| HydrosphereNow let's add the hydrosphere! Millions 
              and trillions of gallons of water! There is so much water that it 
              covers all of the low spots in Earth's lithosphere. We call most 
              of that water the ocean. Here we see the ocean in different colors 
              that show the different temperatures you find on the ocean's surface. 
              Water near the equator is warm (light blues). Water temperatures 
              along the Gulf Coast of the United States reach 90 degrees in the 
              summertime--about like a warm bath. Water near the poles are cold 
              (dark purples)--cold enough to freeze into icebergs.
 Water in the oceans flows 
              in huge currents around the edges of the continents, changing the 
              climate on the land. You can see the cold water flowing along the 
              west coast of the United States, keeping that part of the nation 
              cool. The warm Gulf Stream current flows up the east side of the 
              nation and across the Atlantic Ocean to Europe, keeping the climate 
              warm there. The hydrosphere also includes the water underground, 
              in lakes, rivers, and oceans. This water is usually fresh and is 
              where we get the water we drink and use in our kitchens and bathrooms. Back 
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