is any form of moisture which falls to the earth. This includes
rain, snow, hail and sleet.
occurs when water vapour cools. When the air reaches saturation
point (also known as condensation point and dew point) the water
vapour condenses and forms tiny droplets of water. These tiny
droplets of water from clouds.
cause the water droplets to fall as rainfall.
All rain is
the same. It happens as the result of warm, moist air being cooled,
leading to condensation and in turn rain. The following examples
show three different ways air is cooled causing rainfall.
Warm wet air is forced to rise over high land.
As the air rises it cools and condenses. Clouds form and precipitation
The drier air descends and warms.
in the air (e.g. cloud) evaporates.
The sun heats
the ground and warm air rises.
As the air
rises it cools and water vapour condenses to form clouds.
When the condensation point is reached large cumulonimbus clouds
storms occur. These usually include thunder and lightening due
to the electrical charge created by unstable conditions.
An area of warm air meets and area of cold air.
The warm air is forced over the cold air
Where the air meets the warm air is cooled and water vapour condenses.
Clouds form and precipitation occurs.