Perfumes, colognes and other scents can catch our attention even from a distance. People can generally smell our perfumes or colognes within seconds of us spraying it on, even if they are in another room.
How is that?
This is due to a process called 'diffusion' which happens as soon as the perfume or cologne is released into the air. Being a compressed chemical composition, once the perfume or cologne is sprayed into the air, it coverts into a gas and its particles are mixed with other air particles which very quickly circulate the room. It is this tendency of gases to quickly occupy any volume or space that is called diffusion. The once compact fragrance particles become loosely bonded and are move about rapidly in all directions, eventually spreading out to fill whichever room it occupies and float on the air currents.
And for the simple reason that there is always an air current (except in a vacuum), we don’t have to use our hands to circulate the perfume or cologne fragrance - it is done by mother nature! This is precisely what happens when perfume is sprayed and why its fragrance spreads fast.
Liquids too undergo diffusion, but it happens at a slower pace as the molecules in liquids are more closely packed together or bonded, which gives them less space to move about. Thus, when wearing liquid perfume, the wearer should expect the fragrance to last significantly longer than a traditional spray perfume or cologne.