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Education:
K-Grade 4

A primer on clouds and aerosols for kindergarten through grade 4.

Clouds on Earth

Clouds on Earth are made of many tiny water droplets or ice crystals floating in the sky. Water from oceans, rivers, and lakes turns into a gas called water vapor and rises into the air. When there’s enough water vapor in the sky, it sticks to small particles called aerosol particles and forms tiny water drops. These drops come together to make clouds. Sometimes, when these drops get too heavy, they fall down as rain or snow because of gravity. Clouds are important for Earth’s weather because they can cool the planet by reflecting sunlight back into space or warm it by trapping heat.

Photo of clouds over the ocean taken from the space shuttle in 1982.
A photo of clouds over the ocean taken from the space shuttle in 1982.
Credit: NASA

Clouds on Other Planets

Not all planets have clouds made of water like Earth. Each planet has clouds made of different things. For example:

Venus

Venus has clouds made of sulfuric acid that cover the whole planet. These clouds reflect a lot of sunlight away and trap heat, making Venus very hot.

Two views of the planet Venus from the Mariner 10 spacecraft.
Two pictures of Venus clouds taken by a spacecraft that flew by the planet in 1974.
Credit: NASA

Mars

Mars has water ice clouds and frozen carbon dioxide clouds. These clouds are usually seen in certain places on Mars. Water ice clouds are thin and patchy and usually observed in the winter season.

Twelve orbits a day provide NASA Mars Global Surveyor MOC wide angle cameras a global napshot of weather patterns across the planet. Here, bluish-white water ice clouds hang above the Tharsis volcanoes.
A photo of water ice clouds taken by a NASA satellite orbiting Mars.
Credit: NASA/JPL/MSSS
A photo of frozen carbon dioxide clouds on Mars taken by the NASA Mars Rover Curiosity.
A photo of frozen carbon dioxide clouds on Mars taken by the NASA Mars Rover Curiosity.
Credit: NASA/JPL-Caltech

Jupiter and Saturn

Jupiter and Saturn have clouds made of different chemicals in different layers, like water ice and ammonium hydrosulfide.

Jupiter
Storm clouds on Jupiter taken from the Juno spacecraft.
Credit: NASA

Titan (Saturn’s Moon)

Titan, a moon of Saturn, has clouds made of methane gas.

5 Peering Through Titan's Haze
A picture of clouds on Saturn’s Moon Titan taken by the Cassini Spacecraft.
Credit: NASA/JPL-Caltech

Uranus and Neptune

Uranus and Neptune have clouds made of water ammonia solution, water ice, and methane ice at different levels.

Side-by-side photos of Uranus and Neptune, both taken by Voyager 2.
Left: A picture of the clouds on Uranus taken by the Voyager 2 spacecraft as it flew by the planet.
Right: A picture of storms and clouds on Neptune taken by the Voyager 2 spacecraft as it flew by the planet.
Credits: Left: NASA/JPL-Caltech; Right: NASA

Learn More about Planetary Clouds

We know a lot about clouds on Earth compared to clouds on other planets. Scientists are trying to learn more using special tools and experiments. They hope to understand how clouds work on other planets and what they’re made of. Chambers have been used to study clouds on Earth. The planetary cloud and aerosol research facility will be used to study clouds from other planets.