The Earth’s Core

 

Pages 12-13 (Inside Earth)

 

How do scientists study the Earth?

  • They use indirect observation (instruments & technology)
  • Seismic Waves – shock waves produced by the energy of the earth (earthquakes)
  • Two types of seismic waves: S-waves and P-waves
  • Seismograph – instrument that records the two types of waves that penetrate the earth’s interior and return to the surface
  • The two waves behave differently when they ‘hit’ different structured materials.
    • P waves do not move well through liquid and S waves stop completely.

 

 

What is the Earth’s core made of?

·        Inner Core- P-waves speed up so it is a solid.

·        Temperature of 5000°C

·        Made up of the elements Iron and Nickel

·        It is solid due to the enormous pressure of the Earth.

·        Magnetic property comes from the iron in the core.

·        Outer Core-P-waves slow down and S waves disappear so it is a liquid

·        Also made of the elements Iron and Nickel

·        Temperture ranges from 2200°C to 5000°C

 

What gives Earth its magnetic property?

The movement of the liquid (iron and nickel) in the outer core creates a magnetic field
The planet acts as a giant magnet through the North and South poles
It also creates a magnetic shield around the Earth – this is part of the atmosphere called the magnetosphere
A compass will always point to the North pole because of the magnetic property of Earth