Water is Essential to Life on Earth Earths water is mostly salt water (97.5%). The remaining 2.5% is fresh water, and most of the fresh water is frozen.

Water is Essential to Life on Earth

Earth’s water is mostly salt water (97.5%). The remaining 2.5% is fresh water, and most of the fresh water is

frozen.

Did you know that LESS than 1% of our water supply is readily available for use?

Water can be a:Water can be a:

LiquidLiquid

GasGas

SolidSolid

Liquid WaterLiquid Water Temperature and air pressure determine when Temperature and air pressure determine when

water is liquid. It cannot be too cold or too hot water is liquid. It cannot be too cold or too hot to remain a liquid and the air pressure must be to remain a liquid and the air pressure must be

relatively low.relatively low.

Gaseous WaterGaseous Water• You see water in the form of gas, when you see……..You see water in the form of gas, when you see……..

Water changes from liquid to gas when its heated. Water changes from liquid to gas when its heated. This gas is called water vapor. Although we can’t see This gas is called water vapor. Although we can’t see it, water vapor is all around us. We even release water it, water vapor is all around us. We even release water vapor into the air when we breath, and it’s also vapor into the air when we breath, and it’s also transpired from plants.transpired from plants.

Solid WaterSolid Water• IceIce

• FrostFrost

• GlaciersGlaciers

• Polar Ice Polar Ice CapsCaps

Solid:Solid: When water When water becomes very cold becomes very cold it freezes and it freezes and changes from changes from liquid to solid.liquid to solid.

Frozen water has a Frozen water has a definite form and definite form and shape.shape.

NOW THAT’S ONE BIG NOW THAT’S ONE BIG ICEBERG!ICEBERG!

The Amazing Water The Amazing Water CycleCycle

EvaporationEvaporation

When liquid water heats upWhen liquid water heats up it becomes vaporized and it becomes vaporized and changes into a gaschanges into a gas

Water vapor rises due to a Water vapor rises due to a difference in air pressure difference in air pressure

As water vapor rises it As water vapor rises it becomes cooler; the becomes cooler; the

higher higher it rises the faster it it rises the faster it condensescondenses

Seawater evaporation ponds, on the Isle of Rhé off the coast of France, are used to obtain salt

CondensationCondensation

PrecipitationPrecipitation

Collection

WATER POLLUTIONWATER POLLUTION

EVERYTHING THAT IS LEFT ON THE EVERYTHING THAT IS LEFT ON THE GROUND ENDS UP IN OUR WATER GROUND ENDS UP IN OUR WATER

SUPPLYSUPPLY

“Does One Bag Really Matter?”

What Do You Think Now?

Someone Didn’t Think it Mattered

Other Types of Water Pollution