Sample Response: Scientists found evidence of Earth's magnetic field reversal in rocks on the ocean floor at plate boundaries. These rocks have alternating polarity due to magnetization that occurred during their cooling period. Using radiometric dating, scientists estimate that reversals occur approximately every several hundred thousand years.
<span>The earth’s
magnetic field affects the alignment of elements like iron in <span>rocks</span> due to <span>Ferro-magnetization</span>.
This causes the <span>elements</span> to align in <span>a north</span>-south direction. Therefore scientists
have studied this <span>alignment</span> in ancient
rocks, such as in the layers of <span>sedimentary</span>
rocks, and realized that the earth magnetic field has flipped around 200,000 to
300,000 in the last 20 million years. </span>
