Title: Ch.4, Sec.1
1Ch.4, Sec.1 Inside the Earth
- the Earth is divided into three basic layers
the crust, the mantle the core
- the densest layer is the __________ due to the
immense amount of gravitational pull types of
radioactive elements
- crust the thin and solid outermost layer of the
Earth above the mantle
- the thinnest layer of the Earth with a width of
3 to 63 miles labeled as continental or oceanic
- mostly made from silicon, oxygen aluminum
2Ch.4, Sec.1 Inside the Earth
- mantle the layer of rock between the Earths
crust and core (1,800 miles wide)
- contains most of Earths mass (67) is denser
than the crust
- core the central part of the Earth below the
mantle (2,130 miles wide)
- contains 33 of Earths mass is mostly made
of iron and nickel
3Ch.4, Sec.1 Inside the Earth
- The Physical Structure of the Earth
- the Earth is divided into 5 physical layers
based on physical properties (see pgs. 98 99)
- 1. lithosphere the solid, outer layer of the
Earth that consists of the crust and the rigid
upper part of the mantle we call tectonic plates
(1,800F)
- 2. asthenosphere the plastic layer of the
mantle on which the tectonic plates move (1,800F)
- 3. mesosphere the strong, lower part of the
mantle between the asthenosphere the outer core
(1,800F)
4Ch.4, Sec.1 Inside the Earth
- 4. outer core the liquid layer of the Earth
below the mantle (6,700F)
- 5. inner core the solid, dense center of the
Earth, which is 4,000 miles beneath the surface
(7,800F)
5The Rock Cycle (pgs.30-31)
6Ch.4, Sec.1 Inside the Earth
- tectonic plate a block of lithosphere that
consists of the crust and the rigid, outermost
part of the mantle
- the Pacific plate is the largest has created a
large ring of volcanoes around the Pacific Ocean
called the Ring of Fire
7Ch.4, Sec.1 Inside the Earth
8Ch.4, Sec.1 Inside the Earth
- tectonic plates completely cover the surface of
the asthenosphere
- plates are normally thicker where continents
are thinner under the oceans
- Mapping the Earths Interior
- seismic waves from earthquakes travel through
the Earth at different speeds (slower through a
liquid faster through a solid)
- seismographs measure the times at which
different seismic waves travel through the
Earths interior
9Ch.4, Sec.1 Inside the Earth
10Ch.4, Sec.1 Inside the Earth
1. Why do seismic waves travel faster through
solids? __________________________________________
_________
2. Why do seismic waves travel slower through
liquids? _________________________________________
__________
3. Where is the greatest amount of volcanic
earthquake activity? ____________________________
_______________
4. Is the crust more dense under the oceans or
the continents? Why? _____________________________
_________________
5. What two factors cause metamorphic rocks to
form? ____________________________________________
_______