Earth's Interior

Pages 6-9

How do scientists study the Earth?

  • They use direct observation (drilling rock samples of our 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 are the three main layers of the Earth?

  • The Crust, the Mantle and the Core

How does the temperature of Earth change as we travel through its layers?

  • The top 20 meters is cool. 
  • After that, every 40meters down, the temperature rises 1ºC.  This continues for many kilometers then it slows down but still rises
  • This heat in the center of Earth is from two things - left over heat from the creation of planet Earth and radiation inside our core

How does the pressure of Earth change as we travel through its layers?

  • The deeper you travel, the greater the pressure - more layers are pressing down.