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The Water Cycle |
Click on the picture above and watch the Water Cycle Video. |
The Water Cycle is the journey water takes as it circulates from the land to the sky and back again. The Sun's heat provides energy to evaporate water from the Earth's surface (oceans, lakes, etc.). Plants also lose water to the air (this is called transpiration).
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Different Stages of the Water Cycle
Water goes through three different states in the water cycle. It can be a liquid (water), a gas (water vapor) or a solid (ice).
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1. Evaporation: Water is found in lakes, oceans, swamps, and soil, as well as in all living creatures and plants. When heat is applied the water molecules become excited and spread out. The loss of density is called ‘evaporation’,.
2. Condensation: The water vapor that has risen into the sky cools significantly when it comes into contact with the cooler air found up high. The vapor becomes a cloud, which is pushed around the world by moving air currents and winds. |
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3. Precipitation: The water that has fallen as rain is absorbed into the ground through a process known as ‘infiltration’. Soil and other porous materials can absorb great deals of water this way, while rocks and other harder substances will only retain a small amount of water.
4. Runoff: After the water has fallen and the soil has become saturated, or the snow has melted, the water follows gravity and falls down any hills, mountains, or other inclines to form or join rivers. This process is known as ‘runoff’, and it is how water comes to rest in lakes and returns to the ocean.
4. Runoff: After the water has fallen and the soil has become saturated, or the snow has melted, the water follows gravity and falls down any hills, mountains, or other inclines to form or join rivers. This process is known as ‘runoff’, and it is how water comes to rest in lakes and returns to the ocean.
