12
5
Okay, let’s start off with a joke: What does Earth’s crust have in
common with a dinner table? Give up? They both have plates.
Don’t get it? That’s probably because Earth’s
tectonic plates
don’t look anything like dinner plates. Earth’s plates are giant slabs
of rock. They fit together like the pieces of a puzzle.
Guess what happens to the plates as magma circles through
Earth’s mantle? They go along for the ride. That’s right! The plates
move across the surface of the planet. They float on top of the
mantle like rafts on a sea of moving magma.
On average, Earth’s plates move about two inches (five
centimeters) a year. Your fingernails grow at about the same rate.
The Earth’s
surface is divided
into nine major
plates. The pink
arrows show the
direction the plates
move.
The Puzzle
of Plates
