Cooling soup by blowing on a spoonful prior to placing it in your mouth works because the hotter atoms are literally blown away. This is because the soup is made up of atoms comprised of a range of speeds. The atoms with the higher speeds – the hotter ones – are on top, hovering above the atoms with the lower speeds – the cooler ones. So, the end result of blowing on the spoonful of soup is that the hotter atoms are blown away, while the cooler ones are left behind.
