Oceans

Interesting Facts Ninety percent of all volcanic activity occurs in the oceans. Earth's longest mountain range is the Mid-Ocean Ridge At the deepest point in the ocean the pressure is more than 8 tons per square inch, or the equivalent of one person trying to support 50 jumbo jets. At 39 degrees Fahrenheit, the temperature of almost all of the deep ocean is only a few degrees above freezing. If mined, all the gold suspended in the world's seawater would give each person on Earth 9 pounds. If the ocean's total salt content were dried, it would cover the continents to a depth of 5 feet.

5 main bodies from largest to smallest Pacific – largest and deepest Atlantic – covers 20% of the Earth’s surface Indian – between Africa, India and Indonesia Southern – ice covers some of it all year round Arctic – smallest and shallowest, ice covers some of it year round

Formation of the oceans Gas (water vapor) from volcanoes Condensation – the Earth cooled. Rain fell for tens of thousands of years Asteroids and comets – icy comets and asteroids melted

Composition of seawater Salinity – amount of dissolved solids in a mass of water, usually measured in ppt (parts per thousand) Elements found in seawater: chlorine, sodium, sulfate, magnesium, calcium, potassium, and trace amounts of other minerals. Brackish – where salt water mixes with fresh

The Seafloor Continental margin – ocean basin next to a continent. Continental shelf Continental slope Continental rise

Abyssal Plains Large flat areas that extend across the deepest parts of the ocean basins

Mid-ocean ridges Where tectonic plates pull apart

Zones Surface – receives the greatest amount of sunlight Middle – Receives only a faint amount of blue-green light Deep zone – plants cannot grow, no light, most deep sea animals make their own light using bioluminescence

Waves 2 parts to a wave Two measurements Trough Crest Wavelength Wave height

Wave motion The particle of water is circular Water is not moved from place to place. Only energy is moved

Wave video clip

Breakers As waves approach shore the base of the wave slows down, while the top of the wave continues at the same speed The wave length shortens and wave height increases When the wave reaches a certain height, the wave base cannot support the crest and the wave collapses or breaks

Ride the wave

Tsunamis A wave that forms when an ocean disturbance suddenly moves a large volume of water. Earthquake Landslide Volcanic eruption

Tsunami Far from shore the wave height is short, but the wave length can be hundreds of meters long As the tsunami approaches the shore, it slows down and grows higher

Tsunami interactive

Tides Sea level – average level of the ocean’s surface at any given time Tides – the periodic rise and fall of the ocean’s surface caused by the gravitational force between Earth and the Moon and between Earth and the Sun.

Tides The moon pulls up on the ocean creating a bulge The bulges are largest on the side facing the Moon and the opposite side of the Earth That is high tide

Tides Some areas, have a large difference between high and low tide Tidal range is the difference in water level between a high and low tide