The Water Cycle

The Water Cycle

Brief description

The water cycle is one of the best-known cycles taught in today's science classrooms. The cycle of precipitation, transpiration, evaporation and condensation has a huge impact on river systems as it affects how much water is making its way towards out rivers.

More information

Here is a basic summary of the water cycle.

  • Water is moved from the earth's surface into the air. This is called evaporation. The solar energy from the sun evaporates the water from the ocean, lakes, rivers and even puddles. The evaporated water, now in a gas form called vapour, rises into the air and travels by the wind up over the hills.
  • Water also enters the air by transpiration. This is the loss of moisture from the leaves of plants (just like we do, plants also give off moisture when they breathe)
  • As the water vapour cools, it forms tiny droplets of water in the air and joins together. We see them as clouds. This is called condensation. You can see this when you pour a glass of cold water. The water droplets that form on the outside of the glass are actually from the water vapour in the air, turning back into liquid form as it touches the cold glass.
  • When the water vapour in the clouds becomes too heavy, it falls to the ground as rainfall, snow, hail or fog. This is called precipitation.
  • Water from precipitation either falls directly into the sea, rivers and lakes, or it is taken up by plants, or it is absorbed into the ground (infiltration), or it makes its way into waterways as runoff.

Did you know?

There is actually the same amount of water on the earth as there always has been. But some of what was good clean fresh water is now salty or polluted and there is a greater demand for fresh water as the world population grows.

There is never any new water on Earth. The water that we see and use now has been part of the water cycle for billions of years - pretty much as old as the earth itself. Now go pour yourself a glass of ice c-OLD water!

The best way to learn more is to find a good diagram. You can find plenty more in books or on the Internet:

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