Shop Windows to the Universe

Arches National Park Geology Tour provides an extensive, visually rich description of the geology of Arches, by Deborah Ragland, Ph.D. See our DVD collection.

Mature Stage

When the cumulus cloud becomes big, the water in it becomes heavy. It starts to fall out of the cloud. At the same time, cool dry air starts to enter the cloud. Cool air is heavier than warm air. The cool air creates a wind that blows downward. This wind pushes the heavy water to the ground. It starts to rain.

This cloud is now called a cumulonimbus cloud. Lightning and thunder start to occur. The cumulonimbus is now a thunderstorm.

Shop Windows to the Universe Science Store!

Cool It! is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store.

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Wind

Wind is moving air. Warm air rises, and cool air comes in to take its place. This movement creates the winds around the globe. Winds move at different speeds and have different names based on their speed....more

Rain

Raindrops form when tiny water droplets collide together in clouds to form bigger ones. When they get too heavy, rain falls out of the clouds. Rain is more than 5mm in diameter. The types of clouds that...more

Cumulonimbus

Cumulonimbus clouds belong to the Clouds with Vertical Growth group. They are also known as thunderstorm clouds. A cumulonimbus cloud can grow up to 10km high. At this height, high winds make the top...more

Thunder and Lightning

Lightning is the coolest thing about a thunderstorm. In fact, it is how thunderstorms got their name. Wait a minute, what does thunder have to do with lightning? Well, lightning causes thunder. Lightning...more

Types of Thunderstorms

There are two main types of thunderstorms: ordinary and severe. Ordinary thunderstorms are the common summer storm. Ordinary thunderstorms last about one hour. Rain and small hail occur. Severe thunderstorms...more

Supercell Thunderstorms and Squall Lines

A supercell thunderstorm is a huge rotating thunderstorm. It can last for several hours. These storms are likely to form long lasting tornadoes and large hail. There are two types of supercell thunderstorms....more

Types of Lightning

Lightning occurs during a thunderstorm. Most lightning takes place within a single cloud. Sometimes lightning moves from a cloud to the ground. Other times it jumps from one cloud to another or into the...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF