Oceans
اسلاید 1: OceansWater, water everywhere…But only on the Earth!
اسلاید 2: Over 70% of the Earth’s surface is covered by waterOf that, 95% is salt water – only 5% is fresh water – and part of that is iceOceans
اسلاید 3: All the oceans are really just one body of waterThis is divided into the four named oceans:PacificAtlanticIndianArcticOcean names
اسلاید 4: The oceans are always in motionTides happen twice dailyTides are caused by the pull of gravity by the moon, and to a lesser degree by the sunWhy do you think the sun would pull less than the moon?Tides
اسلاید 5: There are two type of Ocean Currents: Surface Currents-Surface CirculationThese waters make up about 10% of all the water in the ocean.These waters are the upper 400 meters of the ocean.Currents
اسلاید 6: Deep Water Currents-Thermohaline CirculationThese waters make up the other 90% of the oceanThese waters move around the ocean basins by density driven forces and gravityThe density difference is caused by different temperatures and salinityThese deep waters sink into the deep ocean basins at high latitudes where the temperatures are cold enough to cause the density to increase.Currents
اسلاید 7: Ocean Currents are influenced by two types of forces1. Primary Forces--start the water movingThe primary forces are:Solar Heating Winds Gravity Coriolis effectForces
اسلاید 8: 2. Secondary Forces--influence where the currents flowSurface CirculationSolar heating cause water to expand. Near the equator the water is about 8 centimeters high than in middle latitudes. This cause a very slight slope and water wants to flow down the slope. Winds blowing on the surface of the ocean push the water. Friction occurs between the wind and the waters surface.Forces
اسلاید 9: Wind direction
اسلاید 10: WindA wind blowing for 10 hours across the ocean will cause the surface waters to flow at about 2% of the wind speed.Water will pile up in the direction the wind is blowing.Gravity will pull the water down the hill or pile of water.But the Coriolis Force causes the water to move to the right (in the northern hemisphere) around the mound of water.
اسلاید 11: Mounding
اسلاید 12: These large mounds of water and the flow around them are called Gyres. The produce large circular currents in all the ocean basins.Gyres
اسلاید 13: Remember the Coriolis Force move objects to the right in the northern hemisphere, and to the left in the southern hemisphere
اسلاید 14: This powerpoint was kindly donated towww.worldofteaching.comhttp://www.worldofteaching.comIs home to well over a thousand powerpoints submitted by teachers. This a free site. Please visit and I hope it will help in your teaching
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