Evaporation: definition in chemistry
Evaporation: The change of a liquid into a gas (vapor) at its surface, at temperatures below its boiling point.
In any liquid, some particles near the surface move fast enough to escape into the air. Evaporation speeds up with higher temperature, larger surface area, moving air and lower humidity. Because the fastest particles leave, the average energy of those left behind drops, so evaporation cools the liquid, which is how sweating cools the body. Unlike boiling, evaporation takes place only at the surface of the liquid.
Examples
- Puddles drying up after rain
- Sweat cooling your skin on a hot day
- Sea salt made by evaporating seawater in shallow ponds
- Wet laundry drying on a line