Water vapor in the air

When water gets into a zone of cold air, it collects in small droplets and these droplets form fog or clouds. How does fog form? On clear nights, when the earth's surface is cooled, is cooled and the bottom, adjacent to the ground layer of air. Water vapor, which is in this layer is condensed. This means that the tiny water droplets coalesce into larger ones that are visible to the naked eye. Since there are low Surface fog. They are formed most often in places where cold air collects at night: over marshes, small ponds and riverbeds. In contrast, fog, clouds are formed when water vapor occurs at high altitude with cold air flow. The clouds bring with them a lot of water. How much weight one cloud? Approximately 20 000 tonnes. The cloud does not fall, because the water droplets and ice crystals that make up his very small, and the rising air currents keep the clouds in a suspended state.