Structure of the Earth

The Earth is our spaceship through our solar system and the universe. We rely on it for everything, yet we have only been able to map the land which covers 30% of the planet and 95% of the oceans have yet to been explored! We know more about the surface of the moon than our own planet.

Which begs the question, how do we know anything about how the Earth is structured?

What we do know

  • The very centre of the Earth is the core, which is mostly iron and nickel. The inner core is solid and measures 1220 km in diameter.
  • The outer core of the Earth is liquid metal – also mostly nickel and iron. Together, the inner core and outer core are about as large as Mars. The outer core is 2,300 km in diameter.
  • Meteorites often contain bits of nickel and iron. Scientists believe they may be pieces from other planets which exploded.
  • The mantle of the Earth is solid rock, but it’s not completely hard. Because of the intense heat, the mantle is moldable, like play dough. The mantle slowly moves. This movement causes earthquakes and volcanic eruptions.
  • The mantle is 2,890 km deep.
  • The crust of the Earth is made of granite and other solid rock. Sand, soil and crushed rock sit atop the crust. The crust ranges in depth from 5 to 70 km.

Source material:

True or False

Answer the following statements into your book correctly if they are incorrect.

  • the mantle is hotter than the core
  • the crust is the coolest part of the Earth
  • the mantle is the thickest layer of the Earth
  • we would get hotter as we moved further and further underground
  • the core is made up of lead and iron
  • the core is solid despite being so hot it should melt

Make a word search

Use the following short words to make a word search for someone else in the classroom. Try to use as many words as possible.

  • core
  • crust
  • hot
  • inner
  • iron
  • mantle
  • melted
  • nickel
  • outer
  • solid
  • molten
  • rock

Quiz time

Try the attached quiz and see how you go. It’s a modified version of “Who wants to be a millionaire.

Year 8 Rocks and Resources
Rocks and Resources Vocabulary