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← Weather & seasons

Weather & seasons · Droplets and ice crystals

Explore together · A short start and more to discover

What is inside a cloud?

A sky cushion changes shape before Puschel finishes his story.

The Wusels look at pale clouds above a meadow.
The Wusels look at pale clouds above a meadow.

The short answer

A visible cloud consists of tiny water droplets, ice crystals or both. They can form when moist air cools. The water vapour beforehand is invisible; a visible cloud is not simply vapour.

The Wusels look at pale clouds above a meadow.
The Wusels look at pale clouds above a meadow.

See the connection

1. Invisible vapour: Upward arrows show liquid water evaporating. The vapour itself cannot be seen; no white steam is drawn.
1. Invisible vapourUpward arrows show liquid water evaporating. The vapour itself cannot be seen; no white steam is drawn.
2. Tiny cloud droplets: Cooling can turn vapour into tiny droplets. The blue dots are greatly enlarged symbols; many drops together make the cloud visible. Cold clouds may also contain ice.
2. Tiny cloud dropletsCooling can turn vapour into tiny droplets. The blue dots are greatly enlarged symbols; many drops together make the cloud visible. Cold clouds may also contain ice.

Simplified drawings, not to scale. Not a guide for identifying species.

An imagined Wusel scene

Puschel and Flauschi investigate

Puschel finds a cloud shaped like his tail. Flauschi looks up. Flauschi“Now it looks more like a ship.”

As they talk, its shape changes. Puschel grins. Puschel“Then my tail has sailed away.” They stand quietly on the meadow path.

They look for another shape without looking at the Sun. Their sky picture needs no frame, but it still makes a lovely memory.

Little Wusel quiz

Why is “clouds are only water vapour” inaccurate?

Show answer

Water vapour is invisible. Visible clouds contain tiny droplets, ice crystals or both.

Word help
crystal
A solid with tiny building blocks arranged in a regular pattern.
precipitation
Water reaching Earth from clouds, such as rain or snow.
evaporation
Liquid water changes into invisible water vapour in the air.
condensation
Water vapour changes into liquid water, such as tiny droplets.
Explore in more detail

Here you will find longer explanations and further details. You can explore them together.

Understand step by step

How it works – simply explained

How the steps connect
  1. Water enters air invisibly
  2. Cooling allows droplets
  3. Many particles become visible

Water enters air invisibly

Evaporation makes invisible water vapour, a gas rather than a visible cloud.

Cooling allows droplets

Suitable cooling of moist air turns some vapour into tiny liquid drops. Cold clouds may contain ice crystals too.

Many particles become visible

Numerous droplets or crystals redirect light, forming the cloud we see. Not every cloud produces precipitation reaching the ground.

Why clouds are visible but water vapour is not

A pale cloud above a warm drink consists of tiny droplets formed after cooling, not visible water vapour. Vapour itself is invisible. Sky clouds likewise contain many droplets or ice crystals. Adults handle hot drinks; understanding needs no hot experiment.

References for this explanation: [1]

The key points again

Discover

Visible clouds contain tiny water droplets, ice crystals or both. Water vapour itself is invisible.

Understand

When moist air cools, invisible water vapour can turn into tiny droplets of liquid water. This is called condensation.

Connections

Clouds have many forms. Not every cloud brings rain, and shapes can change quickly.

Pictures and sources for adults