What causes clouds?
As warm air rises into the atmosphere, it carries with it water vaporWater in its gas form., which is water in its gas form. As the air cools, the gas molecules move closer together and condense around very small particles of dust or salt in the air. The water vapor turns into its liquid form, water droplets. Clouds are huge masses of condensed water vapor. As the droplets bump into each other, they join to form larger drops. In time, they are large and heavy enough to fall as rain. One rain drop can contain a million cloud droplets! An English naturalist named Luke Howard gave cloud groups these Latin names in 1803: • Cirrus (pronounced SEAR-us, from the Latin word for “curl of hair”) • Stratus (from the Latin word for “layer”) • Cumulus (pronounced CUME-u-lus, from the Latin word for “heap”) • Nimbus…
