The Nano Small Size & Lower Molecular weight makes them light weight & its called aromatic or volatile. it evaporates at normal room temperature , blooms in the air & yours senses like nose detect the smell.

Almost 38 quintillion (38,000,000,000,000,000,000 ) molecule in one drop of essential oils , because of vast number of aroma molecule in one drop it blooms fast and enters or activate or boost the brain to heals the body......