Why does fog form in morning?
Show answer & explanation
Answer: Overnight cooling reaches dew point
Overnight cooling reaches dew point ✓ — Correct! Radiative cooling! Morning fog forms from overnight temperature drop: (1) Clear night—ground radiates heat to space (radiative cooling). (2) Air near ground cools. (3) Reaches dew point—air can't hold moisture, condenses into tiny droplets. (4) Fog: cloud at ground level. (5) Sun rises—warms air, fog evaporates ('burns off'). Radiation fog most common. Valley fog: cold air settles in low areas. Advection fog: warm moist air over cold surface. Fog vs mist: visibility <1km = fog. Dew forms same way on surfaces!
Plants release water at dawn — Wrong. Plants release moisture (transpiration), but fog mainly from radiative cooling overnight lowering air temperature to dew point.
Wind stirs up ground moisture — Wrong. Wind disperses fog rather than creating it. Morning fog forms in calm, still conditions when overnight radiative cooling drops air temperature to dew point.
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