How is Water Important?

• __Life_______ cannot exist without water

• Water is essential for living things to_grow______, __reproduce_________and___perform other functions________.

• 97% of Earth’s water is __salt___water.

• Only _______% of Earth’s water is fresh water.

What are the 3 states of water?

• __solid___________

– Ice –makes up about __3/4_______(fraction)of Earth’s fresh water.

• _liquid________

– River and lakes – 0.34%

– Ground water – found in __aquifer______ make up __23____%.

• _gas________

– Water vapor (clouds) – 0.037%

• Earth’s fresh water supply is renewable because water changes from liquid to gas (called _evaporation_) and from a gas to liquid (called _condensation_). This is known as the___water_ _cycle_.

Water is used for many purposes – List the five main purposes

• ______household__________

– (drinking, cooking, washing)

• _agriculture_______________

– ____irrigation____________ - >supplies water to make land suitable for crops

• ___industrial_____________

– Used for cooling hot machinery, or producing energy

• ______transportation__________

– Many major cities are located near waterways, because the rivers were used to transport goods.

• ______recreation__________

– Swimming, fishing, boating, ect.

Types of Water – List the 3 types of water

• ___Fresh_____Water – Contains only minimal amounts of salt. This is the type water needed by humans, animals and most plants to survive.

• __Brackish______Water – saltier than fresh water but not as salty as sea water. An example would be when a river runs into an ocean.

• ___Salt_____Water– contains about 3.5% salt on average.

– The most salty sea is the ____Dead_______.(bonus pg H128)

– The least salty sea is the Gulf of Finland

Freshwater Pollution

• The major sources of water pollution are____human wastes____________, _industrial waste_________, __agricultural chemicals_____________, and __runoff_______from roads.

• The source of pollution can be either ___point______(easy to identify) or __nonpoint______________(widely spread and not tied to a specific point).

• _Dr. Snow_______________discovered that _cholera____________(a disease causing bacteria found in human waste) contaminated a well in London, killing 500 people.

• After _floods_____________ people often have to boil their drinking water to kill disease causing bacteria.

• __Chemicals____________are sometimes released directly into rivers, or if disposed of underground can leak into ground water.

• Smoke and exhaust are the release sulfuric and nitric acids which make precipitation more acidic. This is called ______acid rain_______________.

• _Heat Pollution__is caused when a factory releases water used to cool machinery into a nearby river or stream. The warmer water causes the temperature of the surrounding water to rise to a level that may not be safe for things living in the water.

Water as an energy resource

• As water moves it has _kinetic___________energy.

• When water is stopped, as in behind a dam, it has __potential___energy.

• _Hydroelectric____ power is electricity produced by the movement of water over a waterfall or dam.

• Hydroelectric power is_Safe_, _clean_ and ___efficient_______________, because water is free and naturally renewed by the water cycle.