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?
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Waters vapor pressure, which is the amount of vapor-phase water that will exist above liquid water, is why this happens. Even Ice had some vapor pressure and will evaporate. At room temperature, water has a vapor pressure of around 0.03 atmospheres, which means you can get roughly 3% water in ambient air at 100% humidity. If you’re below that, the water will evaporate until the humidity reaches 100%. The rate at which it evaporates is based on a difference between water’s vapor pressure and the humidity level in the air. This is why you feel hot/sticky on humid days: your sweat can no longer evaporate as quickly, so your body has trouble cooling off, and your sweat just sticks on you.
At higher temperatures, water has a higher vapor pressure. 100C is the point at which the vapor pressure is exactly 1 atmosphere, which means you can have 100% water in the vapor phase at ambient pressures. This means that the water will boil far more vigorously – if you’re boiling in an open container, the vapor phase above the water will never hit 100% water.
In a closed container, it will boil briefly and then stop once the pressure rises and the vapor-phase water concentration increases.
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