See how uneven the surface of the lithosphere is. There are high mountains ranges like the Rockies and Andes (in reds), huge plains like those in Texas, Iowa and Brazil (in greens), and the deep valleys of the ocean floor (in blues). We walk and climb on this part of the lithosphere.
But the surface of Earth is only the very top of the lithosphere. If you look at the cut-away globe above, you can see the rest of the lithosphere with its many layers like an onion. The very thin crust on top, the thick mantle underneath, and the huge core of liquid iron at the center.
You must be careful with the word "lithosphere," though. It is tricky! "Lithosphere" has different meanings. As we are using it here, it means both the rocky surface and the whole inside of Earth. But the deep interior of Earth is very hot, and even though the rocks there are mostly solid, they can flow over long periods of geologic time like soft butter. This flow on the inside causes the cold, hard surface layer of Earth to break into pieces and move around. This movement causes earthquakes and mountain ranges and is called "plate tectonics." When talking about plate tectonics, geologists use the word "lithosphere" to mean only the cold, hard part at the surface, and not the whole inside of the Earth.
But the surface of Earth is only the very top of the lithosphere. If you look at the cut-away globe above, you can see the rest of the lithosphere with its many layers like an onion. The very thin crust on top, the thick mantle underneath, and the huge core of liquid iron at the center.
You must be careful with the word "lithosphere," though. It is tricky! "Lithosphere" has different meanings. As we are using it here, it means both the rocky surface and the whole inside of Earth. But the deep interior of Earth is very hot, and even though the rocks there are mostly solid, they can flow over long periods of geologic time like soft butter. This flow on the inside causes the cold, hard surface layer of Earth to break into pieces and move around. This movement causes earthquakes and mountain ranges and is called "plate tectonics." When talking about plate tectonics, geologists use the word "lithosphere" to mean only the cold, hard part at the surface, and not the whole inside of the Earth.
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