Have you ever wondered where rain comes from, or where seawater goes? Water on Earth moves in a continuous journey between the sky and the ground called the "water cycle" — an amazing natural process that keeps water available around us all the time.
Stages of the Water Cycle
The cycle begins with evaporation, when the sun's heat warms water in seas, rivers, and lakes, turning part of it into light vapor that rises into the sky. Next comes condensation, when the rising water vapor cools and turns into tiny water droplets that gather together to form clouds.
When the water droplets in the clouds become big and heavy enough, they fall to the ground in a stage called precipitation, which can be rain, or snow if it's very cold. Finally comes collection, when the fallen water gathers in rivers, lakes, and seas, or seeps underground to become groundwater — and the cycle starts all over again.
The water cycle is essential for life on Earth, since it provides fresh water for drinking and farming, and helps regulate the planet's temperature. Since the total amount of water on Earth has stayed roughly the same for millions of years, the very same drops of water keep circling on their endless journey — a wonderful example of nature's balanced systems.
- Evaporation: water turns into vapor from the sun's heat
- Condensation: water vapor turns into droplets forming clouds
- Precipitation: water falls as rain or snow
- Collection: water gathers again in rivers and seas
