Water on Earth!!!Ms. Coulter

Water cycle is a continuous process by which water moves from Earth’s surface to the atmosphere and back.◦ 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

Liquid water changes to a gas called water vapor. Water is constantly evaporating from the surfaces of lakes and oceans and even from the soil.

Plants help too; they draw in water from the soil (via their roots) and release it through their leaves as vapors.

Water evaporates

Warm air carries the water vapor upward. At higher altitudes, air tends to become much colder. Cold air cannot hold as much water vapor as warm air can; resulting in some of the vapor cools and condenses into liquid water. Condensed water clumps around tiny dust particles and become clouds.

Condensation forms clouds

Rain, snow, sleet, or hail. Most precipitation falls back into the ocean

or lakes. Precipitation that falls on land may soak

into the soil and become groundwater. Precipitation may run off the land,

eventually flowing back into the ocean

Precipitation

Most of Earth’s water (97%) is salt water found in the ocean

Only 3% is fresh water; of this 3% about three quarters is frozen in huge masses of ice near the North and South poles.

Almost a quarter of the fresh water is underground.

A tiny fraction of Earth’s fresh water occurs in lakes and rivers.

Distributing Earth’s water

Ocean covers more area than all of the land on Earth combined.

There are four names used for the parts of the ocean:◦ Pacific◦ Atlantic◦ Indian◦ Arctic

But the waters are all interconnected

Oceans

Most of the fresh water is locked in thick sheets of ice that cover Antarctica (South Pole), and Greenland (North Pole).

Huge icebergs (floating chunks of ice) often brake off these sheets. They slowly melt as they float toward warmer waters.

Ice

North America has five Great Lakes which contain nearly 20% of all the water in the world’s freshwater lakes.

Rivers and Lakes

Fills the cracks and spaces in underground soil and rock layers.

Water is soaked into the ground (rain or snow) through spaces between particles of soil and rock. Eventually it reaches a layer of rock it cannot move through.

There is far more fresh water underground than in all of Earth’s rivers and lakes.

Groundwater