First fly into the air

Odorous molecules are usually volatile and can enter the air from the surface of food, flowers or perfume, and then be inhaled into the nasal cavity.

If the structure changes, the smell may change

Carbon chain length, functional groups and spatial configuration all affect the volatility of the molecule and the way it binds to the receptor. Changing just one atom can result in a completely different aroma.

Scent is an ensemble of molecules

Natural odors are often made up of many molecules. Perfumers and food chemists study their ratios, release rates and interactions.