💧 Water Cycle Simulator

Watch Earth's water engine run: the Sun lifts water from the ocean as vapour, clouds build, rain falls, and every drop finds its way back to the sea. Step through the four stages or let it flow.

Free simulation — the cycle runs by itself. Use the stage buttons for a guided tour.
📖 How it works & key facts

Evaporation — the Sun's energy breaks water molecules free of the ocean's surface; they rise as invisible vapour (plants add more, called transpiration). Condensation — rising air cools about 6.5 °C per km; when it reaches its dew point the vapour condenses on dust and salt specks into the tiny droplets that make clouds. Precipitation — droplets collide and coalesce; once a drop is ~100× wider than a cloud droplet it falls as rain, snow, sleet or hail. Collection — water soaks into the ground (groundwater) or runs off overland into streams and rivers, returning to the ocean to start again.

The Sun evaporates about 1,500 cubic km of water every day; oceans supply ~86% of all atmospheric vapour. A water molecule spends ~9 days in the atmosphere, but can stay in the ocean for 3,000+ years. The water you drink is the same water the dinosaurs drank — Earth is a closed loop.