Mid Ocean Ridge

The Mid-Ocean Ridge is the longest mountain range on Earth. It is an underwater chain that gets bigger because of sea-floor spreading. Sea-floor spreading occurs around a divergent boundary in the ocean. It is when old sea- floor splits and lava comes up from the mantle and becomes hard. This is new sea floor. A divergent boundary is where two plates pull apart from each other. A plate is a piece of the earth's crust.

This is a picture of a mid- ocean ridge.