Download Plate Tectonics - Hope Valley Library

How our Earth changes
By Rachel Williams
What makes plates move?
Why do earthquakes happen?
How hot is lava?
Is there a need for
earthquakes?
There are three basic parts to our
earth that vary in size, composition,
temperature and pressure
Crust: Outer skin is a solid layer of
rock that contains both dry land and
ocean floor. Like the skin of an
orange
Mantle: Rock that is hot but solid
and can slowly move
Core: Liquid outer core and solid
inner core and is mostly metal. Lava
is 1,292⁰F-2,282⁰F. That is really hot.
The Earth grows hotter and hotter as
it goes farther into the Earth
Alfred Wegener was the
originator of the drift theory
(1910). He also was the one
who figured out that
freshwater dinosaur fossils
were found in spots across
the country . The thing is the
sections are separated by salt
oceans. That means that
since the dinosaurs could not
cross the water the land had
to be connected at their time.
He was the one that figured
out that plates move over
time.
Way before civilization, there was a super continent called
Pangea. A super continent is a huge mass of land. The slowly
moving mass has, over millions of years, moved our continents to
their current location today.
200 million years ago the plates
moved, and North America, Europe,
and Asia, broke away. Together they
formed Laurasia. Africa, South
America, Australia, and Antarctica
together formed Gondwanaland.
The reason that the plates moved is the currents . The
currents take place in our mantle. Hotter rock rises(lower
density) closer to the surface of the Earth. It cools, and
sinks. This creates a endless cycle of currents in the
mantle. This is what slowly makes the plates move.
There are 20 plates in the world. They float on the mantle, moving 1-8 inches a
year. The plates interact with each other in three ways. They either diverge,
converge, or slip past.
When ocean plates converge, older, denser plates slide underneath the
new ones. Continental plates converge when huge cliffs form from
plates slipping under each other. When one side of the plate is diverging
the other is converging. This means the plates are being smashed
against each other. They can either slip, or form a mountain. When the
plates push together, they form a mountain. This is also known as
converging.
Ocean plates can and continental plates diverge. While one edge of the plate
is converging, the other side is diverging, or pulling apart. When it pulls apart,
new magma comes and fills the gap, making new sea floor. When continental
plates diverge, it creates a rift valley. A rift valley is a canyon of rock.
Earthquakes result from the plates moving against
each other. The movement of the plates forming the
earthquake is also known as a slip past. Sometimes the
plates get stuck, and when released the energy is in
the form of a earthquake. Shock waves are the
vibration after a earthquake. Measured by the Richter
scale for power and Mercalli scale for effect. There are
different types of earthquakes. Surface waves travel
only through the crust. Body waves travel through the
earth itself.
A fault is a crack between
the plates that the plate
slides along.
Farodon, John. How the Earth Works, 1992
Nemeth, Jason. Plate Tectonics, 2012
Simon, Seymour. Earthquakes, 1991
Steele, Philip. Rocking and Rolling,1997.
Stille, Darlene. Plate Tectonics, 2007
picture source list:
http://www.enchantedlearning.com/subjects/astronomy/activities/radiobuttsht
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https://en.wikipedia.org/wiki/Pangaea
http://www.moorlandschool.co.uk/earth/tectonic.htm
http://dreamatico.com/mountain.html
https://www.pexels.com/search/earth/
https://www.pexels.com/search/earth/
http://www.alan.com/wp-content/uploads/2014/07/FrackQuake.jpg