Understanding the Water Cycle
We can learn more about the processes in our local water catchment by looking at the water cycle. You may not realise it, but the water we use today is the same water that has been here since the world began billions of years ago. Water is recycled over and over again and is a finite resource.
Meaning we will never have more, or less water than we do now.
The Water Cycle is a natural cycle of evaporation, transpiration, condensation, and precipitation where water is continuously circulated between the Earth and the atmosphere. Evaporation occurs when solar energy from the sun heats up millions of litres of water from the oceans, rivers, lakes and soils, turning it into water vapour or steam.
Water can also enter the air through transpiration. This is when moisture is lost through the leaves of plants. Water vapour is so light it rises into the atmosphere, cooling as it rises higher and higher until it starts to condense, becoming droplets of water once again and forming into clouds. This process of change is called condensation.
You can see condensation occur when you pour cold water into a glass. The droplets of water that form on the outside of the glass are formed when the water vapour in the air touches the cold glass and turns back into its liquid state.
In the atmosphere, when the water droplets become heavy enough, gravity takes over and they fall back to Earth as precipitation. This can be in the form of rainfall, snow, hail or fog, falling directly into oceans, creeks, rivers or lakes, or into catchments, soaking into the ground, being taken up by plants, or making its way into waterways as runoff.
And the cycle begins again.