
Mist is a phenomenon caused by small droplets of water suspended in the cold air, usually by
condensation
Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to ...
. Physically, it is an example of a
dispersion. It is most commonly seen where water vapor in warm, moist air meets sudden cooling, such as in
exhale
Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing.
This happens due to elastic properties of the lungs, ...
d air in the winter, or when throwing water onto the hot stove of a
sauna. It can be created artificially with aerosol canisters if the
humidity and temperature conditions are right. It can also occur as part of natural weather, when humid air cools rapidly, notably when the air comes into contact with surfaces that are much cooler than the air (e.g. mountains).
The formation of mist, as of other
suspensions
In chemistry, a suspension is a heterogeneous mixture of a fluid that contains solid particles sufficiently large for sedimentation. The particles may be visible to the naked eye, usually must be larger than one micrometer, and will eventually ...
, is greatly aided by the presence of
nucleation sites on which the suspended water phase can congeal. Thus even such unusual sources of nucleation as small particulates from
volcanic eruptions, releases of strongly polar gases, and even the
magnetospheric ions associated with
polar lights
An aurora (plural: auroras or aurorae), also commonly known as the polar lights, is a natural light display in Earth's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic). Auroras display dynamic patterns of br ...
can in right conditions trigger condensation and the formation of mist.
Mist is commonly confused with
fog
Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be con