In short, these compounds are small organic molecules that tend to change quickly from their solid or liquid state to a gas at room temperature. They are called volatile because they change state quickly. When you first open a bottle of essential oil, you instantly notice that the aroma is potent and you can smell it typically even from some distance. The physical and chemical properties of the volatile aromatic compounds that compose essential oils allow them to quickly move through the air and directly interact with the olfactory sensors in the nose. Such unique properties make essential oils ideal for applications inclusion in aromatherapy – using these compounds from plants to help maintain a healthy mind and body – as well as other applications.