Earth's Interior

Earth has multiple layers to it. Mainly 3, but one of them can be split into two portions. These layers are:

• • • Crust

    • Mantle

    • Outer Core

    • Inner Core

Earth's crust is mainly (95%) made up of igneous and metamorphic rocks, with an overall composition between intermediate and felsic. The remaining 5% is made of sedimentary rock, dominantly mudstone.

The mantle includes several layers, all made with the same overall ultramafic composition. The upper mantle of the Earth is typically composed of peridotite, while the lower mantle has a similar chemical composition, it contains different minerals due to the extreme pressures within. The properties of the mantle also vary by depth, as follows:

Lithosphere: solid

Asthenosphere: partial liquid

Upper/Lower Mantle: solid but plastic

"D" layer: (200km of the core) partial liquid

Core-Mantle Boundary: 2900km below

The core is primarily composed of iron, about 5% of nickel, and ranges from 3500-5000 degrees celsius. The outer core is liquid while the inner core is solid (and hotter).

The way we understand Earth's interior is through seismology, which is the study of vibrations within Earth. We look at seismic waves that we refer to as "body waves." These waves are transmitted through earth materials. There are two wave types we measure seismic energy with:

P-waves: Primary waves, move in block-like structure

S-waves: Secondary waves, move like ocean waves

• Educational Crafts

Arts and Crafts activity creating Earth's layers on a paper wheel.

• Clay Molding

Molding the Earth's layers with various colors of clay.