Water on Earth
Oceans cover nearly 71 percent
of Earth's surface.
Most of Earth's water—roughly
97 percent—is salt water that is
found in the oceans.
Eventually,
we
harvest
that salt
for our
use!
 Only 3 percent is fresh water.
 Of that 3 percent, about three
quarters is found in the huge masses
of ice near the North and South
Poles.
Water on Earth
 A fraction more is
found in the
atmosphere.
 Most water in
the atmosphere
is invisible
water vapor,
the gaseous form
of water.
Water on Earth
Less than 1
percent of the
water on Earth
is fresh water
that is available
for animals to
use.
Water on Earth
Water on Earth
 Types of water on Earth
 Oceans
 Ice
 Rivers and Lakes
 Below Earth's Surface

Water that fills the cracks and spaces in underground soil and
rock layers is called groundwater. Far more fresh water is
located underground than in all Earth's rivers and lakes.
The Water Cycle
 Water is naturally recycled through the water cycle.
 The water cycle is the continuous process by which
water moves through the living and nonliving parts of
the environment.
 The sun is the source of energy that drives the water
cycle.
 In the water cycle, water moves from bodies of water,
land, and living things on Earth's surface to the
atmosphere and back to Earth's surface.
The Water Cycle
Water is constantly moving between sea, air and land
The Water Cycle
Water is constantly moving between sea, air and land
heat
The sun shines and
the sea is heated
The Water Cycle
Evaporation
Water is constantly moving between sea, air and land
The water
evaporates and
forms clouds
The Water Cycle
Water is constantly moving between sea, air and land
Condensation
As air rises it cools
and condenses. It
reaches the
ground as rain,
snow, sleet or hail.
The Water Cycle
Water is constantly moving between sea, air and land
Snow forms
Lakes
form
The snow
melts and
flows
The Water Cycle
Water is constantly moving between sea, air and land
The Water Cycle is complete
The Water Cycle
Steps of the Water Cycle
Water Evaporates
Clouds Form
Water Falls as Precipitation
And then it starts again
Water Evaporates
 Evaporation is the process by which molecules at
the surface of a liquid absorb enough energy to
change to the gaseous state.
 Water can evaporate from where?
 Ocean
 Lakes
 Soil, puddles, and even from your skin
 Plants

Eventually the water is given off through the
leaves as water vapor in a process called
transpiration
Clouds Form
 Water molecules find their way into the
atmosphere,
 warm air carries it upward.
 Higher up, air tends to become much colder.
 Cold air holds less water vapor than warm air.
 Some of the water vapor cools and condenses into
liquid water.
 Condensed droplets of water clump together
around tiny dust particles in the air, forming
clouds
Water Falls as Precipitation
 As more water vapor condenses, water
droplets in a cloud eventually become so
heavy that they fall back to Earth.
 Water that falls to Earth as rain, snow, hail,
or sleet is called precipitation.
 Most precipitation falls directly into the
oceans.
 Precipitation is the source of all fresh water
on and below Earth's surface.
 The water cycle renews the usable supply of
fresh water on Earth.
The Water Cycle
How Do People Use Water?
 The water people use at home is just a small
percentage of all the water used in the
United States.
 In addition to household purposes, people
use water for
 Agriculture
 Industry
 Transportation
 Recreation
Agriculture
 Farms need a constant supply of fresh water
 Irrigation is the process of supplying water to areas of land to
make them suitable for growing crops.
 In the U.S., more water is used for irrigating farmland than for
any other single purpose.
Industry
 What objects require water to produce
them?
 Water is needed to produce most objects.
 Water plays a role in the industrial processes
that created them.
 Power plants and steel mills both need huge
volumes of water to cool down hot
machinery.
Transportation
 Oceans and rivers
have been used
for transporting
people and goods
since ancient
times
Recreation
 Swimming, Fishing, Going to the beach, skiing,
snowboarding, Water park etc.
Water Usage
Water and Living Things
 Water makes up nearly two thirds of your body.
That water is necessary to keep your body
functioning.
 Water is essential for living things to grow,
reproduce, and carry out other important
processes.
 Plants use water, plus carbon dioxide and energy
from the sun, to make food in a process called
photosynthesis.
COMPREHENSION CHECK-TOTD
 Write an explanation of the water cycle beginning with
two drops of water in the ocean. You must use key
vocabulary words (evaporation, precipitation,
condensation, etc).