J OURNAL #6 What are the layers of the earth? How is the earth unique?

C HAPTER 2 Earth: A Unique Planet

T ODAY ’ S L EARNING G OAL : Today, we will Identify the 5 structural layers of the Earth Describe why the Earth is unique

T HE EARTH IS UNIQUE FOR SEVERAL REASONS : Only known planet that has liquid water on it’s surface Only known planet that contains a large proportion of oxygen in the atmosphere Known to support life What is life?

E ARTH B ASICS Earth is about 4.6 Billions years old 71% of the surface is ocean Earth is an oblate spheroid Spinning of the earth on its axis makes polar regions flatten

H OW DO SCIENTISTS KNOW THE COMPOSITION OF THE EARTH ? Direct observation is limited to a few kilometers (drilling) Seismic waves are vibrations that travel through Earth. Earthquakes and explosions near the surface produce seismic waves.

E ARTH ’ S I NTERIOR Crust- thin, solid, outermost layer Makes up 1 % of the mass Oceanic crust – crust beneath oceans Continental crust- crust that makes up continents Where is the continental crust the thickest? Mantle – underlies the crust and is denser than the crust Makes up 2/3 of the Earth’s mass 3 zones: lithosphere, asthenosphere, mesosphere Core- center sphere composed of mainly iron and nickel

E ARTH AS A M AGNET Earth has 2 magnetic poles Earth’s magnetic field extends beyond the atmosphere and affects a region of spaced called the magnetosphere.

L ET ’ S REVIEW WHAT WE ’ VE LEARNED What is the shape of the Earth? Oblate spheroid Name 2 characteristics that make Earth unique in our solar system Liquid water on surface and Oxygen rich atmosphere

How do scientists learn about the Earth’s interior? L ET ’ S REVIEW WHAT WE ’ VE LEARNED Seismic Waves What are the 3 Compositional layers of the Earth? Crust, Mantle, Core

What are the 5 Structural Layers of the Earth? L ET ’ S REVIEW WHAT WE ’ VE LEARNED Lithosphere Asthenosphere Mesosphere Outer core Inner core