The conversion of water from one form into the other occurs because of temperature variation. There are four fundamental stages of the water cycle: evaporation, condensation, collection and precipitation (Oki & Kanae, 2006).
Evaporation occurs when the sun heats the earth’s surface changing the surface water into gas, which consequently carried by wind to other places as it rises. The suspended water vapor changes into clouds through condensation. This happens because of a drop in temperature, which facilitates the clinging together of the air-suspended particles. The condensed clouds then fall back on the surface of the earth in the form of precipitation, which is absorbed by plants and also collected in various water bodies such as oceans, lakes and rivers (Jacobsen & Lee, 2006).
In summary, water from rivers, lakes, oceans and other sources turns into vapor as it is heated by the sun. The water changes into vapor, which then rises and condenses to form clouds. Clouds then fall back to the earth surface as rain or precipitation, which is carried to water bodies through run-offs or absorbed into the ground and again taken by plants, which lose it to the atmosphere through evaporation. Similarly, water that goes to water bodies is also lost to the atmosphere through evaporation. This unending cyclic movement of water is what constitutes the hydrological