Science

Earth crust

The outer layer of the earth.
thinnest layer
Made up of both continental
(land)and oceanic crust(under
the ocean).

Earth Mantle

Largest layer of the Earth
Composed of silicate rocks rich in
magnesium and iron
Intense heat causes the rocks to rise
and then cool and sink.
The process is called convection,
which causes the crust to move.
Average temperature 3000

Earth outer core

Liquid layer 2,300 km thick, second
largest.
Composed of liquid iron and nickel.
Lies between inner core and mantle.
Because the magma moves around the
inner core, Earth’s magnetic field is
created.
Average temperature 4000o -5000o

Earth Inner core

A solid ball of metal
Made of solid nickel and iron
Densest layer of the Earth
Average temperature 5000-6000
Spins at a speed faster than the Earth
rotates
So hot it melts everything in the outer
core

Seismic waves

Seismic waves are used to
determine which layers of the
Earth are solid or liquid.
Some seismic waves cannot
pass through certain layers
giving us a clue to the layer’s
composition.