Where does rain come from? The water cycle
The same water goes round and round. The Sun lifts it from the sea as invisible vapour, it forms clouds, falls as rain, and rivers carry it back.
Evaporation
The Sun warms the sea. Our drop turns into water vapour, an invisible gas, and rises into the sky.
The land, clouds and distances are squeezed to fit, and the journey is sped up: a real drop can spend days in the air and years in the sea or underground.
The water cycle: questions and answers
The water cycle is the journey water takes around Earth. Heat from the Sun turns water into invisible water vapour (evaporation). High in the sky the vapour cools into tiny droplets that make clouds (condensation). The droplets join up and fall as rain or snow (precipitation). The water runs into rivers, lakes, the ground and the sea (collection), and the cycle starts again.
What is the water cycle?
It is the never-ending journey of water between the sea, the sky and the land. The water you drink today may once have been in a cloud, a glacier or the ocean.
What are the four stages of the water cycle?
Evaporation: water turns into vapour and rises. Condensation: vapour cools and forms cloud droplets. Precipitation: water falls as rain, snow, sleet or hail. Collection: water gathers in rivers, lakes, the ground and the sea.
Where does rain come from?
Rain comes from clouds. A cloud is made of billions of tiny water droplets. When the droplets bump together and grow big and heavy enough, they fall as rain.
Why does the Sun matter in the water cycle?
The Sun’s heat gives water the energy to evaporate and rise into the air. Without the Sun, the water cycle would stop.
What are clouds made of?
Clouds are made of tiny drops of liquid water, or tiny ice crystals when it is very cold. They form when invisible water vapour cools high in the sky.
Is it the same water every time?
Yes. Earth keeps using the same water over and over. It just keeps changing between liquid, solid (ice) and gas (water vapour) as it moves around.
What the 3D model shows
The model shows a block of land and sea cut out like a model, with the Sun in the top-left corner. On the left is a blue sea you can see into from the side. In the middle is a sandy beach and green hills with trees, and on the right are rocky mountains with snow on top. A river winds from the mountains down to the sea. A glowing drop, labelled “Our drop”, starts in the sea. First it rises faintly into the sky as invisible water vapour (evaporation). High up, a cloud forms around it (condensation). The wind blows the cloud over the mountains, where it turns grey and rain falls (precipitation). Our drop lands near the top of the river and flows downhill back into the sea (collection). Then the cycle repeats.
Common mix-ups
- “Clouds are made of water vapour.” Water vapour is an invisible gas. Clouds are tiny drops of liquid water or ice that you can see.
- “Clouds are like sponges full of water.” Rain falls when tiny droplets join into drops heavy enough to fall.
- “Evaporation only happens when water boils.” Water evaporates at normal temperatures too, from seas, lakes, puddles, soil and plant leaves.
- “New water is made when it rains.” Rain is old water. Earth reuses the same water again and again.
Remember
The Sun lifts water into the sky, it falls back as rain or snow, and rivers carry it to the sea: round and round, forever.
For grown-ups: things to ask
- Before pressing Play, ask: “How do you think water gets from the sea up into a cloud?”
- Pause on “Condensation” and ask: “Where else have you seen water appear out of the air?” (a cold glass, a steamy mirror).
- Try it at home: put a little warm water in a clear bowl, cover it with cling film and put ice on top. Watch “rain” form under the film.
Going deeper (ages 9–11)
What is transpiration?
Plants take up water through their roots and release water vapour through tiny holes in their leaves. This is called transpiration, and it adds a lot of water vapour to the air over forests and fields.
Why does it often rain over mountains?
When wind pushes moist air up a mountain, the air cools as it rises. Cooler air cannot hold as much water vapour, so more of it condenses into clouds and rain. The far side of the mountain is often drier.
Where is most of Earth’s water?
About 96.5% of Earth’s water is salty water in the oceans. Most fresh water is frozen in ice and glaciers or stored underground. Only a tiny amount is in the air at any time.
Does all rain go into rivers?
No. Some soaks into the ground and becomes groundwater, some is taken up by plants, some is stored as snow and ice, and some evaporates again before it reaches the sea.
What this model simplifies
- The land, mountains, cloud heights and distances are not to scale. Real clouds are often thousands of metres up.
- The journey is sped up into about 30 seconds. A real drop might stay in the air for about a week, and in the sea for thousands of years.
- Water vapour is invisible. The faint shimmer above the sea is only there to remind you it is rising.
- One drop is shown following one path. Real water can also soak into the ground, freeze into glaciers or be used by plants and animals.
Sources
- NASA Science for Kids: What is the water cycle?
- NASA Space Place: Unscramble the clouds (what clouds are)
- USGS: Interactive water cycle diagram for kids (advanced)
- NASA Space Place: How much water is on Earth?
- NASA GPM: Earth Observatory water cycle overview
Last updated 10 November 2026. Made by Akhil Paul. Interactive lessons are free to use.