Transcript Plate Tectonics

Layers of the Earth
Lithosphere
Asthenosphere
Crust
• Outermost layer of Earth
– Composition- made of soil, rock, and water
– Thickness- 10-25 miles thick
– States of Matter- solid
– 0 degrees Celsius
Mantle
• 2nd layer- include Lithosphere (lower crust
and upper mantle) & Asthenosphere
– Composition- iron and magnesium
– Thickness- 1,800 miles thick
– States of Matter- part liquid, part solid
– 1000-3000 degrees Celsius
Outer Core
• 3rd layer of Earth- our magnetic field is
produced here
– Composition- made of nickel and iron
– Thickness- 1,430 miles thick
– States of Matter- Liquid
– 3700 degrees Celsius
Inner Core
• Center of the Earth
– Composition- made of nickel and iron
– Thickness- 750 mile radius
– States of Matter- solid
– Up to 5000 degrees Celsius
Earth’s Layers- so what?
Earth’s Layers
25
1800
1430
750
So how far away is the center of
the Earth?
• 25+1800+1430+750
– 4,005 miles
• Is that the radius or
diameter?
– radius
Are the layers all the
same? How do they
differ from one
another?
The layers are made of different
substances and are different
temperatures
• What happens when you heat up a
substance like air?
Warm air
rises!
What happens when you heat up
liquid magma in the asthenosphere
(part of the mantle)?
• Warmer material rises, cooler material
sinks
• The Mantle is composed of mostly liquid
rock that moves due to temperature
differences
• 1000 degrees F at the top, 3000 degrees F
near the bottom.
This moving magma is called
convection currents
What happens to the crust sitting
on top of the mantle?
• The Lithosphere (solid upper mantle
and lower crust) sits on top of the liquid
asthenosphere.
• The Lithosphere is broken into many
sections or plates.
• The plates are shifted and moved by the
convection currents
• The lithosphere is made of two igneous rock
types:
• Continental crust - granite (light)
• Oceanic crust - basalt (heavy)
• Some plates are lighter than others.
• Because granite is lighter than basalt, the
continents sit on top of the denser oceanic plates
• Outer Core-Very hot liquid metals 4,000
degrees F to 9000 degrees F
• Made of Nickel and Iron
• This liquid core produces a magnetic field
that helps protect earth from coronal mass
ejections (CME’s) produced by the sun.
Protective Magnetic Field
• In the Inner Core, temperatures and pressures are
so great, the liquid metals are forced back into a
solid despite the high temperatures that would
normally melt them.
• 45,000,000 pounds of pressure per square inch.
• 3,000,000 times more pressure than felt at sea
level.
How do we know what’s
inside?
Geologists study earthquakes and
volcanoes
Seismic waves
caused by
earthquakes change
direction as they
move through
different materials
(such as solids and liquids)
http://www.classzone.com/books/earth_science/terc/content/investigations/es0402/es0402page03.cfm
Earthquake wave animation:
http://earthquake.usgs.gov/earthquakes/eqarchives/year/2002/2002_11_03_waveani.php
I’m going to dig a hole to _____
Dig a hole to the other side of
Earth
http://www.ubasics.com/dighole/
http://www.livephysics.com/ptools/dig-hole-throughearth.php
I’m going to dig a hole to China!
• You will have to start in Chile, South
America
Will you make it to the other
side?
• If you could survive the temperatures
(over 8,000 degrees F) and the
pressure (3,000,000 times the force of
gravity) and you could “climb” out the
other side (down is towards the center
of Earth), then YES!
• If you could just freefall all the way
through Earth (8,000 miles) it would
take you about 42 minutes falling at
17,700 mph.
http://www.daviddarling.info/childrens_encyclopedia/Dig_a_Hole_to_Ch
ina_Chapter5.html