How does smell work on the atomic level?

Daveman20

Do substances radiate particles? Is it the wind brushing up the surface particles of the substance? Do dense materials usually have less smell?

Mapes

All solids and liquids evaporate material constantly, yes, though the amount can vary by many orders of magnitude between a volatile liquid and a dense solid. And your intuition is correct, denser materials generally evaporate vapor at a smaller rate (ice cubes will disappear from your freezer in weeks, but a chunk of iron will stick around for a long, long, time). But the ability of the nose to detect specific molecules is another factor.

Daveman20

great response, thanks mapes!

SpectraCat

The earlier post regarding density and vapor pressure is correct, however it is worth noting that the density of a material is completely unrelated to its "smell". Helium is less dense than air, but neither has any smell. On the other hand, pure acetone is several orders of magnitude more dense than any gas, yet it has a pungent smell.

On a molecular level, the biology of smell actually has to do with the shapes of molecules and how they "fit" (or fail to fit), in molecular receptors in your nose.