The Earth’s Layers Scientists have spent many years determining what is inside the earth. Geologists can’t use x-rays to see inside the earth or dig a hole deep enough to explore what is deep inside the Earth. They have used instruments to measure earthquake waves move through the Earth. These waves pass through different materials at different rates. By analyzing earthquake waves, geologists have theorized that the interior of the earth consists of layers.

Inside Our Earth Crust Mantle Outer Core Inner Core Scientists have identified three main layers. At the center of the earth, is the core which is 750 miles in diameter. Next we find the outer core at 1,430 miles thick. Then we have the mantle at 1,800 miles. Finally, we have the earth’s crust which is very a thin layer in comparison to the rest of the earth at 10-25 miles. Inside Our Earth

Composition of the Earth’s Layers The crust is made of soil, water and rock. The mantle is hot part melted and part solid iron and magnesium. The outer core is made of hot liquid nickel and iron. The earth’s crust is composed of minerals. This is where we live and where the oceans and mountains are. Underneath the soil and water, is rock. Under the crust, is the mantle of the earth which is made of thick material. The mantle is made of hot, part melted, part solid rock. It is composed of iron and magnesium. This hot melted rock is so deep that we usually do not worry about it, however, sometimes it forces its way through the mantle to the surface of the earth as lava form a volcano. The outer core is composed of liquid nickel and iron, two metals that sank slowly through the mantle to collect at the center of the earth. The inner core is made of solid nickel and iron. Although it is hot enough to be a liquid, the pressure at the center of the earth squeezes metals into a solid. The inner core is made of solid nickel and iron. Composition of the Earth’s Layers

#2 The earth is layered with CORE metallic, inner core is solid, outer core is molten MANTLE solid but is hot enough to flow LITHOSPHERE made of crust and uppermost mantle

Crust Continental Crust (thicker & lighter) - Oceanic Crust (thinner & more dense)

#9 Why is there a different density between the types of crust? The oceanic crust is squeezed by the immense pressure of the oceans above and the granite is transformed into basalt.

Crust Continental Crust is made of Granite Oceanic Crust is made of Basalt

#3 Each layer differs in composition, density, and temperature.

Inner Core Layer: CORE – Inner Composition: Nickel and Iron (solid) Density: 12.6 – 13.0 g/cm3 Temperature: 5000 degrees Celsius

Outer Core Layer: CORE – Outer Composition: Nickel and Iron (liquid) Density: 9.9 – 12.2g/cm3 Temperature: 4400-5000 degrees Celsius

Mantle Layer: MANTLE - Asthenosphere Composition: Silicon, oxygen, iron, & Magnesium Density: 3.3 – 5.7 g/cm3 Temperature: 870 - 2200 degrees Celsius

Lithosphere Layer: Lithosphere (upper Mantle and Crust) Composition Density Temperature

Crust Layer: CRUST - Continental Composition: Granite & oxygen, silicon, aluminum, calcium, iron, sodium, potassium, & magnesium Density: 3.0 – 3.3 g/cm3 Temperature: 0 - 870 degrees Celsius

Crust Layer: CRUST - Oceanic Composition: Basalt & oxygen, silicon, aluminum, calcium, iron, sodium, potassium, & magnesium Density: 2.7 – 3.0 g/cm3 Temperature: 0 - 870 degrees Celsius