Sea Floor Spreading

Sea floor spreading happens at mid-ocean ridges.  Mid Ocean Ridges are mountain ranges underneath the ocean.  In the middle of the ridge is a volcano.  These volcanoes do not erupt the way volcanoes on the surface of the earth do BUT magma does come out of them.When the magma comes out, it hardens.  As it hardens it pushes away the sea floor that was already there.  This is how the sea floor grows or spreads.

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