Avoiding Flawed
Demonstrations:
Greenhouse Effect
Intro/Index
Faulty Demos
Errors, Misconceptions
Testing, Lab Results
Scientifically Strong
Resources
Rebuttals
Acknowledgements
Contact
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Research
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Lack of clarity and accuracy: What are you attempting to demonstrate? What do the results indicate?
It's very difficult to recommend a demonstration, lab, or experiment that does not make itself clear what it is about; what it is doing.
Do the presenters seem to know what they are attempting to demonstrate? Is this clear to the audience /participants?
Does what is actually demonstrated match the claims?
We need to look at the title, introduction, description, interpretation and conclusion --
all of which take form in one way or another in just about any demonstration or experiment.
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Example: CLEAN'S "The Greenhouse Gas Demo"
Youtube caption: "This discusses a short, but very effective and dramatic demo to show the effect on temperature of increased levels of carbon dioxide."
Presenters narrative: "A very simple demonstration... a very effective and dramatic demonstration."
"We want to develop some CO2 in the bottle to see the effect on the temperature of the atmosphere --
change in temperature of the atmosphere, as it is heated."
Conclusion: "Obviously, the carbon dioxide is having an effect." "The point is... well, very easy to demonstrate."
Comments: As far as a description of what the demo is trying to do, and an interpretation of what has just happened, that's it. Not much said.
If the primary goal is to promote a demo that requires a simple set up to display dramatic results, this is certainly successful in being dramatic!
IF results like this could be repeated and verified, this would be amazing. It could challenge all the major scientific findings.
This would indicate that NOAA's climate models, for example, which include estimates of CO2's radiative forcing power, are dramatically underestimated.
A 9 degree Celsius rise, in a half liter volume, with a common incandescent light bulb as the energy source, filtered by a thick layer of PET plastic,
with ambient room temperature
-- that would set scientific research on its heels!
It would also indicate that all the major soda manufactures should probably issue warning labels about leaving half full
PET plastic bottles of soda out in the sun or near bright light sources. They can really heat up fast. Pressure would go up as well. Dangerous.
The demo could be done without thermometers. A 9 degree Celsius temperature difference is one kids could easily feel in their hands, one bottle in each hand.
Which one has CO2 in it? You could tell blindfolded. Now, that would be a dramatic demo anyone could do.
For a science program that really takes what they publish seriously, posting a hands-on science demonstration on-line that claimed results like these,
one would thing that would send
educators, scientists, climate modelers, and media representatives scrambling.
This would represent a huge discovery. How do we explain this? What interpretation do we offer? What do we think happened in the experiment?
What should we do to verify this? How serious should people take it? This is a challenge to our scientific understanding, something somewhere needs to change.
The presenter is positively debonair, delivering the conclusion: "Obviously, the carbon dioxide is having an effect." "The point is... well, very easy to demonstrate."
Hands-on science demonstrations are one of the public's best opportunities to be engaged in science, to experience how science works.
To validate scientific findings. To determine for themselves the importance they should give to specific scientific subjects.
The public can test and verify claims such as these themselves. What is real. What are the fake claims. What information sources can be trusted.
If we were to bring this demo into classrooms and out to the public, tens of thousands of people would repeat this experiment.
In our labs, we ran this demo dozens of times, with many variations. We've tested dozens of demos like this one, also with videos on the internet.
We've check with several science education programs that have done likewise. We compare lab results with scientific theory and calculated estimates.
At the Mobile Climate Science Labs, we're quite confident what the result will be:
As long as careful basic lab techniques are used, students would see for themselves that essentially no (zero) temperature differential actually is produced.
The effect of CO2 on temperature, in a demo of this design, is too small to be measured.
CLEAN's on-line demo does state its goal clearly, and does deliver on that goal: to make dramatic claims.
Alas, we can never recommend a demonstration based on just drama.
Being dramatic can be an important asset, but other factors must
always take priority in our evaluations.
Dramatic claims have been taken straight to the media before, without verification and peer review, repeating tests and validating results.
The scientists who do this will sometimes gain fame, at least for a little while. But, the results are not always good.
It is wise to be a student of history.
First and foremost, in our view, a science demonstration must be scientifically valid.
Our standard is rock solid science for the demos we perform publically, others than those indicated to being under test.
We aim for very high standards for those demos we would prominently recommend, especially those without caveats.
