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Only 3% of the Earth’s water is fresh water (no salt).
2/3 of this water is frozen in ice sheets.
Therefore only 1% of the fresh water on Earth is available.
3 Spheres of Earth
Lithosphere: the solid rocky ground of the Earth’s crust (GROUND)
Atmosphere: the environment surrounding the Earth. (AIR)
Hydrosphere: All water on Earth. (WATER)
Water Cycle
The constant cycling of water through the processes of evaporation and condensation
Water is constantly changing form (gas liquid)
Driven by the sun’s energy
Hydrologist: A person who studies Earth’s water systems
Oceanographer: A person who studies all aspects of the ocean.
Three ways in which fresh water differs from ocean water
are:
Salinity- The amount of salt dissolved
Density- How tightly packed together the material is in a substance. (Ocean water is more
dense than fresh water due to the salt content.)
Freezing point- The temperature at which a liquid freezes
Sources of Fresh Water
1.Lakes, ponds and wetlands
2.Streams and rivers
3.Ground water
4.Glaciers
5.Drainage basins
Drainage Basins- Watershed, The area of land that drains into a body of water such as a
river, pond, lake or ocean.
Divide- separates one basin from another.
The Origin of the Oceans
1.Tectonic Plates- Tectonic plates move changing the position of the continents.
2.Volcanic action- Water trapped in volcanic materials were released as vapour. It cooled,
condensed and fell back to the earth. This water collected in the lowest parts of the
Earth’s surface... The ocean basins.
3.Erosion- Has aided the further development of continental drainage systems as
material is removed and deposited into the ocean basins.
4.Glaciation- Glaciers move materials towards the oceans.
Researching the Ocean Floor
Technologies include...
1. Sonar
2. Satellites
3. Core sampling
4. Underwater photography/ videography
5. Deep sea submersibles
6. Diving
OCEAN CURRENTS
Current: A large amount of ocean water that moves in a particular and unchanging
direction.
2 Types of Ocean Currents...
1. Surface currents- Flow in the top 100-200 m
2. Deep currents- Flow below 200 m
Factors that influence surface currents are:
1.Wind- The energy of the moving air is transferred by friction to the water
molecules causing it to move.
2.Earth rotation- The Earth spins counter-clockwise.This spinning body deflects
winds and currents depending on what side the equator they are on
(Coriolis Effect)
Clockwise in the Northern Hemisphere and Counter clockwise in the Southern
Hemisphere
3.Shape of the Earth’s continentsMoving currents are forced to turn when they meet a solid surface.
Deep Water Currents
The most important influences are:
1.Water temperature-Not the same at every depth.*Cold water is also more
dense than warmer water.
2.Salinity- Higher the salinity, the more dense the water becomes
Local Ocean Currents...
1. Labrador Current- Current that flows around Labrador and is cold water
2. Gulf Stream –Current that flows from the south and is Warm Water