Much is unknown about exactly how we detect and discriminate between various odors. But researchers have discovered that an odor can only be detected in liquid form. We breathe in airborne molecules that travel to and combine with receptors in nasal cells. The cilia, hairlike receptors that extend from cells inside the nose, are covered with a thin, clear mucus that dissolves odor molecules not already in vapor form. When the mucus becomes too thick, it can no longer dissolve the molecules.
Animals depend on odors secreted from their bodies to communicate.
For humans, odors communicate a variety of messages, depending on the odor and the person receiving it. Think of some smells you like. Smell, the subtle sense . The science book of the senses . The intimate sense of smell.