The water cycle is the long journey taken by water from the earth’s surface to the atmosphere before falling back down to the ground.
An infographic to help you understand the water cycle
The main stages
70% of the earth’s surface is covered by water. For more than 4 billion years the same water has been circulating and undergoing constant transformations. It forms what’s called the water cycle, driven by solar energy.
Storage: Water which is not in water courses may become stored in lakes or ponds. On average, it is stored there for 17 years.
Evaporation: Water from oceans, rivers and lakes is transformed under the action of the sun’s heat into vapour and evaporates into the atmosphere.
Condensation: In the atmosphere, the water vapour comes into contact with cold air and condenses, forming tiny droplets which then create clouds.
Precipitation: Once in the clouds, water which becomes too heavy to remain suspended is transformed into rain, snow or hail. Most precipitation occurs directly over the Oceans. On average, a water molecule remains in the atmosphere for 8 days before falling on the continents.
Surface runoff: Part of the water flows along the ground and directly into water courses (rivers, streams, etc.) and eventually into the Ocean. A drop of water remains in a river for an average of 2 weeks before reaching the Ocean.
