Shop Windows to the Universe

Young Voices for the Planet DVD in our online store includes 8 films where students speak out and take action on climate change.

Mature Stage

When the cumulus cloud becomes very large, the water molecules in it become large and heavy. They start to fall through the cloud when the rising air can no longer hold them up. Meanwhile, cool dry air starts to enter the cloud. This is known as entrainment. Because cool air is heavier than warm air, it starts to descend in the cloud (known as a downdraft). The downdraft pulls the heavy water molecules downward, making rain.

This cloud has become a cumulonimbus cloud because it has an updraft, a downdraft, and precipitation. Lightning and thunder start to occur, as well as heavy rain. The cumulonimbus is now a thunderstorm cell.

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:

Traveling Nitrogen Classroom Activity Kit

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

Rain

Rain is precipitation that falls to the Earth in drops of 5mm or greater in diameter according to the US National Weather Service. Virga is rain that evaporates before reaching the ground. Raindrops form...more

Cumulonimbus

Cumulonimbus (weather symbol - Cb) clouds belong to the Clouds with Vertical Growth group. They are generally known as thunderstorm clouds. A cumulonimbus cloud can grow to such heights that it actually...more

Thunder and Lightning

Lightning is the most spectacular element of 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....more

Types of Thunderstorms

There are two main types of thunderstorms: ordinary and severe. Ordinary thunderstorms are the common summer storm. They are usually multicell. Multicell storms consist of a line of thunderstorms in different...more

Supercell Thunderstorms and Squall Lines

A supercell thunderstorm is a huge rotating thunderstorm. It can last for several hours as a single entity. These storms are the most likely to produce long-lasting tornadoes and baseball-sized hail. Tornadoes...more

Types of Lightning

Lightning can take place in several different areas of a thunderstorm. Most lightning (about 80%) occurs within a single cloud and is called cloud-to-cloud lightning. Most of the other 20% of lightning...more

Altocumulus

Altocumulus clouds (weather symbol - Ac), are made primarily of liquid water and have a thickness of 1 km. They are part of the Middle Cloud group (2000-7000m up). They are grayish-white with one part...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA