Kids Research Express

Rain, precipitation of liquid drops of water. Raindrops generally have a diameter greater than 0.5 mm (0.02 in). They range in size up to ab...

Air masses acquire moisture on passing over warm bodies of water, or over wet land surfaces. The moisture, or water vapor, is carried upward...

Despite the presence of moisture and lifting, clouds sometimes fail to precipitate rain. This circumstance has stimulated intensive study of...