The teacher resource binder accompanying the kit makes a number of factual errors. This listing of errors includes only those pertaining to environmental concepts.
Avoid the term "reradiate" if possible. "Reradiate implies the original radiation was stored and then released, which is not the case. "Radiate" is better.
No experts deny the greenhouse effect; most deny the catastrophic predictions associated with the global warming hypothesis. This statement confuses the greenhouse effect with global warming. (Also, this statement in conjunction with one 3 lines later, "The greenhouse effect is a well-established phenomenon" leads students to incorrect conclusions regarding the nature of knowledge and consensus in science.)
Explanation of the greenhouse effect is wrong. Water vapor is the most important greenhouse gas. Infrared is absorbed by greenhouse gases, not reflected. Heat does not build up, but the Earth's radiation balance is modified. The phenomena is not important in heating greenhouses, parked cars, and solar houses; these are primarily heated by lack of convention with surrounding air. (Statement "Still, there is good reason to modify..." is contradicted by the preceding statement.)
In this context, the statement is opinion, not fact.
Explanation of greenhouse effect is wrong. The text confuses thermal energy (heat) and infrared radiation. All energy absorbed by the Earth heats the Earth, which in turn must radiate infrared radiation at an equal rate. "Reradiated" is a confusing term. Heat is not trapped by greenhouse gases.
Understanding of the greenhouse effect is incorrect. Clouds in Venus's atmosphere reflect most of the sunlight it receives (about 70%). The thick carbon dioxide atmosphere gives a significant greenhouse effect, but (as discussed above) this is not the same effect as in a greenhouse.
This statement is ambiguous enough to have a correct interpretation, but the obvious interpretations are wrong. When reduced isolation due to low Sun altitude, shorten daylight hours, and cloud cover are considered, houses in the northern U.S. cannot be adequately heated by solar energy in winter.
Greenhouse effect is misunderstood. The solar water heater and cars described heat up primarily due to lack of convection of air inside the glass or transparent cover with surrounding air.
Explanation of the greenhouse effect is wrong.
Correct listing of constituents by decreasing abundance would be nitrogen, oxygen, argon, water vapor, carbon dioxide, neon, helium, methane, krypton, ozone, helium, nitrous oxide, and others. Many other naturally occurring gases are orders of magnitude more abundant than CFCs.
Statement is misleading regarding issue of resource depletion. The two statements will tend to lead students to erroneously conclude that these fuels will be depleted in the near term and/or that the depletion will occur abruptly. Rates of increase for fossil fuel consumption have decreased primarily because the rate of increase in demand has slowed, not because of resource depletion.
Omits reference to nuclear power and hydroelectric power, which provide 20% and 8% of U.S. electricity, respectively.
The process that heats a greenhouse or car is correctly described, but it is not correctly called the greenhouse effect. The diagram on this page is misleading, since it implies that infrared light rather than heated air is trapped by the greenhouse.
Explanation of greehouse is incorrect. Heat (thermal energy) is confused with infrared radiation. Statement "heat builds up" is misleading, as is diagram.
Additional disadvantages: they can only be used when sunshine is available, they are more limited in where you put them, they require more knowledge to make and use.
Manufacture of solar cells requires mineral and metal resources. The manufacturing process produces toxic wastes as a byproduct.
Need to clarify difference between thermal energy and infrared light/radiation, both of which FOSS calls "heat." It is better to call infrared light "infrared light" (and not call it "heat"), so students don't confuse the two and so students can grasp that infrared light is a means of transferring heat.
The space shuttle is not equipped with solar panels (it occasionally carries experiments that may have solar panels). The shuttle power in orbit is primarily from batteries.
For practical reasons, it is impossible for conventional photovoltaics to ever meet most of our energy needs. The cost can only be brought down so far, because it takes a solar cell years to collect energy equal to what went into the manufacture of the cell. Several problems besides cost are not addressed. While there is no problem in principle with photovoltaics being a significant supplement to electrical power usage, most energy use in the U.S. is for transportation and industry, where solar cells are not a realistic solution.
"2 billion" may overstate the rural population of regions with reliably available sunlight, which is the target population for solar cookers.
© 2002 by Wm. Robert Johnston.
Last modified 13 May 2002.
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