Notes for Inside Earth
Chapter 1 “Plate Tectonics,” section 1 “Earth’s Interior”
Heading/Key idea/Diagrams…
* Exploring Inside Earth
* A Journey to the Center of Earth’
Temperature rises as you go deeper
underground (closer to the center of the
Earth)
Pressure increases as you travel toward
Earth’s center
The Crust
The Mantle
The Core
Earth’s Magnetic Field
Detail, definition, elaboration, caption…
Scientists use 2 main types of evidence to study Earth’s
Interior~
* Direct evidence from rock samples
--geologists have drilled holes as much as 12 km into the
crust for samples
--forces inside Earth “blast rock to the surface from depths
of more than 100 kilometer” (p.8)
* Indirect evidence from seismic waves
--Earthquakes cause seismic waves, vibrations in the Earth
--waves move differently through different materials (they
change speed and direction)
* “The three main layers of Earth are the crust, the mantle,
and the core. These layers vary greatly in size, composition,
temperature, and pressure.” (p. 9)
* High temperatures in Earth’s core are the result of heat left
over from Earth’s formation AND energy released by
radioactive elements inside Earth.
“Pressure results from a force pressing on an area.” (p. 9)
(Think about pressure on your ears when diving to the
bottom of a pool.)
“a layer of solid rock that includes both dry land and the
ocean floor.” (p. 10)
--approximately 5 km-70 km thick (thicker in mountainous
areas like the Himalayas)
***The crust is VERY thin compared with Earth as a whole—
think of the papery outer layer of an onion, or a layers of
plastic wrap around an egg.
**Very hot, semi-solid rock
**The top, rigid layer of the mantle (stuck together with the
crust) is called the lithosphere (lithos=stone)
**The asthenosphere (asthenes=weak) is semi-solid; plastic;
like hot road tar; it is under the lithosphere.
Mostly made of metals; mainly iron and nickle.
* The outer core is a layer of molted (melted) metal; the
outer core is liquid.
* The inner core is a dense ball of solid metal (iron and
nickel) at Earth’s center.
The movement (spinning) of Earth’s outer core generates a
magnetic field~ Earth acts like a bar magnet
* The magnetic field acts like a shield, protecting Earth from
many of the particles streaming toward us from the Sun