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THE WATER CYCLE. Our planet Earth is covered 75% by seas, oceans, lakes and rivers. All living organisms need water to survive, after all, they are made up of mostly water. About 70 percent of the human body is water. .
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Our planet Earth is covered 75% by seas, oceans, lakes and rivers. • All living organisms need water to survive, after all, they are made up of mostly water. • About 70 percent of the human body is water.
Earth’s water moves through the environment in what is called the Water Cycle. • This cycle is very important to life on Earth.
Evaporation: The heat of the sun changes water on Earth’s surface into water vapor. Condensation: The water vapor changes back into liquid water due to the cold air high above the Earth. Precipitation: Water falls from clouds formed by tiny droplets of water. Transpiration: Plants and animals also put water back into the environment.
All the water on Earth today is the same water that was here billions of years ago. • We use water for drinking, bathing, cooking, waste removal, growing crops, feeding livestock, and making materials.
Less than 1 percent of the Earth’s fresh water can be used because most of it is frozen in ice caps and glaciers. • Therefore, it is important to try to conserve water. This can be accomplished by using washers and toilets that don’t need much water. People in arid places can also landscape with native plants instead of grasses and trees that require a lot of water.
REVIEW ( Please use the mouse for the review section…) 1. What is the process by which liquid water becomes water vapor? B condensation A evaporation precipitation C None of the above D
REVIEW ( Please use the mouse for the review section…) • What is the process by which water vapor becomes cloud droplets? B condensation A evaporation precipitation C None of the above D
REVIEW 3. Where is most of Earth’s fresh water? Lakes A Rivers B Glaciers and ice caps None of the above C D
Works Cited… • http://www.kidzone.ws/water/ • http://office.microsoft.com/clipart/ • http://www.epa.gov/OGWDW/kids/cycle.html • Harcourt Science Texas Teacher’s Edition.