Layers of the Earth Sixth Grade Science Unit

Earth’s Beginning Earth, the largest rocky planet, was formed about 4.5 billion years ago. The Earth's interior is divided into four different layers. It is cool on the surface but very hot deep inside the planet. The center, or core, is as hot as 9000 degrees F which is hotter than the surface of the sun.

Earth’s Interior The Earth's interior is made of rock and metal. It has four main layers: 1) the inner core: a solid metal core 2) the outer core: a liquid molten core 3) the mantle: dense and mostly solid rock 4) the crust: thin rock material

Earth’s Layers How are the earth’s layers similar to an egg? Shell=crust Egg white=mantle Yolk=core

Asthenosphere Lithosphere Lithosphere: where crust and top of mantle meet Asthenosphere: The asthenosphere is a portion of the upper mantle just below the lithosphere that is involved in the plate movements. Lithosphere

The Earth’s Surface The Earth's surface is unique from the other planets because it is the only one with liquid water. Water helps to make surface features such as rivers, lakes and oceans. The moving plates of the Earth’s surface form other surface features such as mountains, earthquakes and volcanoes.

Interior of the Earth Many geologists believe that as the Earth cooled the heavier, denser materials sank to the center and the lighter materials rose to the top. Because of this, the crust is made of the lightest materials (rock- BASALTS and granites) and the core consists of heavy metals (nickel and iron).

The Crust The outermost layer of the Earth is the crust. The crust is the layer that YOU live on, and it is the most widely studied and understood. In the oceans, it is about 4 miles thick. On the thickest continents, it extends some 40 miles into the Earth.

The Mantle The region just below the crust and extending all the way down to the Earth's core is called the mantle. The mantle is much hotter and has the ability to flow.

The convection current of the mantle is much like the convection current created in a pot of boiling water.

Lithosphere Athenosphere

The Core Beneath the mantle is the Earth's core. The Earth's core consists of two layers: The outer core It flows like a liquid Mostly made of iron and a solid inner core. It is VERY hot! It is in a solid state even though it is hot enough to be melted. This is due to the enormous amount of pressure on it from the other layers that lie on top.

The Core (continued) The Outer and Inner Cores are hotter still with pressures so great that you would be squeezed into a ball smaller than a marble if you were able to go to the center of the Earth! Because the outer core contains iron, when it flows it generates a magnetic field. This is the source of the Earth's magnetic field.