Thermos Facts for Dummies

thermos bottle cutaway

If you've been paying attention the past decade or two, you probably know that the American educational community is quite concerned about the level of S.T.E.M. knowledge among graduates of schools at all levels. The science-types on our staff are equally concerned, perhaps even more so, at the level of scientific illiteracy demonstrated by freelancers hungry for pennies. So here, without further ado, is more scientific illiteracy from HubPages.com: "The Science of Thermoses," as envisioned by frequent contributor Joan Whetzel.

Joan opened, as she often did, with a bit of misinformation:

"The humble thermos, once called a Dewar flask or a vacuum flask, was invented by Scottish physicist James Dewar."

OK, the James Dewar bit is right (though she demoted him from Sir James Dewar), but we wonder why Joan thought that no one calls these things a Dewar flask or a vacuum flask any more. After all, you can find Dewar flasks for sale at Amazon... Moving right along, Joan gushed about how polar explorers and the Everest expedition made thermoses famous: "...William Perry took them to the North Pole, Ernesto Shakleton took them to the South Pole, and Sir Edmund Hillary carried them up Mount Everest..." The Fridge went to the North Pole? Or did she confuse the former Chicago Bears DL with polar explorer Robert Peary (or pre-thermos explorer Sir William Parry)? She not only demoted the south pole guy, too, but also misspelled both his given name and surname: Sir Ernest Shackleton would probably be amused.

But let's get to the science... of the construction or a thermos, Joan said:

"Any air and moisture in the space between the inner and outer bottles is removed, resulting in a vacuum, though today’s thermoses frequently fill this space with styrofoam as an insulator to prevent the heat or cold from escaping."

We're not sure why she thought you could evacuate only air or moisture, but since any moisture between the two bottles would be water vapor, that's unnecessary verbiage. Oh, and cold can't "escape": that temperature change is the introduction of heat, not the departure of cold. Let's see what else Joan had to say...

• "The mirrored glass liners reflect the heat or cold from the thermos contents back into the contents..." – again, you can't "reflect the... cold," what the mirror does is prevent the transfer of heat out of hot contents or into cold contents by radiation.
• "Thermoses concentrate the heat exchange processes (in the form of conduction, convection, and radiation) to fit the small cavity of the thermos." – We really don't know that this is supposed to mean...
• "Convection heats the inner bottle, thanks to the shape and the lid, which traps the steam from the hot food or liquid allowing it to circulate in the air between the thermos contents and the cap..." – No it doesn't. Convention keeps the liquid at a consistent temperature throughout instead of having hot and cold regions.
• "Radiation reflects the heat off the glass inner bottle, or returns off the Styrofoam insulator, returning the heat back into the contents of the thermos." – As mentioned above, the mirrored surface prevents heat exchange via radiation.
• "[Thermoses are used for] Storing liquid nitrogen or liquid oxygen in labs." – You know what the call those storage containers, Joan? Dewars!

This level of scientific illiteracy is typical of freelancer writers with liberal arts educations, the sort who believe they can contribute to the internet by rewording scientific prose even when they don't quite understand it (we call that the eHow effect). Well, people like our Dumbass of the Day contribute all right: to the stupidification of the internet.

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