The document summarizes Earth's internal structure. It describes that Earth is composed of layers, including a crust, mantle, and core. The crust is the outermost layer and is made up of silicate rocks. Below is the mantle, which is hot and solid but grows denser with depth. At the center is the core, composed of iron and nickel with a liquid outer core responsible for Earth's magnetic field.

1. Chapter 22
Earthʼs Interior
Section 22.1
Earthʼs Structure

2. Objectives
Describe the science of geology
Describe the main layers of Earthʼs
Interior.

3. How have scientists learned about
Earthʼs Interior?
Indirect measurements
 Wave energy
Direct measurements
 Drilling
 Deepest hole drilled was 12 km

4. The Science of Geology
 Geology - the study of Earthʼs composition
and structure
 Composition - what itʼs made of
 Structure - how itʼs put together
 Geologists
 Geo - Earth
 Ology - the study of
 Ists - people who

5. The Science of Geology (cont.)
 Geologists categorize forces that change the
Earth into:
 Destructive forces - break down/destroy
 Constructive forces - build/contruct
 Modern Geology
 Began 1700ʼs
 James Hutton, scottish physican and farmer

6. The Science of Geology (cont.)
Hutton formed the principle of
Uniformitarianism
 the forces acting on the Earth now are the
same ones that have existed I the past

7. A Cross Section of Earth
 Like these “Scotch
Eggs”:
Breading - crust
White - mantle
Yellow - core

8. The Crust
 Crust is made up of
silicates (compounds
that contain silicon and
oxygen-quartz)
 Continental crust -
average depth of 40 km
(8-75km) - made of less
dense rocks such as
granite

9. The Crust (cont.)
 Oceanic crust -
composed of more
dense rocks such as
basalt
 Average thickness of 7
km

10. The Mantle
 Hot but solid rock
 Temper and
pressure increase
the deeper you get
into the mantle
 Rich in iron and
magnesium
 Denser than crust

11. The Mantle (cont.)
 3 layers
Lithosphere - cool,
rigid rock (top layer)
Aesthenosphere -
softer, weaker rock with
the ability to flow (like
taffy)
Mesosphere -
stronger lower part of
the mantle

12. The core
 Composed of iron
and nickel
 Temp. estimated to
be 5500 degrees
Celsius
 Outer core - liquid
Rotation creates an
electric current that in
turn creates the
magnetic field