how come spilled water inside and outside evaporates so quickly despite water’s evaporation point bring 100°, no where near the ambient temperature in home or outside?
In: 365
Note: all of this is only partially correct! Physics is very very complicated, but I won’t go down every rabbit hole in a ELI5. (this is more like ELI15 anyways)
The boiling point of water is 100°C, not the evaporation point (there is no such thing). Every liquid evaporates all the time until its “[partial pressure](https://en.wikipedia.org/wiki/Partial_pressure)” is reached in the air around it. In a big room or outside, the partial pressure of water never reaches the maximum. The partial pressure of water in the air is often referred to as humidity.
The temperature of a substance is the *average* speed of the molecules. This means in any substance, there are quicker and slower molecules. In solids that doesn’t matter much, because even the quickest (hottest) particles don’t have enough energy to escape their neighbours. Solids are held together very strongly.
That is different for liquids. In a liquid the molecules are held together very weakly, which is why they can flow and change their shape easily. Single molecules in a liquid can gain enough speed overcome the attractive forces of its medium and “fly away” from the rest and become a gas in the surrounding air. This process of single molecules leaving the liquid and becoming gas is called evaporation.
If the temperature of a liquid reaches the point where the *average* speed of molecules is high enough to escape, we call this boiling temperature of that liquid (100°C for water). You may ask, why not every molecule evaporates instantly, once the liquid reaches its boiling point. The answer is simple: Even in a boiling liquid, only the *average* speed is high enough to escape and every time a molecule escapes, the liquid “cools down” a tiny tiny bit, because it just lost its quickest (read: hottest) molecule, therefore being under its boiling point on average again. This is also why you can’t heat a liquid over its boiling temperature. The temperature doesn’t rise because more and more quick particles escape and therefore bring down the average speed in the liquid.
Be aware: the boiling point is dependent on the ambient pressure. 100°C is only the correct boiling point for water at sea level so 1 bar of pressure. This is why a pressure cooker cooks quicker: the pressure is higher, therefore the boiling point of water is higher, so the water gets hotter than its “normal” boiling point would allow it to get. Higher temperature means quicker cooking. Fun fact: everything cooks really really really slowly, even in the fridge or freezer. The point is, things go bad way quicker at these temperature than they cook themselves.
BTW: as the quickest molecules leave the liquid first, its overall temperature drops, making it harder for more molecules to escape. This is one of the methods hot liquid (like tee or coffee) cool down by (the other ones being heat transfer to the cup and infrared radiation). You can often see this in a very dry room (for example in winter) as little bit of water vapor over the no longer boiling coffee.
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