The New Childrens Encyclopedia

48

Precious water

Without water, life on Earth could not exist. This

vital resource fills the world’s oceans, lakes, and rivers

or soaks into the earth to form groundwater. A small

fraction of the world’s water exists as ice

or water vapor in the air, or is held

inside the bodies of animals and plants.

FRESH WATER

The salty seas and oceans make up 97 percent

of the world’s water. The rest is fresh water, and

most of it is locked away in the polar ice caps

and glaciers. The fresh water we drink comes

from lakes, ponds, and rivers and accounts for

just 0.6 percent of the world’s water supply.

Water cycle Water moves through a continuous

cycle between the oceans, the atmosphere, and

the land. The water cycle provides fresh water,

which is essential to life on Earth.

Rivers channel

the water back

toward the ocean.

EARTH

O
 The Caspian Sea is the largest inland

body of water in the world.

O
 Lake Baikal in Siberia is the world’s

deepest freshwater lake and the largest

by volume.

O
 Lake Superior in North America

has the largest surface area of any lake in

the world.

O
 The Dead Sea on the border of Israel

and Jordan is the world’s lowest lake and

also one of the saltiest.

FAST FACTS

Most of the

world’s water is

held in the oceans.

Plants release

water into the air

by a process called

transpiration.

The reservoir that forms

behind a dam supplies

people with water.

Some water soaks

through the soil to

form groundwater.

The Sun warms the

ocean, and fresh

water evaporates

into the air.

The clouds

release water

as precipitation

(rain or snow).

Water runs down

the slopes to form

streams and rivers.

A dam interrupts the water

cycle by delaying the return

of water to the ocean.

The Earth’s oceans

contain 324 million

cubic miles (1.36 billion

cubic kilometers)

of water.

7

/^7 

Only 3 percent

of Earth’s water

is fresh water.

As the air rises and

cools over land, the

water condenses

in clouds.