Evaporation

Evaporation is a type of <a href="/facts/Vaporization/0Uxpy1WQ">vaporization</a> that occurs on the <a href="/facts/Interface_(chemistry)/HnIAndVA">surface</a> of a <a href="/facts/Liquid/t9GkLWzt">liquid</a> as it changes into the gas phase. A high <a href="/facts/Concentration/wqBmz5od">concentration</a> of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when <a href="/facts/Humidity/Nwb28VlT">humidity</a> affects rate of evaporation of water. When the molecules of the liquid collide, they transfer energy to each other based on how they collide. When a molecule near the surface absorbs enough energy to overcome the <a href="/facts/Vapor_pressure/whrEr96T">vapor pressure</a>, it will escape and enter the surrounding air as a gas. When evaporation occurs, the energy removed from the vaporized liquid will reduce the temperature of the liquid, resulting in evaporative cooling.
On average, only a fraction of the molecules in a liquid have enough heat energy to escape from the liquid. The evaporation will continue until an equilibrium is reached when the evaporation of the liquid is equal to its condensation. In an enclosed environment, a liquid will evaporate until the surrounding air is saturated.
Evaporation is an essential part of the <a href="/facts/Water_cycle/wALHdKjJ">water cycle</a>. The sun (solar energy) drives evaporation of water from <a href="/facts/Ocean/8W8lYgjD">oceans</a>, lakes, <a href="/facts/Soil_moisture/N9Yo068u">moisture</a> in the soil, and other sources of water. In <a href="/facts/Hydrology/Xh727cnE">hydrology</a>, evaporation and <a href="/facts/Transpiration/XvBpcDbB">transpiration</a> (which involves evaporation within plant <a href="/facts/Stomata/Rer9Nzct">stomata</a>) are collectively termed <a href="/facts/Evapotranspiration/q1h1G3XI">evapotranspiration</a>. 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. With sufficient energy, the liquid will turn into vapor.

Evaporation open-in-new

Evaporation