Tracking the deuterium in raindrops, one molecule at a time

New research led by the University of Massachusetts Amherst refines our understanding of the chemical traces that act as the rain's fingerprint. The work, which appeared recently in Global Biogeochemical Cycles, is crucial ...

Exploring the origin of 'black widow' pulsars

Ph.D. candidate GUO Yunlang and Prof. WANG Bo from the Yunnan Observatories of the Chinese Academy of Sciences investigated the formation of black widow pulsars through ultracompact X-ray binaries (UCXBs) with He star companions.

A nanokelvin microwave freezer for molecules

When a highly diluted gas is cooled to extremely low temperatures, bizarre properties are revealed. Thus, some gases form a so-called Bose-Einstein condensate—a type of matter in which all atoms move in unison. Another ...

Ecosystems get increasingly thirsty due to climate change

A new study shows that future ecosystem functioning will increasingly depend on water availability. Using recent simulations from climate models, an international team of scientists found several "hot spot regions" where ...

Exploring how forest restoration affects water cycles

How would afforestation and restoration of large areas worldwide affect water-fluxes world wide? A new study led by Wageningen University researcher Anne Hoek van Dijke with contributions from Martin Herold, GFZ, has ...

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Evaporation

Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid.

On average, the molecules in a glass of water do not have enough heat energy to escape from the liquid. With sufficient heat, the liquid would turn into vapor quickly (see boiling point). When the molecules collide, they transfer energy to each other in varying degrees, based on how they collide. Sometimes the transfer is so one-sided for a molecule near the surface that it ends up with enough energy to 'escape' (evaporate).

Liquids that do not evaporate visibly at a given temperature in a given gas (e.g., cooking oil at room temperature) have molecules that do not tend to transfer energy to each other in a pattern sufficient to frequently give a molecule the heat energy necessary to turn into vapor. However, these liquids are evaporating. It is just that the process is much slower and thus significantly less visible.

Evaporation is an essential part of the water cycle. Solar energy drives evaporation of water from oceans, lakes, moisture in the soil, and other sources of water. In hydrology, evaporation and transpiration (which involves evaporation within plant stomata) are collectively termed evapotranspiration. Evaporation of water occurs when the surface of the liquid is exposed, allowing molecules to escape and form water vapor, this vapor can then rise up and form clouds.

This text uses material from Wikipedia, licensed under CC BY-SA