On: Next for Nest: A Smoke Detector

[warfangle]

One would think that CO produced by combustion would rise before it fell.

[davidmr → warfangle]

You are both right, in a way, in that neither particularly matters: http://www.newton.dep.anl.gov/askasci/chem03/chem03364.htm

"As would have been predicted by the Second Law of Thermodynamics, CO infused anywhere within the chamber diffused until it was of equal concentration throughout. Mixing would be even faster in the home environment, with drafts due to motion or temperature. It would be reasonable to place a residential CO alarm at any height within the room."