ESCI Lesson 5 Internal Structure of the Earth.pdf

Earth Science Lesson 5: The Internal Structure of Planet Earth Learning Competency: The learners shall be able to identify the layers of the Earth (S11/12ES-Ia-e-7) differentiate the layers of the Earth from each other (S11/12ES-...

Earth Science Lesson 5: The Internal Structure of Planet Earth Learning Competency: The learners shall be able to identify the layers of the Earth (S11/12ES-Ia-e-7) differentiate the layers of the Earth from each other (S11/12ES-Ia-e-8). Lesson Objectives: Describe the Earth’s interior (in terms of crust, mantle, core) Compare the Earth’s layers Layers of the Earth Crust The crust is the thinnest and the outermost layer of the Earth that extends from the surface to about 32 kilometers below. Underneath some mountains, the crust thickness extends to 72 kilometers. Mohorovicic (Moho) Discontinuity) separates the crust and the mantle. Elements in the Earth’s Crust Element Percentage Oxygen 46.60 Silicon 27.72 Aluminum 8.13 Iron 5.00 Calcium 3.63 Sodium 2.83 Potassium 2.59 Magnesium 2.09 Titanium 0.40 Hydrogen 0.14 Mantle extends to about 2900 kilometers from the Earth’s surface. It makes up about 80% of the Earth’s total volume and 68% of its total mass. The mantle is solid. The crust and the uppermost part of the mantle form a relatively cool, outermost rigid shell called lithosphere and is about 50 to 100 kilometers thick. Gutenberg Discontinuity separates the mantle and the outer core. mantle is mostly made of the elements silicon, oxygen, iron and magnesium. The lower part of the mantle consists of more iron than the upper part. This explains that the lower mantle is denser than the upper portion. Asthenosphere – layer of weak, ductile rock in the mantle; situated below the lithosphere Core The outer core is 2900 kilometers below the Earth’s surface. It is made up of iron and nickel. The temperature in the outer core reaches up to 2000°C at this very high temperature, iron and nickel melt. The inner core is believed to have solidified as a result of pressure freezing Lehman Discontinuity separates the outer core and the inner core.