What happens when you open your mouth to speak with your friends and wish your teachers in the cold winter mornings in the school? A white fog comes out of your mouth! All of you enjoy breathing out from your mouths to see more and more of it, don’t you?
Condensation of your exhaled breath
It is Condensation. This fog is created because of the difference between the temperature of your breath and the temperature outside. The air in your lungs is warm and moist, but the air outside is very cold. Condensation is the process by which water changes its state from a vapour or gas to a liquid. It is the same process that is responsible for the formation of clouds. Some other common examples of condensation that you come across in daily life include the formation of dew on the grass in the early mornings, fogging up of spectacles on entering a warm centrally air conditioned building on a cold winter day, and formation of water droplets on the outside of a chilled glass of cold drink on a hot summer day.