubling, and some still do. On the availability of ambient IR, first generation night scopes had x1,000 power, second x20,000 and third x50,000 power, yet all still required supplemental IR light, even using the full 700 nm to 1mm IR range, not just the narrow CO2 band. You point a remote read IR meter at the sky, eventually it his dust, or returns weak/no signal, so you get the lowest display range temp, -18C. Point an remote IR meter at a cloud in the sky you get a reflected signal, warmer than-18C, but still lower than the temperature of the Earth below, unless during a rare inversion. The cloud mass delays cooling, but delayed cooling is not warming. That an errant branch of science evolved on a false premise, designed to promote Carbon commodity markets is Medieval misdirection by Wall Street and our easily misled government, lap dog media and toe licking education system. We have a full spectrum of forcings yet to discover, along with amplifications and bufferings. Hopefully we will have a open and free internet for these much needed discussions.
Humble Science Monk
Anthony – Very intriguing experiment – Thank you for performing it and sharing the results! If you’re game, I’d be very interested in seeing the same experiment run, but with a thermal absorber, rather than a reflector. I would suggest a piece of aluminum sheet (highly thermally conductive) painted on both sides with high-temperature flat black paint. I think this would more closely resemble the mechanism that CO2 exhibits in the atmosphere. Cloud cover would act like a mirror, but CO2 would be a black body for the 15 micron stuff.
For your next act, how are you going to get out of the “wrapping-a-light-bulb-in-aluminum-foil” gambit?
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Jeff Condon says: ‘In my opinion, PSI needed to be rebutted because of they defocus the true climate discussion. Their existence detracts from the seriousness of the main-stream and well considered climate disagreement.”
You bring up an aspect of PSI that is bothersome. Is PSI a covert attempt by ManBearPig types to discredit those who have rejected man-made CO2 Global Warming? Attempt to get those who disagree with AGW to go along with a premise that proponents of AGW will eventually soundly refute, then via pro-AGW media publicize the heck out of.
Sounds tin-foil hat, until you consider a past attempt to discredit “Skeptics” (NASA faked the moon landing|Therefore (Climate) Science is a Hoax: An Anatomy of the Motivated Rejection of Science by Stephan Lewandowsky) as discussed here: http://wattsupwiththat.com/2012/09/01/paging-dr-stephan-lewandowsky-show-your-invitation-list/
Poptech says (May 27, 2013 at 4:01 pm): “I concur, they can claim you pre-heated the iron. They an also claim you changed the ambient room temperature. You should of included a room temperature thermometer.”
The FLIR would have detected a heated iron (it did detect Anthony’s arm). Also, the hot spot on the back of the mirror would have been iron-shaped.
If increased room temp raised the lamp temperature, then Anthony must have blown a lot of cold air at the lamp the instant he took the mirror away. 🙂
Nice experiment Anthony.
A much simpler experiment to show that radiant energy from a cool object can increase the temperature of a warm object is something almost every kid has tried.
On a warm and sunny day ( say 25C ) you take a magnifying glass and a piece of paper. Both of which are at ambient temperature. Now focus the Sun’s rays onto the paper to the smallest dot you can. You will, as we all know, quickly see the paper begin to smolder. It has raised the temperature of the paper to ( at least ) over 200C. Despite the fact that the magnifying glass is still at 25C. An object at the same temperature as the paper has dramatically raised the temperature of the paper.
Now, replace the magnifying glass with a focusing mirror such as those used in telescopes. You keep the mirror covered until you start the experiment so that is does not heat up above ambient temperature. You have of course already set the paper at the correct focal length.
The moment you uncover the mirror, you will have smoking paper from a mirror that is at 25C.
As, I think rgb said, photons don’t know anything about temperature. Whether they are radiated by a CO2 or water molecule and hit the Earth or are concentrated by a lens or mirror, they all heat the surface they hit.
/ikh
Anthony, there’s something these fools fail to acknowledge:
Paramedics often wrap cold/shock patients in aluminised mylar. If the IR reflective properties of that aluminium were zero, they’d use clear plastic instead because it would be cheaper.
We find it is also warmer on a clear but *humid* night (in comparison to a dry one) … as we all recall, CO2 is not the only GHG …
The “sla yers” fail in a really big way when it comes to arguing against this effect.
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Greg House says (May 27, 2013 at 3:56 pm): “The explanation is very simple. A mirror put so close to an object much hotter then the air in the room reduces convective cooling of the object by air.”
So if the experiment is done in a vacuum chamber, and the lamp temp still increases in the presence of the mirror, then this would demonstrate that so-called “back radiation” is responsible? Or do you have some other objections that you haven’t shared with us yet?
I love experiments. I would request some intermediate hold/elevator music during the quiet times however 😉
Kinda trying to do that old BASF thing >
Your model still doesn’t work. It’s as flawed as your claims of “CO2 cools the atmosphere” or a “cooler object can’t radiate to add heat to warmer object”
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Anthony I enjoyed your experiment. That is how science is supposed to be conducted. Galileo’s Leaning Tower of Pisa experiment didn’t require a supercomputer, yet it stood the science of nearly 2000 years on its head.
One quibble. CO2 does cool the atmosphere. Some of the energy removed in cooling the atmosphere is then radiated back to the surface where it heats the surface. Otherwise, if CO2 didn’t cools that atmosphere it would need to generate energy out of nothing to warm the surface.
Consider this, when you placed the mirror in front of the light, everything behind the mirror started to cool.
You are measuring the attainment of steady state, and the level of the steady state with and without mirror. This is actually a quite sophisticated experiment.
At steady state, influx and efflux are equal, and we love to be able to switch one or the other off to be able to measure both.
What I would have also done is allow the system to come to steady state, and then switch off the power, measuring the initial cooling rate. This is a measure of efflux. Repeat with mirror in place and you would have observed a slower rate of cooling. This difference in the two rates is your back-radiation.
AndyG55 says:
May 27, 2013 at 4:56 pm
Very badly designed, by someone with little understanding of the effects of thermal mass.
Anthony assembled the components and ran the experiment precisely the way it was defined to him. Heat was added to the light bulb by back-radiation. Most people would say that the hypothesis of back-radiation not causing the light bulb to take on additional heat was falsified. This may or may not have anything to do with the greenhouse effect in your opinion, but you are free to conduct your own physical experiments along those lines.
Darren Potter says:
Or, is it a covert attempt by skeptics to make themselves look good by making it seem that they are not occupying some extreme end of the scientific spectrum but only a middle ground between extremes on both sides, as expressed in posts like this…
Jeff Condon says:
As I said.
I suggest Anthony re-do the experiment in 2 ways.
1. with the mirror facing away.
2. use a very low mass mirror, eg alfoil or similar, and blow a fan on the back of the alfoil to keep it at room temperature.
@ur momisugly Anthony
“Sometimes I wonder if you guys have some sort of mental block on these simple physics basics, some have suggested that your claims are so absurd that your organization is a “plant” to make rational skeptics look ridiculous like Lewandowsky and company.” -A
Anthony,
I firmly hold this view and have yet to find any solid information to contradict it. I believe the appropriate term is “Assault Clown”. The anonymity of the Internet has allowed the Alinsky Method to be modified such that “Change Agents” can now be supplemented with “Anti-change Agents”
“Snowstormers” and “Sleepers” are also used on other blogs and forums.