A2
Lesson Summary
Vocabulary Link
- crust
- mantle
- core
- inner core
- outer core
- lithosphere
- asthenosphere
- plasticity
- residual heat
- radioactive decay
- Changes in chemical composition allow us to break the Earth into three distinct layers.
- The crust is the solid, rigid outer layer of the Earth.
- The mantle is a dense, hot layer of rock that is directly under the crust. The mantle can be further subdivided into the upper mantle and the lower mantle.
- The core is made primarily of iron and consists of a solid inner core and a liquid outer core.
- The behavior of different layers as determined by changes in physical properties also allows us to break the Earth into two additional layers.
- The solid, rigid lithosphere consists of the crust and the very top part of the upper mantle.
- The asthenosphere is directly below the lithosphere, and consists of plastic rock on which the lithosphere floats.
- The interior of the Earth is heated to a small extent by residual heat, but primarily by radioactive decay.