Why do puddles evaporate in normal weather conditions?

Question

... if the boiling point of water is 100ºC. This also applies to other situations where water evaporates, as in transpiration.

Answer 1

if you have ever paid attention to your science class you would know that in order for water to evaporate it doesn't need to be heated to 100 degrees celcius.

Answer 2

The temperature of water reflects the average velocity of molecules of the liquid. There are some molecules that have a velocity much faster than average and some with a much slower velocity. The fastest molecules will be able to move fast enough to escape from the surface of the liquid.

from --> http://en.wikipedia.org/wiki/Evaporation

The thermal motion of a molecule of liquid must be sufficient to overcome the surface tension and evaporate, that is, its kinetic energy must exceed the work function of cohesion at the surface. Evaporation therefore, proceeds more quickly at higher temperature, at higher flow rates between the gaseous and liquid phase and in liquids with lower surface tension (i.e. higher vapor pressure). Since only a small proportion of the molecules are located near the surface and are moving in the proper direction to escape at any given instant, the rate of evaporation is limited. Also, as the faster-moving molecules escape, the remaining molecules have lower average kinetic energy, and the temperature of the liquid thus decreases. This phenomenon is also called evaporative cooling. This is the reason that evaporating sweat cools the human body.

Answer 3

Water can turn from a liquid to a gas on the surface as the molecules gain enough energy. Wind helps. Higher temp helps. Dry air above the puddle helps. Air can hold only a certain amount of vapor, warmer air can hod more. Water can also sublime or turn directly from a solid to a gas, as it does when snow piles decrease in size when a dry wind blows over them.

Answer 4

1

Answer 5

The water vapour pressure over the puddle is higher than in the breeze blowing it away.
It works if the wind is dry enough, even if the puddle is frozen solid, it will ablate away eventually.

Best of Luck - Mike

Answer 6

water doesn't need to boil to evaporate

Answer 7

well, my hair dries by itself if left and it definitely isn't boiling.