We had a summer rain shower yesterday. Afterwards I could see steam rising off the street as the water evaporated. I could walk barefoot on that street before the shower and while the water was evaporating. If the water was boiling away, surely I wouldn’t be able to walk across it without scalding my foot.
What’s going on here?
In: Planetary Science
The temperature of a puddle of water is really just an average of the energy of all the water molecules that make it up.
While the whole puddle may not be warmer than room temperature, individual water molecules in the puddle can have significantly more energy due to random collisions with other water molecules. If that high-energy molecule is at the surface of the puddle, it can escape into the air.
If enough of these molecules escape the puddle, there won’t be a puddle anymore, it will have evaporated away.
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