Layers of the Earth

Do Now 8/19/13 Which branch of Earth Science would study earthquakes? Which branch of Earth Science would study hurricanes? Which branch of Earth Science would study the warming of the oceans’ waters? Which branch of Earth Science would study asteroids?

Do Now 8/20/13 Name the layers of the Earth. What is the thickest layer of the Earth? What is the thinnest layer of the Earth? What is the hottest layer of the Earth?

Do Now 8/21/13 The crust is about ___________ km thick. True or False. The mantle is a liquid. The deeper you go into the Earth the ________ the temperature. The densest layer of the Earth is the ________.

Key Questions What are the layers of the Earth? What is the crust? What are the characteristics of the Earth’s Crust? What is the composition of the Earth’s Crust? What is the lithosphere? What is the Moho? What is the mantle? What are the characteristics of the Earth’s Mantle? What is the composition of the Earth’s Mantle? What is the asthenosphere? What is the mesosphere? What is the core? What is the outer core? What is the inner core?

What are the layers of the Earth? Crust Mantle Core – Outer Core and Inner Core

What is the crust? The crust is the outermost layer of the Earth Thickness: 5 to 100 kilometers thick Continental Crust: ~ 30 km Oceanic Crust: ~ 5 km

What are the characteristics of the Earth’s Crust? Crust floats on the mantle. Crust is thin. Two layers – Top layer of granite and a more dense bottom layer of basalt. Both layers are found under continents, only the basalt layer is under the oceans. Temperatures increase with depth: 20° C at top and 870° C at bottom.

What is the composition of the crust? Crust is composed of: Oxygen: ~ 50% Silicon: ~ 30% Aluminum: ~ 10%

What is the Moho? Moho: Boundary between the crust and the mantle that is more dense than the crust.

What is the lithosphere? Made up of crust and uppermost layer of the mantle. Approximately 80 km thick. Broken into pieces (tectonic plates) which move around on the asthenosphere.

What is the mantle? The mantle is the thickest part of the Earth. Thickness: ~ 2,900 km Upper and Lower Mantle – they differ in temperature, density, and pressure. These increase as depth increases.

What are the characteristics of the mantle? Temperatures: Top of mantle is ~ 870° C and bottom is ~ 2,200° C. Rock begins to flow like dough as temperature increases.

What is the composition of the mantle? Silicon, Oxygen, Iron, and Magnesium The deeper the rocks are in the mantle, the more iron they hold.

What is the asthenosphere? Upper part of the mantle. Found between 75 km and 200 km deep. Semiplastic layer which moves fluidly due to convection currents.

What are convection currents? Circular movements caused by the heating and cooling of the substance.

What is the mesosphere? Mesosphere: Layer of the mantle below the asthenosphere. 350 to 2,900 km deep. Great pressure - it is solid and more rigid than the rock on top of it.

What is the core? Innermost layer of the Earth. Two layers – Outer Core and Inner Core Thickness: Outer Core is ~ 2,250 km thick and Inner Core is ~ 2460 km in diameter.

What is the outer core? Outer Core: A shell surrounding the inner core. Composed of liquid iron and nickel. Temperature: ~ 2,200° C at its outer surface and ~ 5,000° C at its inner surface.

What is the inner core? Inner Core: Innermost layer of the Earth – Sphere. Composed of solid iron and nickel. Temperature: ~ 5,000° C. Solid due to extreme pressure bearing down.