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Earth Science Rocks! Warm up Jan. 27. Question: What is the primary driving force for surface ocean currents? Density layering Global winds Water temperature differences Salt concentration. Earth Science Rocks!. MYP Unit Question : How do we use water ?
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Earth Science Rocks!Warm up Jan. 27 • Question: What is the primary driving force for surface ocean currents? • Density layering • Global winds • Water temperature differences • Salt concentration
Earth Science Rocks! MYP Unit Question: How do we use water? Area of Interaction: Health and Social Education Learner Profile: Thinker and Balanced
Earth Science Rocks! Standard: Recognize the significant role of water in the Earth’s processes. Essential Question: How currents move water?
What's Up Little Dude CURRENTS What is an Ocean Current?
What are ocean currents? • Currents are a “river” of water within the ocean • There are two types of currents: 1. Surface Currents 2. Deep Currents
SURFACE CURRENTS • Horizontal movement • Powered by the wind • Change directions when they meet a continent • Influenced by the Coriolis Effect • Caused by Earth’s rotation • Clockwise: northern hemisphere • Counter clockwise: southern hemisphere • Affects the climate of coastal areas - warming or cooling the air above it. • Example: Gulfstream carries water from the tropics to the North Atlantic Ocean
Some of the Aleutian Islands of Alaska are at the same latitude as England. Why would England’s climate be much warmer?
What if… • What if you made a raft out of balsa wood and tried to sail it from Peru to Indonesia?
Water Warms Or Salinity Decreases Water Cools Or Salinity Increases Water rises DEEPCURRENTS • Caused by water of different densities • Warm water rises: Cooler water sinks • Salty water sinks, less salty water rises Water sinks DEEP CURRENTS MOVE VERTICALLY
DEEP CURRENT EXAMPLES • Antarctica Current Surface freezes salt remains in water = increase salinity/density Water sinks Up to 500 yrs just to move along ocean bottom to the Equator Bottom of the Earth (South Pole)
DEEP CURRENT EXAMPLES • Mediterranean Sea • Nearly closed sea • Water evaporates salt remains • Increases salinity/density • Water sinks to bottom • Water flows into Atlantic Ocean
Upwelling • The process in which cold nutrient-rich water from the deep ocean rises to replace warm surface water • Very important to tiny organisms like plankton. Fish and birds feed on these organisms.
El Nino • Occurs every 2-7 years • Begins when an unusual pattern of winds forms over the western Pacific. • Warm water moves east.