Download Water in Our World

 Water is the world’s must abundant substance on the Earth’s
surface
o Occurs naturally in all three states
o Essential for life
o Fresh water – water that contains a low concentration of
dissolved salts
o The hydrosphere comprises all the water environments on
Earth: oceans, lakes, rivers, streams, ice caps, glaciers, and
ground water
o Oceans cover about 70% of the Earth’s surface and store
vast amounts of heat
o Ocean waters rise and sink depending on temperature and
density, and their currents
 Salinity- the amount of dissolved salts in water
o Low near the ocean shore, esp. near the mouths of rivers, and is
high in surface water near the equator due to greater
evaporation rate
 Estuaries – Where rivers flow into the ocean
 Most river, lakes, and ground water are fresh water but still
contain dissolved minerals
 The water vapour in the atmosphere evaporates from the land and
oceans
 When the water condenses into clouds, precipitation forms, and
fresh water falls back to Earth
** Complete Water in our World questions**
Create T-chart to compare fresh and salt water
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Salt Water
Covers 71% of the Earth’s
surface
Found in oceans, some salt
lakes and marshes
More dense than fresh water
Greater buoyancy than fresh
water
Not drinkable (without
treatment to remove salt)
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Fresh Water
Covers 2% of Earth’s surface
Found in rivers, lakes, and
streams
Less dense than salt water
Less buoyancy than salt water
Drinkable (with treatment)