Oceans

Importance of Oceans Food Food Recreation Recreation Energy resources (oil & natural gas) Energy resources (oil & natural gas) Transportation Transportation Salt Salt

Origin of Oceans Early Earth was covered with volcanoes Early Earth was covered with volcanoes Gases from volcanoes included water vapor Gases from volcanoes included water vapor Over thousands of years, the vapor built up in the atmosphere Over thousands of years, the vapor built up in the atmosphere Eventually it started to rain – a lot Eventually it started to rain – a lot Oceans formed when this rain filled in low areas called basins Oceans formed when this rain filled in low areas called basins

Contents of Ocean water 96.5% pure water 96.5% pure water 3.5% salts 3.5% salts –Sodium chloride, potassium chloride, etc. –Salinity = how much salt is in the water –Saltier the water, the easier you float

Ocean Currents Caused by wind & Earth’s rotation Caused by wind & Earth’s rotation Currents move in circles Currents move in circles –Coriolis Effect: the shifting of winds from their expected paths because of Earth’s rotation. Northern hemisphere - clockwise Northern hemisphere - clockwise Southern Hemisphere – counter-clockwise Southern Hemisphere – counter-clockwise

Major Surface Currents Major Surface Currents

Notable Currents Gulf Stream –C–C–C–Carries warm water from Caribbean across Atlantic towards England California –C–C–C–Carries cold water from Alaska down Pacific coast East Australian current (EAC) –N–N–N–Northern Australia towards Sydney Harbor

Waves Caused by disturbances moving across the surface of water Caused by disturbances moving across the surface of water Size affected by: Size affected by: –Wind primary cause –How long wind blows –How much open water there is

Wave Structure Crest – High point Crest – High point Trough – Low point Trough – Low point Wave height – Distance from crest to trough Wave height – Distance from crest to trough Wavelength – Distance between crests Wavelength – Distance between crests

Tsunamis Caused by underwater earthquakes Caused by underwater earthquakes Wave moves outward until it hits land Wave moves outward until it hits land

Tides Rise and fall of water levels each day Caused by: –G–G–G–Gravitational pull of Moon –A–A–A–And Sun as well –C–C–C–Creates bulges of water on Earth

Spring Tides Occur when sun, moon, and Earth are aligned Occur when sun, moon, and Earth are aligned High tide is higher than usual, low tides lower High tide is higher than usual, low tides lower Occur twice a month during full and new moon Occur twice a month during full and new moon

Neap Tides Occur when sun, moon, and Earth are at right angles Occur when sun, moon, and Earth are at right angles High tides not as high, low tides not that low High tides not as high, low tides not that low Occur twice a month during quarter moons Occur twice a month during quarter moons