Evaporation is the process where water changes its state -- called phase -- from a liquid to a vapour. Molecules at the water surface gather enough energy to escape into the surrounding air. It occurs at temperatures below the water’s boiling point of 100 degrees Celsius, as when clothes dry. The evaporation speed depends on the water’s temperature and pressure, the movement of the surrounding air, and the size of its exposed surface area.
Other People Are Reading
The application of heat to water passes energy to its molecules. As a result the molecules begin to move rapidly and the distance between them increases. Forces attracting molecules to each other weaken, allowing them to break free at the surface, and fly into the surrounding air. Water from a heated saucepan evaporates faster than from one left standing at a constant temperature.
An increase in air pressure adds more gaseous molecules above the surface of the water and inhibits the ability of water molecules to escape. When the air pressure is reduced, the molecules have a greater chance of breaking free from the surface, and the evaporation rate increases. The fastest way to evaporate water is to place it in a vacuum chamber where there are no other particles stopping the water molecules in their paths.
Evaporation occurs only at the water’s surface. The greater the surface area, the more chance the molecules have of breaking away. Water sprays -- especially droplets in a fine mist -- are a method of rapidly increasing the overall surface area of a given volume of water, and its evaporation rate.
Clothes on a washing line outdoors dry faster when the wind blows. The air flow carries water molecules in a gaseous state away from the liquid (wet) surface. In still conditions, water molecules return from the gaseous to the liquid state, and clothes remain damp for a longer time. A tumble drier mimics the wind effect on a washing line by moving clothes and carrying away moist air through an exhaust. The clothes dry faster than if they were left hanging on an indoor line or frame.
- 20 of the funniest online reviews ever
- 14 Biggest lies people tell in online dating sites
- Hilarious things Google thinks you're trying to search for