Insulated by an outerÂ crust, the surface of the earth acquires nearly all of its heat from the sun. The only exit for this heat to take is through a door marked “Radiation.” And therein lies a tale…Â
Recently, I chanced upon anÂ Atmospheric Science Educator Guide [PDF] published by NASA. Aimed atÂ studentsÂ in grades 5 through 8, it helpsÂ teachers explainÂ how so-called “greenhouse gases” warm our planet Earth.
These guides areÂ interesting on a number of levels, so I recommend that you lookÂ them over. But whatÂ caught my eye was this:
- Question: Do all of the gases in our atmosphere absorb heat?
- Answer: (Allow students to discuss their ideas. Don’t provide the answer at this time.)
Indeed, that’s a good one to think over yourself.Â Almost allÂ of what we’reÂ breathingÂ is nitrogen and oxygen — do these gases absorb heat? Lakes and rocksÂ absorb heat, after all, and therebyÂ reachÂ a higher temperature.Â So canÂ nitrogen and oxygenÂ molecules do the same?
Well, I won’t keep you hanging. After allowingÂ students to discuss it, theÂ instructorÂ is instructed to give them the final verdict.Â
- Answer: No. Only some gases have the unique property of being able to absorb heat.
These are the infrared-absorbing “greenhouse gases,” of course,Â substances like carbon dioxide water vapor, and not nitrogen and oxygen.Â
Now, is something wrong here? Most definitely, for NASA hasÂ a finger on the scale. Let’s reviewÂ a fewÂ basics that NASA should have outlined.