Cloud Types
Identify the three main cloud types — cumulus (fluffy, fair weather), stratus (flat layers, overcast or drizzle), and cirrus (thin wisps, high up) — and understand that clouds form when water vapour in the air cools and condenses into tiny droplets
What a learner can do afterwards
- Name and describe the three main cloud types: cumulus, stratus, cirrus
- Explain that clouds form when water vapour cools and condenses
- Use cloud type to make a simple prediction about the weather
The lesson
You already know that rain falls out of clouds. But clouds do not start out as rain. They start out as water vapour, an invisible gas that is always floating around in the air, even on a sunny day. When warm air carrying that water vapour rises high into the sky, it cools down. Cool air cannot hold as much water vapour, so tiny droplets of water begin to stick together. Millions of those tiny droplets floating together make up a cloud.
Clouds come in different shapes, and each shape has a name. Cumulus clouds are puffy and rounded, like cotton balls scattered across a blue sky. Stratus clouds are flat and gray, and they often spread out to cover the whole sky like a blanket. Cirrus clouds are thin, wispy streaks high above everything else. It is so cold way up there that cirrus clouds are actually made of tiny bits of ice instead of water droplets.
Omar looks up on Saturday morning and sees big fluffy white clouds scattered across the blue sky. He knows those are cumulus clouds, so he grabs his bike, expecting a fine, sunny day. His sister Zoe looks up on Tuesday and sees the whole sky covered by a flat gray blanket. She knows those are stratus clouds, so she packs an umbrella just in case.
Next time you look up, ask yourself: Is it puffy like cotton (cumulus)? Is it a flat gray blanket (stratus)? Or is it a thin wispy streak way up high (cirrus)? The shape hints at the weather to come.
Cumulus is fluffy and usually sunny, stratus is flat and often rainy, and cirrus is thin, high, and icy, but every cloud starts as tiny water droplets floating together.
Watch it
Where it sits
Learn first
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.