Download Chapter 1, Section 1 – Earth`s Interior

Chapter 1, Section 1 – Earth’s Interior
I.
Exploring Inside Earth
a. Two main methods of exploring Earth’s interior:
i. Direct evidence – rock samples
ii. Indirect evidence – seismic waves
1. examine the speed and paths of seismic waves
b. Seismic waves
i. Produced from earthquakes
ii. Measured with seismographs
iii. Two most common types:
1. P waves (primary waves) – able to move through liquid
2. S waves (secondary waves)
iv. Seismic waves do not travel in straight lines or have a constant
speed
II.
A Journey to the Center of Earth
a. 3 main layers of Earth:
i. Crust: top layer of Earth
1. includes water and dry land
2. solid
3. 5-70 km thick
ii. Mantle: layer of hot rock below crust
1. 2,867 km thick
2. made up of three separate layers:
a. lithosphere – uppermost part of mantle and crust
(thick, rock solid)
b. Asthenosphere: middle layer of mantle, solid, but
more flexible than lithosphere (can bend like
plastic)
c. Lower mantle: solid material that extends to core
iii. Core: innermost layer of mantle
1. made of iron and nickel
2. two parts:
a. liquid (molten metal) outer core
b. solid metal inner core (under too much pressure
for iron and nickel molecules to spread out)
b. Core and magnetic field
i. Created by movements in liquid, outer core
ii. Has north and south poles
iii. Magnetic field changes as molten metal moves
III.
Temperature
a. Temp. is cool just below surface, but begins to rapidly increase in the
deeper layers
b. Temp. then increases more steadily and slowly
c. Heat is left over from formation of Earth
IV.
Pressure
a. pressure increases as depth increases