About fragrance notes:
The top notes or head notes are made out of the lightest, most volatile ingredients, perceptible from the very start of diffusion. Top notes last the least amount of time, from a few minutes to almost 2 hours.
Middle notes of heart notes last about 2 to 10 hours, and have a dual function: preserve the freshness of top notes and prepare for the warmth of the base notes.
Base notes are made of heavier fragrances. Used in minute quantities, because of their strenght, their main role is to anchor other notes. They are essential to any composition and ultimately leave an impression of balance.