Dr. Universe: What do clouds do? – Desi, 9, Maryland

Dear Desi,

If you’re anything like me, you like to watch the clouds go by in the sky. Even though some clouds might look like they are just floating around up there, they can do quite a lot for our planet.

The first thing to know about clouds is they are made up of tiny water droplets, ice crystals, or a mix of both—and there are many different kinds of clouds.

There are white and puffy cumulus clouds, thin and wispy cirrus clouds, and tall nimbostratus clouds that stretch high up in to the sky. Believe it or not, when you walk through fog, you are walking through a kind of cloud that’s touching the ground.

I learned about clouds from my friend Von P. Walden, an atmospheric researcher at Washington State University.

One thing clouds can do is move, Walden said. Some clouds move slow, while others— like the clouds of a spinning hurricane—can move about 100 mph. As clouds move, they transport water around our planet.

The clouds above North America are usually moving from the west to the east, Walden said. A lot of the water that makes up clouds comes from the Pacific Ocean.

As the water on the surface of the ocean warms up, tiny water molecules rise into the atmosphere to help form clouds. When the water particles that make up clouds get heavy enough, they will sometimes fall down to earth in the form of rain or snow. When that water falls, we can use it for various things.

We might use it to water plants for food. We can also use water to generate energy from dams for our homes and schools. We sometimes drink it or swim in it. Clouds can also cool us by reflecting sunlight back to space.

It had been raining the morning I went to visit Walden, but the sun was finally starting to shine. He noticed a small rainbow out the window.

We see rainbows when light moves through water droplets and the rays of light scatter around. It’s pretty rare, but sometimes we can spot a phenomenon called a rainbow cloud. These clouds occur very high in the atmosphere. Instead of being white or gray, the cloud is all the colors of the rainbow, or iridescent.

If you ever have a chance to visit the Palouse in Washington state, we have some great clouds. But really, you can watch clouds from anywhere on our planet.

What clouds do you see in your neighborhood? Can you draw their shapes? While investigating your question, I also learned that nephelococcygia is the act of seeking and finding shapes in the clouds. You can keep track of your observations with a pen and paper. Do you notice any patterns about the clouds? How fast do they move? Keep your eye to the sky and share what you discover at Dr.Universe@wsu.edu.

Sincerely,

Dr. Universe