The document discusses the theory of plate tectonics. It explains that the Earth's lithosphere is broken into plates that move slowly over time due to convection currents in the mantle. There are three types of plate boundaries: divergent boundaries where plates move apart, convergent boundaries where they move together, and transform boundaries where plates slip past each other.

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3.  The lithosphere is broken into separate sections
called plates. They “float” on the asthenosphere
 Sea-floor spreading and continental drift into a
single theory – The Theory of Plate Tectonics
 Plate Tectonics – is the geological theory that states
that pieces of Earth’s lithosphere are in
constant, slow motion, driven by convection currents
in the mantle.
 The theory of plate tectonics explains the
formation, movement, and subduction of Earth’s
plates

5. 1. Transform Boundaries –
 Crust is neither created nor destroyed
 Place where two plates slip past each
other, moving in opposite directions

6. 2. Divergent Boundaries
 Place where two plates move apart
 When develops on land, two of Earth’s plates
pull apart. A deep valley called a rift valley
forms along the divergent boundary

7. 3. Convergent Boundaries
 Place where two plates come together
 Converging oceanic plate and oceanic plate collide one
plate is subducted through a trench and volcano islands
are formed
 Converging oceanic plate and continental plates – when
continental plates and oceanic plate collide, the oceanic
plate is subducted and volcanoes on land are formed
 Converging continental plates – where two continental
plates collide, the crust buckles and mountain ranges
form.

8.  The plates are moving at a very slow rate of about one
to ten centimeters per year.
 In areas plates are moving together and others are
moving apart.