The Planet Facts! Part 2
||edHelper's suggested reading level:
||grades 6 to 7
||Flesch-Kincaid grade level:
||asthenes, C-Zone, structural, seismic, magnetosphere, universe, gravitation, magnetism, gravity, mantle, mass, brittle, affected, based, measurement, prefix
||Planet Facts, C-Zone S-Zone What, Crust/Mantle Lithosphere Solid, Mantle Asthenosphere Hotter, Mantle Mesosphere The, Core Inner Core Found, Core Outer Core The, Sir Isaac Newton
Print The Planet Facts! Part 2
The Planet Facts! Part 2
By Trista L. Pollard
1 In The Planet Facts! Part 1, you learned about the Earth's three compositional zones. Now we will explore the five structural zones. The Earth's structural zones (S-Zones) are the lithosphere, asthenosphere, mesosphere, inner core, and outer core. Over the years, scientists have measured seismic waves from earthquakes. These waves have helped scientists to learn more about the inside of our planet.
2 The lithosphere is part of the crust and the upper mantle. The prefix "lithos" is Greek for "stone" or "rock." This layer is solid and the most rigid of the other layers. It is about 15 to 300 kilometers thick. The asthenosphere lies below the lithosphere. This layer is about 200 kilometers thick and contains hotter, softer rock that flows like lava. Its prefix "asthenes" is Greek for the word "weak." Keep in mind; it is not as weak as a brittle piece of wood. However, it is weaker than the other layers. The mesosphere or "middle layer" is found at the lower part of the mantle. Scientists believe it is solid rock.
3 If you travel farther into the center of the Earth, you will come to the inner and outer cores. The outer core, which is about 2,300 kilometers thick, is located about 2,900 kilometers below the surface. Since scientists have not seen this area, they believe the outer core is made of a dense liquid. The inner core is a solid ball that is about 2,400 kilometers in diameter. Scientists believe the inner core is made of solid, dense nickel and iron. It is also located about 5,150 kilometers below the surface. The inner and outer cores make up about 1/3 of the Earth's mass.
|C-Zone||S-Zone||What are they like?|
|Crust/Mantle||Lithosphere||Solid and very rigid rock; about 15 to 300 kilometers thick.|
|Mantle||Asthenosphere||Hotter and softer rock that flows like lava. It is about 200 kilometers thick.|
|Mantle||Mesosphere||The middle layer, which is solid rock. It is below the asthenosphere.|
|Core||Inner Core||Found about 2,900 kilometers below the Earth's surface. It is about 2,300 kilometers thick.|
|Core||Outer Core||The solid, dense metal ball at the center of the Earth. Made of nickel and iron.|
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