The water on Earth is constantly moving. The water cycle is the process in which water is recycled over and over again.
Water is a necessity for all living things on Earth.
The water moves around Earth in different states. These states include liquid, solid, and gas.
Water is found on land, in oceans, rivers, lakes, streams, underground, and in the Earth’s atmosphere.
The Earth is made up of approximately 70% water. The liquid water is found in places such as seas, oceans, rivers, lakes, and underground. Solid ice is found in snow and glaciers, this is usually in the cold regions on Earth such as the North Pole and the South Pole. The gaseous state that water exists is called water vapour. Water vapour is found in the Earth’s atmosphere.
The water cycle is the path that water takes around the Earth. The scientific name for the water is Hydrologic Cycle. Water moves from land to the sky and back again. It doesn’t leave the Earth, instead it is recycled. The water cycle is powered by the sun.
There are four stages of the water cycle:
First evaporation takes place, this is when the sun heats up the water on land, in lakes, rivers, and seas. The water is turned into a gas called water vapour. The water vapour rises into the air (evaporates). Water from trees and plants enters the atmosphere too – this process is called transpiration. Heat forces plants to release water vapour.
Next condensation takes place. This is when the water vapour in the air cools down due to low temperatures and turns into a liquid. The water vapour changes into small drops of water which form clouds. The clouds consist of millions of droplets of water.
Then water falls as precipitation, this occurs when the droplets in the clouds become too big and too heavy for the air to hold them. It falls back down to Earth in different forms. Precipitation can take many forms including rain, hail, and snow.
When the water falls as rain, hail, or snow, it is collected in lakes, rivers, and seas. This is the complete water cycle.
There are different ways in which water is collected:
- Some will fall directly into lakes, rivers, and seas.
- Some will be taken up by plant roots in the soil.
- Some will build on land as snow, ice, or glaciers.
The cycle then starts all over again.