Fog forms when water vapor in the air condenses into tiny water droplets, similar to how clouds are formed, but at ground level. The key factor is the air temperature cooling to the dew-point temperature.
Understanding Fog Formation
Here's a breakdown of the process:
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Cooling to Dew Point: The air temperature needs to cool to what's called the dew-point temperature. The dew point is the temperature at which the air becomes saturated with water vapor, and condensation starts to occur.
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Condensation: As the air cools to the dew point, the invisible water vapor in the air changes into liquid water. This process is called condensation.
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Formation of Water Droplets: The water vapor condenses around microscopic particles in the air, such as dust, salt, or pollutants. These act as condensation nuclei.
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Suspension in the Air: The tiny water droplets formed by condensation remain suspended in the air, creating what we perceive as fog.
In essence, fog is a cloud that forms at ground level due to cooling conditions that lead to water vapor condensing into visible water droplets. For both fog and clouds to form, the air temperature needs to cool to the dew-point temperature—the temperature at which condensation occurs. Once this happens, the invisible water vapour that surrounds us condenses into tiny water droplets and it is these that form fog. (29-Aug-2018)
