The document discusses the structure and composition of the Earth. It is made up of layers from the crust on the outside to the core at the center. The crust and upper mantle make up the lithosphere which rests on the asthenosphere. Below the mantle is the core, with an outer liquid layer and inner solid center. Seismic waves provide evidence about the interior layers since humans have only been able to drill down 12 km.

1. Structure of the
Earth

2. Earth Basics:
Earth is unique because it is the only planet:
a) With liquid water on surface
b) With oxygen in the atmosphere in such a
large proportion
c) That supports life

3. Basic Facts:
1. 4.55 billion years old
2. Made mostly of rock
3. 71% of surface covered with water
4. Slightly flattened sphere
5. Rotates on its axis

4. Layers of the Earth
 Crust
 Mantle
 Core

5. How do we know about Earth’s
interior?
 Deepest hole only 12
km deep (6,400 km to
go) before it was too
hot to drill (356
degrees F)
 Used evidence from
seismic waves

6. Crust:
 Thin, solid outermost layer of the Earth that
makes up less than 1% of the volume of the
Earth
 Two Types of Crust:
 Oceanic
 Continental

7. Mantle:
 Layer of “solid-ish” rock located between the
crust and the core
 able to move through convection currents
 denser than the crust
 makes up 2/3 of the mass of the Earth

8. Mohorovicic Discontinuity
a.k.a.: Moho
 Layer/border between the crust and the
mantle

9. Lithosphere vs. Asthenosphere
 In terms of plate tectonics rather than “spheres of the
Earth”
 Lithosphere – the crust and rocky portion of the mantle
that make up tectonic plates
 Asthenosphere – plastic portion of the mantle that
moves via convection currents

10. Core:
 Central part of the Earth below the mantle;
iron-nickel alloy
 Two Parts:
 Outer Core – Liquid
 Inner Core - Solid

11. Core Temperature
 Heat is both residual from the formation of the
Earth and from energy due to the abundance
of radioactive materials

12. General Trends
 As you head towards the center of the Earth
 Temperature Increases
 Density Increases

13. Magnetism:
 The Earth has a magnetic North Pole and a
magnetic South Pole that creates a magnetic
field around it

14. Gravity:
 The force of attraction that exists between all
objects, the bigger and closer the object is,
the stronger the force of gravity