How clouds are formed

Clouds are formed when water vapor, an invisible gas, turns into water droplets. These water droplets form on tiny particles, like dust, that are floating in the air.

Clouds are made of water droplets. These are so small and light that they are able to stay in the air. But how does the water that makes up clouds get into the sky?

Liquid water changes into a gas when water molecules get extra energy from a heat source such as the Sun or from other water molecules running into them.

These energetic molecules escape from the liquid water in the form of gas. In the process of evaporation, the molecules absorb heat, which they carry with them in the atmosphere. That cools the water they leave behind.

Image credit: NASA/JPL-Caltech/Alex Novati

Heat causes some of the liquid water from places like oceans, to change into an invisible gas called water vapor.

Now we know that clouds are formed when water is evaporated from oceans, to form water vapor, an invisible gas which floats in the air. This is one of the way which tells about cloud formation. But there are even more ways in which clouds form.

Some clouds form when air warms up near the Earth's surface and rises. Heated by sunshine, the ground heats the air just above it. That warmed air starts to rise because, when warm, it is lighter and less dense than the air around it. As it rises, its pressure and temperature drop causing water vapor to condense. Eventually, enough moisture will condense out of the air to form a cloud. Several types of clouds form in this way including cumulus, cumulonimbus, mammatus, and stratocumulus clouds.

Some clouds, such as lenticular and stratus clouds, form when wind blows into the side of a mountain range or other terrain and is forced upward, higher in the atmosphere. The side of the mountains that the wind blows towards is called the windward side. The side of the mountains where the wind blows away is called the leeward side. This can also happen without a dramatic mountain range, just when air travels over land that slopes upward and is forced to rise. The air cools as it rises, and eventually clouds form. Other types of clouds, such as cumulus clouds, form above mountains too as air is warmed at the ground and rises.

Clouds also form when air is forced upward at areas of low pressure. Winds meet at the center of the low pressure system and have nowhere to go but up. All types of clouds are formed by these processes, especially altocumulus, altostratus, cirrocumulus, stratocumulus, or stratus clouds.