An Odor Changes with Every Sniff You Take - and Why Smelling Robots are in the Making
PBS are devoting their first episode of a new series entitled Science Scope to the explanation of the way we experience smells. Contrary to common sense, we don't just "perceive" smells when we inhale, then exhale, but this very dynamic has an impact on the way the odor molecules spread out in the air or water - and thus the odor profile for the next smelling subject (including you)...
When we smell, we introduce a turbulence which can be made visible thanks a dye - among other things - in experiments conducted by John Grimaldi at the University of Colorado-Boulder in a 50-foot long water tank, which traces the course smells take in space. Odors propagate forming rotating eddies which are bigger with smalle eddies within the big ones, in a flow which is "structured", although it has "an element of randomness."
This research is part of a more encompassing national research project which looks at how humans and animals use smells to "map their surroundings," with practical applications in mind - and the longer-term goal of teaching robots how to smell in order, for instance, to lower risks for humans and animals charged with defusing security issues like drugs and bombs.