1. Hot core melts rock. Magma rises through a crack between plates in the middle of the Atlantic Ocean to the Mid-Oceanic Ridge, a huge underwater mountain range. 

2. Fed by the magma, the Mid-Oceanic Ridge grows, pushing the ocean floor away from it in both directions.

3. Heavier ocean floor hits the lighter (continental) land. Ocean floor buckles under the land. (Subduction)

4. The friction creates earthquakes. It also melts rock and creates volcanoes. 

5. The pushing of the colliding plates also makes mountains.