5. The minerals in the ocean plates are deposited when they are still able to orient themselves relative to the magnetic north pole. When they lithify, they are no longer able to reorient themselves to the magnetic pole. Every time there is a magenetic pole reversal, the magnetic minerals will allign themselves before they lithify. We go along with ships (maybe satellites now) and map it out. We can map the orientation of these bands with other locations on the earth. The bands will be roughly the exact same width on either side of the ridge.