Earth's Layers Standard Notes

Front

What is the Earth's crust?

Back

The outer layer of the earth, similar to the skin on an apple (thinnest layer), made up of both continental (land) and oceanic crust (under the ocean).

Front

What is the lithosphere?

Back

The solid, outer section of the Earth, which includes the crust (rocky layer) and the cool, dense, rigid upper part of the mantle.

Front

What is the asthenosphere?

Back

The solid part of the upper mantle, weaker and less rigid (plasticity, like silly putty), over which the crust moves. These plates crash into each other.

Front

What is the oceanic crust?

Back

A thin layer of crust over the ocean basins, more dense than continental crust, mostly basalt rock, thinner and younger than continental crust.

Front

What is the continental crust?

Back

A layer of rock which forms the continents, less dense than oceanic crust, mostly granite, thicker and older than oceanic crust.

Front

What is the mantle?

Back

The largest layer of the Earth, under the crust about 2,890 km, composed of silicate rocks rich in magnesium and iron. Intense heat causes convection, moving the crust.

Front

What is the outer core?

Back

A liquid layer about 2,300 km thick, second largest, composed of liquid iron and nickel, between inner core and mantle. Movement creates Earth's magnetic field.

Front

What is the inner core?

Back

A solid ball of metal, 1,250 km thick, made of solid nickel and iron, spins faster than the Earth rotates, densest layer, with temperatures 5000-6000 degrees C.

Front

What are seismic waves?

Back

Waves of energy caused by earthquakes and other rock movement, travel through some layers of the Earth, recorded with seismographs, used to determine layer composition.

Front

Which layers of the Earth are solid?

Back

Crust and Inner core