Some of what makes popular hands-on demos so challenging, is also what makes them so great:
They are
tested, checked, and verified ten thousand times. Flaws will be discovered. And, when they are, they had better be corrected, very quickly.
They had better work -- every time. You have tens of thousands of kids and parents, thousands of teachers,
and hundreds of scientists and engineers critiquing you from ever angle. Questioning, probing, doubting, examining.
Demos are vetted by staff scientists, education directors, the marketing department, development directors and safety managers.
Independent professional evaluators survey the crowd, and write their opinions of the demo.
Every day, you get the full spectrum of political beliefs and attitudes toward climate science -- you are challenged from every direction..
If it isn't fun, exciting and dramatic, it will be a flop. It absolutely must be safe. Most of all, it must get the science right.
The demo better be right on.
CLEAN's demo makes quite dramatic claims, but does not back up how they could be possible scientifically. It does not interpret what happens in the demo.
The results claimed are not verified. Not once did we get readings anything like what is claimed.
Not once, with dozens of runs and variations. Nor did other educators we've checked with who have tested very silimar versions.
We knew that,
even though the demo should not be expected to produce results from a perspective of theory, still people want to know:
"Did you actually try the demo. What happened?" "What differential temperature readings did you get?"
Answer: Zippo. Bupkis. Too small to measure. The signal is drowned out. Those results do not challenge climate science in the least.
We can not recommend "The Greenhouse Gas Demo."
We do recommend that educators avoid it.
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Example: Keystone Center's: "Too Cool for School -- The Greenhouse Experiment"
The Keystone Center frames "the greenhouse effect" to be largely a matter of belief.
"Many believe that certain gases in the atmosphere trap heat in the air."
This is much the way one
typically approaches a political or ideological subject; a public opinion poll, or a question of religious beliefs.
Educators should consider if that is an appropriate way to
approach a scientific issue in science classes. Matters of politics and religion are
essential in human understanding and thinking.
Science classes
are more focused on matters of facts, evidence.
Investigating what is,
whether or not we as individuals like it,
or want to
believe in it.
Not so much what ought to be, what you would like to be, what is just,
where your values are or in what you place faith. Matters of belief.
Those are essential questions, important for students to study and discuss,
but ones science classes aren't really suited to answer. Shouldn't we do what we do well, what we have a duty to do -- as science educators?
Wording has clearly been very carefully selected. The scientific terms "global warming" and "climate change", or more scientifically accurate
desciptions than the metaphorical term "the greenhouse effect," are carefully avoided. Not even "radiative greenhouse effect"
is used.
Such wording is very common in materials produced for America's schools by the larger energy industry public relations groups, often affiliated
with industry lobbying associations. There is much in common in how one might frame an argument if one were doing political lobbying.
The clearest statement indicating to students what they might expect to accomplished in the experiment, we have found, is:
"In this activity, your job is to develop and test a model that will illustrate what happens to the temperature of the
air around the
Earth when heat is trapped within the Earth’s atmosphere."
The clearest conclusion we have found is:
"2. Explain why the final temperatures of the three containers were different.
The air inside each of the bottles is heated up. The heat in the open container can escape and mix with the cooler air in the room.
The air in the closed containers is trapped, so the temperature in these containers increases more than the open container.
Not all gases trap the same amount of heat due to their molecular structure and density."
Feedback we get from teachers and students is that the material ends up being confusing. Why are we measuring and comparing readings from
literal solid greenhouses in the very same experimental runs together with attempts to measure IR absorption and re-radiation of gases,
referred to metaphorically as "the greenhouse effect"?
The term "the greenhouse effect" still has value and has made its way into the language. Yet, it can also be a confusing term.
Educational material can lessen that confusion, or contribute to it. The term does not have the same degree of value as when it was coined in 1937.
It is a metaphor. Scientists often use more accurately descriptive terms, at least alongside this older term, if not instead of.
We have found that this experiment does not deliver on what it claims it will. The radiative greenhouse effect is not measured.
Differential temperature results in the sealed containers are attributable to experimental error and lack of proper lab techniques,
although the instructions do not discussed this.
We can not recommend "Too Cool for School -- The Greenhouse Experiment." We do recommend that educators avoid it.
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Example: NEED's "Greenhouse in a Beaker"
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Example:
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