New crust is continually being pushed away from divergent boundaries (where sea-floor spreading occurs), increasing Earth's surface. But the Earth isn't getting any bigger. What happens ...

The movement of the plates creates three types of tectonic boundaries: convergent, where plates move into one another; divergent, where plates move apart; and transform, where plates move sideways ...

Keep an eye on the map to see where in the world the activity takes place. Also known as spreading boundary, a divergent boundary occurs where two plates move apart, allowing magma, or molten rock ...