Condensation refers to when water changes from a gas into a liquid. This occurs when water vapour in the air is cooled into tiny liquid drops and forms clouds. The process is helped along by the presence of tiny particles such as dust and smoke in the air that water vapour can collect upon while cooling to form larger drops of water.
Different types of clouds
Cirrus - Clouds that look wispy are usually very high. It is colder high in the atmosphere and the water vapour will have turned to ice. High clouds are unlikely to cause rain.
Stratus - Clouds that stretch across the sky, like a white or grey sheet with stripes, are called stratus clouds. They form at a middle level in the atmosphere. They may produce rain showers or snow.
Cumulus - Clouds that look like cottonwool balls or long rolls of fluff are lower level cumulus clouds. They may be white or grey and can produce drizzle (very light rain) or showers.
Cumulonimbus - Larger cauliflower shaped clouds which reach up into the sky are named cumulonimbus clouds. These clouds may bring thunderstorm and can hold rain, hail or snow.
Fog - Fog or mist is really just low-lying cloud.