According to Met Office, fog forms when numerous small water droplets become suspended in the air. Fog happens most often in heavily polluted industrial areas where water can cling to the small pollution particles in the air.Know More
Met Office notes that the way fog forms depends on the type of fog. One of the most common types is radiation fog, which typically happens in winter during clear-sky conditions. When the thermal radiation in the atmosphere cools the air near the surface of the ground, air becomes less able to hold moisture and fog forms. Fog also forms on hills and valleys due to the different altitudes.
According to Wikipedia, fog is always low-lying due to the fact that its density is generally greater than that of the surrounding air. Fog is almost always formed close to bodies of water, ranging from small lakes and rivers to large oceans. As Met Office explains, evaporation fog is a common type of atmospheric phenomenon that occurs when cold air passes over warm water or very moist land, such as a marsh. The evaporation of the warm water into the lower layers of the air causes it to cool and produce a thick fog.Learn more about Weather & Tides
Hot air rises and cold air falls because cold air molecules are densely packed together, making them heavier, and hot air molecules have more space between them, making them warm enough to rise. It is for this reason that hot air balloons move upwards. In addition to temperature affecting air density, humidity plays a role.Full Answer >
When a cold air mass meets a warm air mass, a front is formed; if the cold air is replacing the warm air, it is known as a cold front. Cold fronts frequently cause rain showers or thunderstorms because they force air in a steep upward direction at the front's edge. They also bring about changes in wind direction and atmospheric pressure.Full Answer >
Hot air rises and cold air sinks due to varying densities. Given the same volume of air, hot air is generally less dense compared to cold air.Full Answer >
Humidity lowers air pressure by displacing nitrogen and oxygen molecules with lighter water molecules. Differences in humidity can cause storms to form. Humid air also presents challenges to pilots.Full Answer >