take a new page in your jotter and design a title page called “earth forces” geography earth...
TRANSCRIPT
Structure of the Earth[Date]
Today I will:
- Know that the Earth is made up of four parts and be able to describe each area.
GeographyEarth Forces
GeographyEarth Forces
The Earth is almost a sphere, but more like a tangerine! It is squashed at the top and the bottom.
GeographyEarth Forces
-The Earth is composed of four different layers.
-Many geologists believe that as the Earth cooled the heavier, denser materials sank to the centre and the lighter materials rose to the top.
- The crust is made of the lightest materials (rock- basalts and granites) and the core consists of heavy metals (nickel and iron).
GeographyEarth Forces
The Earth's Crust is like the skin of an apple. It is very thin
in comparison to the other three layers. The crust is only about 3-5 miles (8 kilometres)
thick under the oceans (oceanic crust) and about 25
miles (32 kilometres) thick under the continents (continental crust).
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The crust is broken into huge pieces called tectonic plates.
These are moving constantly at a few centimetres per year.
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The mantle is composed of very
hot, dense rock. This layer of rock flows slowly due to great
temperature differences from the bottom to the top of
the mantle.
GeographyEarth Forces
At the centre of the Earth lies the core, which is nearly twice as dense
as the mantle because its composition is metallic (iron-nickel) rather than
stony.
The Earth's core is actually made up of two distinct parts: a 2,200 km-thick liquid outer core and a
1,250 km-thick solid inner core.