The Water Cycle

The water cycle is the continuous movement of water between the surface of the Earth and the air. The water cycle involves several steps involving evaporation, transpiration, condensation, and precipitation. It is a continuous cycle where water evaporates into the air and becomes part of a cloud, falls down to earth as precipitation, and then evaporates again. This repeats again and again in a cycle that lasts forever.

Evaporation is when the sun heats up the waters in oceans, lakes, and other bodies of water. The water then changes into a gas. The water or moisture, now a gas, then evaporates into the air. This continuously takes place all over the world.

Transpiration is the process by which plants lose water in the form of water vapor. Transpiration is similar to evaporation by getting the water vapor from plants back up into the air. It is also a part of the Earth's water cycle. It takes place continuously as plants grow using the water that passes through the roots of the plants and is then released into the air.

Condensation occurs when the water vapor in the air becomes cold and changes back into a liquid. During the water cycle, clouds are formed due to condensation. It is also condensation when water droplets from the air form on the outside of a cold drink. Condensation also occurs following a hot shower. The water from the shower changes to a water vapor and the droplets cover the mirror and other objects in the room.

Precipitation is rain, snow, sleet, or hail that falls to the ground. Precipitation occurs during the water cycle when the air can no longer hold water that had been evaporated. The clouds get heavy and the evaporated water falls back to the earth as precipitation.

Rain forms in clouds when the clouds are large enough to have water droplets. The water droplets collide and form raindrops. Snow is formed when water vapor changes directly to a solid at a temperature of less than 32°F. Sleet is basically rain drops that freeze into ice pellets before reaching the ground. Hail is cooled water that freezes on contact with ice crystals in clouds normally occurring in the summer months, and usually during thunderstorms.

When precipitation ends up on the land it soaks into Earth and becomes ground water. The ground water is then used by plants and animals for drinking. Groundwater may be stored in aquifers. Aquifers are underground layers of rock that are saturated with water. This can be brought to the surface through natural springs or by pumping.

If precipitation runs over the soil and collects in the oceans, lakes or rivers it is called runoff. Runoff is the flow of water that occurs when excess storm water, meltwater, or other sources flows over the earth's surface. Once this precipitation ends up in or on the Earth's surface, the water cycle begins all over again.

In summary the Earth's water cycle continuously occurs throughout the world. The four processes include evaporation, transpiration, condensation, and precipitation. Precipitation is water that falls to the Earth through rain, snow, sleet, or hail. As the water reached the Earth's surface it may become ground water stored in aquifers, or if the Earth can no longer hold the water it becomes runoff. The water then flows back into the Earth's different bodies of water.