the earth

• The Earth has a Crust, a Mantle and a Core
• The Crust is made up of a mixture of elements and is 100km thick
• As you go deeper into the Mantle, the texture changes
• The Core is just a ball of molten metal
• The outer core is molten, while the inner core is solid, and is made mainly of iron
• The Core and the upper part of the Mantle are cracked into seven major plates and lots of smaller pieces called tectonic plates
• The tectonic plates are a bit like rafts that float on the molten rock of the mantle
• Most of the plates are moving away from each other
• Occasionally, the plates move very quickly, causing earthquakes and volcanoes
• Earthquakes and volcanoes often occur at the boundary between two tectonic plates
• If you plot active volcanoes and earthquakes on a map of the world, you can see that they line up along the same lines as the plate boundaries
• Plate Tectonics


  The theory that the Earth's surface is made up of moving plates of rock
• In 1912, Alfred Wegener proposed that the continents had previously been joined together in a 'supercontinent' called Pangaea, which then broke apart
• One of the main problems was that Wegener's explanation for why the drifting happened was not convincing
• In the 1930s, scientists suggested that convection currents in the mantle could cause the plates to move
• By the 1980s, Wegener's theory of continental drift had been widely accepted
• Types of Plate Boundary


  • Constructive
  • Destructive
  • Conservative
• Plate boundaries


  The places where plates meet
• Constructive Boundaries


  1. Crust is chided into slabe

  2. Magma (molten rock) rises from the mantle to the gap and gools, seating dust made from igneous rock

  3. Lots of volanio actity and sarthquakes
• Destructive Boundaries


  1. Oceanic plate is forced down into the mantle and melted to give magma, creating volcanoes and ocean frenches

  2. Earthquakes often occur
• Conservative Boundaries


  1. Plates are moving sideways past each other, or are moving in the same direction but at different speeds

  2. Crust isn't created or destroyed

  3. Powseful earthquakes are created

  4. No volcanoes are created
• When continental plates collide the grand fold and creates mountain ranges