Earth’s structure


This topic explores the key concepts of the Earth’s structure as they relate to:

  • the structure of Earth
  • movement of Earth’s crust
  • earthquakes
  • tsunamis
  • volcanoes
  • rocks.

Key concepts of Earth’s structure

The activities in this topic are designed to explore the following key concepts:

  • Earth is made up of layers: the core, mantle and crust.
  • Earth’s crust is divided into plates that move like bricks over freshly laid mortar.
  • Earth’s plate movements are responsible for earthquakes, tsunamis and volcanoes.
  • Earth’s plate movements are responsible for the creation of mountain ranges.
  • Soils on Earth are the result of weathering of rocks.
  • There are three main categories of rock: igneous, metamorphic and sedimentary.
  • Igneous rocks are formed through the cooling of magma.
  • Sedimentary rocks are formed through compaction of sediment over an extended period of time.
  • Metamorphic rocks result through the transformation of other rocks by heat and pressure processes that occur below Earth’s surface.
  • Minerals are the building blocks of rocks.

Students’ alternative conceptions of Earth’s structure

Research into students’ ideas about this topic has identified the following non-scientific conceptions:

  • The location of earthquakes is random.
  • Continents don’t move.
  • Earth is molten, except for its crust.
  • Most of the world’s most spectacular scenery was created by cataclysmic events.
  • An earthquake measuring 6.5 on the Richter scale is one time more powerful than an earthquake measuring 5.5.
  • Rocks stay the same forever.
  • Earthquakes cannot happen where I live.
  • The biggest danger of a volcano such as Mount St Helens is the hot lava.
  • Any crystal that scratches glass is a diamond.
  • Rocks must be heavy.
  • Soil must have always been in its present form.
  • Mountains are created rapidly.
  • Earth’s gravitational attraction is drastically reduced on mountaintops.
  • Boiling or burning radioactive material can reduce the radiation emanating from the material.
  • All radioactivity is man-made.

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