The Earth is composed of four main layers from innermost to outermost: the inner core, outer core, mantle, and crust. The inner core is solid iron and nickel, while the outer core is liquid. Both cores are extremely hot. The mantle is the thickest layer and composed of magma. The crust is the outermost and coolest layer, made of tectonic plates that carry continents and oceans and are in constant movement.

1. EARTH’S STRUCTURE (Oxford pista 10)
The Earth is made up of four different layers: the inner core, the outer core, the mantle and the crust.
The inner core is the centre of Earth. It’s the hottest part of Earth. Its temperature can be 5.500oC. The inner core is
solid and it’s made of iron and nickel. It is about 1.200 km thick.
The outer core is the layer around the inner core. This layer is also very hot, but the inner core is hotter than the outer
core. It is made up of iron and nickel, but it isn’t solid. It’s liquid. It’s about 2.270km thick.
The mantle is the thickest layer of the Earth. It’s about 2900km thick. It is made up of magma. Magma is rock which is
partly melted
The crust is the outer layer of the Earth. It is the hard layer of rock we live on. It’s a relatively thin layer (it’s between 5
and 70 km thick). The crust is not one piece. It is made of tectonic plates. These plates are always moving. There are
two different types or crust: continental crust and oceanic crust. Continental crust carries land. Oceanic crust carries
water. The oceanic crust is thinner than the continental crust
The crust is the coldest layer. Its temperature is coldest near the surface of the Earth and hottest near mantle
Have you listened any sentence you don’t agree to?
PLATE TECTONIC DYNAMICS CD2 ANAYA PISTA6
Lithospheric plates are not static, they move and they change their size and shape. We cannot see these changes
because they happen over millions of year.
Why do the plates change?
The internal energy of the Earth causes convection in the mantle
The movement of rocks in the mantle affects lithosphere, breaking the plates, changing their size and moving them.
Plate boundaries
Lithospheric plate boundaries are especially active. There are three types of boundaries depending on how the plates
touch:
Convergent boundaries: there are the edges between two plates which move toward each other. In general,
one of the plates moves beneath the other and sinks inside the mantle, destroying part of the lithosphere (one
plate reduces it size). There is usually a trench along these boundaries.
Divergent boundaries: these are the boundaries of two tectonic plates that are moving away from each other.
Rifts are formed between them, and through these gaps molten material from mantle often rises up to the
surface, solidifies and forms new lithosphere (plates grow in size). These boundaries usually coincides whit
oceanic ridge.
Transform fault boundaries: also called conservative boundaries, they occur where two plates slide past each
other as they move laterally in opposite directions. No lithosphere is creates or destroyed
Can we call to the boundaries with other names?