Slide2

The Physics of Smell

Introduction Shape Theory Electron Tunneling Vibration Theory Bibliography

Shape Theory (is not the whole truth)

The Shape Theory of olfaction is relatively straightforward: after diffusing through the air to our noses, a chemicals' physical shape acts as a 'key' which fits into a corresponding 'lock' on the surface of our noses. The lock then triggers receptors, which feed information to our brain to be processed into the corresponding odor. We see this same sort of recognition pattern with immune system antibodies as well as certain taste systems in our tongues (1), so it makes sense that our noses use it too. However, as we will see later, shape theory is not the best mechanism for explaining the olfaction process; it's been trumped by quantum physics. In the meantime, the chemical shapes of shape theory can be roughly divided into seven categories:

Ethereal

                light, airy, tenuous


                 oblong, flat molecules

       Camphoraceous                          smelling of the camphor tree

                         relatively spherical molecules

       Musky
                sweet or foul, always compelling

                    flat circular molecules

       Floral

                Valentine's

                    flat circular molecules with a tail

       Minty
                chill, so fresh n' clean

                 molecules that are oblong,
                   but not too much so

       Pungent
                strong, aggravating

                 electrophilic (positively-charged)                        molecules

      Putrid
                repulsive (i.e. Durian fruit)

                nucleophilic (negatively-charged)
                molecules