Layers of the Earth

6min 20s Novice Slovenian Spanish Greek

How were Earth’s layers discovered? What are they?

Earth’s interior is broadly grouped into three main layers on the basis of chemical composition: crust, mantle, and core. An egg analogy is used to show relative thicknesses, and a Big Hunk analogy illustrates how a material of a single composition can be either brittle or ductile depending on temperature. This animation shows briefly how scientists figured out where these layers were, what the layers are, and how the crust is often mistaken for the tectonic (aka lithospheric) plates.

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0:00 Intro
0:46 Seismic waves reveal layers
0:57 Three layers (like an egg?)
1:56 Basic layers
2:01 Crust chemistry
2:53 Mantle chemistry
3:46 Core: Inner and outer
4:47 Crust vs. plate? What’s the difference?
5:36 Earthquakes, volcano, magnetics



  • Layers were deduced by Sir Isaac Newton (1700) to Inge Lehmann (1937)
  • Earth’s 3 main layers: crust, mantle, core
  • Layers are defined by composition
  • Each layer has physical variations due to temperature and pressure
  • The crust is only the upper part of the tectonic (lithospheric) plate. 

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