Like if I spill water and it’s dry when I come back in a couple hours how did it do that without getting up to its boiling temp?
Is it the same type of thing like when my hair is wet and it’s in the process of drying? Because it isn’t at the 212° F or I’d feel it, right?
In: 3
Water is made up of countless molecules.
Each one is moving around, each one has it’s own speed and direction. The temperature from a thermometer is simply an *average* for all the particles hitting it.
Some will be going faster, some will be going slower. And when they hit things they transfer the energy. Two slow ones might hit a third in quick succession. This third atom would then fly off at high speeds from the “one two punch” of the impact.
What this means is that there is some small fraction of a body of water that is traveling at high speeds (and thus “hot”) and capable of escaping a puddle entirely, then free to roam as a gas.
The remainder are cooler now, but pick up energy from the air, the light, the ground, and warm up a bit. Again some are going fast enough to flee….and these hot atoms leave.
The rest are ‘cold’ but pick up energy… and so on.
The hotter a puddle of water is, the larger the fraction of “hot enough” water capable of becoming a gas.
This goes the other way around too. Gaseous water in the air has some molecules that are on the slow side. When they collide with a puddle they may stick, and condense. This is how puddles and droplets can form and grow rather than evaporate.
In reality you always have some molecules slowing and condensing while entirely different ones get a kick, speed up and evaporate. If the puddle grows or shrinks is really a matter of the rates of these two processes, which is based on the *average* temperature.
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