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Plate Boundaries
Earth's crust is broken into huge plates that float on the slowly flowing mantle.
At convergent boundaries, plates push together, making mountains and volcanoes.
At divergent boundaries they pull apart. At transform boundaries they slide past each other.
Pangaea
About 250 million years ago, all land was one supercontinent: Pangaea.
Over millions of years it broke apart and the pieces drifted.
Clues: matching coastlines, matching fossils and matching rocks on different continents!
Plate Speedometer
Plates move only a few centimeters a year.
That's about as fast as your fingernails grow!
Over millions of years, a few centimeters adds up to thousands of kilometers.
