Unit E: Fresh and Saltwater System

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Unit E Fresh and Saltwater System

• Topic 1 A World of Water

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Our Blue Planet

• 74 of the Earths surface is covered by water
  and 97 of this water is salt water.
• All life depends on water. Without water there
  can be no life on a planet. 60 of our bodies,
  84 of an apple, and 98 of a watermelon are all
  water.
• You lose water constantly through sweat,
  breathing, etc. To replenish your supply you need
  to drink an average of 2.5 L/day.

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Major Uses of Water

• Direct Uses Personal use including drinking and
  washing.
• Indirect Uses Industrial and agricultural uses
  including irrigation, cooling, solvent, etc.
  Often leads to the pollution of the water.
• Water use by humans breaks down
• 73 irrigation for agriculture (indirect)
• 22 industrial (indirect)
• 5 personal (direct)

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Benefits and Costs to Water Use

• Benefits include helps create food, jobs, better
  products, more convenience, and a strong economy.
• Costs include starving native plants and animals
  of water, increasing soil salinity (soil loses
  moisture and becomes salty), and pollution of
  water.

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The Water Cycle

• Controls the distribution of water on the Earth.
  The suns energy drives the water cycle.
• Processes include evaporation, condensation,
  precipitation, and runoff of groundwater.

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Fresh Water

• Only 3 of water on Earth is fresh water, and
  most of that is trapped in glaciers.
• Most of the liquid fresh water is in the form of
  ground water.
• Only 0.02 of water is potable safe for
  drinking.
• Four countries Brazil, Canada, China, and the
  U.S. hold 50 of the fresh water on Earth.