Watch this video clip about ocean currents.

Now that you have a little background knowledge about ocean currents, study the map below and answer the questions that follow.

Source: Surface Currents, Windows To The Universe.

1. What is an ocean current?
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   The water of the ocean's surface moves in a regular pattern called surface ocean currents. In this map, warm currents are shown in red and cold currents are shown in black.
   
   
2. What makes them move?
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   The water at the ocean's surface is moved primarily by winds that blow in patterns because of the Earth's spin. Winds are able to move the top 400 meters of the ocean creating surface ocean currents.
   
   
3. How big are they?
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   Surface ocean currents can be very large. The Gulf Stream, a surface current in the North Atlantic, carries 4500 times more water than the Mississippi River. Each second, ninety million cubic meters of water is carried past Chesapeake Bay (US) in the Gulf Stream.
   
   
4. Why are they important?
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   Surface ocean currents carry heat from place to place in the Earth system. This affects regional climates. The Sun warms water at the equator more than it does at the high latitude polar regions. The heat travels in surface currents to higher latitudes. A current that brings warmth into a high latitude region will make that region's climate less chilly.