The Theory of Plate
Tectonics
Chapter 6 Lesson 3
Plate Tectonics
• Earth’s surface is made of rigid slabs of rock,
or plate, that move with respect to each other.
Plate Tectonics Continued
• Lithosphere – rigid crust and uppermost layer
that floats on top of asthenosphere (the
plastic-like part)
• Floats on top and therefore can move.
Plate Boundaries
• Divergent – plates separate from each other
• Convergent – Plates move towards each other
(smash together) One will subduct under the
other. The denser plate goes under.
• Transform – slide past each other. Can get
stuck and then slip causing Earthquake.
Draw this (Doesn’t have to be
perfect)
Draw the best you can
Draw the best you can 
Notice the subduction (Don’t
draw)
Evidence
• Earthquakes – when a plate is stuck then slips
• Volcanoes – magma erupting at plate
boundaries
• Mountains forming where plates push
together.
Plate Motion
• So they move…. But how?
• Convection – circulation of material caused by
differences in temperature.
• Asthenosphere has convection currents.
• The current moves the plates.
Plate Movement Continued
• Basal Drag – kind of like a conveyer belt
moving the groceries at a store.
• Ridge Push – pushes the lithosphere (or plate)
away from the other plate.
• Slab Pull – pulls a plate down towards the
asthenosphere again.
Notice the types of movement
VIDEO!!!!!!!
• https://www.youtube.com/watch?v=0mWQs1
_L3fA