Question

how does hot liquid get cooled by blowing on it?​

Answer 1

Things cool when the hotter molecules escape, which lowers the overall average energy and thus the temperature. When hot molecules of coffee/soup/tea bump into the air above them, they transfer energy to the air. ... That allows the soup to cool off faster: you've blown away the insulation.

Answer 2

Absolutely. By blowing on the hot liquid you're using convective heat transfer to remove heat from the liquid and cool it down to the temperature of your breath (around 98.6 °F). If it's allowed to just sit, it will only be cooling through natural convection. Blowing on it creates forced convection, a much more effective method of heat transfer