Transcript Unit 5 – Structure of the Earth

1.
What is the crust?
http://videos.howstuffworks.com/hsw
/6222-mountain-building-earthsinner-crust-video.htm
1. The crust is the
outmost layer of the
earth.
Is made of hard rocks
 contains silicon and
oxygen (silicates) and
aluminum
 5 km to 50 km thick
2.
What is the mantle?
2. The mantle is the
middle layer of the
earth
 contains lots of iron
and magnesium
silicates
 makes up 82% of
earth’s volume and
68% of earth’s mass
3. What is the core?
Core
Mantle
Crust
http://videos.howstuffworks.com/sciencechannel/29142-100-greatest-discoveriesthe-core-of-the-earth-video.htm
3. The core is the
innermost layer of the
earth
 contains iron and
nickel metals
very dense
 makes up 16% of
earth’s volume and
32% of earth’s mass
Core
Chemical
Mantle
Inner Core
Crust
Outer Core
Physical
Mesosphere
Asthenosphere
Lithosphere
4. What is the
lithosphere?
4. The lithosphere is a
cool, solid outer layer
of the earth
 includes the crust
and outer mantle
 100 km thick
 floats on the plastic
asthenosphere
5. What is the
asthenosphere?
5. The asthensoshpere
is a hot semi-liquid
layer of the mantle just
below the lithosphere.
 Is soft and flows.
6.What is the
mesosphere?
6. The mesosphere is
a solid layer of the
inner mantle.
 Pressure keeps
rocks from melting.
7.What is the
outer core?
7. The outer core is a
liquid inner layer
 Mostly liquid iron
 Thought to be the
source of the
earth’s magnetic
field.
8.What is the 8. The inner core
inner core?
is the
innermost part
of the earth.
o
 4000 C
4500oC
–
9. Who was
Alfred
Wegener
9. Around 1912, Wegener, a
German geologist and
astronomer, proposed
that continents move
• Pangaea –
supercontinent formed
when all of earth’s
landmasses were joined
• Scientists didn’t believe
him for almost 50 years
10. What
evidence
supports
Pangaea?
10.
Fossils of same species on
all continents
 Same rock formations
across continents
 Ancient glaciers were in
the tropics
11. When and
how was the
ocean floor
mapped?
http://videos.howstuffworks.com/hs
w/9068-discovering-mathmeasuring-distance-and-depthvideo.htm
11. The ocean floor was
mapped in the 1950s using
sonar.
12. How does
sea floor
spreading
occur?
12.
Mid-ocean ridge is a huge
crack where the hot mantle
pushes upward.
Crust is older as you move
outward from the ridge
Magnetic field reverses
http://videos.howstuffworks.com/hsw/2656
0-earth-science-the-spreading-seafloorvideo.htm
13. Describe
plate tectonics
13.
Lithosphere is divided into
plates that constantly move
Continental Plates –
lighter
 Oceanic Plates – heavier
http://videos.howstuffwork
s.com/hsw/8638-insidethe-earth-continentaldrift-video.htm
14. What are
divergent
boundaries?
14. Divergent boundaries
are plates that move apart.
Examples:
Mid-oceanic ridge
Great Rift Valley in Africa
14. What are
convergent
boundaries?
14. Convergent plates occur
when plates run into each
other ( subduction zone)
Examples:
Oceanic to oceanic – Japan
Oceanic to continental –
Andes Mountains in South
America
Continental to continental
– Himalayan Mountains in
Asia
Oceanic to
continental – Andes
Mountains in South
America
Continental to
continental –
Himalayan Mountains
in Asia
15. What is a
transform
boundary?
15. In a transform boundary,
plates slide in opposite
directions.
Example: San Andreas Fault,
California