Seafloor spreading? Short answer? Magnitism?

Question

Explain how magnitism is used to support the theory of seafloor spreading?
short answer.
has to make sense---not too technical

Answer 1

The Earth's magnetic field induces an alignment in igneous rock, which becomes literally "set in stone" as the rock cools and hardens. As the magnetic field changes strength and orientation over time, these changes are recorded in the rocks that formed at those times. The study of this type of alignment is known as 'paleomagnetism.'

Studies of the mid-oceanic ridge in the Atlantic found that the ridge was surrounded by parallel bands of paleomagnetic alignment, alternating in orientation as the rock gets farther from the central ridge, and mirroring that on opposite sides.

The only reasonable, and now accepted, explanation for this observation is that the rocks with the same orientation formed at the same time, and then were forced apart and replaced by new rock welling up in between. This process has continued for millions of years, with each successive band of new rock oriented in a different direction, with the newest in the middle, oriented to the Earth's current field.