An ice nucleus is a particle which acts as the nucleus for the formation of an ice crystal in the atmosphere. Icicles A natural ice block in Iceland Ice is the solid form of water. ... Layers of Atmosphere - not to scale (NOAA)[3] Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ...

The presence of ice nuclei increase the temperature that ice will form in the atmosphere from around −42°C to about −10°C. There are many processes that can take place in the atmosphere to form ice particles, the simplest is by water vapor subliming directly onto the solid particle. The presence of an ice nucleus can also cause a previously supercooled water droplet to freeze through contact, immersion or dissolution within the water that would otherwise have stayed in the liquid phase at a given temperature. Snowflakes by Wilson Bentley, 1902 Ice is the name given to any one of the 14 known solid phases of water. ... Sublimation has three separate meanings: Sublimation (physics), the change from solid to gas without passing the liquid state Sublimation (psychology), the transformation of emotions Dye sublimation, the transference of printed images to a synthetic substrate by the application of heat Category: ... Supercooling is the process of chilling a liquid below its freezing point, without it becoming solid. ... In physics and chemistry, freezing is the process of cooling a liquid to the temperature (called freezing point) where it turns into a solid. ...

Ice particles can have a significant effect on cloud dynamics. They are known to be important in the processes by which clouds can become electrified, which causes lightning. They are also known to be able to form the seeds for rain droplets. Cumulus mediocris clouds, as seen from a plane window. ... This article or section needs additional references or sources to facilitate its verification. ... Cessna 210 with cloud seeding equipment Cloud seeding, a form of weather modification, is the attempt to change the amount or type of precipitation that falls from clouds, by dispersing substances into the air that serve as cloud condensation or ice nuclei. ...

Many different types of particulates in the atmosphere can act as ice nuclei, both natural and anthropogenic, including those composed of minerals, soot, organic matter and sulfate. However, the exact nucleation potential of each type varies greatly, depending on the exact atmospheric conditions. Very little is known about the spatial distribution of these particles, their overall importance on global climate through ice cloud formation and whether human activity has played a major role in changing these effects. Particulates, alternately referred to as Particulate Matter (PM) , aerosols or fine particles are tiny particles of solid or liquid suspended in the air. ... Bubbles in a soft drink each nucleate independently, responding to a decrease in pressure. ...

Attempts to measure IN in the lab as recently as May 2007 show that biomass burning-dominated aerosols do not act as ice nuclei.

See also

• Bergeron process
• Nucleation
• Supercooling